Mansonella perstans

Mansonella perstans

Microfilariae of Mansonella perstans (left) and Loa loa (right)

Mansonella perstans is a species of filarial nematode that causes the disease known as mansonelliasis. It is one of the three filarial species that infect humans, the others being Mansonella ozzardi and Mansonella streptocerca. M. perstans is transmitted by the bite of infected Culicoides midges.

Morphology

Mansonella perstans is characterized by its microfilariae, which are unsheathed and measure approximately 200 micrometers in length. The microfilariae can be found in the peripheral blood of infected individuals.

Life Cycle

The life cycle of Mansonella perstans involves two hosts: humans and Culicoides midges. The adult worms reside in the body cavities of humans, such as the peritoneal cavity. Female worms release microfilariae into the bloodstream, where they can be ingested by a biting midge. Inside the midge, the microfilariae develop into infective larvae, which are then transmitted to a new human host when the midge takes a blood meal.

Epidemiology

Mansonella perstans is primarily found in sub-Saharan Africa, with some cases reported in Central and South America. The distribution of the disease is closely linked to the habitat of the Culicoides midges that serve as vectors.

Clinical Manifestations

Infection with Mansonella perstans is often asymptomatic, but some individuals may experience symptoms such as itching, joint pain, and swelling. In rare cases, more severe symptoms can occur, including abdominal pain and neurological manifestations.

Diagnosis

Diagnosis of Mansonella perstans infection is typically made by identifying the microfilariae in blood smears. Blood samples are usually collected at night when microfilariae are most abundant in the peripheral blood.

Treatment

Treatment of Mansonella perstans infection can be challenging. The drug diethylcarbamazine (DEC) is not effective against this species. Ivermectin and albendazole have been used with varying success.

Prevention

Preventive measures focus on reducing exposure to the bites of infected Culicoides midges. This can include the use of insect repellent, protective clothing, and insecticide-treated bed nets.

Related Pages

• Mansonelliasis
• Culicoides
• Filariasis
• Nematode