Prevalence of Cryptosporidium in pigs in China: A systematic review and meta-analysis

Cryptosporidium is an important zoonotic parasite that can infect a variety of hosts, including pigs and humans, through water and food. Many studies on Cryptosporidium infection in pigs have been reported worldwide. However, the meta-analysis of Cryptosporidium infection in pigs in China has not been published. This study retrieved articles related to Cryptosporidium in pigs in China by using four databases: Chinese National Knowledge Infrastructure (CNKI), PubMed, VIP Chinese journal database and Wanfang Data. We retrieved 40 studies related to Cryptosporidium infection in China, and those articles were harvested from the inception to 1 January 2020. We estimated that the overall prevalence of pigs with Cryptosporidium in the selected period was 12.2% (4,349/30,404). In the sampling year subgroup, the prevalence rate after 2010 was the lowest at 8.7% (2,087/18,100). In Northern China, the Cryptosporidium prevalence was 47.9% (34/71). By contrast, the prevalence of Cryptosporidium in Southwestern China was only 6.9% (778/6,445). The infection rate of Cryptosporidium in diarrhoea pigs of 15.6% (74/384) was higher than that in non-diarrhoea pigs at 10.8% (378/2,840). Among the four age groups, the prevalence of weaning pigs of 16.2% (530/3,243) was the highest, and the difference was significant (p < .05). The prevalence of Cryptosporidium in extensive farming was 25.7% (660/3,121), which was significantly higher than in intensive farming 8.7% (566/6,336), and the prevalence of infection was related to the farming modes (p < .05). We also analysed the impact of different geographic factor subgroups (longitude, latitude, precipitation, temperature, humidity, climate and altitude) on the prevalence of pigs. The results showed that cryptosporidiosis was widespread in pigs in China. We suggest that appropriate control schemes should be developed according to the differences in breeding patterns and geographic conditions in different regions, and effective management measures should be developed to reduce the spread between pigs.