Zoonotic gastrointestinal helminths and hemoparasites of baboons in Tana River, Tsavo and Laikipia, Kenya
Maloba, Fredrick Chimoyi
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Zoonotic pathogens are among the most important causes of ill health in humans all over the world. In Kenya, the encroachment of wildlife habitats has led to increased interaction between humans and non-human primates especially baboons hence potential for zoonoses transmission. However, a risk analysis for these zoonoses had not been undertaken in Kenya. The current study aimed to investigate hemoparasites and gastrointestinal parasites of olive baboons (Papio anubis) at the human–baboon interface in Tsavo West National Park, Tana River Primate Reserve and Mutara Ranch in Laikipia County. Laikipia baboons were used to study hematological responses to helminth treatments and pathology. Questionnaire survey was conducted in Tana River and Tsavo on risk factors associated with zoonoses. Baboons were trapped in the wild, sampled for blood, feacal, ectoparasites and thoroughly examined physically. Blood smears were prepared and examined for hematology and haemoparasites. Uncoagulated blood was used for confirmation of haemoparasites with Polymerase Chain Reaction (PCR). Feacal samples were screened for helminth oocysts. Helminths detected included Oesophagostomum, Strongyloides, Trichuris and Enterobius with the highest frequencies being 80.5%, 77.8%, 27.5% and 14.8% respectively in the three study sites. Schistosoma mansoni was only detected in Tsavo baboons (2.1%). There was a significant difference in prevalence of the helminths among the three sites (P<0.05) with Laikipia having the highest frequencies followed by Tana then Tsavo. Infection intensities were light in all the study sites. Following treatment, all the leucocyte parameters did not change significantly (P<0.05) but there was a significant increase in erythrocyte indices (P<0.05) except MCV (P>0.05) though all were still within normal ranges. Hemoparasites were detected by PCR in Tsavo and Tana River baboons only and these included Hepatocystis kochi (90% and 87%), Babesia (10.8% and 16.7 %,), and Entopolypoides (8.7% and 5%) respectively. There was an association between H. kochi infection and lymph node enlargement as well as fever (χ2>3.84, df=1, P<0.05) in both Tana River and Tsavo baboons. Tissue pathology due to helminth revealed nodular lesions with epithelial necrosis due to Oesophagostomum in large intestines, lung fibrosis due to Strongyloides infection and intussusception attributed to Trichuris infection. Schistosoma mansoni infection revealed granuloma formation, parenchymal and periportal fibrosis in liver. Risk factors of zoonosis in Tsavo and Tana River included sharing of river water (6%, 76%), baboon crop raids (65% and 75.1%) and baboon livestock predation (92.9% and 91.8%), consumption of left overs from crop raids/ predation (66%, 19.8%), lack of knowledge of zoonoses (81% and 92%), monkey meat consumption (12% and 2%) respectively. Significant factors included baboon crop raids, left over consumption, and lack of knowledge on zoonosis (P<0.05) in both sites. There was a high interaction between humans and baboons which increased the risk of zoonoses transmission. Public education on zoonosis, training of health staff on zoonoses and improving compensation due to losses caused by baboons is highly recommended to reduce human-wildlife the interaction and potential for zoonoses transmission.