Feline Immunodeficiency Virus (FIV): Symptoms, Diagnosis, Treatment, and Prevention Explained by a Veterinarian

When you take a rescued cat to the vet, you will likely be advised to have it tested for Feline Leukemia Virus (FeLV) as well as Feline Immunodeficiency Virus (FIV), also known as Feline AIDS.

Feline Immunodeficiency Virus infection is a highly prevalent disease among outdoor cats.

This article will explain the symptoms, diagnosis, treatment, and prevention of Feline Immunodeficiency Virus infection.

What is Feline Immunodeficiency Virus Infection (Feline AIDS)?

Feline Immunodeficiency Virus infection is a disease caused by a type of retrovirus that compromises a cat's immune system, leading to various infections. It belongs to the same class of viruses as Feline Leukemia Virus and the human HIV virus.

The virus is primarily transmitted through bite wounds sustained during fights, where the virus in saliva infects white blood cells, such as lymphocytes, in the recipient cat. Due to this mode of transmission, it is more common in outdoor male cats.

What are the symptoms of Feline Immunodeficiency Virus Infection (Feline AIDS)?

Feline Immunodeficiency Virus infection is divided into five stages. We will explain each of them.

Acute Phase

Symptoms in the acute phase include fever, swollen lymph nodes, leukopenia (low white blood cell count), anemia, and diarrhea. The acute phase lasts for several weeks to about four months, during which antibodies against the virus are produced.

Asymptomatic Carrier Phase

The asymptomatic carrier phase is a period with no particular symptoms. It is believed to last for several months to several years. Cats rescued during this period may appear healthy at first glance but will be diagnosed as FIV positive.

Persistent Generalized Lymphadenopathy Phase

During this phase, all lymph nodes are enlarged, but no other symptoms are observed. This phase usually lasts for about 2 to 4 months.

AIDS-Related Complex Phase

Once in this period, immune function begins to decline. Oral inflammation and gingivitis are common, leading to an increase in veterinary visits. Other symptoms include cold-like symptoms, diarrhea, vomiting, and skin conditions.

AIDS Phase

Within one year of the AIDS-related complex phase, symptoms worsen and progress to the AIDS phase. Due to a significant drop in immunity, cats become susceptible to opportunistic infections that would not normally affect them. Anemia, tumors (especially lymphoma), neurological symptoms, severe weight loss, and debilitation also occur. Cats in the AIDS phase are believed to have a lifespan of a few months.

How is Feline Immunodeficiency Virus Infection (Feline AIDS) diagnosed?

Antibodies to the virus appear approximately 4 to 6 weeks after infection. Veterinary clinics have kits that can test for Feline Leukemia Virus simultaneously, and testing is possible for cats aged 2 months and older. If a kitten is rescued, additional tests may be performed at the time of rescue and two months later. If a cat has run away and is injured, testing is also recommended after two months.

Feline Immunodeficiency Virus infection tends to be more common than Feline Leukemia. It's safe to assume that a significant percentage of outdoor cats are infected.

How is Feline Immunodeficiency Virus Infection (Feline AIDS) treated?

Currently, there is no specific treatment for Feline Immunodeficiency Virus infection. Therefore, treatment primarily focuses on symptomatic relief tailored to the specific symptoms.

For stomatitis and gingivitis, antibiotics, anti-inflammatory drugs, and oral disinfectants are used. However, these conditions often recur because they respond poorly to treatment.

In the AIDS-related complex phase and beyond, bacterial and fungal infections such as cold-like symptoms, pneumonia, and enteritis become more frequent. Antibiotics and antifungals are used to treat these.

For anemia, hematopoietic agents or blood transfusions may be administered.

Once a cat enters the AIDS phase, its response to treatment significantly declines. The primary focus becomes prolonging life, such as subcutaneous fluid administration to improve dehydration.

Immune-boosting supplements are available, and some may help improve the quality of life (QOL). These supplements are only handled by some veterinary clinics. Many owners want to do everything they can for their cats, and using such supplements can be a good option. However, in the AIDS-related complex phase and beyond, the goal becomes life extension. Therefore, it is important to have a thorough discussion with your veterinarian about how much treatment to pursue and what improvements are most desired.

How to prevent Feline Immunodeficiency Virus Infection (Feline AIDS)

A vaccine for Feline Immunodeficiency Virus infection was developed and used in Japan, but it has since been discontinued. Feline Immunodeficiency Virus infection can be prevented by avoiding contact with infected cats and keeping cats strictly indoors.

If there is an infected cat living with other cats, they should be isolated. Since this virus is directly transmitted through wounds, its infectiousness is not very strong. Therefore, some owners choose to keep infected and uninfected cats together, but there is always a possibility of infection occurring without the owner's knowledge. It is recommended to keep them separated.

Since transmission can also occur through bite wounds during mating, spaying or neutering is also a preventive measure.

Summary

Feline Immunodeficiency Virus infection, like Feline Leukemia Virus infection, has no cure. Therefore, if it progresses, some form of treatment will always be necessary. Once a cat is diagnosed as positive, it's important to decide on treatment costs, the extent of treatment, and measures to prevent infection in other cats.

Feline Immunodeficiency Virus infection has a long asymptomatic period, allowing cats to live normally for an extended time. To maximize this symptom-free period, ensure your cat has a stress-free life and regularly visit the vet.