Molecular investigation of Anaplasma species in sheep from Heilongjiang Province, northeast China identified four Anaplasma species and a novel genotype of Anaplasma capra.

Anaplasmosis poses a great threat to the livestock industry and human health in most tropical and subtropical regions of the world. This study investigated the presence of Anaplasma in sheep from Heilongjiang Province, northeastern China. A total of 341 blood samples were detected by PCR with species-specific primers based on the msp4 gene of Anaplasma ovis, 16S rRNA gene of Anaplasma phagocytophilum and Anaplasma bovis and gltA gene of Anaplasma capra. The results showed that Anaplasma infection was found in 103 (30.2%) of 341 sheep. The infection rates were 2.6%, 8.8%, 15.8% and 10.0% for A. ovis, A. phagocytophilum, A. bovis and A. capra in sheep, respectively. Co-infection involving two Anaplasma species was found in 25 sheep (8.0%), which were usually A. phagocytophilum and A. bovis (72.0%). Co-infection involving A. phagocytophilum, A. capra, A. ovis with zoonotic potential, was found in one sheep. Sequence analysis revealed that the isolates of A. ovis, A. bovis and A. phagocytophilum identified in sheep were closely related to those previously reported in ticks and other animal hosts. Phylogenetic analysis showed that A. capra could be classified into two distinct clusters based on the gltA gene and the isolates identified in sheep from this study were clustered in the A. capra genotype II, which was clearly distinct with the human isolates. The findings in this study report four Anaplasma species and a novel A. capra genotype in sheep from northeastern China, and improve our knowledge of Anaplasma, contributing to the control of ovine anaplasmosis.

Molecular survey and characterization of a novel Anaplasma species closely related to Anaplasma capra in ticks, northwestern China.

BACKGROUND: Anaplasma spp. are tick-transmitted bacteria that infect a wide variety of wild and domestic animals. These pathogens exhibit a high degree of biological diversity, broad geographical distribution, and represent a serious threat to veterinary and public health worldwide. RESULTS: A novel Anaplasma species was identified in Haemaphysalis qinghaiensis (Ixodidae) in northwestern China and was molecularly characterized by comparison of 16S rRNA, gltA, and groEL gene sequences. Of the 414 samples tested, 24 (5.8%) were positive for this Anaplasma species. On the basis of the 16S rRNA gene, this organism has been found to be closely related to and exhibit the highest sequence similarity with A. capra (99.8-99.9%) that was identified in goats and humans in northern China, but was distinct from other known Anaplasma species. Sequence analysis of the gltA and groEL genes revealed that this Anaplasma species was distinct from A. capra considering the lower sequence identity (88.6-88.7% for gltA and 90.6-91.0% for groEL) and a divergent phylogenetic position. Therefore, we described this Anaplasma species as A. capra-like bacteria. CONCLUSIONS: The present study reports a potential novel Anaplasma species closely related to A. capra in H. qinghaiensis in northwestern China. The zoonotic potential of A. capra-like bacteria needs to be further determined.