As in the Americas, the objective of ESPEN working with Government Health Ministries and partner NGDOs, is the elimination of transmission of onchocerciasis. This requires consistent annual treatment of 80% of the population in endemic areas for at least 10–12 years – the life span of the adult worm. No African country has so far verified elimination of onchocerciasis, but treatment has stopped in some areas (e.g. Nigeria), following epidemiological and entomological assessments that indicated that no ongoing transmission could be detected. In 2015, WHO facilitated the launch of an elimination program in Yemen which was subsequently put on hold due to conflict.In 1992, the Onchocerciasis Elimination Programme for the Americas, which also relies on ivermectin, was launched. On July 29, 2013, the Pan American Health Organization (PAHO) announced that after 16 years of efforts, Colombia had become the first country in the world to eliminate onchocerciasis. In September 2015, the Onchocerciasis Elimination Program for the Americas announced that onchocerciasis only remained in a remote region on the border of Brazil and Venezuela. The area is home to the Yanomami indigenous people. The first countries to receive verification of elimination were Colombia in 2013, Ecuador in 2014, Mexico in 2015 and Guatemala in 2016. The key factor in elimination is mass administration of the antiparasitic drug ivermectin. The initial projection was that the disease would be eliminated from remaining foci in the Americas by 2012.No vaccine to prevent onchocerciasis infection in humans is available.
A grading system has been developed to categorize the degree of skin involvement:
Acute papular onchodermatitis – scattered pruritic papules
Chronic papular onchodermatitis – larger papules, resulting in hyperpigmentation
Lichenified onchodermatitis – hyperpigmented papules and plaques, with edema, lymphadenopathy, pruritus and common secondary bacterial infections
Skin atrophy – loss of elasticity, the skin resembles tissue paper, lizard skin appearance
Depigmentation – leopard skin appearance, usually on anterior lower leg
Glaucoma effect – eyes malfunction, begin to see shadows or nothingOcular involvement provides the common name associated with onchocerciasis, river blindness, and may involve any part of the eye from conjunctiva and cornea to uvea and posterior segment, including the retina and optic nerve. The microfilariae migrate to the surface of the cornea. Punctate keratitis occurs in the infected area. This clears up as the inflammation subsides. However, if the infection is chronic, sclerosing keratitis can occur, making the affected area become opaque. Over time, the entire cornea may become opaque, thus leading to blindness. Some evidence suggests the effect on the cornea is caused by an immune response to bacteria present in the worms.The infected persons skin is itchy, with severe rashes permanently damaging patches of skin. Mazzotti reaction
The Mazzotti reaction, first described in 1948, is a symptom complex seen in patients after undergoing treatment of onchocerciasis with the medication diethylcarbamazine (DEC). Mazzotti reactions can be life-threatening, and are characterized by fever, urticaria, swollen and tender lymph nodes, tachycardia, hypotension, arthralgias, oedema, and abdominal pain that occur within seven days of treatment of microfilariasis.