Apparent absence of Giardia infections among children under 5-years of age with acute watery diarrhoea in Abakaliki, Nigeria.

Although the impact of diarrhoeal disease on paediatric health in Nigeria has decreased in recent years, it remains an important cause of morbidity and mortality in children under 5 years. Rotavirus is recognised as an important aetiological agent, but information on the contribution of intestinal protozoa to watery diarrhoea in this age group in Nigeria is scarce. In this cross-sectional study, faecal samples from children admitted to healthcare centres in Abakaliki, Nigeria with acute watery diarrhoea (N = 199) and faecal samples from age-matched controls (N = 37) were examined for Cryptosporidium and Giardia using immunofluorescent antibody testing and molecular methods. Cryptosporidium was identified in 13 case samples (6.5%) and no control samples. For three samples, molecular characterisation indicated C. hominis, GP60 subtypes IaA30R3, IaA14R3 and IdA11. Giardia was not detected in any samples. This contrast in prevalence between the two intestinal protozoa may reflect their variable epidemiologies and probably differing routes of infection. Given that these two parasitic infections are often bracketed together, it is key to realise that they not only have differing clinical spectra but also that the importance of each parasite is not the same in different age groups and/or settings.