The search for better treatment strategies for mansonellosis: an expert perspective

ABSTRACT

Introduction

Four species of the Mansonella genus infect millions of people across sub-Saharan Africa and Central and South America. Most infections are asymptomatic, but mansonellosis can be associated with nonspecific clinical manifestations such as fever, headache, arthralgia, and ocular lesions (M. ozzardi); pruritus, arthralgia, abdominal pain, angioedema, skin rash, and fatigue (M. perstans and perhaps Mansonella sp. ‘DEUX’); and pruritic dermatitis and chronic lymphadenitis (M. perstans).

Areas covered

We searched the PubMed and SciELO databases for publications on mansonelliasis in English, Spanish, Portuguese, or French that appeared until 1 May 2023. Literature data show that anthelmintics – single-dose ivermectin for M. ozzardi, repeated doses of mebendazole alone or in combination with diethylcarbamazine (DEC) for M. perstans, and DEC alone for M. streptocerca – are effective against microfilariae. Antibiotics that target Wolbachia endosymbionts, such as doxycycline, are likely to kill adult worms of most, if not all, Mansonella species, but the currently recommended 6-week regimen is relatively impractical. New anthelmintics and shorter antibiotic regimens (e.g. with rifampin) have shown promise in experimental filarial infections and may proceed to clinical trials.

Expert opinion

We recommend that human infections with Mansonella species be treated, regardless of any apparent clinical manifestations. We argue that mansonellosis, despite being widely considered a benign infection, may represent a direct or indirect cause of significant morbidity that remains poorly characterized at present.

KEYWORDS:

• Mansonella ozzardi
• Mansonella perstans
• Mansonella streptocerca
• Mansonella sp. ‘DEUX‘
• ivermectin
• diethylcarbamazine
• mebendazole
• albendazole
• doxycycline
• Wolbachia

Article highlights

• Mansonellosis affects hundreds of millions of people across Africa and Central and South America.

• We recommend that human infections with Mansonella species be treated, regardless of any apparent clinical manifestations.

• Anthelmintics such as ivermectin, diethylcarbamazine (DEC) alone or in combination with mebendazole display species-specific effect against microfilariae of Mansonella species that infect humans.

• Antibiotics that target Wolbachia endosymbionts are likely to kill adult worms of most, if not all, Mansonella species that infect humans.

• Alternative antibiotic regimens and new anthelmintic compounds have been tested for the treatment of human filariasis and should be evaluated for mansonelliasis.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

M U Ferreira is supported by scholarships from the Conselho Nacional de Desenvolvimento Cientiífico e Tecnoloígico (CNPq), Brazil, and the Fundação para a Ciéncia e a Tecnologia, Portugal (GHTM project, UID/04413/2020). His Mansonella-related field work was supported by the Fundação de Amparo à Pesquisa do Estado de São Paulo (2013/12723-7), Brazil. J L Crainey acknowledges support from the Fundação de Amparo à Pesquisa do Estado do Amazonas (062.01282/2018 and 002.00200/2019) and a scholarship from CNPq. F G Gobbi acknowledges support from the Italian Ministry of Health Fondi Ricerca Corrente–L2 to IRCCS Sacro Cuore Don Calabria Hospital.