Molecular Epidemiology of Cryptosporidiosis and characterization of the Human Immune Response to Cryptosporidium Spp in Southern India

Abstract

Cryptosporidiosis affects young children and HIV infected adults in the developing world. Among children it is a common cause of diarrhea in under-fives, especially in the malnourished. Infections with Cryptosporidium spp., along with Giardia and enteroaggregative E. coli, also result in long term effects on growth causing stunting and may also result in deficits of cognitive function. Among the HIV infected, Cryptosporidium spp is the most common cause of opportunistic diarrhea in less-developed countries with a clear correlation with worsening cell mediated immunity. Although the pathogen is endemic in these countries, its ability to survive in the environment for a prolonged duration can lead to diarrheal disease epidemics affecting children in the entire community. Prior studies in India identified this parasite in children and in the HIV infected in various parts of the country but little information was available on the circulating species and subgenotypes or immunity to this parasite. In this study, we have documented the prevalent species among children with diarrhea in the community in Vellore and in the hospital setting in Delhi, Trichy and Vellore. In children both in the community and among those coming to the hospital, C. hominis was the most common species with a few infections due to zoonotic species like C. parvum, C. felis and C. meleagridis. Most of the children with cryptosporidial diarrhea both in the community and in the hospital setting were under the age of 2 years. In the community, C. hominis-infected children had a significantly greater severity of diarrhea. Our findings indicate that hospitalization due to cryptosporidial diarrhea is mainly due to C. hominis, probably attributable to greater severity of disease with anthroponotic than zoonotic species. This study has used multiple tools to characterize cryptosporidiosis in children HIV infected adults in India. newline