Molecular characterisation of Cryptosporidium: an emerging parasite.

PURPOSE The aim of the present study was to determine the prevalence of Crytposporidium in local population and to understand its epidemiology by molecular methods. METHODS Faecal samples from 681 children and 804 adults, admitted to tertiary care hospitals in twin cities of Hyderabad and Secunderabad with complaints of diarrhoea; and six calves with diarrhoea, were screened for Cryptosporidium oocysts by microscopy and enzyme linked immunosorbent assay (ELISA). Polymerase chain reaction restriction fragment length polymorphism (PCR RFLP) based identification of Cryptosporidium species in positive specimens was done to elucidate epidemiology of Cryptosporidium. RESULTS Cryptosporidium was found in 52 (7.6%) children and 7(0.9%) adults and 1(16.6%) calf with diarrhoea. The prevalence of Cryptosporidium in children below five years of age was 8.2% and 14.3% in children in the age group of six months to one year. Of the 42 samples genotyped 29 (69%) were C. hominis and 8 (19%) were C. parvum and 5 (11.9%) were mixed infection with the two species. CONCLUSIONS Children in the age group of six months to one year were found to be the most vulnerable. The occurrence of C. parvum, in nearly one third of cases in the present series indicates that the zoonotic transmission is of considerable significance in the epidemiology of Cryptosporidiosis in the study area.