Deconstructing the eradication of new world screwworm in North America: retrospective analysis and climate warming effects

Abstract

Before its eradication from North America, the subtropical‐tropical new world screwworm fly Cochliomyia hominivorax (Coquerel) invaded southwestern temperate areas of the U.S.A., where it caused myiasis in wildlife and livestock. Outbreaks of the fly occurred during years when adult migrants were carried northward on North American monsoon winds from the northern areas of Mexico and south Texas. We deconstruct, retrospectively, the biology and the effect of weather on the eradication of the fly in North America. Screwworm was found to be an ideal candidate for eradication using the sterile insect technique (SIT) because females mate only once, whereas males are polygynous, and, although it has a high reproductive potential, field population growth rates are low in tropical areas. In northern areas, eradication was enhanced by cool‐cold weather, whereas eradication in tropical Mexico and Central America is explained by the SIT. Despite low average efficacy of SIT releases (approximately 1.7%), the added pressure of massive SIT releases reduced intrinsically low fly populations, leading to mate‐limited extinction. Non‐autochthonous cases of myiasis occur in North America and, if the fly reestablishes, climate warming by 2045–2055 will expand the area of favourability and increase the frequency and severity of outbreaks.

New World screwworm (Cochliomyia hominivorax) myiasis in feral swine of Uruguay: One Health and transboundary disease implications

“…Screwworm infestation in this study correlated with higher monthly average temperatures, and fewer cases were detected in winter months with low temperatures. These observations are similar to the seasonal variations in screwworm prevalence in the United States prior to eradication [36]. An increase in infestations associated with higher temperature is concerning because it has been estimated that current global change trends could result in an increase in temperatures in Uruguay of up to 3 degrees Celsius by 2100 [37].…”

Development and calibration of a model for the potential establishment and impact of Aedes albopictus in Europe

“…effect of thermal pollution due to industrial effluents, change in the land use) on mosquito population abundance. The model could also aid in assessing those mosquito control strategies based on the induction of sterility such as the conventional SIT or by the exploitation of the endosymbiont bacterium Wolbachia that can induce both sterility (Bourtzis et al, 2104;Calvitti et al, 2012;Moretti et al, 2018a; see e.g., Gutierrez et al, 2019 for how the impact of sterility could be assessed) and virus protection (Moretti et al, 2018b).…”

Biological invasion risk assessment of Tuta absoluta: mechanistic versus correlative methods

“…Downscaling (i.e., increasing the spatial resolution) of global climate model output addresses two primary limitations: the relatively coarse spatial resolution of global climate models (e.g., hundreds of km) and their statistical bias when compared with observations (Thrasher et al 2012). We used climate scenarios that were tested in previous PBDM analyses (Ponti et al 2014;Gutierrez et al 2019) in an effort to contribute towards providing credible information on regional climate changes, impacts, and risks for stakeholders and policy-makers (Eyring et al 2019).…”