Presence and distribution of Cochliomyia hominivorax (Diptera: Calliphoridae) in South America: ecological niche modeling and epidemiological implications under the One Health approach.

Myasis caused by Cochliomyia hominivorax larvae (Coquerel, 1858), represents a significant sanitary and economic challenge under the One Health approach, affecting human health, livestock production, and biodiversity. Studies on the spatial ecology and distribution of this species in South America (SA) have been scarce. This study aimed to model real and potential suitability areas for C. hominivorax in SA, based on myiasis cases in humans and other vertebrates reported in the scientific literature. The MaxEnt model was developed using WorldClim bioclimatic variables clipped to SA, with 1,000 iterations performed to generate mean logistic distribution models. To mitigate collinearity variables with an absolute correlation coefficient of ∣r∣ < 0.7 were retained. Jackknife tests determined the relative importance of the bioclimatic variables. Brazil and Argentina contained the majority of records, followed by Colombia and Venezuela. Paraguay and French Guiana contributed fewer occurrences. The most frequently recorded hosts were cattle, cats, dogs, and pigs, with great numbers of human cases documented in Brazil and Argentina. Predictive models indicated that west-central Amazonia, eastern Paraguay, northern Argentina, northeastern Brazil, and several countries in northern SA represent moderate to high suitability for species presence (habitat suitability scores 0.80 to 1.00; AUC 0.885). The potential distribution of C. hominivorax in SA was determined by humidity and temperature gradients in tropical and subtropical environments, excluding arid or cold zones. These findings emphasize the need to strengthen epidemiological surveillance and transboundary control strategies, with special attention to domestic hosts, wildlife movement, and human cases in the Southern Hemisphere.