Control of onchocerciasis currently focuses on community-directed treatment with the microfilaricide ivermectin which effectively kills Onchocerca volvulus microfilariae in the human host. The feasibility of elimination by this control strategy has recently been reported for some foci in Africa which has rekindled discussions on evaluating the threshold conditions of elimination of onchocercias...

A method for the selective recovery of living microfilariae from Onchocerca volvulus nodules is described. The microfilariae migrate through solidified agar gel into overlayering Hanks balanced salt solution (HBSS). The highest recovery rates of the worms were obtained with 0.3 and 0.4% agar. Optimal conditions for in vitro cultures of the larvae in HBSS were established; pH range 7.0-7.5, gluc...

Recent studies on the biology and ecology of adult blackflies in relation to the transmission of human onchocerciasis in Guatemala are reviewed. First, earlier studies on the transmission of the disease since its discovery by Dr. R. Robles in 1915 are outlined. Second, eleven blackfly species caught on humans are evaluated for vector status on the basis of their natural and experimental infecti...

We report here the evaluation of the potential of a serologic test to determine the endemicity of onchocercal infection in hyper, meso, and hypoendemic communities by the detection of antibodies to a cocktail of recombinant antigens. Parasitologic parameters of infection prevalence and intensity were compared with serologic results. Infection prevalence by serology was consistently but not sign...

An understanding of the nature of the chromosomes of the filariae is expected to greatly assist the future interpretation of genome data. Filarial development is not eutelic, and there does not seem to be a fixed number of cell divisions in the way that there is in Caenorhabditis. It is not clear whether the chromosomes of the filariae have localized centromeres or whether they are holocentric....

Regular distribution of ivermectin reduces onchocerciasis transmission and morbidity by killing, within humans, the microfilarial stage of the parasite (microfilaricidal effect). In addition, ivermectin exerts a so-called embryostatic effect by which microfilarial production by the adult female worm becomes suppressed during a number of weeks after treatment. To assess the overall effect of ive...

BACKGROUND Recent studies in Mali, Nigeria, and Senegal have indicated that annual (or biannual) ivermectin distribution may lead to local elimination of human onchocerciasis in certain African foci. Modelling-based projections have been used to estimate the required duration of ivermectin distribution to reach elimination. A crucial assumption has been that microfilarial production by Onchocer...

BACKGROUND Ivermectin (IVM) has been used in Ghana for over two decades for onchocerciasis control. In recent years there have been reports of persistent microfilaridermias despite multiple treatments. This has necessitated a reexamination of its microfilaricidal and suppressive effects on reproduction in the adult female Onchocerca volvulus. In an initial study, we demonstrated the continued p...

BACKGROUND This study was carried out in Opi-Agu a tropical semi-urban autonomous community comprising of three villages in Enugu State, Nigeria, between the months of April and June 2010. It was designed to determine the prevalence of Onchocerca volvulus infection and assess the perception of the disease among the inhabitants of this community. METHODS A total number of 305 individuals compr...

To investigate the impact of mass ivermectin treatments in Mexico on Onchocerca volvulus transmission, entomologic surveys were carried out in the two endemic states of Oaxaca and Chiapas. The data suggest that substantial progress towards the goal of elimination has been made. A comparison pre- and post-ivermectin data from a community in Southern Chiapas showed a 97% decrease in seasonal tran...