Hello Casper’s Oil family,
If your pets spend time outside—whether that’s backyard time, ranch life, trail walks, or just sunbathing on the porch—we want to share a few straightforward facts about something that’s worth keeping on your radar: New World screwworm (NWS).
This isn’t meant to alarm you. The goal is simple: awareness + quick action. When pet parents know what to look for, issues are far more manageable.
What Is New World Screwworm (NWS)?
New World screwworm is a type of fly that can lay eggs in open wounds or even in certain body openings on animals, including areas like:
- Eyes
- Ears
- Nose
- Around the genital and umbilical area (especially in newborns)
When those eggs hatch, the larvae—maggots—can burrow into living tissue and feed on it. That’s the key difference between NWS and many “typical” maggots people might have heard about, which usually feed on dead tissue. Because NWS larvae feed on living tissue, the damage can progress fast and become severe—or even fatal—without prompt treatment.
Why Pet Parents Should Pay Attention
Any pet can potentially be at risk if they have:
- A cut, scratch, hot spot, puncture wound, or bite wound
- A healing surgical incision
- Skin irritation from chewing or scratching
- Recent birth (for mother and babies)
Even a wound that seems small at first can quickly become a bigger problem if it’s attracting flies—so staying observant matters.
Signs to Watch For (What You Might Notice at Home)
Here are the most common red flags pet parents may see:
1) Your pet seems unusually irritated
Look for:
- Head shaking
- Scratching
- Biting or chewing at a specific area
- Acting restless or unable to settle
2) A wound that suddenly looks worse
Pay attention to a wound:
- Gets bigger quickly
- Has bloody or unfamiliar drainage
- Looks increasingly inflamed or “angry”
3) A strong foul odor
A rotting or foul-smelling wound is always a reason to call your vet.
4) You see larvae/maggots
You may see larvae directly in the wound. They’re often:
- White or cream-colored
- Sometimes pinkish
5) Your pet seems “off”
General signs of not feeling well can include:
- Lethargy
- Poor appetite
- Signs of pain
Daily Checks: A Simple Habit That Makes a Big Difference
One of the best things you can do is build a quick “scan” into your routine—especially if your pet spends time outdoors.
Check your pet daily for wounds or irritated areas, particularly after:
- Outdoor adventures
- Play sessions that could cause scrapes
- Grooming (when you may notice hidden skin issues)
- An injury or scuffle
- Surgery (incision monitoring is key)
- Giving birth
If you find a wound, keep it clean and protected—and monitor it closely.
What to Do If You Notice Something (Don’t Wait)
If you think your pet may have screwworm—or you see any of the warning signs above—here’s the best next step:
1) Contact your veterinarian immediately
This is urgent because early treatment can prevent the situation from escalating.
2) Don’t try to treat it or remove larvae yourself
We know that’s hard to hear because pet parents want to help right away. But proper removal and wound care need to be done safely and thoroughly, and your vet can also address pain control and infection risk.
Veterinary Treatment: What It May Include
Your veterinarian will decide what’s appropriate for your pet, but treatment often includes:
- Removal of larvae
- Thorough wound cleaning and care
- Medication and follow-up care to support healing
Some isoxazolines (flea/tick preventatives), such as lotilaner (Credelio) and similar products, have been authorized for the treatment of NWS in dogs and cats. In addition, supportive care—like antibiotics for secondary infection—may be necessary depending on the wound.
If You Suspect It: Reporting Helps Stop the Spread
Along with contacting your veterinarian, reporting suspected cases can help with tracking and controlling the spread. Officials may also request samples for confirmation.
- Texas: Texas Animal Health Commission — 1-800-550-8242
- Other states: Most have a similar reporting system through an animal health agency—your vet can help guide you.
The Good News
With quick action, cases are often very manageable. While the USDA notes the overall risk is currently low, staying alert—especially for outdoor pets—can make a big difference for your animal and for community awareness.
For the latest updates, visit screwworm.gov or talk to your local veterinarian.
