Ongoing Transmission of Onchocerca volvulus after 25 Years of Annual Ivermectin Mass Treatments in the Vina du Nord River Valley, in North Cameroon (original) (raw)
Fig 4
Annual transmission potentials.
Annual transmission potentials of Onchocerca spp. from two onchocerciasis foci in North Cameroon. Data is given at the beginning of the rainy season (April) till the end of the dry season (March of the following year). Dark grey: O. ramachandrini; light grey: O. ochengi; white: O. volvulus. Insufficient fly dissection data from 1986, 1989–1992 in Soramboum, and from 1985–1987, 1990 and 1997 in Galim have been extrapolated. In 1976 (color transition of white, light grey to dark grey) no species discrimination was done. ATP with available MTP data ≥ 80% have borders in bold; those with data 80% > x ≥ 30% have normal borders, and those with data < 30% have borders with a dotted line. The dotted line marks the beginning of ivermectin mass treatments. The asterisk indicates the introduction of PCR-based methods for species discrimination in the vector. Prior to 1990, the L3 species was determined according to the following body length criteria: O. volvulus ≤ 750 μm; 750 μm < O. ochengi < 900 μm; O. ramachandrini ≥ 900 μm. A Soramboum, Vina du Nord. Epidemiological data prior to 1998 was published before and modified to fit this graph. Data from 1976 was taken from Touboro, 30 km further downstream. B Galim, Vina du Sud. Epidemiological data prior to 1997 was published before and modified to fit this graph.