Mansonella ozzardi causes 1 of 3 forms of human mansonelliasis, along with Mansonella perstans and Mansonella streptocerca. Mansonella ozzardi is transmitted by Culicoides biting midges in the Caribbean and Simulium blackflies in mainland South America. This infection is more prevalent in men. Farmers and fisherman are at higher risk.
Mansonella ozzardi infection occurs when a midge takes a blood meal from a human, which allows the transfer of filarial larvae to the bite wound. The filarial larvae develop into adults in subcutaneous tissue, mesenteries, and peritoneum, where they produce microfilariae. When a midge takes a blood meal from an infected host, the microfilariae are ingested and develop into larvae in the midge's gastrointestinal tract.
Infection by M. ozzardi is usually asymptomatic. If symptomatic, initial symptoms may include fever, arthralgias, headache, dizziness, coldness in the legs, adenopathy, and hepatomegaly. Cutaneous symptoms include pruritus, angioedema, and hyperpigmentation. Ocular lesions, primarily nummular keratitis, may occur. Peripheral eosinophilia is a characteristic finding.
Codes
ICD10CM: B74.4 – Mansonelliasis
SNOMEDCT: 30865009 – Ozzardian filariasis
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Differential Diagnosis & Pitfalls
Other filarial diseases:
Streptocerciasis (Mansonella streptocerca infection) – Causes shoulder or chest dermatitis and hypopigmentation in an adult patient. The disease is endemic to Central and West Africa.
Mansonella perstans (Dipetalonema perstans) infection – Causes painless conjunctival nodules, pruritus, and serous cavity filariasis. The disease is endemic to Africa and South America. Similar to M. ozzardi, there is peripheral eosinophilia, and microfilariae are detected on peripheral blood smear. However, microfilariae are notably absent from the skin. On microscopic examination, the microfilariae differ from those of M. ozzardi as they are unsheathed and have blunt-ended tails with big nuclei.
Onchocerciasis (Onchocerca volvulus) – Causes cutaneous disease and river blindness. Cutaneous symptoms include papular dermatitis, pruritus, lichenification, atrophy, and a "leopard-skin" depigmentation. The disease is endemic to Africa, Latin America, and the Middle East.
Loiasis (Loa loa) – Causes subcutaneous and ocular filariasis. Cutaneous symptoms include localized swellings, angioedema, and pruritus. The disease is endemic to Central and West Africa.
Pruritus secondary to other systemic diseases, including renal or liver failure, thyroid disease, lymphoma, or human immunodeficiency virus infection, among other causes.
