Heartworms And Your Ferret

Heartworms, called Dirofilaria immitis, are very thin, thread-worms. You won’t see these worms yourself though, as they live within the right side of the heart, and the main artery leading from the heart to the lungs. Heartworms can reach 30cm long, which makes even a few worms incredibly dangerous for a ferret. Heartworms are nasty, and thankfully are not found in the UK. They are transmitted by mosquitos, and are therefore found in warmer countries, such as those in southern Europe. Heartworms reproduce by producing tiny offspring, called microfilaria. These are ingested by feeding mosquitos, mature, and are passed on to other animals when the mosquito feeds again.

If your ferret doesn’t leave the UK, there is no current risk of them being infected by heartworms. However, Pet Passports are becoming more common, so we may see more cases of exotic diseases such as heartworm being seen. The numbers of ferrets who travel abroad however is still low, so heartworm in ferrets is still very rarely seen in the UK.

Heartworms are spread through the bites of mosquitos that carry the infective heartworm larvae. Ferrets are at risk of developing heartworm if they have:

• Not been given preventative medication
• Spent time in a region with mosquitos and heartworms

How serious the symptoms of a heartworm infection are depend on the number of heartworms, how long the infection has been present and the immune response of your ferret. However, as ferrets are small, only a handful of heartworms can be enough to cause serious disease.

In ferrets the signs of a heartworm infection include:

• Coughing
• Laboured breathing
• Weakness
• Loss of appetite
• Abnormal heart beat or the presence of a murmur
• Weight loss
• Fluid accumulation within the abdomen
• If your ferret is experiencing any of these signs then you should make an appointment with your local Companion Care as soon as possible.

Heartworm preventative medication is the best way to protect your ferret from contracting heartworm on holiday. Your vet can advise what the best preventative medication would be for your pet, and give you some to take with you if you will be away for a longer period. Even missing a single dose will put your ferret at risk of contracting heartworm, so it is important up-to-date with treatments.

As this signs of a heartworm infection are quite non-specific and heartworm is not endemic to the UK, if you see your ferret has developed any of the signs of heartworm infestation and you have been abroad it is important to let your vet know you have spent time outside of the UK. A heartworm infection can be diagnosed via a specialised blood test. Your vet may also want to take other, screening blood tests as well as doing imaging to get as much information as possible. This will help your vet plan the best way to manage the infestation. Part of the treatment of a heartworm infestation is an anti-parasitic to kill the worms themselves. This can be a dangerous time for patients as the dead worms can cause a damaging immune response, and can block blood vessels. Sadly, being only small, even with treatment heartworm can be fatal in ferrets.

While humans can be affected by heartworm by being bitten by mosquitos, this risk is incredibly small – less than one hundred cases have ever been reported in the United States, and the disease is often relatively mild in people. Importantly, you cannot catch heartworm from your ferret.