The prevalence of onchocerciasis infection was determined in communities on
7 rivers located in the northern area of the canton San Lorenzo, province
of Esmeraldas. Diagnosis of the infection was obtained by skin biopsies and
recombinant-antigen based-serology. No evidence of infection was detected
in 9 communities studied along the Rio Mataje, which forms the frontier
between Ecuador and Colombia, nor in 10 adjacent communities located on 5
interior rivers. Evidence for Onchocerca volvulus infection was found in 4
communities on the Rio Tululvi with the following prevalence: La Boca (3.5%
by biopsy and 3.9% by serology), Guayabal (9.1% by both biopsy and
serology), La Ceiva (51.5% by biopsy and 53% by serology), and Salidero (4%
by biopsy and 7.7% by serology). A few individuals in these communities
were seropositive for O. volvulus in the absence of detectable dermal
microfilariae: these might harbor very light or prepatent infections. No
clinical disease attributable to onchocerciasis was found. The infected
communities will be included in the ivermectin-based National Control
Program for the disease, with no evidence of the infection having extended
north of the Ecuadorian-colombian border.
