RESUMO
Considerable variation in the frequency of the clinical manifestations of onchocerciasis was seen in the individual endemic foci of the disease in province of Esmeraldas, Ecuador. In hypoendemic areas, 84.6% of all microfilaria-positive inhabitants were found to be free of any clinical manifestations of the disease, whereas in the hyperendemic area clinical manifestations were present in 57.9% of those infected. Ocular keratitis, macular papular rash of the skin and subcutaneous onchocercal nodules of varying frequency were the major clinical variants. Long-standing onchodermatitis and hypertrophy of the skin were rarely seen. Clinical evidence of prolonged ocular and skin invasion by microfilariae was seen only in the hyperendemic area. Of the 26.1% of the microfilaria-positive inhabitants who had onchocercal nodules, 91.7% lived in the hyperendemic area. 41.1% of all nodules occurred in the region of the iliac crest. Clinical conditions associated with high microfilarial density, i.e., elephantiasis of the legs and scrotum, lymphadenopathy, hanging groin, hydrocele and inguinal hernia were seen only in the hyperendemic area. The clinical features were similar to those seen in Africa, but the low incidence of the clinical presentation and severity of the disease suggested a recent infestation of the province.
Assuntos
Oncocercose/patologia , Equador , Olho/patologia , Humanos , Ceratite/etiologia , Linfonodos/patologia , Oncocercose/complicações , Oncocercose/epidemiologia , Pele/patologiaRESUMO
The frequency, intensity and clinical features of onchocerciasis in the two ethnic groups (Blacks and Chachilla--an indigenous tribe) in the endemic foci of the disease in Esmeraldas province (Ecuador) were evaluated. The incidence of infection and intensity of the disease seen in both groups were directly related to the frequency of man-vector contact and not to racial factors. Both groups showed the same rate of positivity in both the hyperendemic and hypoendemic areas. Males of both groups had a consistently higher positivity rate than did females. The Chachilla were found to have a higher mean microfilarial density than Blacks in both types of endemic areas. Certain clinical features of the disease analogous to those seen in the African form were present only in Blacks. No lymphatic involvement or hypertrophic scarring was seen in the Chachilla, suggesting that in the Blacks there may be a generaically related predisposition to lymphatic complications of microfilarial infections.
Assuntos
Etnicidade , Oncocercose/epidemiologia , Adolescente , Adulto , Negro ou Afro-Americano , Fatores Etários , População Negra , Criança , Pré-Escolar , Equador , Feminino , Humanos , Lactente , Masculino , Microfilárias , Pessoa de Meia-Idade , Oncocercose/parasitologia , Oncocercose/patologia , Fatores Sexuais , Pele/parasitologiaRESUMO
In the province of Esmeraldas in Ecuador, 11 endemic foci of onchocerciasis were identified. The major focus, located on Rio Cayapas, consisted of 65 contiguous positive communities with an average infection rate of 51.1%. A distance-dependent characteristic of the onchocerciasis infection suggested that the transmission was centered principally in the areas near the head-waters of the river. This area, inhabited primarily by the indigenous tribe, Chachi, with an infection rate of 85%, was considered an area of hyperendemicity. Towards the river's mouth, where the majority of the inhabitants were Blacks, the rate of infection was 7%. The endemic focus located on Rio Santiago, populated entirely by Blacks and consisting of 17 contiguous positive communities, had an average infection rate of 18.8%. Again, the highest rate of infection, 33%, occurred in the upper reaches of the river. Resulting from the transient and migratory activity of some microfilariae-positive persons, 9 other isolated foci were found dispersed throughout the province. The infection rate of each focus was distinct, reflecting geographical location and ethnic composition. All foci other than the interior regions of Rio Cayapas were areas of hypoendemicity.
Assuntos
Ectoparasitoses/epidemiologia , Oncocercose/epidemiologia , Adolescente , Adulto , Fatores Etários , Animais , População Negra , Criança , Pré-Escolar , Ectoparasitoses/parasitologia , Equador , Feminino , Água Doce , Humanos , Indígenas Sul-Americanos , Lactente , Masculino , Pessoa de Meia-Idade , Onchocerca/isolamento & purificação , Oncocercose/parasitologia , Densidade Demográfica , Saúde da População Rural , Fatores Sexuais , Pele/parasitologia , MigrantesRESUMO
The epidemiology of infection was studied in all endemic foci of onchocerciasis in the province of Esmeraldas in Ecuador. The incidence of infection and the density of microfilariae in the skin, both greater in males than females, increased with age, reaching highest levels at 40-45 years in males and at 60 years and older in females. In the hyperendemic area males and females had the same rate of infection, but the microfilarial density in males exceeded that in females. In the hypoendemic areas males had a higher infection rate than females, but females registered a higher density of microfilariae in the skin. The incidence and location of the onchocercal nodules correlated closely with the density of microfilariae. Adults, aged 50-54 had the highest prevalence of onchocercal nodules, which occurred primarily in the thorax and pelvic regions. Children aged 0-14 years showed a low prevalence of nodules, the head region being the primary site. Of the two diagnostic methods used to detect the presence of microfilariae, most of the diagnoses (85.6%) were made by skin biopsies as compared to those made by the Mazzotti test (14.4%).