Hookworm Hazards: These bloodsucking intestinal parasites becoming resistant to drugs
Fleas and ticks aren’t the only parasites that suck your dog’s blood. Hookworms (Ancylostoma caninum) are intestinal parasites that live in your pets’ guts. Nationwide, they are probably the most common intestinal nematode in dogs, particularly young dogs, says Michael Dryden, DVM, Ph.D., professor of veterinary parasitology at Kansas State University.
Hookworms attach to the lining of the intestinal wall and feed on blood, causing internal bleeding. The eggs they produce travel through the digestive tract, are eliminated with the feces into the environment, and hatch into larvae that live in soil until they enter a dog’s body through the skin or are ingested when dogs lick dirt off themselves, starting the whole process over again. Lovely, huh?
It’s bad enough that dogs (and cats, less commonly) can acquire hookworms. The blood loss they cause can be deadly in puppies. And small dogs can’t tolerate as many worms as large dogs. In older dogs, a load of hookworms can cause chronic illness, with signs such as diarrhea, anemia, and weight loss. They also affect humans: People who go barefoot in hookworm-infected areas can pick them up. But what’s worse is that hookworms are becoming resistant to the drugs that kill them.
Researchers at the University of Georgia and the University of Calgary recently found that half of dogs diagnosed with hookworms around the country hosted worms with some level of drug resistance, not responding to any of the Food and Drug Administration-approved medications used to kill them. That’s a serious problem, and not just in the South, where hookworms have been most common, thanks to warm, moist conditions for long periods each year.
“There are hookworms all over the U.S. and drug-resistant hookworms all over the U.S.,” says Ray Kaplan, DVM, Ph.D., a veterinary parasitology expert and one of the authors of the study.
And just because you live in a dry area doesn’t necessarily mean your dog is at less risk. Hookworms are less common in the Western United States because of the dry conditions, but there was a significantly higher level of resistance there, Kaplan says: “The prevalence was lower, so we had fewer samples, but of the samples we tested, there was actually a higher prevalence of infection with drug-resistant worms.”
That’s probably because while hookworms are less common in that region, when drug resistant hookworms are introduced, there’s no dilution from “plain vanilla drug-susceptible hookworms, like there would be elsewhere,” Kaplan says.
Hookworms are over-represented in racing greyhounds, raised on sandy soil that is particularly welcoming to hookworm larvae, but they can affect any dog. Dogs at greatest risk are those who frequent dog parks or other areas with large numbers of dogs or whose owners don’t practice strict fecal hygiene — in other words, they don’t pick up poop in the yard immediately.
The level of contamination at dog parks varies based on how good owners are about picking up poop, whether the park has regular cleanup by volunteers or a professional service and on whether prevailing warm, moist conditions enable successful survival and transmission of hookworms.
Routine fecal exams at least twice a year can help ensure that your dog isn’t secretly carrying a load of the bloodsuckers. “If these dogs are going to dog parks, maybe (get them tested) four times a year,” Dryden says.
After treatment, dogs should be tested again to make sure the medication did its job. Without a follow-up test, it’s impossible to know if the hookworms are drug resistant. And maybe rethink those visits to the dog park.
— Kim Campbell Thornton
Do you have a pet question? Send it to askpetconnection@gmail.com or visit Facebook.com/DrMartyBecker. Pet Connection is produced by veterinarian Dr. Marty Becker, journalist Kim Campbell Thornton, and dog trainer/behavior consultant Mikkel Becker.
This article originally appeared on South Bend Tribune: Pet Connection: Hookworms becoming resistant to FDA approved drugs
