Prevalence and molecular identification of Balantioides coli isolates from pet guinea pigs in Central China.

Balantioides coli is the only known zoonotic ciliate that can infect humans and is usually acquired from swine. It has, however, been reported in other mammals, including guinea pigs, where infection prevalence and molecular characterization are relatively unknown. In the present study, 32 guinea pigs from two different pet markets in Luoyang city of the Henan province in China were evaluated for ciliate-like trophozoites or cysts by direct fecal smear microscopy. Positive samples were further characterized using 18S rDNA and ITS1-5.8S rDNA-ITS2 sequence analysis. Microscopy indicated that ciliate-like cysts were observed in the fecal samples of several guinea pigs, were spherical in shape, and exhibited sizes of 40-65 µm in diameter. The average cyst-positive prevalence in guinea pigs was 62.5%. Sequence analysis indicated that the guinea pig-derived ciliate isolates belonged to B. coli and included two genetic variants (A and B), of which genetic variant A was more dominant among the guinea pig samples. To the best of our knowledge, the present study is the first molecular identification of B. coli in guinea pigs and provides some important information for investigating the molecular epidemiology of B. coli.

Development of a PCR assay for identification of Neobalantidium coli () in Argentina.

Neobalantidium coli (Pomajbíková et al., 2013) is a cosmopolitan ciliate which colonizes the intestine of humans and animals. Pigs are the most important host and reservoir for this parasite, although others mammals have been described. Humans can acquire the disease through the ingestion of water and food contaminated with cysts and even from person to person contact. Farmers and slaughterhouse workers from rural areas of developing countries have an increased incidence of balantidiosis. In Argentina, despite swine production on family farms covers 70% of domestic consumption requirements; there is a lack of veterinary animal health planning which result in high rate of animal mortality, as well as environmental risk due to inefficient facilities and mismanagement of manure and effluents. At present there are no epidemiological data on balantidiosis in Argentina, except for isolated reports. Therefore, the aims of this study were to establish the frequency of N. coli in pigs raised under different conditions and to explore the zoonotic potential. In order to confirm the identity of Neobalantidium coli like-cysts founded in the feces, a set of N. coli specific primers based on 18S rRNA gene sequences was designed. The molecular identification of N. coli was performed in 88.9% (16 out of 18) of swine stool samples in which cysts had been visualized. The fecal samples obtained from pigs raised on more open farmland showed a lower percentage of N. coli than those obtained from animals raised in swine pens. On the other hand, molecular identification of N. coli was also performed in human feces. Pairwise comparison of sequences obtained from pigs and human fecal samples from the NW Region of Argentina showed a high percentage of similarity, indicating a possible zoonotic transmission.