Trypanosome infection in dromedary camels in Eastern Ethiopia: Prevalence, relative performance of diagnostic tools and host related risk factors
College of Veterinary Medicine and Agriculture, Addis Ababa University, PO Box 34, Debre Zeit, Ethiopia; Institute of Tropical Medicine, Department of Biomedical Sciences, Nationalestraat 155, Antwerp, Belgium; KU Leuven, Faculty of Bioscience Engineering, Department Biosystems, Kasteelpark Arenberg 30, Leuven, Belgium; School of Veterinary Medicine, Wollo University, PO Box 1145, Dessie, Ethiopia; Institute of Tropical Medicine, Department of Clinical Sciences, Nationalestraat 155, Antwerp, Belgium; Institute of Tropical Medicine, Department of Public Health, Nationalestraat 155, Antwerp, Belgium
A cross-sectional study was conducted in Chifra and Dewe districts of Afar region, Eastern Ethiopia, to determine the prevalence, agreement between diagnostic tests and host related risk factors of trypanosome infection in camel. An overall prevalence of 2%, 24.1%, 21.3%, 9.5% and 7.8% was recorded with respectively Giemsa stained thin blood smear, CATT/T. evansi, RoTat1.2 PCR, 18S PCR and ITS-1PCR in a cohort of 399 animals. Only one T. vivax infection was confirmed by TvPRAC PCR indicating T. evansi as the predominant species affecting camels in the study area. No single animal was positive when tested with T. evansi type B specific EVAB PCR. There was slight agreement between the CATT/T. evansi and the molecular tests. Among the PCR methods, RoTat 1.2 PCR yielded a significantly higher positivity rate compared to 18S PCR and ITS-1 PCR. There was no significant difference in the positivity rate observed in each gender of camels (p>0.05). The positivity rate was significantly higher in camels with poor body condition and in older animals when tested using the CATT/T.evansi or RoTat 1.2 PCR (p>0.05). Camels that tested positive with all tests had significantly lower PCV's (p<0.05). This study provides further evidence that T. evansi is endemic in the Afar region of Ethiopia. The latent class analysis indicated an estimate overall prevalence of 19% (95% CI: 13-28). Moreover, the model indicated low sensitivity of CATT/T. evansi (43%) and the PCR tests (39-53%) but higher specificity of the PCR tests (86-99%) and low specificity of CATT/T. evansi (80%). This study suggests that improved sensitivity and reliability of the tests would help diagnosis of trypanosomosis. Further studies are required to determine the prevalence of clinical disease and losses due to trypanosomosis. © 2015 Elsevier B.V.
animal parasitosis; Article; blood smear; cohort analysis; controlled study; cross-sectional study; diagnostic accuracy; diagnostic test; diagnostic test accuracy study; diagnostic value; dromedary; Ethiopia; female; host parasite interaction; infection risk; male; nonhuman; parasite identification; parasite prevalence; polymerase chain reaction; risk assessment; risk factor; sensitivity and specificity; serology; Trypanosoma evansi; Trypanosoma vivax; trypanosomiasis; Animalia; Camelidae; Camelus dromedarius; Trypanosoma evansi; Trypanosoma vivax