Evaluation of an Improved Approach Using Residences of Schistosomiasis-Positive School Children to Identify Carriers in an Area of Low Endemicity

Abstract

School children were used as indicators for the identification of schistosomiasis-positive family members in a area of low endemicity. This study was designed to improve current schistosomiasis control programs by applying this strategy to identify schistosomiasis-positive individuals in a more efficient way. The initial prevalence among school children was 8.6%. However, the prevalence among the family members of these school children increased to 15.5%. In contrast to these findings the prevalence in family members of schistosomiasis-negative school children was 3.8%. Although the applied methodology showed a relatively low sensitivity (50.0%), the high negative predictive value (87.7%) indicates that a few positive family members of school children with a negative stool result will be missed. This shows that this method of evaluation could be a strategy for a more efficient and cheaper identification of schistosomiasis-positive individuals in areas of low endemicity.

The prevalence of schistosomiasis in school-aged children as an appropriate indicator of its prevalence in the community

“…These characteristics include the following: (i) it is the age range established by law for formal schooling in Brazil, which implies compulsory enrollment in elementary schools, (ii) schoolchildren and their families are generally accessible and receptive to this type of testing, (iii) children in this age group are the main targets of WHA-54.19, whose member countries, including Brazil, committed to the minimum goal of providing diagnostic coverage and treatment for helminth infection to 75% of school-aged children in endemic areas by the year 2010 (WHO 2002), (iv) data collected from individuals in this age range may be used to evaluate not only the health threat of schistosomiasis to schoolchildren, but also the need for intervention in the community as a whole (Montresor et al 2002), (v) the school infrastructure reduces the operational costs for parasitological surveys and medication administration because it concentrates activities in a specific physical space and, in addition, provides an excellent opportunity to reach non-enrolled children (Favre et al 2009 9-12 years of age) allows for the follow-up of the impact of treatment over the period of one or two years before they leave school, (vii) the school environment allows for the discussion of various issues related to schistosomiasis and other important threats in the community, promoting more ample debate on disease prevention and control among schoolchildren, families and health agents (Schall 1994), (viii) schoolchildren who were tested positive serve as a good indicator that could lead to the identification of infected family members, including non-enrolled children (Massara et al 2006, Enk et al 2008, (ix) a study conducted in the endemic area of Minas Gerais, Brazil, validated the use of prevalence among individuals in the 7-14 year-old age group to predict S. mansoni prevalence in the community, confirming that it can be used to guide treatment strategies in the endemic area (Rodrigues et al 2000) and (x) this age group has already been targeted in control campaigns carried out by the MS in the 1970's and 1980's, which attests its importance not only as a group that is particularly vulnerable to infection, but also as an important source of information regarding environmental contamination.…”

Predictive Value of School-Aged Children's Schistosomiasis Prevalence and Egg Intensity for Other Age Groups in Western Kenya

“…29 Furthermore, the school setting provides an environment to empower children as agents of health behavior change and an entry point for other community members to access MDA benefits. [30][31][32] Because several other health programs also operate from schools, it is possible to incorporate these surveys into the routine activities. 33,34 In conclusion, our findings show that prevalence and intensity indicators among the 9-to 12-year-olds are comparable to other population groups in the same settings as well as overall community prevalence and are a valid age group to use for sampling purposes for baseline data to determine MDA.…”

Targeting Asymptomatic Malaria Infections: Active Surveillance in Control and Elimination

“…Where risk factors are not well defined, an effective approach might be targeted MDA (tMDA) to households or groups of households identified via passively or actively detected cases. A similar household treatment approach has been suggested for schistosomiasis [73],[74]. Such an approach warrants investigation in the context of malaria control, although the correct drug combination needs to be explored.…”