Tracking human New World screwworm in the Americas: burden, spread, and knowledge gaps

To map the available evidence on human cases of New World screwworm across the Americas and identify guidance relevant to surveillance and management.

Searches were conducted in bibliographic databases (PubMed/MEDLINE, EMBASE, LILACS, Epistemonikos, Google Scholar, La Referencia, and OpenAlex), gray literature sources, and clinical trial registries. Searches were made in English, Spanish, and Portuguese. Eligible sources included peer-reviewed articles, case reports, case series, observational studies, reviews, guidelines, and technical documents addressing human infestation in the Americas.

From 2 332 records identified, 75 studies met the inclusion criteria and were included in the review. Clinical presentations varied and included oral and maxillofacial, cutaneous and wound-associated, otic, nasal, orbital, and cervicofacial infestations. Management generally relied on prompt mechanical larval removal, wound care, and, when required, surgical debridement. Ivermectin was the most used antiparasitic treatment, although no robust comparative evidence was identified. National guidance documents broadly agreed on the importance of larval extraction, case notification, and intersectoral coordination, but differed in their clinical recommendations and the role of ivermectin.

The available evidence is sparse, fragmented, and predominantly descriptive. The findings describe patterns in the published literature and should not be interpreted as estimates of population-level frequency or risk. Nevertheless, recurrent clinical patterns, vulnerable populations, and key public health priorities emerged and can support preparedness, surveillance, and the harmonization of guidance across the region.