Aspergillosis in dogs - what is it?

Aspergillosis is an infection which can be seen in practice, although it is quite uncommon. The reason it is not seen very often by vets is that it rarely infects dogs that are healthy but can infect sick or compromised dogs. This Pets4Homes article we are going to look into the disease, its causes, types, diagnosis, and treatment.

So, what actually is aspergillosis?

It is when a dog becomes infected by the Aspergillus fungus, which is very common in the environment. The fungus lives in places such as hay and straw, and also dust. A common question is if it’s so common, why don’t all dogs tend to pick it up? It’s because aspergillosis is what is termed as an ‘opportunistic infection’ – it will only attack immunocompromised animals or those that have underlying health problems. If a dog is diagnosed in practice with this disease, it is usually secondary to something else that is going on.

The fungus as two types of disease associated with it and these types tend to affect different breeds of dog in different ways. The first form of the disease is called nasal aspergillosis.

Nasal aspergillosis

As the name suggests this type of infection is found in the nose of the dog. Because the fungus infects the nasal cavities, there are types of noses it prefers – the dolichocephalic or long-nosed dogs. This is because there is much more living space for a fungus to thrive inside the nose. Breeds such as greyhounds or Afghan hounds have this type of nose shape and with those, and with all the intricate nasal passages, the fungus is plenty of space to choose from. This makes this type of breed (especially if sick), much more susceptible. The fungal spores enter through the nostrils and set up home in the nasal cavities including the frontal sinuses of the dog's skull.

The second form of the disease is known as disseminated aspergillosis.

Disseminated aspergillosis

This form of the disease means the fungal spores do not just affect the nasal cavity, but the whole body as disseminated indicates the disease is widely spread. The spores are breathed in the same way through the nostrils, but this time the respiratory tract is only the start of the infection. It can spread to other organs of the body. One breed that has been found to be more susceptible to this type of aspergillosis is the German Shepherd Dog. It is unclear why this form works the way it does and seems to affect this breed statistically more than others.

So how does aspergillosis show itself in dogs?

If your dog is diagnosed with this disease, the chances are you will already know about it. It causes a lot of discomfort in dogs, with nasal inflammation and pain in the first type of infection and in the disseminated type, it will cause general sickness.

There are several symptoms of each form that you can be aware of and although your dog may not show all of the symptoms, some are distressing enough in themselves.

Symptoms of the nasal form are:

• Nosebleeds – medically termed epistaxis.
• Increased sneezing, often a sneezing fit.
• Pain – which is often indicated by the dog pawing at their nose.
• A nasal discharge – which in itself can take three forms, serous, mucoid, and purulent.
  • Serous discharge – a clear discharge, much like a normal runny nose.
  • Mucoid discharge – unlike the clear discharge, this is coloured and is often thick.
  • Purulent discharge – this is when your dog is displaying signs of an infection and the body is releasing pus.

The symptoms of disseminated aspergillosis are markedly different. The symptoms comprise of:

• Systemic signs – for example tiredness and lethargy.
• Gastrointestinal or gut symptoms, such as reduced appetite, vomiting, diarrhoea, and possible weight loss.
• Ocular problems – damage to the eye is sadly common with this form of the disease it can even include blindness.
• Joint pain – because the infection would have entered the joints, it can cause pain and lameness in dogs.
• Open wound issues – if the dog has some open wounds prior to becoming infected with this disease you might see pus discharging out of the wounds. This is only the dog’s natural defence and the body trying to get rid of the fungal infection in the dog’s body.

How is this disease diagnosed?

The diagnosis of this disease is dependent on the form it has taken. One of the first and early signs is that you as the owner would notice the problem. Your dog may look unhappy, dull, or be very lethargic. They may also have an upset tummy and pain around the nose area as well.

Nasal form diagnosis

Your dog may undergo a procedure called a rhinoscopy, where the nasal cavity is looked at closely, more commonly the mucus membranes that line the nasal cavity. Additional swabs may be taken of this area to see what can be grown in a laboratory. Fungus tends to grow really well, so results can be fairly quick and accurate.

Disseminated form diagnosis

Because of the way this one works it can be harder for the vets to diagnose. Generally, the pets will have blood tests, urine tests and may also have scans of the body using ultrasound or x-rays. The vet will build a picture from all the results that are found during the testing.

So, if my dog has aspergillosis, what are the treatment options?

Again, this depends on the form of the disease they have.

Nasal aspergillosis treatment

Because this is accessible and confined to one part of the body, it is much easier to treat. The nose is usually flushed out to remove spores and antifungal medication used to help complete the task. This type of operation is normally done under a general anaesthetic.

Disseminated aspergillosis treatment

This form of the disease is not only hard to diagnose, but it is also much more difficult to treat effectively. Although antifungal medication can be used it is seldom successful, although in a small amount cases it can help, the majority of them are too advanced to treat, by the timescale in which they are diagnosed.

Conclusion

Although this disease is not extremely common if you have any worries at all about your dog’s health – especially if they are showing discomfort in the nose area, please contact your vet for further advice.