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Feline Immunodeficiency Virus (FIV)

What is Feline Immunodeficiency Virus?

Feline Immunodeficiency Virus (FIV) is a virus that infects cats and is known to cause progressive disease in cats. The virus itself belongs to a group of viruses that include human immunodeficiency virus (HIV), the cause of acquired immunodeficiency syndrome (AIDS) in humans. Although HIV and FIV belong to the same family of viruses, it is not possible for FIV to be transmitted from an infected cat to humans.

How Do Cats Get FIV?

The most common route of infection of FIV is through bite wounds, therefore the aggressive behaviour exhibited by many free-roaming male cats places them at greater risk of infection. Non-aggressive contact within cat populations does not appear to cause FIV spread. It is also thought that sexual transmission is not a primary means of spread of the virus, however bite wounds inflicted during mating may transmit the virus. It is possible but uncommon for the virus to be transferred from an infected pregnant female to her kittens through either the placenta or through infected milk.

How Do I Know If My Cat Has FIV?

At the time of initial infection, it is unlikely that you will notice your cat being unwell. Clinical signs at the time of initial infection include a fever and enlarged lymph nodes. In most cases, infected cats remain healthy for years following infection.

The virus causes an immunodeficiency that means that infected cats have a poor immune response and are therefore more susceptible to bacterial, viral, fungal and protozoal infections. Most commonly, it is these and other infections that cause the death of the cat rather than the virus itself.

There are no classical clinical signs associated with FIV infection. Symptoms include deterioration in body condition, persistent fevers, and clinical signs related to secondary infection.

How Common Is FIV in Sydney?

Good studies have not been performed to determine the prevalence of FIV infection among the cat population in Sydney. Limited studies have shown that between 7-13% of healthy cats and up to 20% of sick cats may be infected with FIV.

Diagnosis and Treatment of FIV

FIV is diagnosed by performing a blood test.

Currently there is no commercially available test that will differentiate between natural infection and a cat that has been vaccinated with the FIV vaccine.

As in human HIV, there is no specific treatment available to ensure elimination of FIV from infected cats. Treatment of sick cats involves therapy targeted at treating secondary infections.

How Do I Prevent My Cat From Contracting FIV?

The best means of preventing a cat from becoming FIV-positive is to reduce exposure to potentially infected cats. This essentially means housing cats indoors where there is no opportunity for potential aggressive behaviour with an FIV-positive cat and preventing your cat from being bitten.An alternative to this method of prevention is vaccination. The FIV vaccine is a recently released vaccine that can be used on both kittens and adults.

Should I Vaccinate My Cat Against FIV?

If your cat spends time outdoors, and particularly if they are involved in cat fights, then we recommend vaccination. However it should be kept in mind that the vaccination is not 100%protective, and the best protection is to prevent your cat from being bitten. We recognise that there are times when preventing cat fights is impossible, in which case the vaccine is a reasonable alternative.

As there are no commercially available tests that can differentiate between a cat that has been vaccinated from a cat that has been infected, it is important to microchip your cat before vaccinating against FIV. This is because some animal shelters have a policy of euthanasing FIV positive cats; therefore it is possible that a healthy, vaccinated cat could be euthanased if it is not microchipped and the owners cannot be contacted.

If your vaccinated cat has a litter of kittens, it is possible for the kittens to be positive on the test also, so making sure they are microchipped before sale is essential.

The decision to vaccinate a cat should be made after careful consideration of the advantages and disadvantages of vaccination and whether your cat is in the risk group for infection.

If you decide to vaccinate, you MUST:

  • Keep microchip details up to date to prevent euthanasia in a shelter if the cat goes missing.
  • Bear in mind that the vaccination is not 100% protective, therefore there is still a risk of infection.

What Does Vaccination Involve?

  • For cats less than 6 months of age it is recommended that animals are microchipped at the time of vaccination. The vaccination protocol consists of three doses of vaccine given from 8 weeks of age or after. Doses should be given 2-4 weeks apart. After the initial course of vaccines, a yearly vaccination is required.
  • For cats 6 months of age and older, it is recommended that an FIV test is performed prior to vaccination. Cats should test negative before vaccination. It is also recommended that cats are microchipped (if not already) at the time of the first vaccination. The 3 dose course of vaccines is then given 2-4 weeks apart.
  • An annual booster is also required.

Technically, if any one of the vaccinations is more than one week overdue, another course of 3 doses of vaccine, 2-4 weeks apart is necessary.