Treatment of loiasis: a review of clinical management recommendations

Abstract

Background: Loiasis affects more than 20 million residents of endemic regions in Central and West Africa causing chronic and often lifelong disease. Antifilarial treatment options for loiasis include diethylcarbamazine, ivermectin, and albendazole. Safe and effective management requires classifying patients into occult, microfilaremia, and hypermicrofilaremia categories. Treatment is complicated by the risk of severe adverse events, particularly encephalitis. Clear guidance on the appropriate use of antifilarial therapy is therefore of utmost importance. The aim of this review is to evaluate current treatment recommendations and assess their quality and consistency.

Methods: A scoping review was conducted to evaluate treatment recommendations for loiasis. The literature search encompassed multiple databases, including PubMed and specialized medical repositories, without restrictions on publication date or language. The approach included a systematic search with specific loiasis-related keywords and an unstructured search of guidelines from health ministries in endemic countries, along with grey literature and professional recommendations. Renowned tropical medicine textbooks were also consulted. Data were extracted with a detailed table collaboratively developed and reviewed by multiple researchers to ensure consistency and accuracy.

Results: The review identified 33 sources, consisting of nine guidelines, ten reviews, and 14 textbook excerpts. Publications reviewed spanned from 2001 to 2024 with no major innovations in treatment noted. Evidence quality was often low, with only two guidelines detailing their development process. Variability was particularly noted in dosage protocols for diethylcarbamazine, typically dosed incrementally. Ivermectin and albendazole were mostly noted as alternatives based on microfilarial levels. The common microfilarial threshold was 8000 microfilariae per millilitre, dictating treatment strategy adjustments. Adjunctive treatments, such as corticosteroids and antihistamines, were inconsistently proposed to mitigate side effects.

Conclusions: Inconsistencies between some recommendations were observed. There is an urgent need for internationally harmonized, evidence-based guidelines to address these inconsistencies, improve patient outcomes and minimize treatment-associated severe adverse events and fatalities.

Keywords: Loa loa; Guideline; Loiasis; Treatment.

Fig. 1

Flow of literature search