Prevalence, risk factors and characterisation of cryptosporidium species in children presenting with diarrhea at urban and rural health centres in Zambia.

Cryptosporidium species are among the leading causes of diarrhoeal disease especially in children and immunocompromised individuals. The pathogen disproportionately affects settings without adequate sanitation and hygiene especially in developing countries and its genotype isolates vary from place to place. Children under the age of five suffer severe consequences when affected. The study aimed to determine prevalence, risk factors and characterise Cryptosporidium species in children presenting with diarrhoea at urban and rural health centres in Zambia.
Methods: This was a Cross sectional study in under five children presenting with diarrhoea. Stool samples collected from 490 children aged <5years with diarrhoea were assessed for Cryptosporidium oocysts microscopically after concentration with formal ether concentration technique. A single stool sample was collected from each child. A structured questionnaire was used to collect demographics and socioeconomic characteristics. Positive samples were subjected to Polymerase Chain Reaction (PCR) and partial 60kD glycoprotein (gp60) sequence analysis.
Results: The overall prevalence was 10.2% (50/490, 95% CI [7.8 -13.2]) and majority of the infections were in urban areas. Multivariable regression analysis was performed to identify the risk factors of Cryptosporidium infection. Children who came from households where boiling water was not practised (AOR 0.74, 95% CI [0.35-1.58]; p=0.439) and those from high density residential areas (AOR 10.20, 95% CI [2.28-45.66]; p=0.002) were more likely to have Cryptosporidium infection. Genotyping of 16 positive samples (14 from urban and 2 from rural sources) revealed C. hominis (14/16) and C. parvum (2/16). The Cryptosporidium hominis subtypes identified were Ia, Ib and Ie with subtypes families IeA11G3 (1), IbA9G3R2 (2), IaA31R3 (3), IbA9G3 (5), IaA27R3 (1), IaA30R3 (1) and Ia (1). Subtype IbA9G3 and Ia were identified in children from a rural area. Cryptosporidium parvum subtypes were IIcA5G3R2 (1) and IIcA5G3a (1).
Conclusions: All the Cryptosporidium isolates in this study were C. hominis or anthroponotic C. parvum, suggesting that currently anthroponotic transmission dominates in Lusaka and the surrounding countryside. Children who came from household where drinking water was not boiled and from high residential areas were more likely to have Cryptosporidium infection.
Keywords: Children, Cryptosporidium, gp60 gene, Risk factors, subtypes, Zambia.