A newly published study in Conservation Biology warns that efforts to control New World screwworm (NWS) will be weakened if governments focus primarily on legal livestock production systems while overlooking illegal cattle movements, wildlife, protected areas and remote landscapes where infestations can go undetected.
The paper, “Screwworm re-emergence, illegal cattle movements, and emerging risks to wildlife and protected areas in Mesoamerica,” was authored by scientists from the Wildlife Conservation Society (WCS) and partner organizations. The study highlights how illegal and unregulated cattle movements remain an under-recognized driver of regional NWS spread while also creating exposure risks for wildlife populations and protected areas that often fall outside traditional surveillance systems.
Many corridors used for illegal cattle movement pass through or alongside protected areas, creating opportunities for NWS to reach wildlife populations that are rarely monitored. Illegal cattle production and trade are leading drivers of deforestation and habitat degradation in Mesoamerica, placing additional pressures on wildlife populations already facing multiple environmental stressors. Although the population-level impacts of NWS on wildlife remain poorly understood, the authors note that infestations have been documented in species of conservation concern and that insufficient wildlife surveillance limits understanding of potential consequences for biodiversity, ecosystem functioning, and conservation outcomes.
“Much of the discussion around screwworm has understandably focused on livestock production,” said Dr. Lucy Keatts, associate director of WCS’s Health Program and lead author of the study. “Our study highlights two additional gaps: the role of illegal cattle movements in facilitating spread and the limited information available on wildlife infections and impacts. Addressing both will be important for effective long-term control.”
The study documents confirmed, probable and suspected wildlife infestations in Mesoamerica, including cases involving species of conservation concern. Because wildlife are not routinely inspected like livestock, infections may persist undetected in remote areas, limiting the effectiveness of surveillance and response efforts.
The authors warn that protected areas can become surveillance blind spots despite serving as important reservoirs of biodiversity. They argue that wildlife health monitoring should be incorporated into national and regional NWS response plans as part of a broader One Health approach linking animal health, ecosystem health and human well-being.
“We have been monitoring wildlife populations since 2004 using camera traps in this area. We have seen wounded animals before, but these types of lesions started only after screwworm arrived to the country,” said Rony García-Anleu, director of the Biological Research Department for WCS Guatemala and a co-author of the study.
The authors emphasize that wildlife should not be scapegoated as the source of the current crisis. Instead, they argue that wild animals can serve as victims, sentinels and indicators of where NWS risk may be emerging. Substantial knowledge gaps remain regarding population-level and ecosystem-level consequences, and improved wildlife surveillance would support both disease-control objectives and conservation decision-making.
The study calls for stronger coordination among livestock, wildlife, conservation, public health and law enforcement agencies to improve surveillance and response. The authors argue that NWS is inherently a One Health challenge, requiring collaboration across sectors to understand transmission dynamics, identify emerging risks, and implement effective control measures.
“We cannot effectively manage what we do not measure,” Keatts said. “Improving surveillance in wildlife and protected areas would help us detect infestations earlier, better understand their impacts, and support more effective regional control efforts. That will require stronger coordination across animal health, wildlife, conservation, and law enforcement agencies, because no single sector can address this challenge alone.”
