Feline AIDS (Feline Immunodeficiency Virus, FIV)

Cat aids

Feline AIDS is a viral disease that can develop asymptomatically for years.

Has your cat tested positive for feline AIDS? Above all, keep calm. Find out here why a positive feline immunodeficiency virus (FIV) test doesn't always indicate an FIV infection and what you should focus on if your cat is actually suffering from feline AIDS.

What is feline AIDS?

Feline AIDS is a viral infectious disease in cats. It is triggered by the feline immunodeficiency virus (FIV). The viral infection leads to a pronounced immunodeficiency in the cat.

Since cats infected with FIV show similar symptoms to humans infected with HIV (human immunodeficiency virus), the disease is also known as feline AIDS. However, people cannot become infected with FIV.

Symptoms: How do we recognise an FIV infection in cats?

If your cat has become infected with FIV, it can take several years for you to notice the first symptoms of the disease. It depends on the viral strain in question how pronounced the symptoms are. Since there are also five phases of feline AIDS, the clinical picture varies greatly.

The five phases of feline AIDS

Phase Duration Symptoms
acute (sudden) phase Around 1 week The lymph nodes swell (lymphadenopathy). Further symptoms are mild fever, diarrhoea and a general debilitation of the immune system.
asymptomatic phase Months to several years Cats appear healthy.
Swollen lymph nodes phase Weeks to months The lymph nodes swell further and recurring bouts of fever commence. Cats no longer eat and significantly lose weight. The oral mucosa and joints become inflamed (stomatitis and arthritis).
AIDS-related complex Months to years Due to immunodeficiency, the body gradually loses the battle against bacterial infections, leading to all the organs becoming affected. Cats frequently suffer from behaviour disorders and lameness increases. In addition, respiratory and digestion problems come to the fore. Cats can go blind and emaciate significantly.
The end stage: AIDS (acquired immunodeficiency syndrome) Several months Around 10% of sick cats enter this phase. The immune system becomes so severely debilitated that a cure is no longer possible. Cats die due to massive weight loss.

Diagnosis: How is feline AIDS recognised?

The easier feline AIDS is recognised, the easier it is to treat it. Don't wait too long before seeing a vet if your cat is showing signs of an FIV infection.

In order to exclude a viral infection, the vet can carry out several tests.

1. A blood test

When the vet takes your cat's blood, they can either have it examined on the spot or in a separate lab.

Feline AIDS typically leads to all blood cells like red blood cells (erythrocytes), white blood cells (leucocytes) and blood platelets (thrombocytes) reducing in number. At the same time, the concentration of albumin-globulin in the blood increases.

2. Indirect detection

Measuring specific antibodies in the blood is what vets mean by indirect evidence. The antibodies can be detected with an ELISA test or by using the western blotting method.

The disadvantage: a positive test result doesn't always mean that the cat is infected with FIV. Hence, every positive result should be supplemented by a further test or a different method.

3. Direct detection

Feline immunodeficiency virus can be detected in special labs from blood or tissue samples using the PCR method. Hence, vets frequently opt for this method in order to verify a positive test result from indirect detection.

Treatment: Can feline AIDS be treated?

There are currently no means available in the UK to reliably counteract an FIV infection. However, scientists are researching medication that is said to impede the viral enzyme reverse transcriptase.

Vets use supportive measures in order to alleviate the symptoms of FIV cats. They counteract secondary bacterial infections with the help of antibiotics and strengthen the immune system with stimulative substances (paramunity inducers). However, it has been debatable up until now whether the latter have a positive effect or even weaken the immune system.

It's important that outdoor access is forbidden to FIV cats so that they don't infect other cats.

What is the prognosis?

It it proven that FIV cats are at higher risk of tumours and other infectious diseases. Hence, owners have to accept that cats with an FIV infection can die from the consequences of the disease.

Nevertheless, loving and consistent care can allow your cat to reach a good age with a good quality of life.

two cats fighting
Feline AIDS is primarily transmitted in the saliva. Thus, males with outdoor access are particularly likely to become infected, as they are often involved in fights over territory.

Transmission: How do cats get infected with FIV?

Cats of all species – for instance lions or lynxes – can be infected with feline AIDS. This viral disease is therefore widespread worldwide.

If an already infected cat bites another cat, the FIV virus enters the bite wound via its saliva. Males are therefore particularly likely to become infected, because they are more regularly caught up in fights over territory.

In contrast, female cats become infected more often during reproduction, because males bite them in the neck when this is going on. This neck bite is part of the natural reproductive act.

Interesting fact: The FIV virus can only survive from a short time outside of cats. It is deactivated by the environment after a few hours, meaning it is no longer contagious.

Which cells does the virus attack?

If a cat has become infected with FIV, the virus attacks special cells of the immune system – known as T-lymphocytes. Feline immunodeficiency virus weakens them, making the cat more susceptible to bacterial or viral infectious diseases (e.g. feline leukaemia virus, FeLV).

How can an FIV infection be prevented?

If your cat has become infected with FIV, it should no longer leave the house if possible in order to protect other outdoor cats from a potential viral infection. In addition, you should regularly get your cat checked by a vet in order to intervene at an early stage.

Is there a vaccination against FIV?

In 2002, researchers in the US developed a vaccine against the strain of the immunodeficiency virus prevalent there. However, the efficacy of this vaccine is subject to much debate. It has so far not been authorised in the UK.

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