Molecular identification of trypanosoma species infecting dogs in nigeria by analysis of partial internal transcribed spacer-1 of RRNA gene

Abstract

Trypanosomosis is becoming a major health challenge to dogs in the sub-Sahara Africa including Nigeria, but minimal reports are available on the molecular characteristic of trypanosomes infecting dogs in Nigeria. We characterized trypanosomes detected in naturally infected dogs by PCR and sequences analysis of the partial region of the trypanosomes internal transcribed spacer-1of ribosomal RNA (ITS1 rRNA). Animals presented to the University of Nigeria Veterinary Teaching Hospital (UNVTH) in Nsukka, Nigeria for examination and treatment were sampled for laboratory tests. DNA was extracted from 21 blood samples obtained from dogs that were confirmed positive for trypanosome infection by microscopy. ITS-1 was PCR amplified and sequenced bi-directionally. Sixteen samples have good bands, though one of them had unreadable sequence. Analyses of the sequence data by BLAST search on NCBI identified T. congolense, T. brucei gambiense, and T. evansi in 4.8, 4.8, and 91.4%, respectively, from the analysed samples from the infected dogs. Although the top BLAST hits for T. brucei group were due to T. evansi and T. b. gambiense, there is not enough discriminatory power in ITS-1 to distinguish subspecies. The aligned sequences of the trypanozoon were less polymorphic. Phylogenetic trees inferred by unweighted pair group method with arithmetic mean (UPGMA) algorithms separated trypanozoon group from the T. congolense into two distinct clades. In conclusion, this study suggests that the trypanozoon group of trypanosomes cause more canine trypanosomosis in the study area and suggests inclusion of dogs in strategic planning for control and eradication of trypanosomosis in sub-Sahara African countries.