15/03/2025
MULTI-DRUG RESISTANT HOOKWORMS
- In the last several years, there have been growing reports of hookworms that won't go away, even after multiple rounds of treatment.
- A report in 2023 showed a hunting dog kennel with multiple dogs whose hookworms would not clear with any currently available US product, requiring importing a foreign product to treat the infection. Other reports previously identified resistance in Greyhound kennels. I have personally heard of or been involved with several other hunting dog kennels fighting a resistance problem as well.
- Parasites can become resistant to dewormers via exposure to them. As dewormers are used, some parasites can survive. These parasites then breed with each other and create offspring that can also survive the dewormer. Over time, the entire population in an environment (like a kennel or property) can become resistant to that drug.
- Traditionally, we have been able to change drugs and get a response. With MDR parasites, switching drug classes is no longer effective, as these parasites are resistant to multiple classes of drugs!
- Currently, the recommendations are still to continue broad spectrum parasite control year round.
- I recommend sticking with one dewormer year-round and NOT switching drug classes throughout the year. This keeps parasites sensitive to other drugs if needed.
- If you think you're having a problem with MDR hookworms, work with your veterinarian to prove resistance and rule-out more common issues like reinfection or environmental contamination.
Castro et. al. https://doi.org/10.2460/javma.22.08.0377
