Abstract
Parasitism is very common in the worldwide and is a high-risk factor for livestock and income coming from this source. Gastrointestinal nematodes are major parasites of animals particularly of small ruminants. In this study I checked the prevalence of gastrointestinal nematodes in 50 sheep present in different areas of district Multan. The experimental animals were 2 months to 12 months old sheep and were randomly selected from only 3 places located in district Multan. Body condition score and FAMACHA chart were applied to diagnose infected animals. The fecal samples were collected from rectum of individual sheep. Fecal samples were examined under microscope for parasites. The present study revealed the presence of major gastrointestinal nematode parasites with an overall prevalence of 44% in sheep. Haemonchus contortus was the most prevalent in study area.Health related problems like the slow growth, weakness, bleeding, anemia, digestive and liver disorders in sheep due to these gastrointestinal nematodes’ parasites were also studied. Nevertheless, main focus was on gastrointestinal tract. Role of different factors like livestock density, moisture, and temperature in proliferation of these parasites was our second objective. Findings of this study revealed that good management and good wormicide treatment of sheep can reduce the all kind of parasitic infection.
Keywords: Ruminants, anemia, moisture, bleeding, gastrointestinal, parasites, fecal, wormicide, livestock.
Introduction
Pakistan is an agricultural country. Large number of people of Pakistan is directly or indirectly attached with agriculture and livestock industry. Livestock industry employs about 30 million people in Pakistan. It improves the living standard and health of people of our country. This industry fulfills the variety of our basic needs such as wool, meat, milk and raw material for crops. We can also export many products obtained from livestock and earn huge sum of money. People take proper care of livestock and earn 10 -25 % of their total income from this sector (Abdul Rehman et al., 2017).
The livestock production play a crucial role in firming the socio-economic status of pastoralists by decreasing poverty. It helps in considerable maintenance of rural farmers who encounter lack of resources (Gadahi et al., 2009). It is estimated that about 55.1% value-added products of agriculture along with 11.6% national GDP has been provided by Pakistan’s livestock division. According to commercial review of Pakistan conducted in 2011-2012, there was 4% continual increase in gross value from 5.29 to 5.51 billion Euro.
In the past, smallholders conquered livestock sector for survival. Nowadays, the rural inhabitants, farmers and dispossessed people are getting enough income from livestock employment (Gadahi et al.,2009; Khajuria et al., 2012). According to past 15 years (Iqbal and Jabbar, 2005) record, a predominant doubling of sheep and goats (Khajuria et al., 2012) in Pakistan. This increase might be due to low inputs e.g. fodder, startup investment, and conservation costs rather than huge ruminants (Terefe et al., 2012). A good raw material for many products is sheep milk. It is especially used for cheese production in milk processing industry (Park et al., 2007). Sheep milk was found to be more viscous, having less freezing point and greater specific gravity when compared to cow milk (Haenlein and wendorff, 2006). Total protein volume in sheep milk is much higher as compared to milk of other animals such as cows and buffalos.
According to animal Census of 2006, 26.5 million sheep are present in Pakistan. The worldwide population of sheep is very much important in livestock economy (Raza et al., 2010). Despite the value of minor ruminants and giant populace, this massive source has provided little benefit to countries. There are many reasons which affect the productivity of livestock industry such as inadequate generation, restricted supervision, veterinary care deficit, meagre nutrition, poor system of animal production, and the most important is disease. Taking a part of this last segment I will work on internal parasites in general and nematodes in specfici of sheep of the selected areas in district Multan.
Literature Review
Livestock is facing threats in Pakistan. Among all threats, parasitism is the main hindrance for emergence of lucrative sheep industry (Asif et al.,2008). Parasites living in gastro intestine can’t be able to resist diseases lead to substantial mortality and even death. According toNgategize et al. (1993), ovine fasciolosis is the cause of economic harm in hilltops of 48.4 million Ethiopia annually as shown by existing statistics on mass loss (46.5%), condensed propagative efficacy (48.8%), live censureand death (4.7%). There is only 30% mortality in beefs and 20% in grownups regarding issues of health and diseases (Sisa, 2007). Diseases caused by parasites is the biggest issue in poor developing countries.
Parasitism is one major problem found in goat and sheep. It is a worldwide considerable problem for the farmers. These parasites are coccidia, round worms, tape worms and liver flukes. Many studies revealed that gastrointestinal nematode parasites act as limiting factor and causes economic losses especially in small ruminants (Jones, 2001). Several other factors also reduce the overall production of livestock. These factors are improper care, unhygienic environments, extreme climatic conditions, nutrional problems, direct contact infected animals and parasites present in or on the body of animals.
Problems due to parasites
Parasitology is the branch of biology which deals with the studies of parasites (Reinecke 1983). Parasites, from the Greek “situated beside”, are “organisms that live on or within some other living organism, which is known as the host” (Reinecke 1983). Mostly these Parasitic worms are typically belonging to the helminth taxa. The parasitic helminths of veterinary importance are contained by the Phyla Nematoda (round worms), Platyhelminthes ( flatworms, tape worms and flukes) and Acanthocephala (thorny headed worms) (Bowman 2014). In domestic animals, nematodes are a major cause of infection in animals and losses in production (Sykes 1994; Corwin 1997; Zajac 2006). Ovine haemonchisos is a serious economic disease which may result in rapid deaths; severe anemia and fever (Urquhart et al,.1996). Gastroenteric verminosis is caused by extremely composite multicellular disease-causing nematodes present in gastric intestinal cavity of the ruminants’ livestock (McRae et al., 2015; Belina et al. 2017).
Gastrointestinal nematodes parasites are one of the main cause of losses of our livestock as well as their productivity especially in sheep (Raza et al., 2010). Infection due to these parasites abridged food consumption and digestibility via protein loss through epithelial openings (Holmes, 1987). The relative protein deficiency is the protein modification to immune sensitivity and mucosal amends resultant growth rate reduction (Coop et al.,1982, 1985), subordinate immune retorts (Coop et al., 1995; Stear et al., 2000a) and sometimes death (Gulland et al., 1993). The infection provoking nematodes generally cause momentous economic dead in livestock after stern pathological illnesses. As a result of hunger loss, meagre growth and severe anemia, there will be decreased meat manufacturing, fabric and milk ultimately lead to death (Gonzalez et al., 2003; Toscan et al., 2017).
When a sheep is infected with Teladorsagia circumcincta (abomasal nematode), the junctions between epithelial cells of stomach wall growing beeves are destroyed. This causes short growth and protein deficit problems. After a continued and hefty infection, bulky mucous produces and other problems arise such as pepsinogenemia,hyperplasia, reduced acidity, gastrinemia, and inappetence.
There are many factors affecting contagion severity including host’s nutritive status, defensive immune response in terms of heritably measured difference, and degree of synchronized contamination (stear et al., 2003).
Adult T.circumcincta does not feed on blood but its larval forms are pathogens cause serious infection. The development of larvae occurs in gastric glands and cause lump development in abomasum and causes widespread injury to parietal cells of mucosa (Roeber et al., 2013). It decreases production of HCl. So, pepsinogen fail to change into pepsin and minimum protein digestion occur. Mostly subclinical infection occurs such as poor weight gain and reduced wool production.
Prevalence of gastrointestinal (GI) nematodes parasites
Parasitic worms are typically belonging to the helminth taxa which are distributed across the world. The parasitic helminths of veterinary importance are contained by the Phyla Nematoda (round worms), Platyhelminthes (flatworms and tapeworms) and Acanthocephala (thorny headed worms) (Bowman 2014).
Due to safety consequences and commercial status, livestock population such as cattle, due to gastrointestinal nematode have always concerned significant devotion (simpson, 2000). A wide range of nematodes present in livestock which belongs to species Nematodirus, Oesophagostomum, Trichuris, Haemonchus, Strongyloides, Trichostrongylus, Cooperia, and Bunostomum. The developing countries are facing serious infections due to Helminthes(Abdurezak, 2015).
Haemonchuscontortus is one main fecund strongylid nematode in worldwide. The female nematode produces a large number of eggs per day. These eggs contaminate the pastures. The main pathogenic stages are L4 and adults. The feeding of L4s and adults on blood cause the main pathogenic effects like severe anemia and its symptoms appear after two weeks of infection (Roeber et al., 2013). These stages are harmful and causes severe infection which leads to death in sheep. There are many signs of infection include hemorrhagic, anemia, dark colored feces, oedemia and rapid death (Sultan et al., 2010). The presence of Haemonchus in mixed infections adversely affects the health of livestock and caused serious other diseases like anemia, anorexia, massharm and in many cases, expiry may ensure (Emery et al., 2016). Haemonchus contortus is not cause of diarrhea, therefore, its presence is not detected easily as compared to other nematodes.
The impact and prevalence of nematodes in the host is affected by many factors like the species, the target organ, their life cycle and their strategy to establish in their host. They are also affected by the host’s immune system, which in turn is influenced by age and size of the animal (Greeret al. 2009), species or breed, hormones, previous infection, management of the farm including nutrition, grazing management, anthelmintic utilization (Sykes 1994; Coop and Kyriazakis 2001). There are several aspects that might transform animals’ invulnerability including trauma, nutritive shortages, and hormonal fluctuations. Furthermore, it has been proved that malnourishment is involved in low immunity that escalates parasitism as well as egg cracking. (Houdijk et al., 2009). So, healthy animal with good immunity is required to produce eggs by nematodes. Nematode handling necessarily depends on both protein nourishing level and diet.
Understanding the epidemiology of nematodes together with good management usually results in few clinical cases of parasitism. It is also observed that there is some association between gastrointestinal parasites and risk factor such as age, gender and species of host. The younger sheep or lambs has more susceptibility to helminthiasis than mature sheep (Dagnachewet al., 2011).
Climatic conditions and prevalence of Gastrointestinal nematode parasites
The availability of diverse parasites along with distributed species are examined by ecological conditions e.g. relative humidity, temperature and environmental needs to develop free-living phases effectively (Beveridge et al., 1989). So, climate directly determine the distribution of parasites.
Typical agroclimatic circumstances offer a suitable atmosphere for various nematodes to complete their life cycle and it’s a biggest contest faced by livestock industry (Mushtaq et al., 2013). In this way gastrointestinal parasite infection has drastic effects on sheep industry and is therefore a limiting factor in sheep production (Jones, 2001). In developed world particularly those areas where there are poor nutritive and unhygienic conditions is facing problems due to Helminthes infections that are prevalent in small ruminants. The well-established world has major issue of health due to infection of gastrointestinal nematode (GIT) of small ruminants which are main parasites of GIT tract. Appropriate environmental factors are different depend on parasite-host species.The diverse epidemiology of livestock’s gastrointestinal parasites depends on environmental states that basically regulate prevalence and harshness of different parasitic illnesses in a specific area. These factors include running does, temperature, flora, rain, and dampness (Takelye, 1991).
The distributions of sheep’s gastrointestinal nematodes in different sheep presence zones also determine by three main periodic rain forms such as non-seasonal (unchanging), straw-hat, and midwinter rainfall region. These regions mostly contain all nematodes except O. columbianum, which is only present in summer and non-seasonal zones. Nevertheless, there is a variation of their frequency in different climatic zones which can be particularly detected between different areas of each country. Many gastrointestinal nematodes are present commonly in those regions where the typical yearly rainfall is 280 mm or above.
Although the availability of Haemonchus contortus is restricted in areas of damp summer climate with modest figures but it commonly present in unvarying rainfall regions. The adult populations of H.contortus amplified in spring according to the recent research on fecal egg count. High fecal egg counts cause pasture contamination. therefore, so it directly determines population of nematodes in next season. Teladorsagia circumcincta females are fewer productive as compared to H.contortuswhich releases 100-200 eggs per day and it is found in only few areas.
Parasite-host Interactions
There is a direct effect of grazing behavior on the time at which a host interacts parasites at stage of free-living.The study of developmental stages of monoxenous nematodesis crucial to recognize the relation of parasite spread with grazing behaviors. After release from the host body, these free living and infection-free parasites become infective parasites at their third stage (L3) when release from host body. Then herbivore host ingest after assimilation through an herbivorous mass, shedding occurs and fourth stage larvae (L4) is produced prior to be matured productive grown-ups (L5). So, ingestion of parasite can be reduced with help of changing in behavior of animals during grazing (Fox et al., 2013).
Grazing behavior is one main cause of infection in small ruminants. Gastrointestinal nematodes spread very easily in various parts of country by the free-range grazing over the year. In this way these endoparasites are responsible for productive losses in small ruminants in worldwide (Raza et al., 2014). These habits have diverse features with respect to age and species of animals (Cornell et al., 2004). For example, in case of clean area, adult species select to graze there having some feces but it is impossible for young animals to discriminate areas. As a result, lambs might graze in high L3 numbered areas.Based on all above observations, it can be said that animal species have specific habits of grazing according to their health status. Moreover, animals can be categorized with respect to immunological response. During the life of adult animals, they are adequately exposed to parasites in order to produce a reasonable immunity status. They excrete bulky feces having low FEC compared to young animals (Coles, 2002).
It is notice that control and strength of macro-parasite outbursts is affected by grazing behavior caused by three-dimensional heterogeneity It also depends on the different time of exposure to living staged parasites. There is a difference of grazing behavior effect on the basis of host-parasite grouping, the fecal evasion behavior is beneficial in case of low immunity of host against parasites during developmental period. But is can being risky for macro-parasites who have extended growth times on meadow. The developmental time is increased after parasitic species co-infection that shows grazing policy at peak. Mostly, anorexia after parasitic infection is useful for host by diminishing parasite load and ingestion wound throughout grazing period.
According to Catto et al. (2005), a rise of FEC in cows after pre-calving to dissuading was sufficient to rise grassland pollution. Waller (2003) emphasized that sheep has met the similar circumstance as vindicated by the delivery to deterring period called peri-partum dated. During this, animals suffer from stress condition in response to immunity because of hormonal changes leads to increased level of parasitism in same area. Thus, sheep serve as a contamination way for other animals and accountable for meadow contagion (Iqbal et al., 2005). The risk of infection in lambs can be decreased if specific strategies of anthelmintic treatments are adopted. Females are suggested to be assigned in definite maternity paddocks while in at peri-partum period. The L3 survival under less humidity and high grounds locality should be less satisfactory.
Gastrointestinal nematodes remain a major risk to gain an efficient production in small ruminants. So, we are trying to control these parasites with use of anthelmintic. Currently there is a need to find some other suitable solutions of this problem because it decreases our productivity. Scientists are also interested to seek some appropriate, inexpensive and more effective methods of controlling these pathogens and parasites.
Life cycle of parasitic GIN
There are two phases of parasitic life cycle of nematode: one is pre-parasitic also called as free-living and other is parasitic. Environmental surroundings are needed for pre-parasitic stage but, there is need of vulnerable host for parasitic stage. Mostly, life cycle of nematodes comprises following stages: egg, 1st larva (L), and adult stage. The first larval stages are L1……. L5. The infective stage also called as 3rd larval stage stabs the duodenal mucosa leads to maturation of L4 followed by immature adult stage named as L5 and finally leads to adult stage. Both health and immunity status of the infected hosts is dependent on successful infection (Angulo-Cubillan et al., 2007; Kandil et al. 2017).
Mostly nematodes are sexually dimorphic and adult form live in the digestive tract of sheep population. A large number of eggs are produced in digestive tract of females. All nematodes have alike pattern of life cycle except Nematodes spp in which the development of larvae takes place in eggs. These eggs are pass in the feces of host animal. It takes 24 to 48 hours to hatch Strongylid eggs which are 70–150μm in diameter. The feeding of larvae is on bacteria followed by hatching. After passing two larval stages, there is 3rd stage ensheathed larvae occur in feces/soil known as L3s. Although the function of this sheath is to provide protection of L3 stage againstweather situations but it also prevents it from nourishing. After absorbing L3s form, host is infected.
After this larva reaches in the stomach of host animal. L3 stage loses its protective sheath. Then finally it develops into its L4 and pre-adult stages, respectively (Levine, 1968). The feeding of L4s besides adults on blood cause the main pathogenic effects like severe anemia and its symptoms appear after two weeks of infection (Roeber et al., 2013). These stages are harmful and causes severe infection which leads to death in sheep. Hypobiosis is the phenomenon in which the development of larvae is arrested during hostile conditions generally close to the grazing season and this is specific for Haemonchus and Teladorsagia species (Roeberet al., 2013).
Pathogenicity and clinical signs in host animals
The global issue for poor developed countries is parasitic disease because these parasites cause the serious Infection in livestock population. Some parasites live inside the body of animals such as nematodes and trematodes. Sheep and other animals act as final or intermediate host for many parasites. The majority parasites are nematodes that infects cattle and trivial ruminants. Prime parasites of GIT tract in small ruminants are nematode. Due to lack of pathognomonic signs, it is difficult to diagnose GIN clinically.
Nevertheless, the investigation of epidemiology of parasites is majorly depends on diagnosis of GIN contaminations. Flotation and larval culture are diagnostic tools in which ante mortem is being detected for nematode infections in Livestock by microscopic examination of egg or fecal larvae. Mc Master technique is highly reliable method to diagnose nematodes infection in veterinary parasitology (Vadlejch et al., 2011).
FLOTAC and Mini-FLOTAC Techniques
These techniques have basis of microscopic observation of GIN eggs that are floated in NaCl solution having specific gravity and stuck on glass outward (WILLIS, 1921). In this method, eggs are separated from fecal debris and smears in short time. Thus, probable increased of fecal samples having eggs of small ruminants, specific for those individuals who were facing bright or severe taints. Willis technique is another name of flotation which offers many amendments. It is still valuable for detection of light infection in ruminants (BASSETTO et al., 2011; SANTOS et al.,2014b). Many keys are helpful to identify eggs of different nematodes species based on morphology (MAFF, 1979; Soulsby, 1987; Urquhart et al., 1996). Many studies prove that some other methods such as centrifugation début method,
A wide-reaching identified technique known as McMaster technique has been modified recently. The Brazilian laboratories mostly follow the protocols of Ueno and Gonçalves’s guide. They recommended 4g mixing of cattle feces in saturated solution of 56ml sodium chloride (specific gravity 1.2) and 2g fecal sample of small ruminants mixed with 58 ml solution of NaCl (UENO; GONÇALVES, 1998). The egg of cattle and small ruminant has corresponding 50 EPG and 100 EPG respectively. It is noticeable that eggs counting is only justified after the correlation of it with load of worms present in GIT of animal. According to studies, there is an important link exist between worm load and EPG. It means that infection due to GIT nematodes parasites in sheep is can be indicated by fecal egg counts. The estimation of parasite burdens can be best identified by quantification of egg/gram in feces (Roeber et al., 2013).
It might be difficult to quantify fertility except for T. Circumcincta showed that longer prolific worms have eggs accordingly (Stear et al., 1995, 1997a). Nematode size and number determine the pathogenicity for species of sheep nematodes especially in case of H. Contortus (Strain and Stear,200). (Strain and Stear, 2001). In only one animal, the total number of eggs in feces indicates both number of nematodes and eggs rested by each worm known as fecundity. The concentration of fecal eggs could be affected by variances in output and condition of feces. Possibly, it is insignificant fecal output of 2-4-fold as compared to big difference in fecal egg counts between animals. A very solidand reliable connotation during cautious and usual infections is present between the adult female T. Circumcincta length and egg creation (Stear and Bishop, 1999). The worm length in sheep is different and also related toamount of pepsinogen in plasma (Stear et al., 1999). Consequently, the mean length and number of worms is correlated with severity of infection caused by T. Circumcincta.
Molecular analysis
Polymerase chain reaction and DNA sequencing are involved to identify parasitic species precisely. These innovative and extremely subtle molecular techniques are identifying nematodes equal to species level (Tan et.al., 2014). Karry Mullis has introduced the most useful method known as PCR in 1986 in which the later modifications were done in 1988 by Saiki in using DNA polymerase enzyme (thermostable) extracted from Thermus aquaticus bacteria called taq. The purpose of this technique is to amplify nematode’s DNA based on thermal cycling so that ratio of parasite species can be detected in mixed infection (Hassan et al., 2017). Firstly, denaturation was done by heating double-stranded genomic DNA. The second step is called annealing/hybridization in which temperature decreased to anneal primers with DNA strands. After that, Taq polymerase enzyme involved in DNA extension followed by rise in temperature (Gasser 2006). Nowadays, PCR has been modified.
Latest techniques have been developed to accurately identify parasites based on DNA tactics i.e. qPCR known as real-time PCR (Samson et al., 2002; Sweeny et al., 2011), standard PCR and multiplexed-tandem PCR (Roeber et al., 2012; Bisset et al., 2014).These PCR techniques have a common feature that the targeted region which have to be identified is located inside region of ribosomal DNA gene array called internal transcribed spacer region 2 (ITS2). Although these molecular techniques have enhanced sensitivity and specificity in diagnosing naturally developed contaminations in sheep but the DNA-based assessments also proposed the potential of robotic stages (Roeber et al., 2012). The current real time PCR has provided good and reliable results to identify parasites as well as involved in parasite DNA quantification.
The functions of gastrointestinal nematodes include immune destruction, and increase the animals’ vulnerability to other illnesses. The defensive methods used by immune system of host and infectious nematodes in GIT (Grencis et al.2014). Different mechanisms have been induced for host resistance so that flexible negative results and disease are produced. These mechanisms are humeral, cellular mediate and immunomodulate (Zvinorova et al., 2016).
Severe infection due to gastrointestinal nematodes have some complex signs and symptoms. These are hemorrhagic, anemia, dark colored feces, oedemia and rapid death (Sultan et al., 2010). Infection due to blood-sucking nematodes results weight loss, anemia, appetite cost, and diarrhea. Parasites, after sucking blood from membrane of intestinal mucosa leads to itching and puffiness of the duodenal coating. While compete with host for getting nutrients, parasites might loss nutrients. So, when the mucosal membrane of intestine is damaged, it causes loss of protein, malabsorption, and weakened ingestion. Besides all, due to nutrient deficiency and blood loss, RBCs and electrolyte are lost. Collective result of these events in infected animals is anemia.
Body condition scores (BCS) are also helpful to identify the infected individuals. Body score is determined by physical examination of body muscles of leg and abdomen. The deposited fat is measured above and surrounded vertebrae in thigh parts of body (Seyoum et al., 2018). One strategy to improve body condition score of animals’ is the reduction of negative impact of gastrointestinal parasites by supplementing the diet with protein-rich food (Hosteet al., 2016).
The non-hematophagous worms such as Teladorsagia circumcincta and Trichostrongylus colubriformis infected by helminth is diagnosed by using this method. Infections due to mix parasites can be identified by record of BCS once-a-month. There are many symptoms of infection such as decreased in anorexia, feed intake, and desiccation with less association of FECwith BCS Honhold et al. (1993). This helped for the determination of health status of animals. Therefore, mean of parasitic egg count would be higher in significant to deprived physique condition of animals.
FAMACHA© system is convenient to forecast the strength position of sheep that merely. It only perceives sheep flock for the incidence of GIT nematodes. FAMACHA© chart was introduced in South Africa as a diagnostic tool that provides help and facility to farmers using a defined color chart to compare color of ocular mucous membrane so that they can locate those animals who needed anthelmintic action. This is the most easy and effective too for screening host condition (P. Chandrawathani et al., 2013).
FAMACHA© chart categorizes the grade of little ruminants suffering from anemia on the basis of color of eye membrane on a ruler 1 including normal eye color red to ruler 5 which has pale eye color white (Idika et al., 2013).Hematocrit values, FAMACHA© scores, and FECs are genetically parallel to each other in sheep (Bath et al., 2005).
Moreover, it is recommended from farmers who have poor resources that there can be integrated control of nematodes if this system would be adopt. But it must be implied with body condition score so as to predict the sheep condition. One difficulty is that farmers are unable to differentiate between parasite infected and non-infected sheep due to lack of information and practices. We still have no valuable tool and disease constraints for diagnosis of nematode infection present in household animals.
Control oF GI nematodes
Now a day’s various methods are available for control of gastrointestinal nematodes. Nevertheless, a very important and effective way is to use broad-spectrum anthelmintic to evade from parasitic disorders (Waller and Thamsborg, 2004). Different classes of drugs are used against gastrointestinal parasites, the common ones are benzimidazoles, macrocyclic lactones, and imidazothiazole.
Anthelmintics
The development of the first broad spectrum anthelmintic thiabendazole (benzimidazole) in 1961 changed the way to treat parasites in worldwide. Since then, many drugs have been developed (Lanusse and Prichard 1993). Anthelmintics can be classified by their chemical structure and/or their mode of action. In Europe there are only two action families of anthelmintics registered for small animals.
1: Benzimidazoles (BZ): albendazole, fenbendazole, and oxfendazole are currently licensed for use in deer using the same dose rates as for cattle except for albendazole for which the dose rate is 33% higher than for cattle.
2: Macrocyclic lactones (ML): ivermectin, abamectin, eprinomectin and moxidectin are currently licensed for use in ruminants but only as topical pour-on formulations using the same dose rates as for cattle. There is little information on the efficacy of other formulations.
Effectiveness can never be comes as indicated by several hearsays of GIN of small ruminant resistant to anthelmintic in US (Zajac and Gipson, 2000; Terrill et al., 2001; Mortensen et al., 2003; Kaplan, 2004).These drugs are used to handle parasites but their disproportionate practice causes some serious problems and parasites gain resistance against these drugs. The growing development of anthelmintic resistant become a major problem and this is known as unique greatest challenges to the livestock industry (Waller 1997).
The low efficacy of drugs is mainly due to their misuse, it may be dose and/or frequency of application (Sultan et al., 2016) which may result in economic losses. So, the excessive and at improper time anthelmintic usage has given rise considerable and extensive complications with resistant to anthelminthic in nematode inhabitants. So, the amended ways to control parasitic nematodes is a noticeable need of global interest. Number of methods are used to minimize the resistance level of drugs like larval development assays (LDA), fecal egg count (FEC) and egg hatch test. The role of tanniferous substances against the Gastrointestinal nematode’s parasite is significant in sheep (Virginie et al, 2003). Moreover, an increased egg output has been noted in certainly diseased goats given polyethylene glycol, a tannins inhibitor compound (Kabasa et al., 2000). So, there is a growing interest to progress substitute methods which rely less on anthelmintic drugs.
1.8.2. Vaccination
The recent development of a commercial subunit vaccine against Haemonchus contortus in sheep “Barbervax®” have limited effectiveness in mostly cases.
1.8.3. Grazing management
Grazing management has been investigated many times for control of GIN. Hoste and Torres-Acosta (2011) proposed two main types of grazing strategies which they classified as defensive or offensive.
a- Defensive: To avoid parasites.
b- Decrease the stocking rate (diluting) or rotational grazing (evasive).
c- Offensive: To decrease the availability of nematodes by removal of infective stages on pasture.
d- Grazing alternate species which are not hosts for the target nematodes (Hoste and Torres-Acosta 2011).
1.8.4. Nutritional status of animals
During periods when the animal has high demands for nutrients, e.g. the periparturient period and also young animals growing rapidly, the immunological response has a lower priority for available nutrients (Coop and Kyriazakis 1999). If the animals are supplemented during these periods there can be a beneficial effect on parasite resistance and/or resilience by the host. Protein supplementation has reduced caterpillar burdens and FEC in merino ewes (Kahn et al.2003). Nevertheless, the same study indicates theresult of supplementation for animals with a resistant genotype which was less effective than for randomly selected animals (Kahn et al.,2003).
Research Question (s)
1: What types of nematode parasites are found in sheep present in district Multan?
2: Which are the convenient and efficient techniques and methods to diagnose the nematode infections and causative agents?
3: What are possible effects of nematode parasites on sheep?
Research Objectives
1: To isolate and identify nematodes in the gastrointestinal tract in sheep of district Multan.
2: To examine nematode specific diseases prevalent in sheep.
3: To seek and recommend appropriate treatment of the diseases caused by these nematodes.
2.1. Study Zone
The duration of this study was January 2019 to June 2019 in Multan, Pakistan. Total area of district Multan is 133 square kilometers having 71.48 longitude and 30.20 latitude. It is located at 129 meters above the sea level. It is also known for hottest weather in Pakistan and 25.6°C is the twelve-monthly normal temperature. Their average annual precipitations are 7.3 in (186 milli meters). The mean annual rainfall of this district is 175 mm with a bimodal pattern. The study area was agricultural structure comprising both crops and livestock where the 2nd foremost animal species were sheep raised by agriculturalists.
2.2. Experimental animals
Present study on sheep population of all age groups and both genders was conducted present in Multan area. The trial animals were home-grown breeds which were reserved under outdated wide supervision arrangement. The collection of samples was according to age difference in oldness, gender and physique ailment. Age of both sexes was determined by dentition. Conventionally, young animals were those who were less than 6 months old but above the 6 months or equal to one year was considered adults (Kumssa et al 2010). The animals of current study had an age below 6 months up to 1 year. The body condition score was obtained using formulae of Kripali et al.(2010) and were grouped as poor, medium and good. These sheep did not receive any wormicide at least three months prior to the start of study trials.
2.3. Sampling and Design methods
A field follow-up study was performed on 50 sheep collected from 3 sheep farms. These animal farms were located in different areas of district Multan of Pakistan. The study was carried out in February to May in 2019. The animals required to study in each farm was categorized by method of systematic random sampling. Total sample size was 50 as per estimation of 95% confidence level and 5% accuracy. Samples were collected by each farm on equal proportions. Simple Random sampling method was adopted to collect fecal samples fromrectum of different sheep (experimental animals) by means of clean and pliable scarves. These samples were placed in sterile, closure polytheneplastic bags marked with types, area, domiciliary ID, oldness, and animal gender.
Each fresh fecal sample was about 10-15 grams. The male to female ratio of collecting samples was 20: 80. After collection of these samples from the rectum of each animal, each sample was placed at room temperature. The fecal samples were collected in 4 intervals. These samples were transferred to a cool container that was air tight till these were brought to laboratory of Virtual University in Multan campus. Samples were chilled at 4°C prior to time of analysis.
2.4. FAMACHA© chart and body condition score (BCS)
At the time of sampling, two scores were calculated i.e. FAMACHA© chart and body condition score.
2.4.1. Body condition score:
The purpose of this score is to identify the infected sheep individuals. In present study, it was determined through physical examination of body muscles of leg and abdomen and confessed areas ofabove and round the backbones in thigh parts of body. The BCS was calculated as per the formulae of Kripali et al. (2010) and were categorizedinto poor, medium and good.
2.4.2. FAMACHA© chart score:
FAMACHA chart was used for diagnosis of infected animals. For this purpose, animals were captured, and their color of eyes was examined. The score was mentioned by comparing with a uniform five-colored set extending from normal red-pink to terminal white anemia called FAMACHA also called as FafaMAlan CHArt (Malan et al., 2001). The visible signs of anemia were implied via developed FAMACHA system for example an indicative gauge which is quickly modest, involved color valuation of the membranous conjunctiva (a thin, clear membrane present in front of eye) (Van Wyk and Bath, 2002).
Acquired data after conception record, the palpation, and microscopic examination was used to find out incidence of parasitic gastrointestinal nematode based on their morphological features.
2.5. Autopsy inspection and epidemiology
Autopsy was done after collecting adult or larval stages from gut insides and identified based on morphology to count the number of worms in host body next to slaughtering (Maff, 1986).
2.6. Blood tests (To spot contagion)
The infections were distinguished by immunological and serological tests. First blood samples were taken from the body of sheep. These blood samples were used to diagnose infection or diseases.
2.7. Parasitological examination
The current study has fundamental aim to know about the presence of specific parasites on the basis of eggs in particular with relation to unlike morbidity parameters instead of identification of species of parasite. The fecal tasters? were kept in a labeled collective flask and then added formalin (10%) in each universal bottle to preserve these samples. Fecal samples wereexamined according to Hayat and Akhtar (2000) and Soulsby (1987) using flotation and sedimentation methods which are parasitological usual straight and ancillary techniques. The collected samples were also analyzed qualitatively by flotation method while the quantitative method was McMaster egg counting. In these methods, saturated sodium chloride (s.g=1.2) solution was used as flotation fluid as mentioned by Charles, 2006. The identification of eggs of diverse parasitic species was done by method of Soulsby (1982). The EPG counter provided the infection grademarked as bright, reasonable and immense (Spartan) after subjecting positive samples. The light infection was checked by 50-799 egg count while 800-1200 indicated moderate and larger than 1200 of eggs/gram feces reflected severe infection (Soulsby E.,1986). The individual nematode was studied on the basis of morphology by standard diagnostic and larval culture assays.Some techniques such as direct microscopy and sedimentation are also adopted to investigate fecal sample. In this way, it will be possible to morphologically identify eggs and cysts.
2.7.1. Wisconsin flotation method
This method was also used to isolate GIN eggs following two steps. Firstly, took1g of feces and was mixed with tap water of about 25ml.Filtration of this solution was done by cheese stuff. Then the sample was suspended in saturated sucrose solution (10ml). After, suspension was centrifuged by transferring sample in 10ml centrifuge tube and covered with cover slip. The spinning wad was done at 4000g for 5 minutes at room temperature. While centrifugation, GIN eggs were concentrated contrary to cover slip. This cover slip was removed and examined and magnified at 40 X. Then filled this centrifuge tube with saturated solution of sucrose followed by covering with cover slip and centrifuged again.
2.7.2. McMaster Technique
We can just identify incidence and nonappearance of parasitic eggs in samples of feces by easy and simple technique which is known as flotation technique. Several other techniques have been devised for calculate the eggs of nematodes in each gram of feces of small ruminants. Gordon and Whitlock discovered the greatest fruitful procedure in 1939. The basis of this method was flotation of eggs in presence of NaCl saturated solution under Mc Master chamber. Having known volume capacity, this chamber allowed to estimate total number of eggs in feces. According to Mc Master technique, took 4g fecal sample from cattle and mixed with 56ml saturated salt solution having specific gravity 1.2.In case of ruminant fecal sample, took 2g feces and suspended in 58 ml of sodium chloride solution (UENO; GONÇALVES, 1998). Mc Master technique was highly reliable method to diagnose nematodes infection in veterinary parasitology (Vadlejch et al., 2011).
This technique was also used to isolate and quantify eggs of GIN and included following stages. In first step, took 2g feces and suspended in tap water (43ml). These fecal samples were mixed thoroughly in tap water. This solution was filtered by tea Strainer. After this, suspension containing eggs were transferred to centrifuge. Now this suspension was centrifuged for 4 minutes at 1500rpm at room temperature.
Decanted supernatant and suspended it in saturated NaCl solution. After this, tube having concerted gastrointestinal nematode eggs was covered and shook well. Then, cover slip was removed followed by microscopic examination at amplification of 4X. Same methodology was performed for each remaining sample. From egg of each small ruminant, there was 50 EPG and 100 EPG respectively. Apparently, the egg count was performed to find the prevalence of the gastrointestinal nematode in animals.
The nematodes were identified by coproculture method according to MAFF (1979) for the purpose of finding larval stages. In step 1, fecal samples having parasitic eggs were grinded into fine powder using pestle mortar/ spatula. The 2nd step involved to kept this crushed sample into closed glass jar/ Petri dish. The incubation was done at 26°C for 7 days followed by examination of sample for the samples for larval presence using keys (MAFF, 1979). In this way, all samples were examined under microscope for parasitic examination.
2.8. Fecal larvae count (FLC)
Larval culture method was also used to study the epidemiology. For the estimation of the larvae from feces, sedimentation methods such as the Baermann technique was used. The Baermann technique usually consist of a funnel with a clipped tube attached at the bottom end or a conical flask with a rounded bottom. Small amount of fecal sample was inserted over a gauze/filter paper at the top. The conical flask was filled with water to cover the fecal material. This was incubated for a variable period between “overnight” to 20 hrs. at “room temperature”. The active larvae passed through the gauze/filter paper and collected at the bottom of the conical flask. The larvae were either collected by opening the bottom of the clipped tube or by siphoning the fluid from the top of the flask. Larvae were subsequently counted and number per gram calculated. In small ruminants the FLC for worms has a good correlation with the actual worm burden, making it a reliable diagnostic technique (Mackintosh et al., 2014b).
2.9. Analysis of Data
After performing laboratory experiments, this data and figures entered and arranged in to the sheet of microsoft excel. The statistical analysis was done using known software SPSS version 21. Then, a descriptive data was obtained. For measuring role of related determinants such as age, species, gender, and agroecology in prevalence of GIT helminths, this data was analyzed through multiple logistic regressions (Thrusfield, 2007). The statistical tools that were implied include: Percentages calculation, logistic regression and odd ration calculator by chi-squareas well as to find out relation between parasitic prevalence and animal species, gender, age, and agroecology. While analysis, the significance level was P < 0.05 and 95% was confidence level.
Figure 2.1 Fecal Samples
Figure 2.2: Solution of Fecal samples
Figure 2.3: Mixture of fecal sample prepared for centrifugation
Figure 2.4: Fecal samplesready for microscopic examination
3.1. Prevalence of GIN in sheep
In present study, only 50 small ruminants were selected and sampled across the different locations. In this study only sheep population were examined for gastrointestinal nematodes. The coprological examination discovered that overall incidence of GIN was 44% (22/50) in sheep animals. All the sheep examined from 3 different sheep farms. Out of 3 farms, samples of 2 farms showed that there was high frequency of GIT nematodes while sample from 1 animal farm showed low prevalence. The prevalence of different nematodes parasites which were identified in our study have been also reported already in Pakistan and across the world.
The prevalence of infections due to several gastrointestinal nematode was documented in all breeds of sheep which were located in different animal farms in Multan district and its surrounding areas. No statistically significant difference was found in any breed of sheep for epidemiology of GIN infection.
Parasitological examination was carried out by flotation, Mc Master, and sedimentation techniques using standard protocols (Hansen, 1994; Shah-Fischer, 1989). Keys of Soulsby (1982) were used to identify nematodes eggs as described by Hayat & Akhtar (2000). Total 22 positive fecal samples were authenticated by parasitological practices qualitatively. These were processed to EPG count by McMaster egg counting method. There are three stages of Infection on the basis of egg counts obtained by fecal sample. One of light (50-799), second is moderate (800-1200) and the last one is massive (>1200). According to our results, 10(45.45%) was light, 7(31.81%) was moderate and 5(22.72%) was massive (infested) (Table 3.1).
Table 3.1: Extent of infection’s severity in infected sheep based on FEC
| Infection intensity | Positive samples | Infection rate (%) Prevalence (%) = Number of positive samples divided by total examined samples multiplied by 100 |
| Light | 10 | 45.45% |
| Moderate | 7 | 31.81% |
| Less severe | 3 | 13.63% |
| more severe | 2 | 9.09% |
| Total | 22 |
Note: Egg counts were light (50-799), moderate (800-1200) and massive (>1200). (Soulsby, 1986).
3.2. Identification of gastrointestinal nematode eggs from samples
Keys of Soulsby (1982) were used to identify the eggs of different parasite species as described by Hayat & Akhtar (2000). Out of 50 samples examined, Haemonchus contortus, Trichostrongylus axei and some otherspecies of nematode parasites were recorded respectively 10(20%), 7(14%) and 5(10%) as shown in Table 3.2. The foremost parasite was Haemonchus contortus (20%), then was Trichostrongylus axei (14%) and mixed type of nematodes parasites were 10%. The results showed that main nematodes fitting to species Trichuris, Nematodirus, and Haemonchus were observed. Furthermore, it was also noted that, small ruminants were also affected by multiple parasites other than nematodes in the form of mixed type of infection (Table.3.2).
Table 3.2: Prevalence of Haemonchuscontortus, Trichostrongylus and other species nematodes on the basis of morphological characteristics of parasitic eggs.
| Species of nematode | No. of examined samples | No. of Positive samples (%) |
| Haemonchuscontortus | 50 | 10(20%) |
| Trichostrongylusaxei | 50 | 7(14%) |
| Mixed infectionH.contortusandTrichostrongylus spp. | 50 | 5(10%) |
| Total samples | 50 | 22(44%) |
| Variables | No. of examine | Positive sample | Standard Deviation | Prevalence% | X² | P-Value |
| Age | 4.88* | 0.027 | ||||
| young | 30 | 17 | 0.504 | 56.67 | ||
| Adult | 20 | 5 | 0.444 | 25 | ||
| Total | 50 | |||||
| Sex | 0.99NS | 0.319 | ||||
| Male | 10 | 3 | 0.483 | 30 | ||
| Female | 40 | 19 | 0.505 | 47.5 | ||
| Total | 50 | |||||
| Body condition score | 10.96** | 0.004 | ||||
| Poor | 12 | 10 | 0.389 | 83.33 | ||
| medium | 31 | 11 | 0.486 | 35.48 | ||
| Good | 7 | 1 | 0.377 | 14.29 | ||
| Total | 50 | |||||
| Season | 0.32NS | 0.569 | ||||
| Dry | 25 | 10 | 0.5 | 40 | ||
| Wet | 25 | 12 | 0.509 | 48 | ||
| Total | 50 | |||||
| Fecal consistency score | 8.87* | 0.012 | ||||
| Pellet | 6 | 6 | 0 | 100 | ||
| smooth | 20 | 8 | 0.502 | 40 | ||
| soft | 24 | 8 | 0.481 | 33.33 | ||
| Total | 50 | |||||
| FAMACHA© score | 39.64** | 0 | ||||
| Red | 29 | 11 | 0.493 | 37.93 | ||
| Red-pink | 10 | 5 | 0.527 | 50 | ||
| Pink | 8 | 5 | 0.517 | 62.05 | ||
| Pink-white | 3 | 3 | 0 | 100 | ||
| Total | 50 |
Table 3.3: Association between risk factors and prevalence of GIT nematodes
Non-significant (NS)= P>0.05; * Significant= P<0.05; **Highly significant=P<0.01
Note: Here color red indicates score 1 while color pink-white indicates score 4. Score 5 was not observed in present study. Animals with conjunctiva of pink and pink-white ocular have a greater mean EC compared to animals having red orpinkish red ocular conjunctiva (ZewduSeyoum et.al., 2017) (Table 3.3).
3.3. Risk factors and gastrointestinal nematodes in host animals
The incidence of GIT nematode infections of sheep evaluated by sex indicated that female individuals have more vulnerability to infection. The prevalence of males and females were 30% and 47.50%, respectively that showed variation between sexes was non-significant (P>0.05). (Table 3.3). But a significant difference was exist(p<0.05) between adult and young animals as shown by prevalence percentages i.e. 56.66% and 25.00% respectively( Table 3.3).
The prevalent infection in animals having poor physique was significantly higher than that of good and medium physique condition scores (P < 0.01) in accordance with 83.33% (poor), 35.48% (medium) and 14.29% (good) respectively (Table 3.3).
The FAMACHA© chart result showed highly significant association with the infection of animals (P < 0.01). Infection of animals dependedupon eggs of parasites present in fecal matter. Sheep with higher egg per gram (EPG) and high FS powerfully suggests that worm burden was mainly contributed to Anemia as this score have a powerful positive relationship with egg per gram of feces (EPG).
3.4. Relationship between risk factors and prevalence of gastrointestinal nematodes
3.4.1. Interlink of Body Condition Scores with Nematode Infection
A significant difference was found in body condition score and infection with gastrointestinal nematode. Present study showed that an animal which had poor body condition score shed more nematode eggs as compared to good body condition score. The reasons behind this poor bodily condition are synchronized bacterial and parasitic infections or malnutrition which causes poor response to infectious stage of the parasites immunologically resultant to weaker infection as compared to other groups. There was large amount of nematodes eggs in poor bodily conditioned animals (83.33%) than those of medium (35.48%) and good body condition (14.29%) according to table 3.4 and fig 3.1. Body condition score showed significant association with GIT nematode infection (P < 0.01) (Table 3.4) which showed that medium and poor body condition of small ruminants are highly infected with nematodes which may be due to animals having good body condition score has more immunity as compared to weak animals (Table 3.4).
Table 3.4: Relationship between Body condition score and prevalence of gastrointestinal nematodes.
| Body condition | ||||
| Variables | No. of examined samples | Positive samples | SD | Prevalence (%) |
| Poor | 12 | 10 | 0.389 | 83.33 |
| medium | 31 | 11 | 0.486 | 35.48 |
| Good | 7 | 1 | 0.377 | 14.29 |
Note: Body condition scoring (BCS), was scored according to this formula 1= very poor, 2= very thin, 3= thin, 4= good, 5= very good (Geurden et al., 2006).
Figure 3.1: Nematode infection and body condition scores
3.4.2. Relation between Fecal Consistency and gastrointestinal infection
The global occurrence of GIN contamination was significantly changed (P < 0.05) between fecal uniformity. Animals with evacuated pellet was found at higher prevalence than plane fecal stuff defecated animals hence animals with the soft/diarrheic fecal matter showed less gastrointestinal infection (Table 3.5 and Fig 3.2). There was also a momentous connotation among fecal consistency samples in the total egg count. Therefore, a negative interlink exist between FSC and FC. Sheep has high FC pellet if there is higher total fecal egg count (FEC) value of 1906.25 ± 712.560, whereas lesser mean FEC cost of 105.66 ± 289.62 in sheep defecated soft fecal matter. FC determination revealed that 100%, 40.00% and 33.33% of the animals has normal feces, soft feces and diarrhea, respectively.
Table 3.5: Relationship between Fecal consistency and prevalence of gastrointestinal nematodes
| Fecal consistency | ||||
| Variables | No. of examined samples | Positive samples | SD | Prevalence (%) |
| Pellet | 6 | 6 | 0 | 100.00 |
| Smooth | 20 | 8 | 0.502 | 40.00 |
| Soft | 24 | 8 | 0.481 | 33.33 |
Note: The Fecal Consistency was scored as a pellet, smooth, and soft (Dornyet al. 2011).
Figure 3.2: Fecal Consistency and Nematode Infection
3.4.3. The FAMACHA© chart and Nematode Infection
FAMACHA©score determination was done through comparison between conjunctiva color and scores on chart in which 1 indicated non-anemic sheep yet showed low intensity of infection present, while 4 indicated severely anemic sheep which showed very high intensity of infection present. The FAMACHA© chart result showed highly significant association with the infection of animals. Infection of animals was depended upon eggs of parasites present in fecal matter. A high FS value in sheep with higher egg per gram (EPG) suggests that worm burden was mainly contributed in anemia. FAMACHA© score have a strong positive correlation withEPG. FAMACHA© score increases as the EPG increases (Sissay et al.). High frequencies of FAMACHA© scores 1 was recorded in (58%) while 6% animals 4 which denotes very anemic.
Table 3.6: Association between FAMACHA© scores and infection of gastrointestinal nematodes
| FAMACHA© scores | ||||
| Variables | No. of examined samples | Positive samples | SD | Prevalence (%) |
| Red | 29 | 11 | 0.493 | 37.93 |
| Red-Pink | 10 | 5 | 0.527 | 50.00 |
| Pink | 8 | 5 | 0.517 | 62.05 |
| Pink-white | 3 | 3 | 0 | 100.00 |
Note: The high egg count was obtained in animals having pink or pinkish whitecolored ocular conjunctiva have as compared to those with red or reddish-pink colored ocular conjunctiva (Seyoum et.al., 2017).
In addition to, there was no score 5 was noticed in our study.
Figure 3.3: The FAMACHA© score and Nematode Infection
3.4.4. Age and gastrointestinal nematodes
The prevalence of gastrointestinal parasites is largely predisposed by age of the host animal. On the basis of concerned age groups, the higher infection was reported in suckling as compared to adult animals. In present findings, infection rate was 56.66% (17 of 30) in young and 25.00% (5 of 20) in adult animals (Table 3.7b and fig 3.4). It may be due to a weaker immunological response and more closeness with unhygienic environment.
Table 3.7a: Association of age and gastrointestinal nematode infection
| Age of animal in month | No. of examined samples | Infected animal (%) |
| 2 | 10 | 7 (70%) |
| 6 | 20 | 9 (45%) |
| 12 | 20 | 6 (30%) |
| Total individuals | 50 | 22 |
Table 3.7b: Association of age and gastrointestinal nematode infection
| Age | ||||
| Variables | No. of examined samples | Positive samples | SD | Prevalence (%) |
| young | 30 | 17 | 0.504 | 56.66 |
| Adult | 20 | 5 | 0.444 | 25.00 |
Figure 3.4: Age and gastrointestinal nematode infection
3.4.5. Sex factor and gastrointestinal nematode infection
Males and females both have 30% and 47.50%, prevalence of infest respectively with variation between the two sexes were non-significant(P>0.05) (Table 3.8). Females with highly infested prevalence might be due to hormonal changes and stress during pregnancy (Table 3.8 and fig 3.5).
Table 3.8: Relationship between sex and gastrointestinal nematodes.
| Sex | ||||
| Variables | No. of examined samples | Positive samples | SD | Prevalence (%) |
| Male | 10 | 3 | 0.483 | 30.00 |
| Female | 40 | 19 | 0.505 | 47.50 |
Figure 3.5: Sex and gastrointestinal nematodes
3.4.6. Association between season and infection
A non-significant difference of larval development was observed in dry season and wet season. There was greater record in damp period than dry season. A very parched andwarm weather may kill meadow-living larvaein summer season. Thegastrointestinal nematode infection in presence of hot and moist environments was most Spartanbecause larvae can only grow at the optimum temperature of 50° to 80° Celsius under 5cm least top rainfall. It was also seen that light infection occurs in dry season and massive infection occur in wet season (Table 9 and fig 4.6). The environmental factors such as temperature and humidity might be suitable to survive pre parasitic stages of nematodes.
Table 3.9: Association between season and prevalence of gastrointestinal nematodes
| Season | ||||
| Variables | No. of examined samples | Positive samples | SD | Prevalence (%) |
| Dry | 25 | 10 | 0.5 | 40.00 |
| Wet | 25 | 12 | 0.509 | 48.00 |
Figure 3.6: Association between season and infection
In this study, the prevalence of different endoparasites was attributed to prevailing agro-climatic surroundings for examples, grazing of adult and young animals on poorly shattered land, overstocked animals. This gives an ideal path for developing host infestation of the host for endo-parasites spread clinically. Malnutrition might be cause of low immunity as indicated by greater nematodes infection rate in surveyed regions. The investigated livestock area has dependence on grazing on weakened range-lands. It has also been analyzed that cattle, goats and sheep graze using alike pasture because of lack of barriers.
Figure 3.7: Eggs of gastrointestinal nematodes in positive fecal sample
Figure 3.8: Eggs of nematodes in fecal samples
Figure 3.9: Larval stages of gastrointestinal nematodes in fecal sample
Figure 3.10: Adlut nematodes
- Discussion
Gastrointestinal nematodes are an important economic and clinical problem in the livestock industry. As according to several studies, the GIT nematodes are responsible for damage of yield producing small ruminant in many countries of the world (Demelash et al., 2006). Various features of helminth infestation have been discovered by many authors in diverse Pakistani zones (Raza et al., 2007, Ijaz et al., 2009; Khan et al., 2010; Farooq et al., 2012) and the record of prevalence is 25-92%. But the reported studies still have some extra species of helminths addition to Multan area, and difference in rate of different infection of helminths species was also observed in unlike parts of country.
The major GIT nematodes were present according to this study and 44% prevalence was recorded in sheep. At least one kind of GIT nematodes are involved to pasteurize the infected animals. However, the current finding is slightly different as compared to other findings in which prevalence of pure nematode infestations was (37.5%) from southern Punjab of Pakistan by Raza et al. (2014). In current study, there was comparatively higher prevalence of GINs to a former statement on the extensively managed system. This could be due to the available environmental conditionsthat support the infective larval stage of most nematodes in terms of extended existence and progress (Rossanigoand L. Gruner, 1995). Sheep graze on same pasture and that’s will be allowed by collective pasture system that leads to high prevalence.
The current studied prevalence was lower as compared to recorded by Pandit et al. (2003) and Raza et al. (2007), which were 81.17 and 62% respectively. In contrast to current findings, there are other results that were reported such as 16.4% (central region of ethiopia) (Bekele et al., 1992), 98.9% (region of Ethiopia) (Amenu, 2005) respectively. These differences might be due to size of sample taken, categories of methods used, and region dependent that is showing host ranges as well as climatic and biological diversity (Njau et al., 1990).
In present findings, the most dominant parasite was Haemonchus contortus (20%), then Trichostrongylus axei (14%) and mixed type of parasites are 10%. The results showed that the presence of nematodes are major ones which belongs to Trichuris, Haemonchus, and Nematodirus species.
Haemonchus contortus was the utmost widespread nematode discovered in current study. This finding approves with findings of Jatoi, Pakistan (Raza et al.,2012), Himachal Pradesh, India (Katoch,1999), and Bokova, Cameroon (Mbuhet al., 2008).
According to this study, the one of the obvious Gastrointestinal nematodes of small ruminants was also Trichostrongylus. These results coincides with the results of (Darzi et al 2004 Beveridge I, 1989) who reported that the H. contortus,T. circumcincta and Trichostrongylus spp were major GIT nematodes in Australia who infect sheep and goats. In crunnet findings Trichuris and Strongyloides are those species who were unwell characterized in the form of mixed type of infection. These results coincide with the results of (Asanji and Williams, 1987; Ahmed and Ansari, 1987; Njau, 1987; Guiomaraes and Walter, 1987; Uriarte and Valderrabno, 1989, Pal and Qayyum, 1993) who had already identified these various species of nematodes in different parts of the world.
The high prevalence of different parasitic species might be because of suitable climate conditions of Multan district so that parasites can be survived and transmitted. Therefore, there is extreme value of these GIT nematodes that leads to serious losses both directly and indirectly in the economy of many parts of the country.
The second major reason of high prevalence could be due to several species of nematode search reliable places surrounded by natural water reservoirs of the tobas because of lack of necessity of an intermediate host to complete their lifespan (Gulland and Fox, 1992), egg hatching and for the development of larvae.
Many parameters also been examined in this study to check nematode infections. These parameters include high egg counts, FAMACHA© 3-4 score, and fecal consistency and body condition score.BCS and weights of animals are used to determine proper health status and condition of sheep. Compared to eye assessment, this is very much easy and accurate with advantage of low cost and practicality. This method was described by many authors for to check both strength and nutritious status of sheep (Sakkinen, 2005; Ndlovu et al., 2007). BCS analysis is done to calculate fat developmentand muscling above and surrounded loin region of vertebrae (Russel, 1991).
The current study shows that there is greater parasite egg count in animals of poor BCS. This report agrees with the reports of Kanyari et al. (2009) and Tasawar et al. (2010) who confirmed that endo-parasites readily infect animals of lower body weight compared to those of higher body weight animals.
Simultaneous bacterial and parasitic infections cause body conditions to be poor. The infective stage of parasites is mainly due to poor immunological response resultant is greater infection susceptibility as compared to other groups. Nematodes produce eggs depends on host immunity because the good healthy animal causes egg suppression of host due to innate immunity. Therefore, nematodes management can be made possible by protein feeding and nutrition level. But here the disadvantage is only lack of specificity for parasitic infections.
The effective way to diagnose animals exposed to nematodiasis is FAMACHA© chart utilized by smallholders according to present study investigation. Recently, FAMACHA© score showed a strong positive correlation with egg per gram of feces (EPG). FAMACHA© score 1 was recorded in (58%) while 6% animals were very anemic as shown by FAMACHA© score 5. FAMACHA© score increases as the EPG increases (Sissay et al., 2007). Present research discovered that, infection rate of GIN was more in sheep which have pink and pink-white color of conjunctiva compared to red and red-pink conjunctiva colored animals. Similar findings are also reported by Seyoum et al.,2018 who concluded that mean egg count of pink & pink-white colored ocular conjunctiva was higher in animals with than those of red & red-pink ocular conjunctiva.One benefit of FAMACHA score structure is that there are five varied haematocrit including healthy, non-anemic, and severely anemic. Thus, there is easy to treat by adjusting steps according to worm season at any given time.
In the current findings, the effect of seasons on prevalence was significant. This study revealed that slight infection occurred in dry season and massive infection occurred in wet season. Prevalence of gastrointestinal nematodes was maximum in damp season with highest precipitation.Later, it reduced throughout the dry season due to increased number of nematode (L3) larvae during damp period. These findings agree with Desalegn, (2005), Ahmed, (2010), Beveridge et al., (1989) who reported that environmental conditions become advantageous at the start of rainy period in which infective larvae survive. The maturation of hypobiotic larvae is done due to continuous infection cycle between the host and pasture dependent conditions.
Many studies revealed that the infection levels can be determined by agroecology for parasites species. There was high prevalence of GIT helminthiasis through the year in variable categorized host and weather condition. Gastrointestinal nematode infection was most severe in warm, humid environment. In present study significant difference of larval development was also observed in dry season and wet season. There was higher prevalence in wet season than dry season. These present results were similar to record of western Ethiopia in which there a positive association of environmental factors with occurrence of GIT helminths belonging todiverse species of host was elaborated (Regassa et al., 2006).It may be due to hot climate or dry environment which leads to larval death on the pasture in summer season because the larva grows at optimal temperature of 50° and 80° Celsius and 5 centimeters rainfall.
The current investigation has shown that the prevalence of infection is highly related with age of host. It is revealed from age-wise results that level of infection is decreased among sheep having younger age. This result relates with Maqsood et al., (1996), (Diriba and Birhanu, 2013) and Darzi et al., (2004 who indicated that there is more chance of parasitic disease in young animals while immunity is developed in certain.
Presentanalysisare also comparable with the discoveries of Dagnachew et al. (2011) who described that the significant immunity is somehow related to small number of parasites in gastro-intestine of adult hosts. Thus, the host body infection is basically connected with age. Our results are also according to the results of Magona and Musisi (2002), Tariq et al. (2008) and Raza et al. (2007) who explained that there is significant risk of GIT infections according to age of animal and it is more prevalent in young goats compared to adults. Parallelconsequences are also presented by Tasawar et al. (2010) that nematode parasites mostly attack on younger animals than elder stage animals.
The low prevalence ratio among adults of this study might be because of immunological adulthood by way of the grownup animals. The acquired resistance is developed after recurrent acquaintance. Many studies have revealed this hypothesis that acquired immunity produce in older animals against GIT parasites (Gamble and Zajac 1992; Knox, 2000). Likewise, the higher prevalence in young age also been discussed by many authors (Gupta et al., 1976; Raza et al., 2007). There are many factors which affect helminths frequency such as educational level, financial volume of farmers, habits of grazing, appropriate anti-helminthic usage, and managing standards (Gadahi et al., 2009).
Summary
Sheep are the second most dominant specie in punjab. Sheep population have much importance because sheep industry is the source of a veriety of products like milk, meat and fur. Now a days this industry faces many problems due to many risk factors. One of among risk factors is parasitism. Nematodes are very harmful parasites which are responsible for the great economy losses to the world hence it is necessaryto overcome this problem. These parasites check the growth of animal and increase the mortality rate in animals like sheep. In this way these limiting factors minimize the overall production of livestock industry. Present work revealed that gastrointestinal nematode parasites are responsible for causing different health problems such as Anemia, gastric ulcer and weakness. The main objective of this work was to isolate and identify gastrointestinal nematodes in the gastrointestinal tract in sheep. The fecal sample have been collected from the rectum of sheep. These sheep were kept in three different sheep farms. A systemetic random sampling method was applied to choose study animals. The fecal samples were stored in cool place. For the investigation of epidemiology of gastrointestinal nematodes fecal samples were examined. Some other methods such as direct microscopic examination, centrifugation floatation technique and sedimentation techniques were also used to investigate fecal sample. These fecal samples was categorized as positive and negative in respect to presence or absence of parasitc eggs respectively. After fecal sample examination, identification of the eggs or cysts were made on the basis of morphology and size of eggs. Present study proved that overall prevalence of gastrointestinal nematodes parasites in sheep is 44%. Present study showed that Haemonchos contortus is most prevalent specie in Multan area.
It was also noted that early diagnosis of this parasite is extremely important to stop its infectious effects and productivity losses to sheep industry. Results of present study showed that Fecal egg count (FEC) and fecal occult blood(FOB) tests are useful for the investigation of H.contortus infection earlier from day 11. According to crunnet study FAMACHA is considered as good indicator for Haemonchosis and have correlation with fecal egg count.
The second aim of crunnet study was to investigate and find the nature of health issues due to these parasites. It was also found that the use of morbidity parameters like high egg count, FAMACHA chart, body condition score, and fecal consistency in examining nematode infections play important role. Present study also showed that there is some association between gastrointestinal nematode parasites and rsik factors. These risk factors are age, season, breed and sex of host. It was also realized that parasitic stages of parasites are also play important role in epidemiology of these parasites. Present work explained that the younger sheep or lambs are more susceptible for parasitic infection as compared to adult’s sheep.Crunnet results showed that parasitic infection is maximum in female sheep and minimum in male individals. It was also noted that wide range of anthelmintic classes are available but they provide little effectiveness. However, many non-chemical strategies are also helpful to control haemonchosis. For statistical analysis simple mean, percentage and standard deviation was applied.
Conclusion
It was concluded that high prevalence of helminths infection is present in Multan area. The observation of current study revealed that gastrointestinal nematodes were most dangerous endoparasites in sheep. Among all gastrointestinal nematodes, the most widespread spp found in study area was Haemoncus contortus. These parasites act as limiting factor in livestock industry as well as reduced the growth rate in sheep. In the present study the prevalence of these parasites was 44% which showed that sheep population face great health issues due to these nematode parasites. Present study provides the information about high risk helminths infection which is associated with low education level of farmers. According to this study, mostly animals (sheep) were parasitic infected especially those sheep which graze on dirty pastures. Data of this study suggested that good grazing management is necessary for control of GIN. In present work, It is confirmed that farmers can minimize the rate of parasitic infection by adopting two main types of grazing strategies which they classify as defensive or offensive. It was also proved that Protein supplementation diet is beneficial in many cases for reducing caterpillar burdens and FEC in sheep. We can improve health status of sheep by adopting all preventive measures and by using wormicide drugs.
Recommendations
1: Review and interpret medical litrature for the awareness about risk factors that are responsible for diseases in animals.
2: Summarize a survey that assesed issues regarding to health of livestock.
3: Offer specific guidance to minimize risks associated with parasitic infection.
4: Using advance diagnostic tools for detection of specific parasitites.
5: It is recommended to adopt two main types of grazing strategies which they classy as defensive or offensive.