The infection and molecular characterization of Cryptosporidium spp. in diarrheic pigs in southern China.

Cryptosporidium spp. is recognized as an opportunistic zoonotic parasite that infects humans, wild and domestic animals, and is also a major cause of diarrhea-related disease in immunocompromised individuals, considered a global public health concern. Pig is considered as one of the reservoir hosts of Cryptosporidium spp. can transmit cryptosporidiosis to humans and other animals. However, limited studies on the distribution of Cryptosporidium spp. in diarrheic pigs have been published. Objective of the current study was to investigate the infection and species/genotypes of Cryptosporidium spp. from feces of diarrheic pigs in southern China. A total of 1254 fresh fecal samples were collected from 37 intensive pig farms in Jiangxi, Hunan and Fujian provinces, and were screened for Cryptosporidium spp. infection using a nested PCR assay targeted the small subunit rRNA (SSU rRNA) genes. The overall infection rate of Cryptosporidium spp. was 4.5% (57/1254), including 5.5% (17/307) in suckling piglets, 2.7% (8/299) in weaned piglets, 7.4% (7/95) in fattening pigs and 4.5% (25/553) in sows, respectively. In addition, two human-pathogenic species Cryptosporidium scrofarum (80.7%, 46/57) and Cryptosporidium suis (19.3%, 11/57) were identified. C. scrofarum and C. suis were observed in pigs tested in all age groups. Interestingly, a high colonization incidence of C. scrofarum (16/57) was observed in suckling piglets. This study revealed the prevalence and species of Cryptosporidium spp. in diarrheic pigs in three provinces of southern China, which suggested that diarrhea maybe not a direct factor affecting the prevalence of Cryptosporidium spp. in pigs. More prevention and control of this parasite in pigs should receive greater attention from farmers in investigated provinces.

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

A high genetic diversity of Enterocytozoon bieneusi in diarrheic pigs in southern China.

Enterocytozoon bieneusi is an important pathogen that is responsible for over 90% of documented cases of human microsporidiosis worldwide, causing a threat to public health and husbandry development. In immunocompromised patients, it can cause persistent diarrhoea, wasting diathesis and malabsorption and developing life-threatening chronic diarrhoea. However, there was little information on the prevalence and multilocus genotypes of E. bieneusi in diarrheic pigs in three provinces of southern China. In this study, 1254 faecal samples of diarrheic pigs were collected from 37 pig farms in Hunan, Jiangxi, and Fujian provinces in southern China, and were investigated the prevalence and genotypes of E. bieneusi by nested polymerase chain reaction (PCR) based on the internal transcribed spacer (ITS) region of the nuclear ribosomal DNA gene. The overall prevalence of E. bieneusi was 5.7% (72/1254) in three provinces. Furthermore, the difference was statistically significant (p < 0.001) in the prevalence of E. bieneusi in age groups. ITS sequence analysis revealed that 13 E. bieneusi genotypes were identified, including 8 known genotypes (EbpC, n = 30; Henan-IV, n = 21; CH5, n = 6; EbpA, n = 3; KIN-1, n = 2; O, n = 1; GX3, n = 1; CHS5, n = 1) and 5 novel genotypes (JX1, n = 2; JX2, n = 1; JX3, n = 2; FJ1, n = 1; FJ2, n = 1), and the genotype EbpC was the preponderant genotype. Phylogenetic analysis indicated that all genotypes of E. bieneusi were clustered as the zoonotic group 1. Moreover, a high genetic diversity of E. bieneusi were identified in this study, which the 64, 57, 52 and 64 samples were identified by multilocus sequence typing (MLST) at MS1, MS3, MS4 and MS7 loci, respectively. Then, 45 samples were successfully amplified and sequenced at four loci, forming 41 distinct multilocus genotypes (MLGs). These findings suggest that diarrheic pigs may potentially threaten to transmit E. bieneusi to humans, revealing E. bieneusi genetic variability in diarrheic pigs in three provinces of southern China.

Prevalence and Subtype Distribution of Blastocystis sp. in Diarrheic Pigs in Southern China.

Blastocystis sp. is a common pathogen that infects the intestines of humans and animals, causing a threat to public health. However, little information on the prevalence and subtypes of Blastocystis sp. in diarrheic pigs in China is available. Herein, 1254 fecal samples were collected from diarrheic pigs in 37 intensive pig farms in Hunan, Jiangxi, and Fujian provinces in southern China, and the prevalence and subtypes of Blastocystis sp. were investigated. Blastocystis sp. was detected by PCR assay, which amplified the small subunit rRNA (SSU rRNA) gene. Overall prevalence of Blastocystis sp. was 31.4% (394/1254), including 21.5% (66/307), 33.1% (99/299), 58.9% (56/95), and 31.3% (173/553) in suckling piglets, weaned piglets, fattening pigs, and sows, respectively. Moreover, age and region factors were significantly related to prevalence of Blastocystis sp. (p < 0.05). Four Blastocystis sp. subtypes were identified, including ST1, ST3, ST5, and ST14. The preponderant subtype was ST5 (76.9%, 303/394). To our knowledge, ST14 was firstly found in pigs in China. The human-pathogenic subtypes (ST1, ST3, ST5, and ST14) that were observed in this study indicate a potential threat to public health. These findings provided a new sight for studying the genetic structure of Blastocystis sp.