[3] These studies have demonstrated that M. perstans has the ability to induce a variety of clinical features, including angioedema Calabar-like swellings, pruritus, fever, headache, eosinophilia, and abdominal pain.

In 1890, the microfilariae of M. perstans were first discovered by Manson in the blood of a patient from West Africa who was hospitalized with sleeping sickness in London.

The adult worms of M. perstans were first recovered during post mortem examination of two aboriginal Indians in British Guiana from their mesentery and subpericardial fat.

[4] While Mansonella infections are often asymptomatic, they can be associated with angioedema (similar to Calabar swellings of loaisis), recurrent pruritic subcutaneous lesions, fever, headaches, arthralgia, and neurologic manifestations.

[6] This occurs when adult worms of M. perstans invade the conjunctiva or periorbital connective tissues in the eye.

The symptoms of M. perstans may be confounded with those of other filarial infections, such as onchocerciasis, lymphatic filariasis and loiasis, because coinfection often occurs.

Upon examination of the fundus of his left eye, a narrow, white, motionless, and linear lesion of 6–7 mm was found.

He was then treated with a second course of DEC (400 mg daily in two doses for eight days, after a three-day dosage increase), and by the end of treatment, he did not have pruritus, but his visual impairment was unchanged.

While ocular symptoms occur quite frequently in symptomatic M. perstans infection, intraocular localization had not been described prior to this study.

[8] M. perstans might potentially interfere with the host's regulatory mechanisms and influence the outcome of other infections, such as malaria, tuberculosis and HIV, which often thrive in similar environments.

Various species of Culicoides can be found worldwide, and in some areas, their high numbers make them a biting nuisance to humans and domestic animals.

Culicoides species are stout flies with short vertical probosces and wings folded scissor-like over their abdomens at rest.

During a blood meal, an infected midge (Culicoides grahami and C. austeni) introduces third-stage (L3) filarial larvae onto the skin of the human host, where they penetrate into the bite wound.

The DEC, or Mazzotti test, has been shown to have minor effects on microfilariae intensity, but it is not of practical use for diagnosis of mansonelliasis.

[12] Numerous trials evaluating traditional antifilarial drugs such as ivermectin and DEC, as well as other benzimidazoles such as mebendazole, albendazole, levamisole, and thiabendazole, have been conducted.

Recently, clinical trials assessing the effectiveness of doxycycline to treat M. perstans infection have also been documented.

[3] A 2009 study in Uganda evaluated the effects of ivermectin, albendazole, and a combined regimen of both drugs on M. perstans infected individuals: Single doses of ivermectin alone had no marked effect on M. perstans microfilaraemias in the 12 months after treatments, with the counts remaining to pretreatment values.

It has been more effective than both ivermectin and DEC—with a greater number of responders, a more significant reduction in microfilariae levels, and the ability to eliminate the infection more efficiently.

Thiabendazole has been shown to result in a small but significant decrease in microfilariae and in eosinophil count, and symptoms as treatment for symptomatic M. perstans infection.

[14] These markers were reduced even further following the administration of the second dose, showing that thiabendazole may be effective in M. perstans infection.

[14] In a recent comparative study, thiabendazole at a higher activity than single drug treatments such as ivermectin, DEC, and mebendazole, but lower activity than the combined regimen of mebendazole and DEC.[3] However, more research may be needed into confirm the correct dosage and true effectiveness of thiabendazole in combating M. perstans infection.

[3][15] Doxycycline has been shown to decrease the development, embryogenesis, and fertility of worms in species that harbor the intracellular endosymbiont Wolbachia.

Wolbachiae are bacterial endosymbionts of insects and many filarial nematodes, such as Onchocerca volvulus, Wuchereria bancrofti, and Brugia malayi.

[17] In 2009, Coulibaly et al. conducted an open-label randomized trial of doxycycline, an antibiotic, for Mansonella perstans infection.

[19] On one hand, doxycycline has been shown to be one of the only successful treatments for M. perstans, and could facilitate the eradication of filarial parasites.

However, some scientists argue that the treatment of filariasis with doxycycline may select worms that will have already integrated Wolbachia genes into their genome, which could potentially have unforeseen consequences.

Such lateral gene transfer has occurred in various geographic isolates of B. malayi, in which a fraction of the Wolbachia endosybmiont genome is integrated into the chromosome of its nematode host (the parasite).

[19] Combination treatments consisting of DEC plus mebendazole, or ivermectin and albendazole, have been shown to result in a highly significant fall in microfilariae.

M. perstans is also found in the Americas in Venezuela, Trinidad, Guyana, Suriname, northern Argentina and the Amazon basin.

Despite the high prevalence of M. perstans in areas of tropical Africa, such as Uganda, the Congo, the Republic of Cameroon, and Gabon, no vector programs have been instituted for any of the mansonelliasis-causing parasites.