Chapter 1: The Menace of the New World Screwworm

The New World Screwworm (NWS), scientifically known as Cochliomyia hominivorax, is a parasite that instills fear in many, with its name translating to "man-eater." Despite its ominous title, awareness of this pest remains low among the general public, especially regarding its impact across rural regions from Florida to California and down to the Panama Canal.

The NWS is notorious for laying vast numbers of tiny eggs, ranging from 200 to 500 at a time, in open wounds of mammals. Once these eggs hatch, they release hundreds of minuscule worms that burrow into the flesh. The resulting infection is excruciatingly painful, and attempts to remove the worms can lead to them embedding even deeper into the tissue. The idea of having numerous worms consuming flesh is horrifying, and if left untreated, the consequences can be fatal.

These screwworms pose a significant threat because a single infestation can yield hundreds of flies, which in turn lay thousands of eggs on nearby animals. They are not selective about their hosts; their appetite extends to cattle, deer, dogs, and even humans. Historically, cattle were particularly targeted, with ranchers recalling tales of calves suffering agonizing deaths as swarms of New World Screwworm flies emerged from their carcasses.

The origins of the name "man-eater" stem from a severe outbreak in South America, particularly on Devil’s Island, where thousands of these flies led to numerous fatalities over several years. The larvae not only lay eggs in wounds but also consume the flesh, hindering healing and leaving the wound susceptible to further infections and death.

Between 1900 and 1950, screwworms caused millions in cattle losses, devastating ranches and severely affecting productivity. They were especially harmful to newborn calves and their mothers, often targeting those that had just given birth. A single cut from barbed wire could invite a deadly infestation, leading many ranchers to accept screwworm attacks as a grim reality of frontier life. However, the advent of specialized radiation technology provided a glimmer of hope for controlling these pests.

In 1957, a concerted effort to eradicate these parasites commenced, a program that persists today. By dispersing infertile screwworms, the USDA and various international collaborators have successfully pushed the screwworm population out of the United States and into Central America. Today, an invisible barrier exists between Panama and Colombia, preventing the reinfestation of North America, maintained by millions of sterilized worms released from planes regularly.

The USDA's innovative control method involves breeding millions of these pests in specialized facilities. At a critical developmental stage, the flies are exposed to radiation, rendering them infertile. Once sterilized, they are transported in boxes and released from aircraft. The sheer volume of these sterile insects competes with their fertile counterparts, significantly reducing reproductive rates. Consequently, the larvae that cause the flesh-eating menace are virtually eliminated.

This initiative is led by the USDA in conjunction with the Comisión Panamá–Estados Unidos para la Erradicación y Prevención del Gusano Barrenador del Ganado (COPEG), which operates out of Panama, managing the labs and overseeing the aerial dispersals. Flights are typically conducted every other day, dropping approximately 14.7 million sterilized insects over the jungles of southern Panama weekly.

On the surface, this plan may seem outlandish and reminiscent of government overreach, yet it has proven effective. Sterilization offers multiple advantages: it is cost-effective, does not introduce genetically modified organisms into the ecosystem, maintains environmental integrity, and spares the mammalian hosts that would otherwise suffer from larvae infestations. Previous control methods often relied on harmful pesticides that affected both the screwworms and their hosts.

This strategy contrasts with initiatives targeting disease-carrying mosquitoes that involve genetically altered insects, which have sparked public concern. Insect sterilization, however, lacks such negative perceptions.

The program incurs substantial costs annually, suggesting that taxpayer funds may contribute to its operations, including fuel for the planes dropping millions of screwworms in Panama.

I consulted my wife, a veterinarian who interned briefly at the USDA. She advised against discussing the project around USDA employees, noting their almost unbearable pride in its success. And rightly so—their unconventional approach worked, ensuring that younger generations are largely oblivious to the terrifying reality of the New World Screwworm Fly.

Thus, the United States continues its weekly mission of dropping millions of these flesh-eating worms across Central America.

In this video, explore why the U.S. drops millions of screwworms in Panama every week and the science behind this unusual pest control method.

Chapter 2: The Dangers of Nature's Most Hazardous Trees

This video highlights the most dangerous trees you should avoid at all costs, including their characteristics and the risks they pose to humans.