Estudios comparativos clínicos y epidemiológicos de la oncocercosis entre dos grupos raciales del área hiperendémica de Ecuador / Comparative clinical and epidemiological studies between 2 racial groups in the hyperendemic area of onchocercosis in Ecuador

Se evaluó la importancia de los factores raciales en la epidemiología y las manifestaciones clínicas de la oncocercosis en la raza negra y la raza indígena Chachi, dos grupos étnicos diferentes del área hiperendémica del foco oncocercótico ecuatoriano. Los Chachi presentaron una significativa mayor densidad de microfilarias en la piel. De los negros, 72,2 por ciento presentaron lesiones oncocercóticas en la piel comparado con 56,4 por ciento en los Chachi. Se encontró mayor prevalencia de nódulos palpables en los Chachi (51,4 por ciento vs. 43,0 por ciento). La presencia de microfilarias en la cámara anterior del ojo fue más frecuente en los Chachi (51,9 por ciento vs. 34,2 por ciento), pero se evidenció una mayor prevalencia de corioretinitis y atrofia del nervio óptico en los negros (17,6 por ciento vs 11,2 por ciento y 8,5 por ciento vs. 0,5 por ciento, respectivamente)

Onchocerciasis in Ecuador: prevalence of infection on the Ecuador-Colombia border in the Province of Esmeraldas

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 per cent by biopsy and 3,9 per cent by serology), Guayabal (9,1 per cent by both biopsy and serology), La Ceiva (51,5 per cent by biopsy and 53 per cent by serology), and Salidero (4 per cent by biopsy and 7,7 per cent 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.