BackgroundAnaplasmosis is caused by obligate intracellular bacteria in the genus Anaplasma. These bacterial pathogens are transmitted by ticks and impact both human and animal health. This study was conducted to determine the prevalence and molecular characterization of Anaplasma spp. in ruminants sampled in Xinjiang, northwest China.MethodsA survey was performed in August 2012 in rural areas of six counties in Xinjiang province. A total of 250 blood samples from ruminants were collected and tested for the presence of Anaplasma spp. by PCR. Positive samples were genetically characterized based on the 16S rRNA and msp4 genes.ResultsThe results showed a high prevalence of Anaplasma spp. in ruminants, with at least three different Anaplasma species detected (A. phagocytophilum, A. bovis and A. ovis). The mean prevalence of single infection with each species was 17.6% (A. phagocytophilum), 4.8% (A. bovis) and 40.5% (A. ovis). Coinfection occurred in 20 (8.0%) animals. Phylogenetic analysis of the 16S rRNA gene of A. bovis and A. phagocytophilum revealed a higher degree of genetic diversity for the latter. The results for A. ovis showed genotypic variation among geographic regions in China. In addition, a closely related isolate to the canine pathogen A. platys was identified in ruminants.ConclusionsThis survey revealed a high prevalence of Anaplasma sp. infections in sheep and cattle in the northwestern border regions of China, indicating the potential risk of transboundary disease.
The application of anti-tick vaccine has been shown to be the most promising alternative strategy compared to the current use of acaricides that suffer from a number of serious limitations. The success of this method is dependent upon identification and cloning of potential tick vaccine antigens. Previously, we have cloned 21 positive clones (named from Hq02 to Hq22) by immunoscreening complimentary DNA (cDNA) libraries of Haemaphysalis qinghaiensis; however, some of those clones did not contain open reading frames (ORF). In this study, we amplified the entire sequence of Hq07 by using rapid amplification of the cDNA ends. Hq07 contains an ORF of 1,233 bp that encodes for 410 amino acid residues with a coding capacity of 47 kDa. Search of the cloned sequences against GenBank revealed that Hq07 is a calreticulin (CRT)-similar clone and designated HqCRT. Expression analysis by reverse transcription-polymerase chain reaction showed that this gene is ubiquitously expressed at different developmental stages and in different tissues of H. qinghaiensis. The gene was expressed as glutathione S-transferase-fused proteins in a prokaryotic system. Western blot analysis revealed that native HqCRT was secreted into their hosts by ticks during blood sucking. Vaccination of sheep with rHqCRT conferred protective immunity against ticks, resulting in 54.3% mortality in adult ticks, compared to the 38.7% death rate in the control group. These results demonstrated that rHqCRT might be a useful vaccine candidate antigen for biological control of H. qinghaiensis.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.