Screwworm myiasis is spreading in America, raising public health concerns.

The blowfly, scientifically known as Cochliomyia hominivorax, is a fly that lays eggs in wounds or mucous membranes of animals and humans. The eggs hatch into larvae that feed on the host's tissues, causing a disease known as myiasis. Although most common in cattle , it can also infect sheep, goats, horses, and even humans, causing a variety of illnesses, from painful infections to severe sepsis.

Human cases are alarming. In 2025 alone, 166 cases were reported in Honduras, 117 in Nicaragua, 69 in Costa Rica, 41 in Mexico, three in El Salvador, one in Belize, and one imported case in the United States . In Panama, where the outbreak began in 2022, nearly 50,000 cases have been reported in livestock and 161 cases in humans. International HEALTH authorities emphasize that this disease is mandatory for reporting due to its potential for spread.

The economic consequences are devastating. In Mexico, the halt in live cattle exports to the United States is resulting in losses of approximately $30 million per month. This situation threatens the stability of livestock production in the region, especially among small-scale producers who lack the resources to adequately treat infected animals.

In the absence of vaccines and specific pharmacological treatments, the most effective strategy remains the release of sterilized male flies to reduce pest reproduction. Mexico and the United States have agreed to open a facility in Chiapas that will produce up to 100 million sterile flies per week to contain the outbreak. However, experts warn that strict livestock movement controls and improved sanitation remain crucial.

Scientists consulted by EFE emphasize that this health crisis is closely linked to poor hygiene and poverty. "Environmental, animal, and human health are inextricably linked," explained Rodrigo Morchón, a professor of parasitology at the University of Salamanca, who called on the international community to strengthen surveillance measures to contain the epidemic, which is currently concentrated in the Americas but threatens to become a more serious problem unless urgent action is taken.