River blindness: a success story under threat?

María-Gloria Basáñez, Sébastien D S Pion, Thomas S Churcher, Lutz P Breitling, Mark P Little, Michel Boussinesq, María-Gloria Basáñez, Sébastien D S Pion, Thomas S Churcher, Lutz P Breitling, Mark P Little, Michel Boussinesq

Abstract

The success of the Onchocerciasis Control Programme is undeniable and exemplary, say the authors, but it is too early to claim victory against river blindness.

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1. Life Cycle of O. volvulus
Figure 1. Life Cycle of O. volvulus
Mean dimensions of parasite stages are: Adult females, 35–70 cm × 400 µm; adult males, 2–4 cm × 150–200 µm; microfilariae, 250–360 × 5–9 µm; L1 larvae, 200 µm × 12 µm (front) and 20 µm (rear); L3, 440–700 × 20 µm. L1 larvae molt into L2, pre-infective larvae, and L2 into L3, infective larvae [5]. (Illustration: Giovanni Maki, derived from a CDC image at http://www.dpd.cdc.gov/dpdx/HTML/Filariasis.htm)
Figure 2. Distribution of Onchocerciasis Showing Current…
Figure 2. Distribution of Onchocerciasis Showing Current Status of Global Onchocerciasis Control
Red areas represent areas receiving ivermectin treatment. Yellow areas represent areas requiring further epidemiological surveys. The green area is the area covered by the Onchocerciasis Control Programme in West Africa. Pink zones indicate the special intervention zones, i.e., previous OCP areas receiving ivermectin and some vector control. Map redrawn from [53,75,76]
Figure 3. The Incidence of Blindness and…
Figure 3. The Incidence of Blindness and Excess Mortality Rate, by Sex, Plotted against O. volvulus Microfilarial Load
Arithmetic mean of microfilarial counts from two skin snips, taken from the right and left ileac crests, using a 2-millimeter Holth corneoscleral punch. (A) Blindness; (B) excess mortality rate. Error bars denote 95 percent confidence intervals [10,22].

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