Mansonella		Contents		Rev 05/19/2026
		Classification		Hosts
		Morphology and Anatomy		Life Cycle
Return to Mansonella Menu		Economic Importance		Damage
		Distribution		Management
Return to Onchocercidae Menu		Feeding		References
		Nemaplex Home Page		Go to Dictionary of Terminology

Classification:

Nematoda

Chromadorea
Spiruria

Spirurida

            Filarioidea

   Onchocercidae

Mansonella Faust, 1929

Type species of the genus: Mansonella ozzardi (Manson, 1897) Faust, 1929

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Morphology and Anatomy:

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Distribution:

Mansonella perstans is endemic throughout West, East, and Central Africa, and is also highly prevalent in some neotropical regions of Central and South America where it was likely introduced.

M. ozzardi is a New World species with a patchy distribution, and is found in Central America, South America (Argentina, Bolivia, Brazil, Colombia, Guyana, Suriname and Venezuela) and several Caribbean islands.

M. streptocerca is an Old World species that occurs in tropical regions of West and Central Africa.

Generally, the transmission of Mansonella spp. is highly focal and local prevalence varies widely within endemic regions. Travel-related cases in residents of non-endemic countries are unusual but have been documented.

CDC, 2018

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Economic Importance:

Vector-borne filarial nematodes, several are parasitic in humans:

• M. perstans primarily human-associated; vectors are biting midges of the genus Culicoides.

• M. ozzardi primarily human-associated but patas monkeys (Erythrocebus patas) have been experimentally infected. Primary vectors are biting midges of the genus Culicoides. In some areas of South America, the black fly Simulium amazonicum and in Haiti, the midge Leptoconops bequaerti may act as concurrent vectors.

• M. streptocerca is primarily a parasite of humans, but infections in wild chimpanzees have been reported on rare occasions. Primary vectors are biting midges of the genus Culicoides.

Ref: CDC DPDx 2018

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Feeding:

Food Sources and Feeding strategies for the genus Mansonella

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Biology and Epidemiology

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Hosts:

Humans

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Life Cycle:

Filarioid nematodes are subcutaneous parasites transmitted by the bite of hematophagous arthropods which harbor a larval stage.

Mansonella perstans example: During a blood meal, an infected midge introduces third-stage (L3) larvae onto the skin of the human host, where they penetrate into the bite wound  . They develop into adults that reside in body cavities, most commonly the peritoneal cavity or pleural cavity, and less frequently in the pericardium  . The size range for female worms is 70 to 80 mm in length and 120 um in diameter, and the males measure approximately 45 mm by 60 um. Adults produce unsheathed, subperiodic microfilariae (200 um long, 4.5 um wide) which enter peripheral circulation  . A midge vector ingests microfilariae during a blood meal  . After ingestion, the microfilariae migrate from the midge’s midgut through the hemocoel to the thoracic muscles of the arthropod  . There the microfilariae develop into first-stage larvae  and subsequently into third-stage infective larvae  . The third-stage infective larvae migrate to the midge’s proboscis  and can infect another human when the midge takes a blood meal  .

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Damage:

Causal agents of Mansonellosis

Symptoms of mansonellosis are generally mild and many infections are asymptomatic, particularly among individuals living in endemic regions. A complicattion is that the geographic distribution Mansonella infections overlaps with that of other filarial diseases.  It can be difficult to be certain that symptoms identified in studies of patients in endemic areas were due to Mansonella or to co-infection with other parasites.

 When symptoms occur they appear related to migration of adult worms and include transient subcutaneous swellings (similar to those caused by Loa loa), pericarditis and pleuritis, and ocular symptoms (e.g., impaired visual acuity) if microfilariae enter the eye. Non-specific symptoms including fever, fatigue, pruritus, arthralgias, and abdominal pain may occur. Headache and neuropsychiatric symptoms also have been reported. Signs may include lymphadenopathy and eosinophilia (CDC DPDx 2018).

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Management:

Vector control.

Infections can be treated with ivermectin.

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References:

CDC 2018. National Center for emerging and zoonotic indectious diseases (NCEZID); Division of Parastic Diseases and Malaria.

Simonsen, P.E., Onapa, A.W. Asio, S.M. 2011S109-S120. Mansonella perstans filariasis in Africa. Acta Tropica 1205:S109-S120,