Co-endemicity of Plasmodium falciparum and Intestinal Helminths Infection in School Age Children in Rural Communities of Kwara State Nigeria.

BACKGROUND:Malaria and intestinal helminths co-infection are major public health problems particularly among school age children in Nigeria. However the magnitude and possible interactions of these infections remain poorly understood. This study determined the prevalence, impact and possible interaction of Plasmodium falciparum and intestinal helminths co-infection among school children in rural communities of Kwara State, Nigeria. METHODS:Blood, urine and stool samples were collected from 1017 primary school pupils of ages 4-15 years. Stool samples were processed using both Kato-Katz and formol-ether concentration techniques and microscopically examined for intestinal helminths infection. Urine samples were analyzed using sedimentation method for Schistosoma haematobium. Plasmodium falciparum was confirmed by microscopy using thick and thin blood films methods and packed cell volume (PCV) was determined using hematocrit reader. Univariate analysis and chi-square statistical tests were used to analyze the data. RESULTS:Overall, 61.2% of all school children had at least an infection of either P. falciparum, S. haematobium, or intestinal helminth. S. haematobium accounted for the largest proportion (44.4%) of a single infection followed by P. falciparum (20.6%). The prevalence of malaria and helminth co-infection in the study was 14.4%. Four species of intestinal helminths were recovered from the stool samples and these were hookworm (22.5%), Hymenolepis species (9.8%), Schistosoma mansoni (2.9%) and Enterobius vermicularis (0.6%). The mean densities of P. falciparum in children co-infected with S. haematobium and hookworm were higher compared to those infected with P. falciparum only though not statistically significant (p = 0.062). The age distribution of both S. haematobium (p = 0.049) and hookworm (p = 0.034) infected children were statistically significant with the older age group (10-15 years) recording the highest prevalence of 47.2% and 25% respectively. Children who were infected with S. haematobium (RR = 1.3) and hookworm (RR = 1.4) have equal chances of being infected with P. falciparum as children with no worm infection. On the other hand children infected with Hymenolepis spp. (p<0.0001) are more likely to be infected with P. falciparum than Hymenolepis spp. uninfected children (RR = 2.0). CONCLUSIONS:These findings suggest that multiple parasitic infections are common in school age children in rural communities of Kwara State Nigeria. The Hymenolepis spp. induced increase susceptibility to P. falciparum could have important consequences on how concurrent infections affect the expression or pathogenesis of these infections

Prevalence of children infected with double infection by age and sex.

<p><u>Key:</u> PF = <i>P</i>. <i>falciparum</i>; SH = <i>S</i>. <i>haematobium</i>; HW = Hookworm; HN = <i>Hymenolepis</i> species, EV = <i>Enterobious vermicularis</i></p><p>Prevalence of children infected with double infection by age and sex.</p

Overall prevalence and infection intensities (expressed as geometric mean parasite count of positive samples) of parasitic infections in school children in Kwara State Nigeria.

<p>Overall prevalence and infection intensities (expressed as geometric mean parasite count of positive samples) of parasitic infections in school children in Kwara State Nigeria.</p

Logistic regression predicting the occurrence of anemia in relation to parasitic infection among the school children.

<p>*Significant at p<0.05</p><p><u>Key:</u> PF = <i>P</i>. <i>falciparum</i>; SH = <i>S</i>. <i>haematobium</i>; HW = Hookworm; HN = <i>Hymenolepis</i> species, EV = <i>Enterobious vermicularis</i></p><p>Logistic regression predicting the occurrence of anemia in relation to parasitic infection among the school children.</p

Prevalence of single parasitic infection among children by sex.

<p><u>Key:</u> PF = <i>P</i>. <i>falciparum</i>; SH = <i>S</i>. <i>haematobium</i>; HW = Hookworm; HN = <i>Hymenolepis</i> species, EV = <i>Enterobious vermicularis</i></p><p>Prevalence of single parasitic infection among children by sex.</p

The proportion of children with anemia by type of infection.

<p><u>Key:</u> PF = <i>P</i>. <i>falciparum</i>; SH = <i>S</i>. <i>haematobium</i>; HW = Hookworm; HN = <i>Hymenolepis</i> species.</p

Prevalence of single parasitic infection among children by age.

<p>*Significant p<0.05</p><p><u>Key:</u> PF = <i>P</i>. <i>falciparum</i>; SH = <i>S</i>. <i>haematobium</i>; HW = Hookworm; HN = <i>Hymenolepis</i> species, EV = <i>Enterobious vermicularis</i></p><p>Prevalence of single parasitic infection among children by age.</p

Geometric parasite density per microlitre of blood by type of infection.

<p>PF vs PF+HN = p< 0.001; PF + HW Vs PF + SH = p< 0.001;<u>Key:</u> PF = <i>P</i>. <i>falciparum</i>; SH = <i>S</i>. <i>haematobium</i>; HW = Hookworm; HN = <i>Hymenolepis</i> species.</p