The virus is highly serious and contagious, which means prevention is key to protecting our cats. In this guide, we’re going to talk all about feline immunodeficiency virus in cats, from what it is to how to manage it. 

What Is FIV?

Feline immunodeficiency virus (FIV) is a retrovirus that affects the immune system of cats. It’s similar to how HIV works in humans, but FIV is species-specific. This means it only affects cats and can’t spread to humans, dogs, or other animals.

The virus invades their white blood cells, which are crucial for fighting off infections. Over time, the immune system becomes weaker, making the cat vulnerable to secondary infections and illnesses. 

While this doesn’t mean that cats with FIV are always sick, it simply means they require extra care to maintain their health.

How Does FIV in Cats Spread?

The virus spreads mainly through bite wounds, as the virus is highly concentrated in the cat’s saliva. This usually happens when infected cats fight other cats, as the saliva with the virus will be introduced into the other cat’s bloodstream. 

In some cases, FIV can also spread from mother to kittens during pregnancy or nursing. They can also be transmitted through blood transfusions, but this is rare due to donor screenings. 

What Are the Stages of an FIV Infection in Cats?

FIV progresses in three stages, each with its own set of symptoms. These stages are the acute phase, the asymptomatic phase, and the progressive immune dysfunction phase. Here are the stages of an FIV infection.

Stage 1: Acute Phase

The acute phase of FIV in cats occurs within 1 to 3 months after infection. This is when the virus starts to spread to the lymph nodes. During this phase, the immune system will attempt to fight off the virus and respond, resulting in mild or temporary symptoms. 

Some cats recover quickly and appear healthy again as the virus transitions to the next stage. Here are the common symptoms in the acute phase of FIV:

• Fever. A low-grade fever is often one of the first signs, though it may go unnoticed. You may notice a slight increase in your cat’s temperature when touched. 

• Swollen Lymph Nodes. Enlarged lymph nodes, which may feel like small lumps under the jaw or in the groin, are key indicators of the immune system fighting off an infection. 

• Lethargy. Cats may seem less energetic or prefer to sleep more than usual. They might choose to lie down even after being provided with the toys and attention they usually like. 

• Loss of Appetite. Your cat may also have a reduced appetite, even when given their favorite treats and foods. Persistent cases often lead to weight loss. 

• Minor Infections. Cats may develop mild infections, with symptoms such as sneezing or skin irritation. This is a sign that the virus has started to suppress your cat’s immune system. 

Stage 2: Asymptomatic Phase

The asymptomatic phase, also called the latent stage, is the longest phase of an FIV infection. It can last anywhere from several months to a few years. 

During this time, the FIV lies dormant in the cat’s body and replicates at a slower rate. In most cases, there will be no visible symptoms during this stage. Cats may appear completely healthy. 

In this stage, the virus slowly destroys the cat’s white blood cells, weakening the immune system over time. FIV-positive cats may still transmit the virus to other cats, even if they don’t show any physical signs. This phase can also last for several months or years.

Stage 3: Progressive Phase

In the final stage, the cat’s immune system becomes immensely suppressed and weakened. Their CD4+ T lymphocytes are significantly depleted. As a result, cats with FIV start to develop symptoms related to other chronic, recurring infections and other opportunistic health issues. 

Here are the symptoms of the progressive phase:

• Chronic Infections. Respiratory, skin, and urinary tract infections can present with differentiating symptoms. These conditions can cause coughing, sores, and pain.

• Weight Loss and Wasting Syndrome. Cats may lose weight even when they eat normally. This can be seen in a loss of muscle mass as well as a poor coat condition.

• Gastrointestinal Issues. Chronic diarrhea and vomiting are common signs in the advanced stages of FIV. 

• Oral and Dental Issues. Mouth ulcers, tooth loss, and gingivitis in cats can all cause inflammation of the gums and mouth. This results in severe discomfort for cats. 

• Neurological Symptoms. Seizures, tremors, behavioral changes, increased vocalization, and difficulty walking are some of the neurological symptoms associated with advanced FIV in cats.

• Cancer. Cats with advanced FIV are at an increased risk of developing cancers, such as lymphoma.