Lungworm in cats - Understanding the risks

Most dog owners in the UK are aware of the potential threat that lungworm can pose to our canine companions, and a lot of work has been done in recent years on the part of veterinary professionals and canine pharmaceutical companies to raise awareness. The condition is one that was relatively rare in the UK until a few years ago, beginning with a few isolated cases, which then developed into a pattern of localised lungworm hotspots-but now lungworm is considered to be endemic across the whole of the UK.

However, lungworm is not unique to dogs, and it can in fact affect cats too-and cats that tend to hunt prolifically are at particular risk of the condition, as lungworm larvae can affect birds and rodents. Some cats can carry the parasite without it causing them any harm and in some cases, this can lead to the cat in question developing a natural immunity to sickness caused by lungworm-but for some cats, lungworm can cause serious illness, and even potentially prove fatal.

In this article, we will examine lungworm in cats in more detail, including the risk factors, how lungworm affects cats, and what you can do to prevent it. Read on to learn more.

What is lungworm?

Lungworm is a type of parasitic worm that comes in various different species-the type that is most likely to infect cats is called Aelurostrongylus abstrusus, and this is a different variant to the two respective strains of lungworm that can affect dogs. Lungworm larvae can be carried by a whole range of different hosts including slugs and snails, rats, mice and birds-a wide range of common wildlife that your cat may come into contact with regularly, particularly if they hunt.

Cats can ingest lungworm larvae by eating their prey or carrying it in their mouths, and which then migrate throughout the body before taking up residence in the lungs, where they can cause a range of problems. Adult lungworms can grow up to 10mm in length, making them visible to the naked eye if present in your cat’s faeces or vomit, but the larvae and eggs are too small to be seen-so do not rely upon the physical sighting of worms to confirm infection.

Because lungworm is now endemic all across the UK, most cats will have come into contact with the parasite at some point, and in many cases, cats that are hosting lungworm will ultimately develop immunity to it after a few months, leading to the eggs, larvae and adult worms present being expelled from the body, and providing resistance to future cycles of infection.

However, not all cats will develop this immunity, and even for those that do, the phase between ingestion and immunity developing can have a significant impact on the cat’s health, as their lungs will likely contain a heavy load of adult worms, eggs and larvae.

What are the symptoms of lungworm in cats?

As mentioned, it is entirely possible that your healthy adult cat may have already contracted, passed and developed immunity to lungworm already, particularly if they are avid hunters. Even in cats that do become ill due to the condition, noticeable symptoms of the infection may not occur, and if they do present, may be mistaken for a range of other respiratory conditions such as feline influenza or other forms of respiratory infections.

In cats that are affected by lungworm, they are apt to have a persistent chronic cough, suffer from noisy, laboured breathing or appear to gulp for air, and may lose weight and condition fairly acutely and quickly.

If your cat displays symptoms of this type, lungworm will probably be one of the conditions that your vet will consider as part of their differential diagnosis, and in order to confirm or rule out the condition, they may ask for a sample of your cat’s faeces for testing, as well as using X-ray examination and/or a bronchoscopy of the lungs to make a firm diagnosis.

Whilst a simple blood test is generally all that is required to diagnose lungworms in dogs, this is a species-specific test, and no equivalent exists for the strain of lungworm that affects cats.

Can lungworm in cats be treated or prevented?

Many cats will already have built up a natural immunity to lungworm, but you should not rely upon this assumption in order to keep your own cat safe. However, you can buy a simple combined spot-on treatment for your cat that protects against lungworm, usually sold as a combined product that also functions as a flea and tick treatment too. This is generally only available from your vet, so talk to them about the options available for your cat as part of their general flea and worming protocol.

For cats that have developed lungworm, treatment is possible and generally effective, assuming that diagnosis and treatment are not left too late and significant damage to the lungs has been avoided.

Prevention is of course better than a cure-and knowing the risks for cats is an important part of protecting your cat against the parasite.