Macrofilaricides and onchocerciasis control, mathematical modelling of the prospects for elimination.
BACKGROUND
In most endemic parts of the world, onchocerciasis (river blindness) control relies, or will soon rely, exclusively on mass treatment with the microfilaricide ivermectin. Worldwide eradication of the parasite by means of this drug is unlikely. Macrofilaricidal drugs are currently being developed for human use.


METHODS
We used ONCHOSIM, a microsimulation mathematical model of the dynamics of onchocerciasis transmission, to explore the potentials of a hypothetical macrofilaricidal drug for the elimination of onchocerciasis under different epidemiological conditions, as characterized by previous intervention strategies, vectorial capacity and levels of coverage.


RESULTS
With a high vector biting rate and poor coverage, a very effective macrofilaricide would appear to have a substantially higher potential for achieving elimination of the parasite than does ivermectin.


CONCLUSIONS
Macrofilaricides have a substantially higher potential for achieving onchocerciasis elimination than ivermectin, but high coverage levels are still key. When these drugs become available, onchocerciasis elimination strategies should be reconsidered. In view of the impact of control efforts preceding the introduction of macrofilaricides on the success of elimination, it is important to sustain current control efforts.
Alley
W S
WS
Onchocerciasis Control Programme, World Health Organization, Ouagadougou, Burkina Faso.
van Oortmarssen
G J
GJ
Boatin
B A
BA
Nagelkerke
N J
NJ
Plaisier
A P
AP
Remme
J H
JH
Lazdins
J
J
Borsboom
G J
GJ
Habbema
J D
JD
D000818:Animals; D000969:Antinematodal Agents / Q000008:administration & dosage / Q000627:therapeutic use; D003140:Communicable Disease Control; D003198:Computer Simulation; D005369:Filaricides / Q000008:administration & dosage / Q000627:therapeutic use*; D006801:Humans; D007303:Insect Vectors; D007559:Ivermectin / Q000008:administration & dosage / Q000627:therapeutic use; D017181:Onchocerca volvulus / Q000187:drug effects / Q000472:pathogenicity; D009855:Onchocerciasis / Q000188:drug therapy* / Q000453:epidemiology / Q000517:prevention & control*; D012984:Software
D000969:Antinematodal Agents; D005369:Filaricides; D007559:Ivermectin