The effect of antimalarial chloroquine therapy and prophylaxis on concurrent infection with Onchocerca volvulus in Ecuador.

The effect of chloroquine phosphate on Onchocerca volvulus in vivo was studied in Ecuadorians undergoing treatment for malaria. All persons with a diagnosis of acute malaria and treated with 2500 mg of chloroquine over 3 d showed a 100% reduction of dermal O. volvulus microfilariae 7 d after treatment. However, 28 d after treatment the microfilarial densities returned to their pre-treatment levels and at 35 d they had increased to 121.6% of their pre-treatment values. Treatment did not appear to have any effect on the adult O. volvulus examined histologically in extirpated nodules. Patients treated for acute malaria and subsequently kept on a prophylactic regimen of 500 mg chloroquine weekly showed a reduction of 56.7% from pre-treatment microfilarial density after 27 weeks. Patients who underwent nodulectomy as well as treatment for acute malaria and were given 500 mg of chloroquine prophylactically for 27 weeks showed a reduction in dermal microfilarial density of 93.6%. Symptoms of onchocerciasis were reduced in the latter group of patients, with the elimination of all acute dermatological changes within 6 weeks. Ocular examination of these surgically and chemotherapeutically treated individuals revealed reductions of 94.9% of microfilariae in the anterior chamber, 95.9% of live microfilariae in the cornea, and 95.1% of dead microfilariae in the cornea. There was a reduction of 69.8% in corneal fluffy opacities. No alteration in the visual acuity or in visible lesions in the posterior segment was recorded. The results suggest that a complex interaction between chloroquine and O. volvulus takes place in vivo, which can be beneficial to the patient over a long period.(ABSTRACT TRUNCATED AT 250 WORDS)

Onchocerciasis in Ecuador, 1980-1986: epidemiological evaluation of the disease in the Esmeraldas province.

An increase in both the prevalence (68.3%) and intensity of infection (106.2%) occurred in the Ecuadorian onchocercal focus during the 6 year period, 1980 to 1986. In 1986, a higher prevalence of infection was noted in males (53.6%) than females (33.1%), but a greater rate of increase of infection over the 6 years was seen in females than males (75.7% vs 61.9% respectively). In all endemic areas, the Chachi race had a higher prevalence of infection as well as higher increase rate of infection than the Black. In the hyperendemic and hypoendemic areas the highest increase of infection was seen in the Chachi female and Chachi male respectively. The prevalence of infection in 1986 was greater than that in 1980 for all ages, with the greatest increase of infection in the 1-4 year age groups. There was an average increase of 106.2% in the microfilarial skin density with an increase seen in all age groups. A higher microfilariae density increase was seen in the hypoendemic (100.0%) than the hyperendemic (66.5%) areas. The Blacks showed a greater microfilarial density increase than the Chachi (155.1% vs 70.7% respectively) with the Black female showing the highest increase (117.6%) in the hyperendemic area and the Black male showing the highest (155.6%) in the hypoendemic area. Along the Rio Cayapas, high microfilarial densities were found in 3 major areas on the river, a reflection of man-vector exposure.

Onchodermatitis--correlation between skin disease and parasitic load in an endemic focus in Ecuador.

Onchocerciasis is a chronic parasitic infection in which infiltration of the skin by microfilariae has been associated with a number of different pathological changes. This survey compared the prevalence of different forms of skin disease in two villages, one of which was located within the endemic zone for onchocerciasis (Zapallo Grande), in a lowland rain forest area of western Ecuador. The commonest skin diseases in both villages were scabies, pyoderma and pityriasis versicolor. In addition changes closely correlated with the presence of microfilariae in skin snips were found in Zapallo Grande--such as atrophic gluteal changes, and acute and chronic papular dermatitis. The only other skin disease associated with onchocerciasis was widespread tinea corporis due to T. rubrum. The Amerindians in the endemic onchocerciasis area were more likely than Negroes to have generalized atrophic changes of the skin, whereas in the latter group significant numbers of individuals had no obvious skin lesions but large numbers of microfilariae were detected in skin snips. Acute papular dermatitis was common in both groups and in biopsied lesions microfilariae could usually be identified within the epidermis or close to the dermo-epidermal junction. One patient had developed severe reactive onchodermatitis (Sowda). Swabs taken from onchocercal skin lesions showed no evidence of skin surface carriage of Staphylococcus aureus. Changes classically associated with onchocerciasis such as pretibial hypopigmentation (leopard skin) and hanging groin were notably absent in this population.

Onchocerciasis in Ecuador: absence of microfilaraemia.

Blood samples from 497 people positive for onchocerciasis in the hyperendemic onchocercal focus in Ecuador were analysed for the presence of microfilaraemia using the Knott technique. No evidence of Onchocerca volvulus microfilaraemia was found, nor that of any other microfilaria.