Prevalence and Risk Factors of Gastrointestinal Parasites in Sheep in Kajiado North Sub-county, Kenya

Abstract

Gastrointestinal parasitism (GIP) in small ruminants, particularly sheep and goats is the main cause of inestimable socio-economic losses globally. The parasites pose a serious threat to livestock production and the livelihoods of livestock keepers especially in developing countries like Kenya, which lie within the tropics where arid and semi-arid lands (ASAL) cover more than half of the total land area and droughts are frequent. Despite the magnitude of this problem, there is limited information on the prevalence of these parasites and the main factors that drive their epidemiology. The aim of this study was to assess the diversity and prevalence of GIP in sheep in Kajiado North Sub-county, Kajiado County, Kenya, as well as assess whether breed, age, sex, deworming regimes, season, and elevation play a significant role in the epidemiology of these parasites. A cross-sectional mixed research method (quantitative and qualitative) was used to assess the problem. The study was conducted between February and May 2023 focusing on Red Maasai, and Red Maasai x Dorper sheep crosses, the most common types of sheep within the study area. The study period covered two seasons (dry and wet) and 16 farms (high and low elevations). Faecal samples were collected from randomly selected sheep (<1 year and > 1 year), which were further categorized on the basis of gender (male, female), time interval between deworming and the time of faecal sapling (<3 months and > 3 months). Faecal samples were analysed for eggs and oocysts through the test tube floatation technique with saturated sodium chloride and sedimentation using 0.1% methylene blue for qualitative examination of coccidian oocysts and helminths eggs respectively. It further incorporated McMaster technique for faecal oocyst/ egg counting from faecal samples positive of GIP. The faecal samples that were positive for strongyle-type eggs and coccidia oocysts were further analysed for genera of nematodes by faecal sample culturing in an incubator of 27o C for 7 days after which the hatched larvae were harvested by Baermann’s technique using Lugol’s iodine solution for xiv nematodes identification and coccidia identification through sporulation using 2.5% potassium dichromate in an incubator of 27o C for 5 days respectively. A total of 640 samples were collected. Out of 640 samples, 584 (91.3%) were positive for one or more GIP. The study revealed the presence of strongyle-type nematode eggs (80%), Eimeria spp. oocysts (60.8%), and tapeworm eggs (5.2%) in the study area. The prevalence was significantly (p<0.05) higher in the wet season (93.6%) than in the dry season (89.3%). With respect to deworming, sheep dewormed less than 3 months before the faecal sampling date had a slightly higher prevalence (91.5%) than those dewormed >3 months before the sampling date (90.9%). GIP prevalence was higher in Red Maasai x Dorper crosses (92.6%) than the Red Maasai breed (89.5%). With respect to the age of the sheep, young sheep had a significantly (p<0.05) higher prevalence (98.1%) than old ones (89.9%). In terms of gender, ewes had a higher prevalence (91.5%) than the rams (90.9%), but the difference was not statistically significantly (p > 0.05). With respect to body condition, GIP prevalence was higher in sheep with good body condition score (BCS) (98.3%) than sheep with a poor (92.6%) and medium (88.9%) BCS. In addition, the prevalence was significantly (p<0.05) higher (94%) in sheep grazing on high elevation than those from low elevation (86.8%).