Mansonelliasis  is the condition of infection by the nematode Mansonella. The disease exists in Africa and tropical Americas, spread by biting midges or blackflies. It is usually asymptomatic. Symptoms and signs
Infections by Mansonella perstans, while often asymptomatic, can be associated with angioedema, pruritus, fever, headaches, arthralgias, and neurologic manifestations. Mansonella streptocerca can manifest on the skin via pruritus, papular eruptions and pigmentation changes. Mansonella ozzardi can cause symptoms that include arthralgias, headaches, fever, pulmonary symptoms, adenopathy, hepatomegaly, and pruritus. Eosinophilia is often prominent but do not occur in all cases of Mansonelliasis. M. perstans can also present with Calabar-like swellings, hives, and a condition known as Kampala, or Ugandan eye worm. This occurs when adult M. perstans invades the conjunctiva or periorbital connective tissues in the eye. M. perstans can also present with hydrocele in South America. However, it is often hard to distinguish between the symptoms of Mansonelliasis and other nematode infections endemic to the same areas. Causes
Mansonelliasis is caused by nematodes (roundworms) in the Mansonella genus that reside in the skin or certain body cavities. The specific species are M. perstans, M. streptocerca and M. ozzardi. Vectors and life cycle
During a blood meal, an infected midge (genus Culicoides) or blackfly (genus Simulium) introduces third-stage filarial larvae onto the skin of the human host, where they penetrate into the bite wound.
This allows for the microfilariae that would have been in the tissue to migrate to the liquid phase of the specimen. Additionally, to differentiate the skin-dwelling filariae M. streptocerca and Onchocerca volvulus, a nested polymerase chain reaction (PCR) assay was developed using small amounts of parasite material present in skin biopsies. Prevention
Prevention can be partially achieved through limiting contact with vectors through the use of DEET and other repellents, but due to the predominantly relatively mild symptoms and the infection being generally asymptomatic, little has formally been done to control the disease. Treatment
There is no consensus on optimal therapeutic approach. The most commonly used drug is diethylcarbamazine (DEC), but it is, however, often ineffective. Although other drugs have been tried such as praziquantel, ivermectin, and albendozole, none has proven to be reliably and rapidly effective. Mebendazole appeared more active than DEC in eliminating the infection, and had comparable overall responses. Thiabendazole evidenced a small, but significant activity against the infection. A combination of treatments, DEC plus mebendazole, was much more effective than single drug doses. Epidemiology
Mansonelliasis is found in Latin America from the Yucatán peninsula to northern Argentina, in the Caribbean, and in Africa from Senegal to Kenya and south to Angola and Zimbabwe. M. ozzardi is found only in the New World, M. steptocerca is found only in the Congo Basin, and M. perstans is found in both the previously described areas of Africa and Latin America.