Detection and Phylogenetic Characterization of Anaplasma capra: An Emerging Pathogen in Sheep and Goats in China

Abstract

Anaplasma capra is an emerging pathogen, which can infect ruminants and humans. This study was conducted to determine the occurrence of A. capra in the blood samples of sheep and goats in China. Using nested polymerase chain reaction (nested-PCR) targeting the gltA gene and conventional PCR targeting the heat shock protein (groEL) gene and the major surface protein4 gene (msp4), A. capra was detected in 129 (8.9%) of 1453 sheep and goat blood samples. The positive rate was higher in goats (9.4%, 89/943) than in sheep (7.8%, 40/510) (χ2 = 1.04, p > 0.05, df = 1). For sheep, A. capra was found in 17 sites from 2 provinces. The prevalence was 28.6% in sheep from Liaoning province, which was higher than in Henan Province (7.3%). For goats, A. capra was detected in 35 sites from 7 provinces. The prevalence varied from 0 to 19.4% in the goat sites examined. The prevalence rates were 19.4, 19.3, 10, 8.8, 6.8, 1.8, and 0% in goats from Guizhou province, Henan Province, Inner Mongolia Autonomous Region, Shanxi Province, Xinjiang Uygur Autonomous Region, Yunnan province, and Gansu province, respectively. Based on the analysis of the A. capra citrate synthase gene (gltA), two variants were identified. Variant I showed a high sequence similarity to the A. capra, which were previously reported in sheep, goats, Ixodes persulcatus, Haemaphysalis longicornis, Haemaphysalis qinghaiensis, and humans. Variant II was only found in Luoyang, Anyang, and Sanmengxia, of Henan province. To our knowledge, this is the first detection of this variant of A. capra in sheep and goat blood in China. Phylogenetic analysis based on groEL and msp4 genes showed that the Anaplasma sp. sequences clustered independently from A. capra and other Anaplasma species with high bootstrap values. We found A. capra DNA in sheep and goats in China, providing evidence that sheep and goats can be infected by A. capra. We also found that this zoonotic pathogen is widely distributed in China. This study provides information for assessing the public health risks for human anaplasmosis.

Novel variants of the newly emerged Anaplasma capra from Korean water deer (Hydropotes inermis argyropus) in South Korea

“…Notably, extensive genetic variation was detected in msp2. Consistent with our results, sequence variation at the studied gene markers has been reported previously among isolates from ticks, sheep and goats [12,[15][16][17][18][20][21][22][23][24][25]. Similarly, genetic variation is common in other Anaplasma species [40][41][42][43][44][45].…”

“…Epidemiological data for this pathogen in wildlife are lacking in Korea; however, our findings are similar to those obtained from wildlife (five takins, three Himalayan gorals, three Reeves's muntjacs, one forest musk deer and one wild boar) in China [24]. In addition, a low percentage of infection rate was reported cattle, sheep and goats in China, Sweden and Korea [15][16][17][18][19], indicating that A. capra has a broad host range. Occurrence of infection during the study period from 2015 to 2018 indicates the persistence of the infection in KWD, suggesting that the species may act as a reservoir for this pathogen.…”

“…Our genetic profiling results indicated that the newly generated 16S rRNA gene sequences shared a homology of > 99.5% with sequences of A. capra strains from humans, sheep, goats, cattle and ticks [12,15,16,18,20,22], suggesting that they likely are within the same species of bacteria [38,39]. Clustering of sequences named A. centrale from deer (Cervus nippon nippon) (GenBank: AB211164) and cattle (GenBank: AF283007) in Japan and from ticks (Haemaphysalis longicornis) in Korea (Gen-Bank: GU064903), as well as Anaplasma spp.…”

“…The provisional name Anaplasma capra was assigned after its initial characterization in goats (Capra aegagrus hircus) in China [12]. Later, it was isolated from sheep, goats and cattle in different geographical regions [15][16][17][18][19] as well as from various tick species (Haemaphysalis qinghaiensis, H. longicornis, Ixodes persulcatus) [12,[20][21][22][23]. Infection of A. capra was also reported in six wild animals in China including three takins (Budorcas taxicolor), two Reeves's muntjacs (Muntiacus reevesi) and one forest musk deer (Moschus berezovskii) [24].…”

Subclinical Infections of <i>Anaplasma phagocytophilum</i> and <i>Anaplasma bovis </i>in Dogs from Ibaraki, Japan

“…Anaplasmosis is a tick-borne disease caused by Anaplasma, and is a globally emerging disease in both humans and animals (1). The major species of Anaplasma include A. phagocytophilum, A. platys, A. centrale, A. marginale, A. bovis, A. ovis, and A. capra (2). In particular, A. phagocytophilum is an important pathogen that causes zoonotic life-threatening diseases, including human granulocytic anaplasmosis (HGA), tick-borne fever in ruminants, equine granulocytic anaplasmosis, and canine granulocytic anaplasmosis (CGA) (3)(4)(5).…”