If you have been following livestock related national news over the last week you have seen the reports that new world screwworm has officially crossed the Mexico-Texas border and a calf was identified in south Texas that has been affected by the pest. The larvae were found on the umbilical area of a three-week-old calf in Zavala County, TX. The last reported new world screwworm infestation in the US was reported back in the 1960’s. While this is a significant concern to livestock producers in the Southwest US, and for a significant portion of the US beef industry, we in Ohio are at a lower risk.
Given the geographic distance from Texas, and our climate, it highly unlikely the pest would be able to establish itself in Ohio. However, livestock agriculture is no longer a local business. Livestock are transported every day from coast to coast and border to border. Producers of all livestock species should be aware of the risks if they do import a livestock species from the SW US. This is a new problem that will not be solved overnight, and it may again take several years to eradicate it from US soil. The current eradication strategy is through the release of sterile flies, that will mate with the wild pest, to slowly reduce the population. A facility in Panama is shipping sterile flies, another facility is near completion in Metapa, Mexico, and a US facility is being constructed on Moore Air Base in Edinburg, TX. The Texas facility is expected to be completed in November of 2027.
New world screwworm (NWS) is not just a concern to beef cattle producers. The pest can affect all livestock species, wildlife, and humans. The NWS adult flies have a lifespan of about 28 days during which they lay eggs about 4 times and can lay up to 300 eggs each time. They deposit their eggs into open wounds on warm-blooded animals. The eggs only take about 10 to 12 hours to hatch, and the larvae begin immediately feeding on living tissue and will develop into an adult in 3 to 7 days. The flies prefer to lay eggs in the evening, which means the larvae can begin feeding by the next morning.
Producers which have transported livestock from the SW should pay attention to open wounds, or sensitive areas on their animals. This would be navels on newborn animals, vulvas on those that have recently given birth, sheaths on bulls, and recent wounds or surgical sites. The wounds will swell overnight or ooze cloudy fluid with the unmistakable smell of decaying flesh. You should inspect the wounds for larvae, which will initially appear as a small grain of rice with dark spines. If NWS is suspected, you should contact your veterinarian immediately.
Again, I am not raising the alarm but encouraging awareness. We have had countless examples over the last two years of how animal disease outbreaks have spread across the US due to the way we move livestock. I will take the opportunity again to stress the importance of basic biosecurity practices. Producers should treat any animal that has been brought onto the farm or has been commingled with livestock from other farms and brought back home as a source of disease transfer. Any new animal should be quarantined away from your resident livestock for a minimum of 30 days. During this time, you should closely monitor them for signs of illness and contact your veterinarian if there are concerns.
As I mentioned, there is a risk for humans. If you plan to travel this summer to the SW US or a country in Central America, you should take precautions. Any wound that rapidly swells, or where pain increases, should be inspected by a medical professional. If you contact livestock or wildlife on your trip, you should practice good personal hygiene (hand washing) and wash your clothes as soon as possible.
There will be an official announcement in the near future, but I want to let the community know that the Wayne-Ashland Dairy Services Unit will not be hosting a Twilight Tour this summer. The group has identified a site for the 2027 tour and will be making that announcement soon. As far as other programs, the 2026 OSU Manure Science Review will be held on July 22nd at Homan Inc in Maria Stein, OH. If you are interested in the event, you can register at waterquality.osu.edu.
We will be sending out the next edition of the OSU Extension – Wayne County ANR newsletter on July 1st. In it we will have a listing of our programs for the remainder of the summer and into this fall. If you would like to receive a copy, or have any other questions, contact me at the OSU Extension office at 330-264-8722 or email me at yost.77@osu.edu. I hope you have a great summer.
This article was previously published in The Daily Record.