Prevalence and genetic characterization of Cryptosporidium, Enterocytozoon, Giardia and Cyclospora in diarrheal outpatients in China.

BACKGROUND: Cryptosporidium spp., Enterocytozoon spp., Giardia spp. and Cyclospora spp. are important intestinal protozoan parasites causing diarrhea in humans, livestocks and wildlife and have a significant impact on public health. No reports exist about simultaneous prevalence rates or genotyping data of these four parasites in outpatients from China.

METHODS: Fecal specimens from 252 diarrhea patients in a pediatric clinic (n = 169) and an intestinal clinic (n = 83) of a hospital in Shanghai, China, were collected between October 2012 and March 2013. All samples were examined for the presence of the four parasites by using molecular methods.

RESULTS: In total, 76/252 (30.16%) patients were positive for at least one intestinal parasite, of which Cryptosporidium spp., Enterocytozoon bieneusi and Giardia intestinalis were detected by nested PCR in 34 (13.49%), 34 (13.49%) and 17 (6.75%) of the fecal specimens, respectively. Sequence analysis showed that all Cryptosporidium-positive specimens were C. andersoni and that most G. intestinalis- positive patients were infected by assemblage C, which is usually found in canids, while only one sample was from assemblage B. Eight patients were co-infected with Cryptosporidium spp. and Enterocytozoon, while one was co-infected with Cryptosporidium and Giardia.

CONCLUSIONS: The patients infected with Cryptosporidium and Enterocytozoon bieneusi had higher infection rates in winter than in spring in this area. Data indicated that C. andersoni is the fourth major Cryptosporidium species infecting humans in addition to C. hominis, C. parvum and C. meleagridis. Our study also revealed a short-term outbreak of cryptosporidiosis and microsporidiosis and sporadic cases of giardiasis that occurred among humans in Shanghai, China.