Prevalence of Trypanosoma evansi trypanosomosis in young camels in West Niger

Abstract

An epidemiological survey was carried out in the pastoral area of West Niger to compare Trypanosoma evansi prevalence in young and adult camels. In total, 233 camels of all ages and both sexes were sampled in two regions with different ecological and climatic characteristics: the first one in the North (Ingall and Ighazer) was a dry and grassy valley; the second one further down south (Tchintabaraden and Abalak) was wetter, with dunes containing many ponds with trees. The microhematocrit centrifugation technique (MHCT) and card agglutination test for trypanosomosis (CATT evansi) were used to determine the prevalence. MHCT showed low sensitivity (only one positive case), whereas CATT evansi revealed a total prevalence of 12.0%. Seropositivity varied with the regions and seasonal herd moves (P < 0.001). Camels established in the Northern region were less infested than those in the Southern one (11.4 vs. 29.4%, respectively). Camels moving between both regions were the least affected (3.2%). All age groups were infested with no significant statistical difference, in particular between less than one-year old and older camels (6.9 and 13.7%, respectively). Four camel calves less than one year of age were seropositive: one was 11-months old and the other three less than two-months. Seropositivity could originate from an active infestation or from colostral IgG. Further studies are needed to specify whether infestation of camel calves less than two-months old is or not active by analyzing the immune status of camel dams and/or using a sensitive technique for Trypanosoma serological detection.