title: Trypanosome infection in dromedary camels in Eastern Ethiopia: Prevalence, relative performance of diagnostic tools and host related risk factors.
abstract: 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.
authors.affiliation: 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, B-2000 Antwerp, Belgium; KU Leuven, Faculty of Bioscience Engineering, Department Biosystems, Kasteelpark Arenberg 30, B-3001 Leuven, Belgium. Electronic address: fikruregassa@yahoo.com.
authors.forename: Regassa
authors.initials: R
authors.lastname: Fikru
authors.affiliation: School of Veterinary Medicine, Wollo University, PO Box 1145, Dessie, Ethiopia.
authors.forename: Yimer
authors.initials: Y
authors.lastname: Andualem
authors.affiliation: College of Veterinary Medicine and Agriculture, Addis Ababa University, PO Box 34, Debre Zeit, Ethiopia.
authors.forename: Terefe
authors.initials: T
authors.lastname: Getachew
authors.affiliation: Institute of Tropical Medicine, Department of Clinical Sciences, Nationalestraat 155, B-2000 Antwerp, Belgium.
authors.forename: Joris
authors.initials: J
authors.lastname: Menten
authors.affiliation: Institute of Tropical Medicine, Department of Public Health, Nationalestraat 155, B-2000 Antwerp, Belgium.
authors.forename: Epco
authors.initials: E
authors.lastname: Hasker
authors.affiliation: College of Veterinary Medicine and Agriculture, Addis Ababa University, PO Box 34, Debre Zeit, Ethiopia.
authors.forename: Bekana
authors.initials: B
authors.lastname: Merga
authors.affiliation: KU Leuven, Faculty of Bioscience Engineering, Department Biosystems, Kasteelpark Arenberg 30, B-3001 Leuven, Belgium.
authors.forename: Bruno Maria
authors.initials: BM
authors.lastname: Goddeeris
authors.affiliation: Institute of Tropical Medicine, Department of Biomedical Sciences, Nationalestraat 155, B-2000 Antwerp, Belgium.
authors.forename: Philippe
authors.initials: P
authors.lastname: Büscher
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D002162:Camelus; D021901:DNA, Intergenic / Q000235:genetics; D016054:DNA, Protozoan / Q000235:genetics; D005002:Ethiopia / Q000453:epidemiology; D016133:Polymerase Chain Reaction; D015995:Prevalence; D016053:RNA, Protozoan / Q000235:genetics; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D012307:Risk Factors; D014352:Trypanosomiasis / Q000175:diagnosis / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary*
chemical_list: D000913:Antibodies, Protozoan; D021901:DNA, Intergenic; D016054:DNA, Protozoan; D016053:RNA, Protozoan; D012337:RNA, Ribosomal, 18S
keywords: Dromedary camel; Ethiopia; Prevalence; Risk factor; Trypanosoma evansi; Trypanosoma vivax; Trypanosomosis