The importance of racial factors in the epidemiology and clinical manifestations of onchocercosis in the Afro-Ecuadorian and Chachi indigenous races, two distinct ethnic groups in the hyperendemic area of the Ecuadorian onchocercal focus, were evaluated. No difference in the disease prevalence among the two races was noted, although the Chachi had a significant higher dermal microfilariae intensity. Approximately 72.2% of the Afro-Ecuadorians presented with onchocercal skin lesions, as compared to 56.4% of the Chachi. Pretibial depigmentation, sowdah, scrotal elephantiasis and hydrocele were only documented in the Afro-Ecuadorians. Greater prevalence of palpable nodules was found in the Chachi (51.4% vs. 43.0%). Chachi presented with more nodules in the head (25.6% vs 17.6%) and iliac crest (40.1% vs. 30.3%) regions while the Blacks had more nodules in the sacrococcygeal region (18.2% vs 10.8%). Microfilariae in the anterior chamber was seen more frequently in the Chachi (51.9% vs 34.2%). However, a higher prevalence of chorioretinitis and optic atrophy was seen in the Afro-Ecuadorians (17.6% vs 11.2% and 8.5% vs 0.5% respectively). Several possible causes for these differences are discussed
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% presentaron lesiones oncocercóticas en la piel comparado con 56,4% en los Chachi. Se encontró mayor prevalencia de nódulos palpables en los Chachi (51,4% vs. 43,0%). La presencia de microfilarias en la cámara anterior del ojo fue más frecuente en los Chachi (51,9% vs. 34,2%), pero se evidenció una mayor prevalencia de corioretinitis y atrofia del nervio óptico en los Negros (17,6% vs 11,2% y 8,5% vs. 0,5%, respectivamente)