French Heartworm
Heartworm is a major parasite of dogs in many parts of the world and causes serious health problems in unprotected animals.
In Europe the 'common' form of heartworm (Dirofilaria immitis) is prevalent in areas around the Mediterranean and is spread by mosquitoes.
Vets occasionally see this form of heartworm in imported dogs arriving from affected areas. However this may become more of a problem as UK dogs travel on mainland Europe under the Pet Travel Scheme.
In the UK a different type of heartworm is already present. Up until quite recently the parasite Angiostrongylus vasorum (French heartworm) was thought to be limited to certain areas in Cornwall and Wales. Only one case had ever been reported in the south-east of England but that all changed at the end of 1999 and through 2000 as veterinary surgeons were presented with increasing number of these cases.
Since 2000 we have diagnosed several cases of Angiostrongylus vasorum at Parkvets. As of 2006 we would now consider this parasite endemic in south-east England. Although most cases have occurred in dogs that are known to eat snails we have found a few cases where owners were unaware that their pets had this habit so do not think that just because you have never seen your pet eat a snail that they actually do not.
It is suggested that the most likely way that this problem has been spread is by the fox population for which snails and slugs make up an important part of their diet. The foxes in turn pass on the parasite back to the slugs and snails in their stools.
What is Angiostrongylus vasorum?
Angiostrongylus is a parasitic worm, the adult lives in the heart and arteries of the lung of the dog, fox and other animals that are affected by it.
How can your dog become infected?
This happens as a result of your dog eating a slug or snail that harbours the immature form of the worm.
Can my dog catch it from an infected dog or fox?
No, the only route of infection is from eating an infected slug or snail.
What are the signs of infection?
Some dogs with a subclinical condition (one which does not manifest itself outwardly) may have a low-grade infection for months or years without showing signs. However the most common signs of infection are rapid breathing and cough (occasionally blood is brought up). In more severe cases some dogs are presented in heart failure or collapsed and others show signs of bleeding problems.
What should I do if my dog starts coughing?
Don't panic! Take it to your vet. There are many reasons why a dog may start coughing. However if your dog is known to eat snails then a veterinary examination is definitely a good idea. If your vet is uncertain of the cause of the cough they will probably recommend doing various tests to investigate the cause. This may include chest x-rays, blood tests, stool analysis and obtaining samples of mucus or fluid from the airways in the lungs. Obviously if you have seen your dog eating slugs or snails remember to mention this to your vet.
Can this condition be treated?
If Angiostrongylus is identified early in the course of the infection anti-parasitic drugs can be used to treat it effectively. If complications have already occurred then treatment is less likely to be successful.
Can I prevent my dog from getting infected?
Yes, monthly treatment with an appropriate wormer obtained from Parkvets will be effective.
'Bubbles' Tale
During March 2000 'Bubbles' a nine-month-old spaniel was rushed into one of the Parkvets clinics. She was breathing heavily and coughing, her abdomen had also started to swell up with fluid.
Tests showed that she was suffering from severe right-sided heart failure, which is an unusual condition in such a young dog. In spite of all efforts to stabilise her condition, the problems worsened and sadly she died two days after admission.
A post mortem showed that death was due to large clumps of worms blocking the main arteries in the lungs, which is what had caused the right-sided heart failure.
Subsequent questioning of the owner confirmed that Bubbles was a known snail eater.
Fortunately most of the cases we have seen are not this severe and we have been able to treat them successfully but one other dog as well as Bubbles has sadly died as a result of this condition.
Summary
This form of heartworm is now an established and frequent finding presenting a real risk to dogs in south-east England. We are now suspicious of lungworm in any young dog that presents with a cough, with or without a history of eating snails.
Prevention is so much better than cure so we recommend worming monthly with a prescription* wormer containing Moxidectin or Fenbendazole. Please contact us ASAP if you are worried about your dog.
*Medications are only available to animals that are under the care of Parkvets.
