21/04/2026
♥️ Heartworm is spreading through Europe. The UK is still considered to be non-endemic, but dog imports and pet travel are increasing the numbers.
♥️ Heartworm is spread when a mosquito bites an infected dog, and then bites more dogs - depositing the heartworm larvae through the bites.
♥️ The larvae migrate through tissues into the bloodstream then mature into adults in the lungs, pulmonary arteries, and the right side of the heart.
♥️ Symptoms are subtle at first - persistant cough, lethargy especially after exercise, weight loss. They may then progress to difficulty breathing, collapse, swollen tummy, pale gums, dark urine, and shock.
♥️ Tests include blood tests, x-rays, ultrasound scans, ECGs.
♥️ The treatment is not pleasant. Drugs used to kill adult worms are much stronger than drugs that kill larvae. They are known as ‘adulticides’. There would also be strict exercise restriction, plus antibiotics.
♥️ One of the biggest risks of treatment happens when the worms die. They break apart, and can send fragments into pulmonary vessels which can cause a blockage (known as an embolism). This increases the risk of inflammation or even sudden death. Even successful treatment can leave dogs with permanent damage to their hearts and arteries.
💚 Routine prevention is the answer. Milbemycin Oxime (found in Milbemax worming tablets) kills larvae before they mature. It then leaves the dog’s system. This is why worming needs to be repeated, in order to interrupt the life cycle of any nasties your dog picks up before they mature and start doing real damage. Worming at least FOUR times a year (every three months) is enough to do this.
♥️ TREATMENT = Risky and expensive
💚 PREVENTION = Safer and cheaper