The prevalence and risk factors for hydatidosis in man, sheep and goats in northwesternTurkana district, Kenya
Abstract
Hydatidosis is a cyclo-zoonotic disease caused by larval stages of the parasitic tapeworms
of the genus Echinococcus. The disease is a public health importance among the Turkana
pastoral community. The previous estimates of hydatidosis prevalence in livestock in
northern Turkana have recorded inconsistent estimates over time because they depended
on slaughter-house data. The socioeconomic aspects of hydatidosis including knowledge,
attitudes and practices (KAP) that favour the transmission of the disease in endemic setting
are inadequately studied.
The objectives of the present study were to estimate the prevalence of hydatidosis in man,
sheep and goats and assess level of agreement between ultrasonography and Enzyme
Linked Immunosorbent Assay (ELISA) tests. Others were to assess the risk factors
associated with the disease and map out the prevalence in the study area.
The study was carried out in northern part of Turkana District, conveniently stratified into
three regions: Oropoi, Mogilla and Kibish. A total of 93 sheep, 467 goats and 982 people
were screened for hydatid cysts by ultrasonography. In this study, blood samples were
collected from the animals screened by ultrasound and serum separated for laboratory
analysis. ELISA test was applied to all; the sera from the livestock in laboratory analysis.
Twelve dogs were sacrificed and postmortem examination carried out in order to assess the
worm burden. The potential risk factors associated with the hydatid disease in man and his
livestock were assessed using questionnaires, observations and interviews to 61 household
heads. Global Positioning System (GPS) was used to take co-ordinates of the sampled
points and the adakaar locations.
The results showed that 4.3%, 1.5% and 1.6% of sheep, goats and human screened were
positive for hydatidosis, respectively using ultrasonography. The ELISA results showed
that 81% and 37% of sheep and goats were infected, respectively. The computed Kappa
statistic was 0.02 indicating that the two tests did not agree well. There was mild to
moderate infections in dogs with Echinococcus granulosus and all of them had Taenia
hydatigena worms on postmortem examination.
The potential risk factors associated with hydatidosis were analyzed in the multivariate
analysis. The independent variable which was significantly (P<0.05) associated with the
outcome of the hydatid disease in human was the clan. Other factors analyzed in this study
were not significant though their contributions towards high infection rate were observed
in the univariate analysis. The region and presence of a dog in the household were the
potential risk factors that significantly predicted outcome of hydatidosis in sheep in the
multivariate analysis. Three most important potential risk factors associated with
hydatidosis in goats in the analysis were; region, the number of goats, and the number of
camels slaughtered in ceremonial festivities. Thematic maps of the sampled locations,
prevalence of hydatidosis in man and the three species of domestic livestock have been
produced.
Based on the findings of this work, Echinococcus granulosus cycle is still going on in
Turkana despite intervention measures .which are in place. Overall, the prevalence of
hydatid disease in humans has gone down except in some specific areas including Nanam
and Kaikor locations of northern part of Turkana District. In sheep and goats there was
little change in prevalence of hydatid disease. Further research is recommended on the
Turkana pastoralists clan differences and their contribution to the transmission cycle of the
hydatid disease.
Citation
Master of Science in Veterinary Epidemiology and EconomicsPublisher
Department of Public Health, Pharmacology and Toxicology, University of Nairobi, Kenya