Gastrointestinal Parasitism in Goats and Role of Seasonal Changes on Their Prevalence: A Study of Nepal

Goat farming is the good source of income for people living in countryside, Nepal. This occupation supports socioeconomic living of many people in developing countries. Gastro-parasitic infections in goats can decrease the meat supply in a country where demand of goat meat is ever increasing. The objective of this study was to identify the gastrointestinal parasites in feces of goats and impact of seasonal changes on their prevalence. This is a cross-sectional study done on 212 goats from Kapilbastu, Nepal. For this study, feces of goats were collected during summer and winter and observed microscopically to find the causative organisms. The result showed the helminths from trematode (22.22%), cestode (12.5%) and nematode (65.27%) caused heavy gastrointestinal infection in 144 microscopically positive samples taken from Kapilbastu, Nepal. The major helminths were Toxocara (16.66%), Oesophagnum (8.32%), Strongyloides (6.25%) and Trichuris (4.86%) among nematodes, Fasciola (15.97%) caused highest infection among trematode and Taenia (9.72%) among cestode. The prevalence of these infections was significantly higher during summer than winter. The higher prevalence of these helminths is the indication of supply contaminated food and water. Moreover, unawareness and ignorance about such diseases can increase the infection rate. Proper management of goat farm together with good cattle rearing training can increase the productivity.


INTRODUCTION
Goat production is an important occupation that supports socioeconomic life throughout the developing countries. Goat farming in Nepal is increasing every year due to increasing demand of meat and is considered potential small scale industry due to low capital investment and higher profit.
Usually, many Nepalese farmer living in countryside rear goats as a supplementary occupation and this solve their monetary problem to certain extent (Ghimire 1987).
Although goats are resistant to many diseases, gastrointestinal parasitic infections (GPI) can occur mainly due to subtropical climate and poor management. Poor management and unsanitary habitats can lead to several infections which ultimately reduces meat production from goats. GPI affect millions of livestock worldwide causing heavy economic loss. Furthermore, many studies show seasonal changes can affect the growth rate and prevalence rate GPI in goats (Nwosu et al., 2007, Sukupayo andRayamajhi 2018). Besides seasonal changes, global warming and increasing environmental pollution have aided the spread of parasitic diseases.
Among parasitic diseases, helminths are the commonly occurring parasites that affect survival and productivity of these animals. Gastrointestinal (GI) nematodes rank highest on global index with Haemonchus contortus on top (Perry et al., 2002). Animals are exposed to massive helminths infection when they are maintained in an unhygienic, dark, congested and poorly kept ranches and also when fed with contaminated food and water. The goats suffering from GPI show reduced feed intake and alteration of gastrointestinal motility leading to diarrhea. This has negative impact on host metabolism causing the reduced protein and energy retention, and disturbed mineral and water balance (Blackburn et al 1991). The most common intestinal helminths causing GPI in goats are Trichostrongylus spp, Heamonchus spp, Oesophagostumum spp, Fasciola spp, Bunostomum spp, Trichuris spp, etc. The larva of intestinal helminth is released after the host ingests the eggs. The larva penetrates the interior part of small intestine for about 2-10 days before moving to the caecum where it moults to adult (Hunter HJB 1994).
Therefore, the present study aimed to identify the prevalence and risk factors associated with GPI in goats in Kapilbastu, Nepal. Knowing the prevalence and risk factors can help to make appropriate control program. This can also serve as reference to other farms and villages and suggest them goat management and elimination of parasitic infections.

Study Area
The study took place in Kapilbastu which is one of the districts in province No. 5, Nepal. The district is situated at a height of 93 to 1,491 meters (305 to 4,892 ft) above sea level. It is situated at the Southern plains of Nepal at about 330 km west from capital city Kathmandu. The district covers a total of 1,738 km 2 area. The summer is hot with temperature above 27 °C and winter temperature remains below 15 °C. Due to extremely hot and cold climatic conditions, the animals suffer from different helminthic diseases.
Animal husbandry is the common occupation of the people living in the countryside of Nepal. They often raise animals like buffalo, cow, goats, sheep etc to support their living. Chicken and goat are the most common source of meat in Nepal. The demand of goat meat is often higher in most of the cities in Nepal which makes the price expensive.

Sample Collection and Storage
For this study, secondary data source was taken from a study done on goats by Tripathi RP at Tribhuvan University, Nepal in 2015. Fecal samples from goat were collected during summer and winter seasons. Total 212 samples were processed; 106 during summer and 106 during winter. Fresh rectal fecal samples of goats were collected in a labeled plastic bag and were fixed with potassium dichromate (2.5%) and then stored in refrigerator at 4 0 C for later examination by microscopy.

Laboratory Examination
The fecal goat samples were examined by differential floatation and sedimentation technique. The floatation technique was used for the detection of nematode and cestode eggs. Sedimentation technique is used for the detection of trematode eggs (Chaudhari et al., 2003 andGibbons et al., 2007). In sedimentation technique, the eggs get deposited at the bottom of the tube after the centrifugation with zinc sulphate solution. A drop of deposited material was taken on the slide by pipette and a drop of methylene blue was added. The smear was examined under a microscope at 4X and 10X.

Statistical Analysis
Data were analyzed by using chisquare (x²) test. A p-value of <0.05 was considered significant.

RESULTS AND DISCUSSION
Out of a total of 212 fecal samples processed through flotation and sedimentation technique, 144 (67.92%) samples showed the presence of helminthic eggs. This study showed the presence of various helminths from the classes trematode, cestode and nematode. Altogether 18 genera of helminths were observed i.e. 3 genera of trematodes, 2 genera of cestodes and 13 genera of nematodes. The overall prevalence percentage of each species is given in the following table 1.

Seasonal Prevalence of Helminth Parasites in Goats
Helminthic infection were higher 86 (81.13%) in summer than winter 57 (39.6%) out of 106 samples studied in each seasons.
Nematodes caused more infection than other classes. However, the seasonal prevalence of different genera during winter and summer were not found statistically insignificant (χ2= 3.749, p=0.065, not shown).

Seasonal Prevalence of Trematode in Goat
Among trematode class, Fasciola, Dicrocoelium and Paramphistomum were identified from goat feces. These organisms caused infection at higher rate in summer. Fasciola sp infection is the main agent of infection both during summer and winter. Other genera of trematode caused fewer infections (shown in Figure 1).

Seasonal prevalence of Cestode in goat
Taenia and Moniezia were the causative agents from class cestode. Taenia infection was higher during summer (5.55%) than winter (4.16%). Moniezia infection was also higher in summer but not a big difference than winter.

Figure 2. Seasonal prevalence of Cestodes in goat
Seasonal prevalence of Nematode in goat Nematodes were the main causative agent of parasitic infection in goats among all classes. Toxocara dominated the infection (8.33%) among all other genera both in summer and winter. Oesophagostomum was second major infection causing genera with prevalence rate of 4.16% both in summer and winter. Strongyloides, Trichuris, Capillaria and others also caused significant number of infections.

Table3.
Seasonal prevalence of Nematodes
Examinations of fecal samples revealed the prevalence of GI parasitic infections in goats throughout the year. During this study, there were considerable differences for the development and propagation of parasites depending on seasons. Moreover, summer season favors the spread GI parasites than winter (60.42%>39.6%).
Nematodes caused highest number of infections among all parasites; 38.88% in summer and 26.39% winter. Cestodes caused minimum number infections; 8.33% in summer and 4.17% in winter. All the classes of helminths identified during fecal examination showed higher prevalence during summer. In a study by Sukupayo and Rayamajhee (2018), nematodes were the highest occurring helminths followed by trematode and cestode and prevalence of GPI was also in accordance with our study. Factors responsible for this may be constant exposure to infections, rapid growth of infecting organisms and continuous deposit of infections on the pastures by adult animals as well as poor animal husbandry practices.
The prevalence rate of trematode seems higher for Fasciola, 8.33% in summer and 7.14% in winter. This prevalence rate is not a big difference depending on seasons. Also, Dicrocoelium prevalence was found but very few, 2.08% in summer and 1.38% in winter. Similarly, the present also found there was significant number cestode infection in goats. Paramphistomum was also noticed during the fecal examination but only during summer (2.775). Likewise, cestode consisted of genera Taenia and Moniezia. Among them, Taenia was the mojor threat with prevalence rate 5.55% rate in summer and 4.16% in winter. Besides, Moniezia sp also posed little prevalence in goats. The prevalence rate was 2.77%in summer and 1.40% in winter. Furthermore, various genera of nematode were identified in prevalence. Among the major threats were Toxocara with prevalence rate 8.33% both in summer and winter. Oesophagostomum also caused considerable number infections; 4.16% both in summer and winter.
Other main agents are Strongyloides, Trichuris and others. The prevalence caused by parasites like Toxocara, Oesophagnum and some others were almost the same both in summer and winter. The prevalence of nematodes was higher than our study in Meghalaya, India (Das et al 2017) Karki et al (2011) had closer results to our study.

CONCLUSION
In this study, helminths like trematode, cestode and nematode had major contribution gastro-parasitic infection in goats. Nematodes caused highest prevalence rate. Toxocara, Oesophagostomum, Trichuris etc from nematode, Fasciola from trematode and Taenia from cestode class had higher contribution.
Except, Toxocara and Oesophagostomum, all other parasites caused more infection during summer than winter. This higher Infections prevalence rate may due to poor hygienic conditions or contaminated water and fodder. Thus, those farmer rearing cattle like goats should get training on cattle rearing and management of their farm which can help to increase the productivity.