Do camel hippoboscids transmit camel trypanosomiasis in the tsetse-free region of northern Kenya?
Joel Bargul1,2, Kevin Kidambasi1,2, Mark Carrington3 and Daniel Masiga2
1Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology, P.O. Box 62000-00200 Nairobi, Kenya 2Animal Health Theme, International Centre of Insect Physiology and Ecology, P.O. Box 30772-00100 Nairobi, Kenya 3Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
Background:
There are no tsetse flies (known biological vectors of African trypanosomiasis) in the northern Kenya region under study, but camel trypanosomiasis is prevalent. Tabanids and Stomoxys spp are known to mechanically transmit trypanosomes. However, little is known about the role of camel hippoboscids in transmission of trypanosomiasis.
Objectives:
We aim to:
(i) determine prevalence of camel trypanosomiasis,
(ii) document trypanosome species associated with camels and hippoboscids, and
(iii) evaluate vectorial capacity of hippoboscids in disease transmission.
Methodology:
Hippoboscids (n>2400) and camel blood samples (n=249) were collected from Laisamis (northern Kenya) for molecular analysis through PCR to identify trypanosomes. Laboratory colony of hippoboscids was initiated to study their ability to transmit trypanosomes in mice.
Outcomes:
Only one camel was found to be positive for trypanosome infection by microscopy and the parasites were mouse-infective. The prevalence of camel trypanosomiasis by ITS1 PCR amplification was 40.96% (n=102/249). All positive samples were infected with Trypanosoma vivax. Mixed infections with T. vivax and T. evansi were detected in three camels (1.2%), while only one camel had both T. vivax and T. congolense. Further, we recorded infection prevalence of 45.3% (53/117) in hippoboscids and again, T. vivax was detected in all infected fly samples. Double (3/117) and triple infections (1/117) were observed consisting of T. vivax, with either T. evansi or T. congolense. Thus, T. vivax is the predominant cause of camel trypanosomiasis in northern Kenya. The ongoing experiments will determine whether hippoboscids could transmit disease pathogens in mice.