Background: African animal trypanosomosis, transmitted cyclically by tsetse flies or mechanically by other biting
flies, causes serious inflictions to livestock health. This study investigates the extent of non-tsetse transmitted animal
trypanosomosis (NTTAT) by Trypanosoma (T.) evansi and T. vivax in domestic animals in the tsetse-free regions of
Northern Ethiopia, Afar and Tigray.
Methods: A cross sectional study was conducted on 754 dromedary camels, 493 cattle, 264 goats, 181 sheep,
84 donkeys, 25 horses and 10 mules. The microhaematocrit centrifugation technique was used as parasitological
test. Plasma was collected for serodiagnosis with CATT/T.evansi and RoTat 1.2 immune trypanolysis (ITL) while buffy
coat specimens were collected for molecular diagnosis with T. evansi type A specific RoTat 1.2 PCR, T. evansi type B
specific EVAB PCR and T. vivax specific TvPRAC PCR.
Results: The parasitological prevalence was 4.7% in Tigray and 2.7% in Afar and significantly higher (z = 2.53,
p = 0.011) in cattle (7.3%) than in the other hosts. Seroprevalence in CATT/T.evansi was 24.6% in Tigray and 13.9% in
Afar and was significantly higher (z = 9.39, p < 0.001) in cattle (37.3%) than in the other hosts. On the other hand,
seroprevalence assessed by ITL was only 1.9% suggesting cross reaction of CATT/T.evansi with T. vivax or other
trypanosome infections. Molecular prevalence of T. evansi type A was 8.0% in Tigray and in Afar and varied from
28.0% in horses to 2.2% in sheep. It was also significantly higher (p < 0.001) in camel (11.7%) than in cattle (6.1%),
donkey (6%), goat (3.8%), and sheep (2.2%). Four camels were positive for T. evansi type B. Molecular prevalence of
T. vivax was 3.0% and was similar in Tigray and Afar. It didn’t differ significantly among the host species except that
it was not detected in horses and mules.
Conclusions: NTTAT caused by T. vivax and T. evansi, is an important threat to animal health in Tigray and Afar. For
the first time, we confirm the presence of T. evansi type B in Ethiopian camels. Unexplained results obtained with
the current diagnostic tests in bovines warrant particular efforts to isolate and characterise trypanosome strains that
circulate in Northern Ethiopia.