WPX26: New World screwworm raises awareness, not alarm, for pork producers

10 June 2026

3 minute read

By: Sarah Mikesell

North America

Dr. Dusty Oedekoven, chief veterinarian at the National Pork Board, spoke to The Pig Site’s Sarah Mikesell at the 2026 World Pork Expo about the first case of New World screwworm and its impact, if any, on the swine industry.

Dusty, what should producers know about New World screwworm?

An instance of New World screwworm was recently identified in some cattle in southern Texas. While this is concerning, it’s not unexpected. The USDA, producers and state animal health agencies have been preparing for this possibility for some time. 

Now that it's here, there are some tips worth noting. First, it's really important for animal owners of all kinds, whether livestock or pets and especially in areas where the parasite has been identified, to make sure that you're observing your animals closely for signs of infestation. That could be a wound that's not healing, or you can see a visible sign of what we call myiasis, which is the fly larval infection of those wounds. 

It's important to monitor your animals very closely on a daily basis. This is just part of normal good animal husbandry observation, and you should report any suspicious signs to your veterinarian. 

Second, if you're planning to move animals, particularly across state lines, it's always important to consult with your veterinarian about requirements, including getting a certificate of veterinary inspection. 

Could New World screwworm change state guidelines for animal transfers?

It's not uncommon for state animal health agencies to increase the requirements for inspection or other requirements related to the movement of animals into their state to try to prevent the spread of diseases. That's the fabric of animal disease prevention that we have in our country, which is the need to have an accredited veterinarian inspect those animals and ensure that they're free of signs of contagious infectious diseases. 

In this case, New World screwworm is not a contagious disease, but it is a parasitic disease. We would consider it a foreign animal disease because we haven't had it in the United States for some time. 

We heard about New World screwworm in relation to cattle, but it can impact any open wound, right?

The female fly lays her eggs in open wounds and mucosal membranes. That can be in any warm-blooded animal, not just livestock. One of the last infestations in the US was in 2016-2017, and that was primarily in Florida Keys deer. 

It was also found in other wildlife and even pets, with dogs showing signs of infestation. We talk about it and hear about it in cattle, and the most current case involves a calf. However, Mexico has reported cases in a variety of different animals. 

How does this outbreak roll into the National Swine Health Strategy?

The National Swine Health Strategy is a producer-led initiative to improve swine health, and it really comes down to two goals. 

1. Keep foreign and emerging diseases out 
2. Reduce the impact of the domestic diseases that we have

The recent discovery of New World screwworm really ties into our mission and reminds us of why we plan for the introduction of novel diseases or foreign animal diseases. Many current disease prevention practices can have some applicability to preparedness against New World screwworm.

Will New World screwworm have an impact on the swine industry or National Swine Health Strategy?

I don't see it as having a big impact on what we're doing in areas of focus right now. Fortunately, this is a parasitic disease. It is relatively identifiable when it has a clinical impact. 

It is treatable in many cases, and it's seasonal. We see more flies in general in the summertime. In the wintertime, this fly is very susceptible to cold temperatures, and it doesn't do well in the cold. I live in South Dakota, so we may never see this fly. 

Bottomline, this has a different type of a response than we would see with a viral disease, such as African swine fever virus. It's really nothing to panic about. Producers should just be more aware, be alert to the signs and report anything you see to your veterinarian.