Integrated rapid mapping of onchocerciasis and loiasis in the Democratic Republic of Congo: impact on control strategies.
BACKGROUND
Onchocerciasis can be effectively controlled by annual mass treatment with ivermectin in endemic communities. However, in communities that are endemic for loiasis there may be significant risk of severe adverse reactions after ivermectin treatment. Planning of control requires therefore mapping of these two infections using rapid assessment tools developed for each disease. These tools were initially implemented independently till the feasibility of combining them was demonstrated. This paper reports the results of integrated mapping in four epidemiological zones in the Democratic Republic of Congo and its implications on operational decision-making on ivermectin treatment.


METHODS
Rapid assessment surveys were conducted between 2004 and 2005 using both rapid epidemiological mapping of onchocerciasis (REMO) and rapid assessment procedure for loiasis (RAPLOA). The survey results were subjected to a spatial analysis in order to generate for each of the two diseases maps of the estimated prevalence of infection throughout the four zones.


RESULTS
Surveys were undertaken in 788 villages where 25,754 males were examined for palpable onchocercal nodules and 62,407 people were interviewed for history of eye worm. The results showed major differences in the geographic distribution of the two diseases. Loiasis was highly endemic in some areas, where special precautions were required, but not in others where routine ivermectin treatment could proceed.


CONCLUSIONS
Integrated rapid mapping of onchocerciasis and loiasis reduces both time and cost of surveys and greatly facilitates operational decision-making on ivermectin treatment in areas where loiasis might be co-endemic.
African Program for Onchocerciasis Control, Epidemiology and Vector Elimination, Rue Naba Zombre 1538, Sector 9 Door Number 1473, Ougadougou, Burkina Faso. afeworkh@oncho.afro.who.int
Afework Hailemariam
AH
Tekle
Honorat
H
Zoure
Samuel
S
Wanji
Stephen
S
Leak
Mounkaila
M
Noma
Jan H F
JH
Remme
Uche
U
Amazigo
D000818:Animals; D015023:Democratic Republic of the Congo; D019353:Endemic Diseases; D004812:Epidemiologic Methods; D005369:Filaricides / Q000627:therapeutic use; D006801:Humans; D007559:Ivermectin / Q000627:therapeutic use; D008117:Loa; D008118:Loiasis / Q000453:epidemiology* / Q000469:parasitology / Q000517:prevention & control; D008297:Male; D009854:Onchocerca; D009855:Onchocerciasis / Q000453:epidemiology* / Q000469:parasitology / Q000517:prevention & control; D015995:Prevalence; D013997:Time Factors
D005369:Filaricides; D007559:Ivermectin