Molecular seasonal, age and gender distributions of Cryptosporidium in diarrhoeic Egyptians: distinct endemicity.

Cryptosporidiosis is a worldwide gastrointestinal disease caused by the protozoan Cryptosporidium parasite. It has a broad range of seasonal and age-related prevalence. We aimed to study the molecular prevalence and seasonality of Cryptosporidium over a period of 1 year in a cohort of Egyptian diarrhoeic patients. Stool samples were collected from 865 diarrhoeic patients attending outpatient clinics of Cairo University hospitals, from all age groups over a 12-month period, examined microscopically for faecal Cryptosporidium oocysts by the acid-fast staining method and for copro-DNA detection using nested polymerase chain reaction (nPCR) assays. PCR-positive samples were characterised molecularly by nPCR-restriction fragment length polymorphism (RFLP) to determine Cryptosporidium genotypes. Cryptosporidium copro-DNA was detected in 19.5% of the collected samples throughout the year, with a major peak in summer (August) and a small rise in spring (April). Infection was mainly C. hominis (95.8%) followed by C. parvum (3.0%), affecting all age groups, with predominance in the pre-school age group, and decrease with age. There were statistically significant associations between the detection of Cryptosporidium and season, diarrhoea, patient age and drinking water, while gender, contact with animals and presence of mucus in stool showed no association. Cryptosporidium in diarrhoeic Egyptians was of distinct endemicity, with the bi-model mostly influenced by population dynamics, with a clear high prevalence in pre-school children and predominating anthroponotic (C. hominis) transmission throughout the year. The obtained results highlight Cryptosporidium as a water contaminant and an important cause of health problems in Egypt, necessitating further studies of the risk factors.