Guillermo Zea-Flores

Learn More
To eliminate transmission of Onchocerca volvulus, semiannual mass treatment with ivermectin (Mectizan; donated by Merck & Co) has been underway in Guatemala since 2000. We applied the 2001 World Health Organization (WHO) elimination criteria in the Santa Rosa focus of onchocerciasis transmission in Guatemala (10,923 persons at risk). No evidence of parasite(More)
Residents of five hyperendemic communities located in the central focus of onchocerciasis in Guatemala were treated with ivermectin (Mectizan) or placebo every six months for 30 months. The effects of treatment on prevalence and the intensity of skin infection (microfilarial skin density [MFD]) were evaluated. Significant and persistent reductions in both(More)
Adult Onchocerca volvulus, extracted from nodules before, and at intervals of two weeks to 12 months after, a single 150 micrograms/kg dose of ivermectin, were examined longitudinally and by sequential transverse sections. The mean number of male worms per nodule fell, and the proportion of nodules with no male worm rose, within two weeks of ivermectin and(More)
BACKGROUND Elimination of onchocerciasis (river blindness) through mass administration of ivermectin in the six countries in Latin America where it is endemic is considered feasible due to the relatively small size and geographic isolation of endemic foci. We evaluated whether transmission of onchocerciasis has been interrupted in the endemic focus of(More)
Onchocerca volvulus worms in nodules from Guatemalan patients treated with four, eight, or 11 single doses of ivermectin (150 micrograms/kg of body weight) that were given once every three months were examined by routine histologic techniques and compared with worms in control nodules from untreated persons living in the same location over the same time(More)
In Latin America, onchocerciasis is targeted for elimination by 2012 through twice-yearly mass treatment of the eligible population with ivermectin. In Guatemala, two of the four historical endemic foci have demonstrated elimination of transmission, following World Health Organization guidelines. Using established guidelines ophthalmological, serological,(More)
Skin punch biopsies were performed in 54 selected patients with onchocerciasis participating in a clinical trial with amocarzine (CGP 6140) in Ecuador and Guatemala. Skin snipping for counting microfilariae of Onchocerca volvulus was done before treatment (day 0) and day 4 and 8 following start of the therapy which consisted of 3 mg/kg amocarzine(More)
This paper assesses the effects on adult Onchocerca volvulus of monthly doses of ivermectin (150 micrograms/kg) given over 4, 8, and 12 months to patients in Guatemala. Nodules were removed 4 months after the last dose; the adult O. volvulus were extracted by collagenase digestion, studied by histological techniques, and compared with worms from untreated(More)
Adult Onchocerca volvulus worms, extracted from nodules of Guatemalans by collagenase digestion, were examined whole and by histological techniques. One group of persons received a single 150 micrograms/kg dose of ivermectin; two other groups (one with older and one with younger nodules) received four similar doses of ivermectin at 6-month intervals. For(More)
To assess the effect of ivermectin treatment on the immunologic status of individuals with onchocerciasis, 27 patients from Guatemala were studied before and at 6-month intervals during 2 years of repeated semiannual treatment with ivermectin. T cell proliferative responses to onchocercal antigen increased transiently by 6 months (mean stimulation index(More)