dc.description.abstract |
Recent evidence indicates that preschool children (PSC) living in S. mansoni highly
endemic areas are at similar risk of schistosomiasis infection and morbidity as their
school aged counterparts. Recognizing this fact, the World Health Organization (WHO)
is considering including this age group in control programs using mass drug
administration (MDA), in the highly endemic areas. However, detailed epidemiological
information on S. mansoni infection among PSC is lacking for many endemic areas,
including in Tanzania. This study was conducted to determine the prevalence and
intesnsity of S. mansoni infection among PSC in Lake Victoria’s Ukerewe Island, in
North-Western Tanzania, and the factors associated with infection in this age group.This
was a cross-sectional study involving 400 PSC aged 1- 6 years of age. The Kato-Katz
(K-K) technique and the point of care circulating cathodic antigen (CCA)
immunodiagnostic test were used to diagnose S. mansoni infection in stool and urine
samples, respectively, and a pre-tested questionnaire was used to collect demographic
data and water contact behaviour of the children through their parents/guardians. GPS
data of the households of study participants and water contact points nearest to their
homesteads was obtained. Data collected was entered into data collection forms,
notebooks, and then transferred into the Microsoft Excel software for consistency data
checks and data cleaning. Analysis was done using STATA 13 and ArcGIS ArcMap
10.2.2. Chi squared test for difference in frequencies were performed. Potential
associations were assessed at a bivariate level; then, factors with P-value <0.2 were
entered into multivariate model. Sex and age group term were entered as a priori into
the multivariate model. Stepwise backward logistic regression was used to determine
whether these variables were independent factors of S. mansoni. Independent risk factors
of faecal egg counts were identified in a linear regression model using a log-transformed
egg per gram of faeces (epg) as outcomes variable and social demographic factors as
explanatory variables. The odd ratios of each of the risk factors associated with faecal
egg counts were obtained by taking the antilogarithm of the regression coefficient.
xiv
Based on the K-K technique, 44.4% (95% CI: 39.4-49.4) preschool children were
infected with S. mansoni and the overall geometric mean eggs per gram of faeces (GMepg) was 110.6 epg with 38.2% and 14.7% having moderate and heavy intensity
infections respectively. Based on the CCA, 80.1%, (95% CI: 76.0-84.0) were infected if
a trace was considered positive, and 45.9%, (95% CI: 40.9-50.9), were infected if a trace
was considered negative. Reported history of lake visit (AOR= 2.31, 95% CI 1.06 - 5.01,
P<0.03) and the proximity to the lake shore (<500m) (AOR= 2.09, 95% CI: 1.05-4.14,
P<0.03) were significantly associated with S. mansoni infection. Reported lake visit
frequency (4 -7days/week) was associated with heavy intensities of S. mansoni infection
(P<0.00).The prevalence of S. mansoni infection in the study population using K-K and
CCA trace is negative was moderate. The frequency of lake visits, the proximity to the
lake shore were associated with the infection of S. mansoni and its intensity. These
findings call for the need to include the PSC in MDA programs, public health education
and provision of safe water for bathing. |
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