Persistent Occurrence of Cryptosporidium hominis and Giardia duodenalis Subtypes in a Welfare Institute.

Few data are available on the transmission dynamics of intestinal protozoa in children in welfare institutes. In this study, fecal specimens were collected from 396 children in a welfare institute in Shanghai, China during December 2011 (207 specimens), June 2012 (78 specimens), and September 2013 (111 specimens), and examined for Cryptosporidium spp., Giardia duodenalis , and Enterocytozoon bieneusi by PCR analysis of the small subunit rRNA, triosephosphate isomerase, and internal transcribed spacer genes, respectively. The Cryptosporidium hominis and G. duodenalis assemblage A identified were further subtyped by multilocus sequence typing. Altogether, Cryptosporidium was detected in 39 (9.8%) children, with infection rates of 11.6% (24/207), 9.0% (7/78), and 7.2% (8/111) in December 2011, June 2012, and September 2013, respectively. Infection rates were higher in children of 0-12 months (20.4% compared to 0-7.3% in other age groups, P = 0.0001) and those with diarrhea (17.9% compared to 7.7% in those with no diarrhea, P = 0.006). In contrast, G. duodenalis was detected in 161/396 (40.7%), with infection rates of 48.3% (100/207), 35.9% (28/78), and 29.7% (33/111) in December 2011, June 2012, and September 2013, respectively. There were no significant gender- or diarrhea-associated differences, but the G. duodenalis infection rate in children of 13-24 months (50%) was significantly higher than in the age groups of 0-12 months and > 48 months (29.8-36.5%, P = 0.021). Co-infection of Cryptosporidium and G. duodenalis was seen in 19 (4.8%) children, but no E. bieneusi infection was detected in this study. All Cryptosporidium -positive specimens belonged to the subtype IaA14R4 of C. hominis , while all G. duodenalis -positive specimens belonged to sub-assemblage AII. Both were the same subtypes in a previous outbreak of cryptosporidiosis and giardiasis in a hospital ward hosting children from the welfare institute. Results of the study indicate that there was a persistent occurrence of limited C. hominis and G. duodenalis subtypes in the small enclosed community, with differences in age distribution and association with diarrhea occurrence between cryptosporidiosis and giardiasis.