Immunodeficiency Syndrome in Cats

The immunodeficiency of cats (also Felines acquired immune deficiency syndrome , commonly known as " Cat AIDS ", English Feline Acquired Immune Deficiency Syndrome - FAIDS ) is a viral infectious disease of cats . The pathogen is the Feline Immunodeficiency Virus (FIV) from the retrovirus family . The virus weakens the immune system and triggers secondary diseases that lead to death. It is thus similar to the cause of AIDS in humans, but is not dangerous for them. So far, virus strains have been isolated from nine different cat species; in many other species antibodies have been found that indicate infection.

Occurrence

The pathogen occurs worldwide, of 400 million cats worldwide an estimated 44 million (11%) are infected. The number could be even higher as 10-15% of cats infected with FIV are seronegative . The different FIV strains infect all cats and all ages. Clinically, the disease mostly occurs in animals that are older than five years. Infection lasts a lifetime.

Domestic cats kept in isolation and not in contact with fellow cats are hardly at risk. The main risk group includes older male cats with a pronounced territorial behavior in environments with a high density of cats, as the animals are then more often involved in fights. Normal social contact between cats does not lead to contagion.

transmission

The virus can be found in saliva , blood and cerebrospinal fluid . The main transmission is believed to be via bites. This assumption is supported by the observation that seropositivity increases with the age of the cats. It has been experimentally confirmed that cats can transmit the virus to the fetus in the womb . Infection of kittens through colostrum and breast milk is also possible. However, this frequency of these transmissions fluctuates with different FIV strains and is the exception rather than the rule overall. The "horizontal" transmission is much more important than the vertical one.

Pathogenesis and Symptoms

For the course of the infection at the cellular level, see the main article Feline Immunodeficiency Virus

The course of infection can be divided into four stages: an acute, an asymptomatic, a non-specific and a terminal AIDS-like phase. After an initial infection, the cat immediately produces virus-specific antibodies and cytotoxic T cells , but is unable to overcome the infection completely despite the violent immune reaction, and the virus remains permanently in the body in all the cases examined so far.

The primary infection manifests itself in fever , neutropenia and lymphadenopathy . From this transitional stage, the animals usually recover quickly and the disease appears to come to a standstill for several months. During this time, the number of CD4-positive cells in the blood steadily decreases. The ratio of CD4- to CD8-positive cells shifts and the B- and T-cells malfunction .

In the further course FAIDS has no clear symptoms, as it is partly characterized by secondary infections as a result of the immune deficiency. The first AIDS-like symptoms only become visible about five to nine years after the infection. Because FIV can also infect cells of the nervous system such as glial cells and astrocytes , neurological symptoms such as delayed reactions, temporary paralysis, changes in behavior and anisocoria may occur .

Depending on the stage of the disease more symptoms: bad skin, fever, diarrhea , behavioral disorders due to encephalopathy , chronic inflammations ( conjunctivitis , gingiva , oral mucosa inflammation ), severe weight loss, loss of appetite ( anorexia ) and swelling of the lymph nodes .

The time course of the disease also depends on the FIV subtypes. With some more pathogenic strains, 5 to 25% of domestic cats die within a year.

diagnosis

FIV-FeLV rapid test, both evidence are positive

Due to the very variable clinical picture, a diagnosis can only be made by serological detection of the antibodies (theoretically also by virus isolation).

The currently available rapid tests are based on an ELISA for antibodies against p24 inner bodies and / or gp40 proteins. They are meanwhile equal to extensive laboratory tests. However, false-positive results are possible; in older tests they mainly occurred as a result of contamination with calf serum. Verification via virus isolation , PCR , Western blot or indirect immunofluorescence test is therefore useful. Antibody detection should be assessed carefully in kittens under six months of age, as the antibodies may be maternal antibodies without the virus being transmitted from the mother to her offspring. In the early phase of an FIV infection, an antibody test can still be negative, then a follow-up test is required 60 days after the suspected infection. In animals vaccinated against FIV, antibodies can be detectable for up to three years after vaccination.

FeLV infection and feline infectious peritonitis should be considered in the differential diagnosis .

treatment

A therapy to cure FAIDS does not yet exist. Sick cats must be excluded from the open air so as not to endanger other cats. Normal social contacts without fights and rank fights among cats living together in a household usually do not lead to infection.

To increase the lifespan and quality of life of a sick cat, we recommend:

• the treatment of secondary infections caused by the immune deficiency,
• keeping the sick animal in an environment that is as stress-free as possible,
• antiviral chemotherapy, administration of interferon alpha and regular blood tests.

However, the disease is currently not curable. One can only try to alleviate the symptoms of the disease.

prophylaxis

A vaccine against FIV was approved in the US in the summer of 2002 , but it is not available in Europe.

Individual evidence

1. ↑ Feline immunodeficiency virus vaccine , accessed April 9, 2013.
2. ↑ Luis Isamu Barros Kanzaki, David J. Looney: Feline immunodeficiency virus: a concise review. In: Frontiers in Bioscience. Vol. 9, January 2004, ISSN  1093-9946 , pp. 370-377, Review. PMID 14766374 , doi : 10.2741 / 1235 .
3. ↑ Katrin Hartmann: In-house tests in small animal practice - for which cat infectious diseases are they "useful"? In: Kleintiermedizin No. 5 2016, pp. 218–227.

This article is about a health issue. It is not used for self-diagnosis and does not replace a diagnosis by a doctor. Please note the information on health issues !