Molecular Characterization of Entamoeba spp. in Pigs with Diarrhea in Southern China

Simple Summary China is an important country in the world for pig breeding and pork consumption, yet only two provinces have reported Entamoeba spp. infections. In this study, fecal samples of pigs with diarrhea were collected from three provinces in southern China, and Entamoeba spp. infection was detected by nested PCR. The results showed that the total infection rate was 58.4%. Entamoeba polecki and Entamoeba suis were detected. The ST1 and ST3 subtypes of Entamoeba polecki were detected, and a relatively serious mixed infection was found, with the most common form of mixed infection being Entamoeba polecki ST1 + Entamoeba polecki ST3. These findings provide baseline data for preventing and controlling Entamoeba spp. infection in southwestern China. Entamoeba spp. is a common zoonotic intestinal protozoan that can parasitize most vertebrates, including humans and pigs, causing severe intestinal diseases and posing a serious threat to public health. However, the available data on Entamoeba spp. infection in pigs are relatively limited in China. To characterize the infection of Entamoeba spp. within pigs in southern China, 1254 fecal samples of diarrheic pigs were collected from 37 intensive pig farms in Hunan, Jiangxi and Fujian provinces and the infection of Entamoeba spp. was investigated based on the small subunit rRNA (SSU rRNA) gene. The overall infection rate of Entamoeba spp. was 58.4% (732/1254), including 38.4% (118/307) in suckling piglets, 51.2% (153/299) in weaned piglets, 57.9% (55/95) in fattening pigs and 73.4% (406/553) in sows, respectively. Moreover, age and the sampling cities in Jiangxi and Fujian provinces were found to be the key factors influencing the infection of Entamoeba spp. (p < 0.05). Two subtypes (ST1 and ST3) with a zoonotic potential of Entamoeba polecki and Entamoeba suis were detected in all age groups of pigs and all sampling areas, with the predominant species and predominant subtype being E. polecki (91.3%, 668/732) and E. polecki ST1 (573/668), respectively, and E. polecki ST1 + E. polecki ST3 (78.6%, 239/304) being the most frequently detected form of mixed infection. Severe Entamoeba spp. infection and zoonotic subtypes were found in this study, exposing a large public health problem in the study area, and strategies need to be implemented to eliminate the risk in the future.