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Mansonellosis

[Mansonella ozzardi] [Mansonella perstans] [Mansonella streptocerca]

Scolex of Mesocestoides sp. stained with carmine. In this field, two of the suckers are clearly visible. Note that lack of rostellar hooklets.

Microfilaria of M. perstans in a thick blood smear stained with Giemsa, from a patient from Cameroon.


Proglottids of Mesocestoides sp., collected from the stool of a dog.

Microfilaria of M. ozzardi in thick blood smears, stained with Giemsa.  Note the hook-like end to the tail.

Causal Agents

Filarid nematodes in the genus Mansonella: M. ozzardi, M. perstans, and M. streptocerca.


Life Cycle

Mansonella ozzardi

Life cycle of Brugia malayi

During a blood meal, an infected arthropod (midges, genus Culicoides, or blackflies, genus Simulium) introduces third-stage filarial larvae onto the skin of the human host, where they penetrate into the bite wound The number 1. They develop into adults that commonly reside in subcutaneous tissues The number 2. Adult worms are rarely found in humans. The size range for females worms is 65 to 81 mm in length and 0.21 to 0.25 mm in diameter but unknown for males. Adults worms recovered from experimentally infected Patas monkeys measured 24 to 28 mm in length and 70 to 80 µm in diameter (males) and 32 to 62 mm in length and .130 to .160 mm in diameter (females). Adults produce unsheathed and non-periodic microfilariae that reach the blood stream The number 3. The arthropod ingests microfilariae during a blood meal The number 4. After ingestion, the microfilariae migrate from the arthropod's midgut through the hemocoel to the thoracic muscles The number 5. There the microfilariae develop into first-stage larvae The number 6 and subsequently into third-stage infective larvae The number 7. The third-stage infective larvae migrate to arthropod's proboscis The number 8 and can infect another human when the arthropod takes a blood meal The number 1.

Mansonella perstans

Life cycle of Wuchereria bancrofti

During a blood meal, an infected midge (genus Culicoides) introduces third-stage filarial larvae onto the skin of the human host, where they penetrate into the bite wound The number 1. They develop into adults that reside in body cavities, most commonly the peritoneal cavity or pleural cavity, but less frequently in the pericardium The number 2. The size range for female worms is 70 to 80 mm in length and 120 µm in diameter, and the males measure approximately 45 mm by 60 µm. Adults produce unsheathed and subperiodic microfilariae, measuring 200 by 4.5 µm that reach the blood stream The number 3. A midge ingests microfilariae during a blood meal The number 4. After ingestion, the microfilariae migrate from the midge's midgut through the hemocoel to the thoracic muscles of the arthropod The number 5. There the microfilariae develop into first-stage larvae The number 6 and subsequently into third-stage infective larvae The number 7. The third-stage infective larvae migrate to the midge's proboscis The number 8 and can infect another human when the midge takes a blood meal The number 1.

Mansonella streptocerca

Life cycle of Wuchereria bancrofti

During a blood meal, an infected midge (genus Culicoides) introduces third-stage filarial larvae onto the skin of the human host, where they penetrate into the bite wound The number 1. They develop into adults that reside in the dermis, most commonly less than 1 mm from the skin surface The number 2. The females measure approximately 27 mm in length. Their diameter is 50 µm at the level of the vulva (anteriorly) and ovaries (near the posterior end), and up to 85 µm at the mid-body. Males measure 50 µm in diameter. Adults produce unsheathed and non-periodic microfilariae, measuring 180 to 240 µm by 3 to 5 µm, which reside in the skin but can also reach the peripheral blood The number 3. A midge ingests the microfilariae during a blood meal The number 4. After ingestion, the microfilariae migrate from the midge's midgut through the hemocoel to the thoracic muscles The number 5. There the microfilariae develop into first-stage larvae The number 6 and subsequently into third-stage larvae The number 7. The third-stage larvae migrate to the midge's proboscis The number 8 and can infect another human when the midge takes another blood meal The number 1.

Geographic Distribution

Mansonella streptocerca is found in Africa; Mansonella perstans occurs in both Africa and South America; and Mansonella ozzardi occurs only ins the Americas, from Mexico south to South America and in the Caribbean.

Clinical Presentation

Infections by Mansonella perstans, while often asymptomatic, can be associated with angioedema, pruritus, fever, headaches, arthralgias, and neurologic manifestations. Mansonella streptocerca can cause skin manifestations including pruritus, papular eruptions and pigmentation changes. Eosinophilia is often prominent in filarial infections. Mansonella ozzardi can cause symptoms that include arthralgias, headaches, fever, pulmonary symptoms, adenopathy, hepatomegaly, and pruritus.

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  • Page last reviewed November 29, 2013
  • Page last updated November 29, 2013
  • Content source: Global Health - Division of Parasitic Diseases and Malaria
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