Deadly dog parasite spreads across Denmark as vets issue warnings

Danish veterinarians are warning dog owners about a rising threat from French heartworm (Angiostrongylus vasorum), a potentially fatal parasite spread by slugs, national broadcaster DR reports.

The disease, once concentrated in Zealand, has now spread nationwide, with clinics in North Jutland reporting monthly cases. A recent screening of over 500 dogs in Aalborg revealed that 3% were infected without owners’ knowledge.

“This is an infection that’s here to stay,” said Thomas Larsen, regional manager for four Anicura veterinary clinics in North Jutland. “We see it every month now.”

While the parasite cannot spread directly between dogs, it thrives in contaminated feces. Slugs ingest parasite eggs from dog waste, then infect new hosts when dogs ingest slug slime on grass or carrion.

Veterinarians’ advice to prevent infection

Pick up all dog waste – Even if it’s not your dog’s. Reducing feces in parks and forests cuts the parasite’s lifecycle. “When we decrease the amount of feces containing parasite eggs, we lower the risk of transmission,” Larsen explained.

Test regularly – Clinics recommend annual or biannual testing (spring/autumn) to catch infections early. Infected dogs may show no symptoms for months.

Watch for warning signs – Fatigue, coughing, shortness of breath, weight loss, vomiting, or diarrhea could indicate infection. Rare cases involve bleeding disorders or slow-healing wounds.

Despite the risk, vets emphasize that dogs should continue their usual outdoor routines. “Don’t keep your dog indoors out of fear,” Larsen said. “Just stay vigilant.”