[Show abstract][Hide abstract] ABSTRACT: Background
Leishmaniasis is a vector-borne disease, which is still endemic in the west and northwest area of China. Canines are the major reservoirs of Leishmania, the etiological agent of human visceral leishmaniasis. Phlebotomus chinensis is the main transmission vector of zoonotic visceral leishmaniasis (ZVL).
In this study, rK39 dip-stick, ELISA and PCR methods were used to investigate the prevalence of canine leishmaniasis (CanL) in Beichuan County, Sichuan Province, China.
Among the 86 dogs which were included in the study, 13 dogs were positive using the dip-stick test (15.12%), while 8 dogs were positive using ELISA (9.30%) and 19 dogs were positive for PCR (22.03%). In total, 32 dogs were positive for one or more tests (37.21%). Interestingly, phylogenetic analysis based on the partial 7SL RNA fragment provided evidence that an undescribed Leishmania species, which is clearly a causative agent of CanL and human visceral leishmaniasis, does exist in China. This result is consistent with our previous study.
Our work confirmed that canine leishmaniasis is still prevalent in Beichuan County. Further control is urgently needed, as canine leishmaniasis is of great public health importance. The phylogenetic analysis based on 7SL RNA segment provides evidence for the existence of an undescribed Leishmania sp. in China.
[Show abstract][Hide abstract] ABSTRACT: Leishmaniasis is a geographically widespread disease, caused by protozoan flagellates of the genus Leishmania. This disease still remains endemic in China, especially in the west and northwest frontier regions. To date, the phylogenetic relationships among Chinese Leishmania isolates are still unclear, and the possible taxonomic diversity remains to be established. In this study, the ITS1-5.8S fragments of ten isolates collected from different foci in China were determined. To infer the phylogenetic relationships among them, seven sequences of Chinese Leishmania isolates retrieved from GenBank were also included. Both parsimony and Bayesian analyses reveal an unexpected but strongly supported clade comprising eight newly determined isolates, which is sister to other members of subgenus Leishmania. In combination with genetic distance analysis, this provides evidence of the occurrence of an undescribed species of Leishmania. Our results also suggest that (1) the isolate IPHL/CN/77/XJ771 from Bachu County, Xinjiang Uygur Autonomous Region is not Leishmania infantum but Leishmania donovani; (2) the status referring to an isolate MRHO/CN/88/KXG-2 from a great gerbil in Karamay as Leishmania turanica, formerly based on multilocus enzyme electrophoresis, is recognized; (3) an earlier finding demonstrating the L. donovani identity of isolate MHOM/CN/80/801 from Kashi city is corroborated; (4) the three isolates from eastern Jiashi County, Xinjiang Uygur Autonomous Region, causing desert type of zoonotic visceral leishmaniasis (see Wang et al., Parasitol Int (in press), 2010), belong to L. donovani instead of L. infantum. In addition, the results of this study make an important contribution to understanding the heterogeneity and relationships of Chinese Leishmania isolates, further indicating that the isolates from China may have had a more complex evolutionary history than expected.
Full-text · Article · Oct 2010 · Parasitology Research