Canine Heartworm Disease: Prevention and Welfare in Affected Dogs

Heartworm disease causes serious and painful cardiovascular and pulmonary damage in dogs, and is an increasing concern for UK pets travelling abroad.

Key Facts

Dirofilaria immitis is transmitted by mosquitoes and endemic in southern Europe, Mediterranean countries, and globally
Adult worms live in the right heart and pulmonary arteries causing severe pathology
Clinical signs include exercise intolerance, cough, and eventually heart failure
Treatment of established infection is complex, expensive, and carries significant welfare risks
Prevention with monthly macrocyclic lactone products is highly effective and widely available

Welfare Considerations

Heartworm disease causes progressive cardiac and pulmonary damage that results in significant chronic suffering. Exercise intolerance, coughing, and respiratory distress impair quality of life as the disease advances. The treatment of established infection with melarsomine involves a complex protocol including periods of enforced rest, during which dying worms can cause pulmonary embolism. Dogs undergoing treatment face risks of serious pulmonary complications that are potentially life-threatening. Prevention is vastly preferable to treatment from a welfare perspective. As UK dogs travel more widely and as climate change expands mosquito ranges in Europe, heartworm awareness among UK dog owners is increasingly important.

What You Can Do

Use appropriate preventative medication before and during travel to heartworm-endemic regions
Consult your veterinarian about heartworm testing on return from risk areas
Never discontinue preventative treatment without veterinary guidance
Support efforts to control mosquito populations in high-risk environments