title: Trypanosoma vivax is the second leading cause of camel trypanosomosis in Sudan after Trypanosoma evansi.
abstract: BACKGROUND
  This study was conducted in response to recurring reports from eastern Sudan of camel trypanosomosis that can no longer be treated by currently available trypanocidal drugs. One hundred and eighty-nine blood samples were obtained from camels in different herds and local markets in the western part of Sudan, and a cross-sectional study was carried out between December 2015 and February 2016 to identify the causative agents and possible circulating genotypes.
  
  
  RESULTS
  The prevalence of trypanosomes detected using the conventional parasitological techniques of Giemsa-stained blood smears, wet blood smears and the microhematocrit centrifugation technique (MHCT) was 7% (13/189), 11% (21/189) and 19% (36/189), respectively. However, a multi-species KIN-PCR targeting the ITS region revealed that the prevalence of Trypanosoma evansi was 37% (70/189), while that of T. vivax was 25% (47/189). Consequently, we used a T. evansi-specific PCR (RoTat1.2 VSG gene) to analyse the KIN-PCR-positive samples and a T. vivax-specific PCR (Cathepsin L-like gene) to analyse all of the samples. The prevalence of T. evansi was 59% (41/70), while the prevalence of T. vivax was 31% (59/189). Mixed infections were detected in 18% (34/189) of the samples. These results were further confirmed by sequencing and a phylogenetic analysis of the complete internal transcribed spacer (ITS) region of T. evansi and the TviCatL gene of T. vivax.
  
  
  CONCLUSIONS
  We conclude that T. vivax was newly introduced to the camel population and that T. evansi is no longer the single cause of camel trypanosomosis in Sudan. The presence of T. vivax in camels detected in this study is a challenge in the choice of diagnostic approaches, particularly serology, and PCRs. However, an analysis of drug resistance should be performed, and the genotypic variation should be verified. To our knowledge, this is the first molecular study on T. vivax and mixed-infection with T. vivax and T. evansi in Sudanese camels.
authors.affiliation: Department of Pathology, Parasitology and Microbiology, College of Veterinary Medicine, Sudan University of Science and Technology, P.O. Box 204, Khartoum, Sudan. ehabmssd7@gmail.com.|National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, 080-8555, Japan. ehabmssd7@gmail.com.
authors.forename: Ehab
authors.initials: E
authors.lastname: Mossaad
authors.affiliation: Faculty of Veterinary Medicine, University of Khartoum, P.O Box 32, Khartoum-North, Sudan.
authors.forename: Bashir
authors.initials: B
authors.lastname: Salim
authors.affiliation: National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, 080-8555, Japan.|Research Center for Global Agromedicine, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, 080-8555, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Suganuma
authors.affiliation: National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, 080-8555, Japan.
authors.forename: Peter
authors.initials: P
authors.lastname: Musinguzi
authors.affiliation: Tsetse and Trypanosomosis Control Department, Central Veterinary Research Laboratory, Animal Resources Research Corporation, Ministry of Livestock, Fisheries and Rangelands, Khartoum, Sudan.
authors.forename: Mohammed A
authors.initials: MA
authors.lastname: Hassan
authors.affiliation: Faculty of Veterinary Medicine, University of Khartoum, P.O Box 32, Khartoum-North, Sudan.
authors.forename: E A
authors.initials: EA
authors.lastname: Elamin
authors.affiliation: Department of Pathology, Parasitology and Microbiology, College of Veterinary Medicine, Sudan University of Science and Technology, P.O. Box 204, Khartoum, Sudan.
authors.forename: G E
authors.initials: GE
authors.lastname: Mohammed
authors.affiliation: Department of Pathology, Parasitology and Microbiology, College of Veterinary Medicine, Sudan University of Science and Technology, P.O. Box 204, Khartoum, Sudan.
authors.forename: Amel O
authors.initials: AO
authors.lastname: Bakhiet
authors.affiliation: National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, 080-8555, Japan.|Research Center for Global Agromedicine, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, 080-8555, Japan.
authors.forename: Xuenan
authors.initials: X
authors.lastname: Xuan
authors.affiliation: Department of Pathology, Parasitology and Microbiology, College of Veterinary Medicine, Sudan University of Science and Technology, P.O. Box 204, Khartoum, Sudan.
authors.forename: Rawan A
authors.initials: RA
authors.lastname: Satti
authors.affiliation: Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, 080-8555, Japan.
authors.forename: Noboru
authors.initials: N
authors.lastname: Inoue
mesh_terms: D000818:Animals; D002162:Camelus / Q000469:parasitology*; D019411:Clinical Laboratory Techniques / Q000379:methods; D016000:Cluster Analysis; D003430:Cross-Sectional Studies; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D010274:Parasitology / Q000379:methods; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D015995:Prevalence; D017422:Sequence Analysis, DNA; D013397:Sudan / Q000453:epidemiology; D014345:Trypanosoma / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D014353:Trypanosomiasis, African / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary*
chemical_list: D016054:DNA, Protozoan; D021903:DNA, Ribosomal Spacer
keywords: Dromedary camels; Sudan; Trypanosoma evansi; Trypanosoma vivax; Trypanosomosis