The phenomenon is so common when DEC is used that this drug is the basis of a skin patch test used to confirm that diagnosis. The drug patch is placed on the skin, and if the patient is infected with O. volvulus microfilaria, localized pruritus and urticaria are seen at the application site. Nodding disease
This is an unusual form of epidemic epilepsy associated with onchocerciasis although definitive link has not been established. This syndrome was first described in Tanzania by Louise Jilek-Aall, a Norwegian psychiatric doctor in Tanzanian practice, during the 1960s. It occurs most commonly in Uganda and South Sudan. It manifests itself in previously healthy 5–15-year-old children, is often triggered by eating or low temperatures and is accompanied by cognitive impairment. Seizures occur frequently and may be difficult to control. The electroencephalogram is abnormal but cerebrospinal fluid (CSF) and magnetic resonance imaging (MRI) are normal or show non-specific changes. If there are abnormalities on the MRI they are usually present in the hippocampus. Polymerase chain reaction testing of the CSF does not show the presence of the parasite. Cause
The cause is Onchocerca volvulus. Life cycle
The life of the parasite can be traced through the black fly and the human hosts in the following steps:
A Simulium female black fly takes a blood meal on an infected human host, and ingests microfilaria. The microfilaria enter the gut and thoracic flight muscles of the black fly, progressing into the first larval stage (J1.). The larvae mature into the second larval stage (J2.
The international scientific community was initially skeptical of Hisettes findings, but they were confirmed by the Harvard African Expedition of 1934, led by Richard P. Strong, an American physician of tropical medicine. Society and culture
Since 1987, ivermectin has been provided free of charge for use in humans by Merck through the Mectizan donation program (MDP). The MDP works together with ministries of health and nongovernmental development organisations, such as the World Health Organization, to provide free ivermectin to those who need it in endemic areas.In 2015 William C. Campbell and Satoshi Ōmura were co-awarded half of that years Nobel Prize in Physiology or Medicine for the discovery of the avermectin family of compounds, the forerunner of ivermectin. The latter has come to decrease the occurrence of lymphatic filariasis and onchocerciasis.Ugandas government, working with the Carter Center river blindness program since 1996, switched strategies for distribution of Mectizan. The male-dominated volunteer distribution system had failed to take advantage of traditional kinship structures and roles. The program switched in 2014 from village health teams to community distributors, primarily selecting women with the goal of assuring that everyone in the circle of their family and friends received river blindness information and Mectizan. Research
Animal models for the disease are somewhat limited, as the parasite only lives in primates, but there are close parallels. Litomosoides sigmodontis , which will naturally infect cotton rats, has been found to fully develop in BALB/c mice.