title: Detection of Trypanosoma lewisi from wild rats in Southern China and its genetic diversity based on the ITS1 and ITS2 sequences.
abstract: Trypanosoma lewisi has widely been considered as a non-pathogenic rat trypanosome. However, more and more cases of humans infected with T. lewisi have been reported around the world, indicating that it can infect humans in some undetermined circumstances. Quick and sensitive diagnosis of infection by T. lewisi is important for both treatment of patients and epidemiological studies of this parasite. In this paper, three methods i.e. wet blood smear (diagnosis by microscopy), PCR and LAMP were used to detect T. lewisi from 238 wild rats (Rattus norvegicus) collected from the field in Huadu, Guangdong province, China. Infection rates of these samples detected by the 3 methods was 6.7% (16/238), 12.6% (30/238), and 18.9% (45/238), respectively. LAMP could detect all samples shown positive by microscopical observation of wet smear and by single PCR indicating good potential for application in the detection of T. lewisi. So far as we know, this is the first report of the LAMP method being used to detect T. lewisi in wild rats. The specific T. lewisi LAMP primers were able to amplify the target fragment from the genomic DNA of 19 T. lewisi strains isolated from Huadu, Guangdong province (n=16), Changchun, Jilin province of China (n=1) and from Thailand (n=2). Based on the analyses of ITS1 (internal transcribed spacer 1) and ITS2 sequences, these 19 strains show a very close genetic relationship with over 96-97% similarity to the other corresponding sequences of T. lewisi published in Genbank. Phylogenetic trees of the species in the subgenus Herpetosoma were constructed, based on the ITS1 and ITS2 sequences, and these results also indicate that they are closely related and in the same clade.
authors.affiliation: Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences, and Key Laboratory of Tropical Diseases Control, Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510275, PR China.
authors.forename: Hai-Jun
authors.initials: HJ
authors.lastname: Tang
authors.forename: You-Gen
authors.initials: YG
authors.lastname: Lan
authors.forename: Yan-Zi
authors.initials: YZ
authors.lastname: Wen
authors.forename: Xi-Chen
authors.initials: XC
authors.lastname: Zhang
authors.forename: Marc
authors.initials: M
authors.lastname: Desquesnes
authors.forename: Ting-Bao
authors.initials: TB
authors.lastname: Yang
authors.forename: Geoff
authors.initials: G
authors.lastname: Hide
authors.forename: Zhao-Rong
authors.initials: ZR
authors.lastname: Lun
mesh_terms: D000818:Animals; D001769:Blood / Q000469:parasitology; D002681:China; D016054:DNA, Protozoan / Q000235:genetics*; D021903:DNA, Ribosomal Spacer / Q000235:genetics*; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D051381:Rats; D012680:Sensitivity and Specificity; D013785:Thailand; D014350:Trypanosoma lewisi / Q000235:genetics* / Q000302:isolation & purification; D014352:Trypanosomiasis / Q000469:parasitology* / Q000662:veterinary
chemical_list: D016054:DNA, Protozoan; D021903:DNA, Ribosomal Spacer