By Zachary Stieber
Contributing Writer
The Centers for Disease Control and Prevention has issued a health alert warning about parasitic flies migrating closer to the United States.
An outbreak caused by New World screwworm has emerged in Tamaulipas, a Mexican state that shares a border with Texas.
While no cases have been identified in the United States, the CDC said it released a health alert “to increase awareness of the outbreak and to summarize CDC recommendations for clinicians and health departments in the United States on case identification and reporting, specimen collection, diagnosis, and treatment of NWS, as well as guidance for the public.”
NWS infestations occur when screwworm flies lay eggs in body cavities, and the eggs develop into parasitic maggots that eat flesh.
The infestations primarily take place in animals, but humans can also become infested.
The current NWS outbreak in Central America and Mexico has led to at least 24 human hospitalizations and tens of thousands of cases among animals, including eight active cases in Tamaulipas.
NWS infestations used to be common in the United States, but an effort centered around releasing sterile male flies successfully eradicated the pest in the United States and some other countries. A barrier along the border of Panama and Colombia prevented the reintroduction of NWS into Central America and northward until recently, when it was breached, which U.S. officials attribute to unregulated cattle movement and increased human movement through the Darien Gap at the Panama-Colombia border.
People are being warned that they’re at increased risk of becoming infested if they spend time in areas where flies are present and they have an open wound, sleep outdoors, or are suffering from malnutrition.
People in those areas should clean and cover all wounds, no matter how small and regardless of location, the CDC said. They should also wear loose-fitting, long-sleeved shirts, pants, socks, and hats, and avoid spending time around livestock or in rural areas. People should also avoid sleeping outdoors and use bed nets if they are sleeping in quarters where windows are left open and do not have screens.
Doctors should keep NWS in mind when seeing patients with visible larvae or egg masses in a wound or body cavity. Other signs include foul odor, bloody discharge, and swelling, in addition to recent travel to an area where NWS is known to be spreading.
All suspected human cases should be immediately reported to state and federal officials. The CDC is available to provide confirmatory testing.
Medical personnel should remove and kill all larvae and eggs from suspected cases, rather than throwing them out. The best way is to use ethanol, according to the CDC.
