Objectives
Infection with Plasmodium falciparum parasites may result in a wide spectrum of symptoms ranging from asymptomatic to mild or severe. A number of factors are associated with this heterogeneous response to P. falciparum infection. In the present study, associations of sub‐microscopic asymptomatic P. falciparum with Schistosoma species and TNF (rs1800629) polymorphism were investigated.
Methods
361 clinically healthy primary school children were microscopically screened for S. haematobium, S. mansoni and P. falciparum. Sub‐microscopic asymptomatic P. falciparum infections were determined by PCR. Genotypic profiles were identified using ARMS‐PCR. Logistic regression was used to assess the association of sub‐microscopic asymptomatic P. falciparum with Schistosoma species and TNF (rs1800629) polymorphism.
Results
17.2% of the children were infected with S. mansoni, and 27.4% were infected with S. haematobium. Microscopic examination of thick smears detected only one child infected with P. falciparum. Based on PCR results, 46.1% were infected with sub‐microscopic asymptomatic P. falciparum. Children carrying heterozygous AG (OR: 16.964, 95% CI: 0.496–586.547) and homozygous GG (OR: 2.280, 95% CI: 0.111–46.796) genotypes of rs1800629 were associated with an increased likelihood of sub‐microscopic asymptomatic P. falciparum infections compared with those carrying homozygous AA genotype. Children without S. haematobium infections (OR: 1.051, 95% CI: 0.146–8.985) and S. mansoni (OR: 2.658, 95% CI: 0.498–14.184) also had an increased likelihood (risk) of being infected with sub‐microscopic asymptomatic P. falciparum compared with the Schistosoma‐infected groups. However, all the associations observed were not statistical significant.
Conclusion
No associations were observed between rs1800629 and schistosomiasis with sub‐microscopic asymptomatic P. falciparum infections. This study also reports a high prevalence of sub‐microscopic asymptomatic P. falciparum infection concomitant with low malaria transmission.