Mansonella perstans infection
Mansonella perstans infection occurs when a female 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 deep connective tissue and serous cavities, 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.
Mansonella perstans is highly prevalent in endemic regions in Africa and South America. Although often considered nonpathogenic with subclinical infections, M perstans can cause various symptoms including fever, arthralgia, fatigue, headache, conjunctival nodules, and abdominal pain. Cutaneous symptoms include pruritus, subcutaneous nodules, urticaria, and angioedema. In severe cases, M perstans can cause serositis, with pericarditis, hepatitis, or encephalitis.
Coinfection with other filarial diseases, especially Wuchereria bancrofti, is common. Treatment of M perstans infection is difficult as most antifilarial agents have limited efficacy. It has been recently discovered that certain strains of M perstans harbor the intracellular bacterial endosymbiont Wolbachia. These strains are effectively eradicated using anti-wolbachial therapy with doxycycline.
B74.4 – Mansonelliasis
420811004 – Infection caused by Mansonella perstans
Differential Diagnosis & Pitfalls
- 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 ozzardi infection – Causes pruritus, angioedema, and hyperpigmentation but not serositis. The disease is endemic to the Caribbean and South America. Similar to M perstans, there is peripheral eosinophilia, and microfilariae are detected on peripheral blood smear. On microscopic examination, the microfilariae differ from those of M perstans as they are sheathed and have pointed tails with small 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.