Prevalence of <i>Cryptosporidium</i> spp. in Yaks (<i>Bos grunniens</i>) in China: A Systematic Review and Meta-Analysis.

Abstract

<i>Cryptosporidium</i> spp., the causative agent of cryptosporidiosis, can infect a variety of hosts. So far, there has been limited information regarding <i>Cryptosporidium</i> spp. infection in yaks (<i>Bos grunniens</i>). Here, we performed the first systematic review and meta-analysis for <i>Cryptosporidium</i> spp. infection in yaks in China. To perform the meta-analysis, five databases (Chinese National Knowledge Infrastructure (CNKI), VIP Chinese journal database, WanFang Data, PubMed, and ScienceDirect) were employed to search for studies related to the prevalence of <i>Cryptosporidium</i> spp. in yaks in China. The total number of samples was 8,212, and the pooled <i>Cryptosporidium</i> spp. prevalence in yaks was estimated to be 10.52% (1192/8012). The prevalence of <i>Cryptosporidium</i> spp. in yaks was 13.54% (1029/5277) and 4.49% (148/2132) in northwestern and southwestern China, respectively. In the sampling year subgroups, the prevalence before 2012 (19.79%; 650/2662) was significantly higher than that after 2012 (6.07%; 437/4476). The prevalence of <i>Cryptosporidium</i> spp. in cold seasons (20.55%; 188/794) was higher than that in warm seasons (4.83%; 41/1228). In the age subgroup, the yaks with age < 12 months had a higher prevalence (19.47%; 231/1761) than that in yaks with age ≥12 months (16.63%; 365/2268). Among 12 <i>Cryptosporidium</i> spp. species/genotypes, the <i>C. bovis</i> had the highest prevalence. Moreover, the effects of geography (latitude, longitude, precipitation, temperature, and altitude) and climate on <i>Cryptosporidium</i> spp. infection in yaks were evaluated. Through analyzing the risk factors correlated with the prevalence of <i>Cryptosporidium</i> spp., we recommend that effective management measures should be formulated according to the differences of different geographical factors, in order to prevent cryptosporidiosis and reduce economic losses in yaks in China.