Research Article: Molecular epidemiology and risk factors of Anaplasma spp., Babesia spp. and Theileria spp. infection in cattle in Chongqing, China

Date Published: July 15, 2019

Publisher: Public Library of Science

Author(s): Zuoyong Zhou, Kai Li, Yingying Sun, Junge Shi, Hexian Li, Yiwang Chen, Haoyue Yang, Xiao Li, Bi Wu, Xiaoxia Li, Zhiying Wang, Fangjun Cheng, Shijun Hu, Gordon Langsley.


Tick-borne pathogens (TBPs) seriously affect cattle production and can be economically damaging. The epidemiology of these organisms in the Chongqing municipality of China is not well described. This study aimed to investigate the prevalence and risk factors of TBPs including Anaplasma spp., Babesia spp. and Theileria spp. in cattle in Chongqing municipality. The results showed that 43.48% (150/345) of cattle were infected with at least one TBP, of which single infections were detected in 104 (30.14%), double infections in 34 cattle (9.86%) and triple infections in 12 (3.48%) of the cattle. The overall prevalence of Anaplasma spp., Theileria spp. and B. bigemina were 22.32%, 23.19% and 7.24%, respectively. Among these, the prevalence of A. bovis, A. central, A. phagocytophilum, A. platys, A. marginale, T. sinensisi and T. orientalis were 8.41%, 7.83%, 4.93%, 4.35%, 2.61%, 22.32% and 2.60%, respectively. We could not detect B. bovis, T. annulata, T. luwenshuni or T. uilenbergi in cattle. Cattle ≥1-year-old were more likely to be infected with Theileria spp. [adjusted odd ratio (AOR) = 2.70, 95% CI = 1.12–6.56)] compared with younger cattle, while cattle ≥1-year-old had reduced susceptibility to B. bigemina (AOR = 0.14, 95% CI = 0.03–0.60). Cattle living at higher altitude (≥500 m) were more susceptible to B. bigemina (AOR = 6.97, 95% CI = 2.08–23.35) and Theileria spp. infection (AOR = 1.87, 95% CI = 1.06–3.32). The prevalence of Theileria spp. on farms with cats was significantly higher than that without cats (AOR = 2.56, 95% CI = 1.12–5.88). Infection with A. bovis and A. central were significantly associated with A. phagocytophilum infection. Furthermore, there were significant associations between A. bovis and A. central infection, T. sinensisi and A. marginale infection, and B. bigemina and T. orientalis infection. This study provides new data on the prevalence of Anaplasma spp., Babesia spp. and Theileria spp. in cattle in Chongqing, and for the first time we reveal a possible relationship between the afore-mentioned pathogens, which will help in formulating appropriate control strategies for these pathogens in this area.

Partial Text

Tick-borne pathogens (TBPs) have always attracted the attention of researchers, not only for their damaging influence upon livestock production but also for their public health threat [1]. Among the tick-borne diseases, anaplasmosis, babesiosis and theileriosis are the most important and are distributed widely. These organisms affect cattle worldwide [2]. Till now, five Anaplasma pathogens (A. marginale, A. bovis, A. centrale, A. phagocytophilum, and A. platys) have been reported to cause bovine anaplasmosis, of which A. phagocytophilum has been shown to infect a variety of animals and humans [3–5]. Two mainly Babesia pathogens, Babesia bovis and B. bigemina, were found responsible for bovine babesiosis [6], and three species of Theileria including T. annulata, T. sinensis, and T. orientalis (also named T. sergenti) were the main causative agents of bovine theileriosis [7–10], and recently, T. luwenshuni has also been detected in blood samples from cattle and yaks [9].

For the first time, this systematic study investigated the epidemiology of Anaplasma spp., Babesia spp. and Theileria spp. infection in cattle in Chongqing, China. The infection rate of Anaplasma spp. in our study was lower than that reported in Algeria [5] and in Tunisia [16], but higher than that reported in northwest China [30]. The prevalence of A. bovis (8.41%) in cattle in Chongqing was higher than that of cattle reported in other locations, where the prevalence varied from 3.9% to 6.2% [5,16,18,30]. In contrast, the prevalence of A. centrale (7.83%) was lower than that of cattle in previous studies (range between 12.1%-39.4%) [5,11,16,31,32]. Compared to the high prevalence of A. marginale in cattle in Madagascar (89.7%), north-eastern Uganda (82.9%) [11], South Africa (57%) [31], Thailand (39.1%) [13] and in China (31.6%)[33], we demonstrated a relatively low infection rate of A. marginale (2.61%) in Chongqing. In addition, 4.93% of cattle tested positive for A. phagocytophilum in this study, which was similar to the positivity rate (5.3%) of this pathogen in white yaks [30]. A. platys infection in cattle was first reported in Algeria [4], while Ben et al. reported a prevalence of A. platys-like species (3.5%, 13/367) in cattle in Tunisia [34]. In this study, we noted a prevalence of A. platys (4.35%, 15/345) in cattle for the first time in Chongqing.

The results of the present survey indicated that infection of cattle with Anaplasma spp., Babesia spp., and Theileria spp. is widespread in Chongqing. We provide a possible relationship between afore-mentioned pathogenic infections, which will help in formulating appropriate control strategies for these pathogens in this area.