Mass drug administration significantly reduces infection of Schistosoma mansoni and hookworm in school children in the national control program in Sierra Leone

December 6th, 2012

In 2009 for the first time, Sierra Leone’s National Neglected Tropical Diseases Control Program did a joint school-based mass drug administration (MDA) using praziquantel and mebendazole, targeting school-aged children in endemic districts. Six months later, it conducted a cross-sectional sentinel site survey to evaluate the impact of the treatment regimen.

It found that school-going children in Sierra Leone suffered significantly fewer S. mansoni and hookworm infections after this first round of MDA. Prior to the MDA, the overall prevalence (and intensity) of S. mansoni, hookworm, Ascaris lumbricoides, and Trichuris trichiura in those sentinel sites was 69.0% (170.8 eggs per gram of feces, epg); 41.7% (71.7 epg); 1.8%, and 3.8%, respectively. Six months after MDA, prevalence (intensity) of S. mansoni and hookworm decreased to 38.2% (47.3 epg) and 14.5% (8.7 epg), respectively, representing reductions of 44.6% (65.2%) and 72.3% (87.9%). In addition, the proportion of children who were moderately or heavily infected with S. mansoni fell from 35.6% pre MDA, to 9.9% post MDA.

Researchers collected data at fifteen sentinel schools from six districts highly endemic for Schistosoma mansoni, meaning that over 50% of the population was infected, and moderately to highly endemic for hookworm (prevalence > 20%). They selected approximaely 30 children, ages 9-14 years, from each school and examined stool samples using the Kato-Katz method.

The results from the study provide evidence regarding the effectiveness of joint MDA using praziquantel and mebendazole for treating school-aged children for schistosomiasis and soil transmitted helminthes. Reducing the burden of infection also benefits infected children by helping to reduce co-morbidities such as anemia, ultimately improving their health status and ability to develop into healthy, productive adults.

Mary H Hodges1, Nsa Dada2, Anna Warmsley2, Jusufu Paye1, Momodu M Bangura3, Emanuel Nyorkor4, Mustapha Sonnie1 and Yaobi Zhang5

  1. Helen Keller International, PO Box 369, Freetown, Sierra Leone.
  2. Liverpool School of Tropical Medicine, Liverpool, UK.
  3. National NTDCP, Ministry for Health and Sanitation, Freetown, Sierra Leone.
  4. School of Community Health and Clinical Sciences, Njala University, Bo, Sierra Leone.
  5. Helen Keller International, Regional Office for Africa, Dakar, Senegal.

(The above is a summary of a research article published in BMC Infectious Diseases 2012, 12:16