Potential Role Of Ornithodoros Moubata In African Swine Fever Epidemiology Along Kenya Uganda Border

Abstract

Development of strategies for control of African swine fever (ASF) requires an in depth investigation of risk factors for the disease transmission. Such factors include exposure of pigs to Ornithodoros moubata (O. moubata), the known vector for ASF. The cross sectional study used a random sampling approach where 640 pig keeping households were randomly selected. Data collection done using a questionnaire followed by blood sample collection from domestic pigs. The study used tick specific enzyme-linked immunosorbent assay (ELISA) test (rtTSGP1 ELISA) to quantify the prevalence of pig exposure to the ASF tick vector and assessed risk factor for exposure. The test involved the use of a recombinant form of omTSGP1 to screen for anti-tick antibodies in exposed pigs. The results showed that of 181 out of 1085 pigs sampled (17%) were exposed to tick bites. Kenyan side of Busia had the highest prevalence of exposed pigs (22%) compared to Ugandan side (10%). The odds of exposure in farms that did not control ticks was about twice compared to those that controlled ticks in Busia county but in Uganda tick control had no influence. The result further show that acaricide control and farmer education interpreted as level of awareness can lead to reduction in the risk of pig exposure to ticks. There was significant association between tick exposure and previous ASF like outbreaks on farms, with Chi-square (P<0.05) and (Cramer's V value of 0.079) interpreted as ticks could play a role in the ASF outbreaks in Uganda. This study established that the pigs in the study region are exposed to tick bites from O. moubata and therefore ticks present a risk for ASF maintenance and transmission. The study recommends a further sampling of ticks and analysis of ASF virus infection rate in the ticks followed by virus characterization to determine the extent of risk that the ticks portend.