Rapid mapping for onchocerciasis

When ivermectin became available for the treatment of onchocerciasis, and its potential for mass treatment became apparent, 85% of those infected lived outside the range of the Onchocerciasis Control Programme (OCP). A new tool was urgently needed to determine the geographical distribution of the disease, and to identify which communities to treat.

A new tool to rapidly assess the onchocerciasis situation was developed, called 'rapid epidemiological mapping of onchocerciasis' or 'REMO'. Using this tool, communities at high risk from onchocerciasis could be quickly and cheaply identified and mapped.

REMO has become a key tool in the control of onchocerciasis. It is used to provide basic information for planning of large-scale ivermectin treatment. Complete country maps targeting areas for treatment are available. Integration of REMO with geographical information systems (GIS), has enabled control programmes to obtain better estimates of the number of people infected and the burden of disease.

REMO works by using geographical information, particularly the presence of river basins, to identify communities likely to be at high risk of onchocerciasis. A sample of these communities is then assessed for the prevalence of onchocerciasis by feeling for worm-containing nodules in 50 adults per village.


TDR's role in developing REMO was catalytic and proactive. TDR was a major driving force in initiating the process and bringing various players together. TDR:

  • Built on the knowledge and experiences of detailed mapping activities carried out by the OCP
  • Worked closely with WHO HealthMap to develop a geographic information system for analysis of the onchocerciasis data
  • Developed a REMO manual and guidelines for analysis of REMO results, in conjunction with control personnel
  • Carried out the first implementation of REMO and its first large-scale application, with funding from the World Bank
  • Worked in close collaboration with APOC (the African Programme for Onchocerciasis Control), which took over further implementation of REMO in 1996.