Entomological investigations are important and essential aspect of malaria vector control, as these investigations provide information on vector species, their distribution, density, bionomics and susceptibility/ resistance to insecticides used for malaria control. In addition these investigations are useful for the monitoring of potential vectors and the role they could play in disease transmission. Information collected through entomological surveillance techniques assist in the understanding of the spatial and temporal changes in vector species, efficacy and effectiveness of vector control measures employed for malaria vector control.
Conducting of regular entomological surveillance on a wide scale is costly & labour intensive. Hence these investigations cannot be carried out in all locations where malaria transmission occurs but have to be limited to selected localities in each district/province. To increase the usefulness of data collected from surveillance and to maximize the use of available resources entomological investigations are carried out in
1. Sentinel sites
2. Selected localities where potential outbreaks are expected
3. During outbreaks or epidemics
Criteria for selection of sentinel sites
Sentinel sites are identified at district level and are monitored at regular intervals to determine seasonal changes in vector densities and also more importantly to monitor changes in vector bionomics and characteristics.
A sentinel site should usually be an area where malaria transmission risk is present over a period of time or where increased potential for vector breeding is well established. High risk area may be a previously malaria risk area or an epidemic prone area.
Epidemic prone area could be an area;
(I) subjected to frequent or seasonal out breaks/epidemics.
(11) where environmental changes have occurred due to human activity or as a result of changes in climate, resulting in increased vector breeding potential.
Criteria for selection of areas for spot checks
Spot checks need to be carried out in areas not covered by the sentinel surveys when
(1) malaria cases are reported or an increase in malaria cases is reported.
(11) environment changes in favour of vector breeding (e.g. climatic changes, disasters, development projects and human activities such as gem mining, timber felling, quarry pits etc.) is reported
(111) migratory populations from malarious areas are present.
More details on entomological surveillance carried out in the malaria programme can be obtained from the Guidelines for entomological surveillance.
Cattle Baited Hut Locations
distribution map of cattle baited hut locations