Molecular detection of Giardia and Cryptosporidium infections among asymptomatic Nigerian children using multiplex real-time PCR.

Giardia intestinalisand Cryptosporidium species are protozoan gastrointestinal parasites that are the leading cause of chronic infantile diarrhoea. They are the leading causes of childhood sickness and death worldwide, and they can induce malnutrition, anaemia, diarrhoea, and stunted growth. In Nigeria, there are currently few prevalence studies on the simultaneous identification of Giardia and Cryptosporidium infections in asymptomatic primary school students utilizing molecular detection techniques. To address the sensitivity issues associated with cyst identification in faecal samples using microscopy, multiplex real-time polymerase chain reaction (PCR) was used to investigate genomic DNAs extracted from stool samples from 184 asymptomatic school children for Giardia and Cryptosporidium, and questionnaires were used to collect epidemiological data. The overall infection rates for Cryptosporidium spp. and G. duodenalis were 1.1% and 1.6% respectively. Schoolchildren who used pit latrines were more likely to have Giardia (2.3%) and Cryptosporidium (2.3%). In contrast, children who did not wash their hands after using the toilet were also more likely to have these protozoan parasites (2.4% and 4.9%). This study shows that Giardia and Cryptosporidium are present among asymptomatic schoolchildren in Nigeria, despite their low prevalence. More large-scale investigations using PCR-based multilocus genotyping in asymptomatic schoolchildren are recommended.