Cambodia National Centre for Parasitology/Entomology and Malaria Control
Integrated serosurveillance for parasitic diseases and vaccine preventable diseases in Cambodia
Cambodia has been validated for eliminating LF since 2016 and for eliminating both measles and maternal and neonatal tetanus since 2015. These are tremendous achievements; however, recent drops in coverage for vaccine preventable diseases threatens some these gains and there is a need to conduct surveillance to ensure that gains are sustained and that there is no recrudescence in the high risk areas. Integrated serosurveillance in Cambodia would provide substantial cost savings over disease-specific surveys, is logistically easier, and is less disruptive for communities. Serosurveys can provide rich information on exposure patterns for NTDs as well as a measure of population-level immunity to VPDs (and hence may serve as a validation of coverage). In this study, the team in Cambodia will revisit 2 historically high risk provinces in the north. This study builds on the work of a 2012 national serosurvey, which found that this northern region had the highest LF antibody response and is consequently considered to be at highest risk for re-emergence of LF. This study will be an integrated assessment of tetanus and other VPDs (measles, rubella, diphtheria), as well as malaria.
Integrated serosurveillance for parasitic diseases and vaccine preventable diseases in Cambodia
Cambodia has been validated for eliminating LF since 2016 and for eliminating both measles and maternal and neonatal tetanus since 2015. These are tremendous achievements; however, recent drops in coverage for vaccine preventable diseases threatens some these gains and there is a need to conduct surveillance to ensure that gains are sustained and that there is no recrudescence in the high risk areas. Integrated serosurveillance in Cambodia would provide substantial cost savings over disease-specific surveys, is logistically easier, and is less disruptive for communities. Serosurveys can provide rich information on exposure patterns for NTDs as well as a measure of population-level immunity to VPDs (and hence may serve as a validation of coverage). In this study, the team in Cambodia will revisit 2 historically high risk provinces in the north. This study builds on the work of a 2012 national serosurvey, which found that this northern region had the highest LF antibody response and is consequently considered to be at highest risk for re-emergence of LF. This study will be an integrated assessment of tetanus and other VPDs (measles, rubella, diphtheria), as well as malaria.
Assessing school-based MDA recall with community-based coverage surveys in Cambodia
The purpose of this study is to assess the feasibility of a community-based survey for measuring coverage of school-based MDA, specifically by looking at the reliability of child and parental recall for MDAs targeting soil-transmitted helminths.
Preliminary Findings and Lessons Learned:
There is currently little to no evidence on the reliability of young children at recalling whether or not they participated MDA. This issue is important because where MDA is school-based, parents may not be able to provide accurate proxy responses on behalf of their children. A study was conducted in Cambodia whereby gold standard registers of all children were created, based on school enrollment rosters. During the MDA outside observers (local to the region) recorder whether or not each child in the register received the drug. Then a month later the team went back and conducted a household survey and asked children to recall whether or not they participated in the MDA. The study was conducted according to the protocol. 600 children were followed up in the household survey, all of whom are enrolled in school and were listed on the gold standard register. Unfortunately there was some miscommunication and the site selected by the program team was one of the highest coverage sites in the country. While great for the Cambodian program, this means that the true coverage for the 600 individuals was 100%. All 600 children accurately recalled that they had participated in the MDA. With these results we are not able to assess recall. Of the parents who were surveyed, 97% correctly knew that their child had participated in MDA while 3% said that they did not know.
The result of greatest interest was the ability of the children to accurately identify which drug they took as part of the MDA. Children were shown 3 different drugs (Albendazole, Mebendazole and a decoy pill not available in the area). 15% of children and 5% of adults mistakenly believed the child had taken the decoy pill. This study did, however, gather interesting information on the frequency of unprogrammed deworming. 12% of parents (and 5% of children) said that the child had received some deworming medication outside of school. The majority of this came from health centers.