Cats

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FELINE LEUKEMIA VIRUS (FeLV)

FeLV is a oncogenic virus which means it can cause cancer directly as well as attacking the immune system. It makes the cat susceptible to developing chronic infections like AIDS does. It is not transmittable to humans. It is most commonly found in catteries (catteries can be FeLV free) and households with many cats, because the spread of the virus requires close, prolonged contact between cats. The virus is transmitted via saliva, mucus, urine, faeces and blood. Contaminated bowls and bedding are thought to be the commonest route of transmission. Cats under 6 months have an increased risk of catching the virus if exposed. A FeLV queen will infect her kittens. The cat may temporarily harbour the virus or remain a carrier. Shedding may be intermittent. Whether the cat then goes on to develop the disease is very complex and every cat is different. Cats carrying FeLV virus may show no disease symptoms, but still infect other cats. FeLV may be the underlying cause of a huge range of other illnesses.

Symptoms

Fever, loss of appetite, weight loss.

• Blood problems, e.g. anaemia, clotting defects, reduced defence against infection.
• Cancer of the blood (leukaemia) or solid tumours (called lymphoma or lymphosarcoma). Lymphosarcomas are the commonest of all cat cancer (10 - 30%) and FeLV is found associated with these tumours in about 50% of cases.
• Persistent infections e.g. severe or re-occurring cat flu, bad skin or inflammation of the mouth.

Treatment

There is no specific treatment for FeLV. Once your cat is sick there is only supportive treatment for the secondary diseases that your cat may develop. It is likely to be the cause of your cat's death. This virus is very difficult to diagnose and our lab thinks we only pick up 30 % of cats with FeLV. Repeat blood testing at set time intervals does help but still it is very unlikely that we diagnose all cats with FeLV. It is important to decide if you want to treat FeLV infected cats as they could pass on the virus to contact cats.

Prevention

There is a vaccine available for FeLV. At Lort Smith we don't give this vaccine unless asked. FeLV is thought to be uncommon in Australia (1% of sick cats). It is also most likely spread before 6 months of age so vaccinating older cats may be superfluous. This vaccine is one of the two vaccines thought to be associated with vaccine-induced fibrosarcomas in the U.S. (the other is rabies) though these tumours aren't common. However vaccination is the only way to prevent this disease. A cat with a negative FeLV status going into a house with a FeLV positive cat should definitely be vaccinated otherwise you are taking a risk. Once vaccinated a cat will have a vaccine induced positive result to a FeLV blood test.

  FELINE IMMUNODEFICIENCY VIRUS OR AIDS

Feline immunodeficiency virus (FIV) was "discovered" shortly after HIV however this virus has been in Australian cats for at least 40 years. FIV does not infect humans and HIV does not infect cats. FIV acts exactly the same as HIV in that it attacks the immune system. Clinically it is very similar to FeLV although it is a completely different virus. FIV does not directly cause cancer like FeLV but does "allow" cancer to develop by causing the immune system to fail to recognize and remove cancer cells.

FIV is spread mainly through bites. Transmission from an infected queen to her kittens occasionally occurs but it is uncertain whether this occurs during gestation or after birth when the kittens ingest infected milk. Sexual contact is not a primary means of spreading FIV. Once your cat is infected it is infected for life, however the cat may appear normal for many years. It is thought that some cats may not go on to develop immunodeficiency, and incubation times of about 4 - 6 years have been suggested.

Male cats are three times more likely to become infected than females and strictly indoor cats are unlikely to become infected. Free roaming toms are at the highest risk as they fight a lot and will travel distances to find queens. The prevalence of infection increases with age and the average age of diagnosis is 5 years.

Symptoms

• Fever, loss of appetite, weight loss, diarrhoea, depression.
• Decreased immune response any infection.
• Any cancer (lymphoma/lymphosarcomas are the most common).
• Persistent infections e.g. severe or re-occurring cat flu, bad skin or inflammation of the mouth.

Treatment

Like FeLV there is no specific treatment for FIV. Treatment is aimed at the secondary and opportunistic infections. There is currently no vaccine available. Diagnosis is made via blood tests however these tests are not completely accurate. In Melbourne in unwell cats (I.E. cats where FIV is suspected) 20% are positive at our lab. Western Australia reports 25%. This means FIV must be considered a common infection in Australia .

Prevention

Desexing your cats and keeping your cat indoors at night greatly decreases the risk of fighting and acquiring FIV. Keeping your cat constantly inside lowers that risk further and in single cat households the cat would need to escape to be at risk. Removing local strays will help as well as decrease other contagious diseases and preserve wildlife. Infected cats should be kept indoors as much as possible to prevent them from infecting other cats. Where an FIV positive cat is found in a multi-cat household it is important to test the other cats as it may have bearing on whether to euthanase the infected cat.

Treatment

Cats with mild symptoms may only require nursing however if your cat is in the high risk group, or if your cat is not eating or drinking, or is depressed then you should take your cat to see your veterinarian. Flu tends to cause clear (serous) discharges. If the discharges change or include blood then again its time to go to the vet. A green runny nose in a cat usually involves a bacterial infection. Your vet may prescribe some drugs for your cat, but hand in hand with this medicine is nursing care which you need to provide.

Cats with blocked-up noses can't smell their food and are reluctant to eat so tempting them with smelly food such as sardines can help. Sometimes putting food in their mouth will give them the flavour and then they will eat. Their eyes and noses must be kept clean. Warm salty water is the easiest. (Use 2 cups of boiled water that has cooled and add 1 teaspoon salt. Not very much salt at all. Sterile saline for cleaning contact lens is also fine.) The cat must be kept warm and comfortable and should be encouraged to drink. If your cat has a blocked nose have the cat in the bathroom while you are having a shower as the steam helps. Children's vaporizers can be used either with just water or with the eucalyptus solution provided. Having the cat purr also helps.

Prevention

Vaccination will not totally prevent cat flu in all cases, but most vaccinated cats will avoid the disease, or only develop mild symptoms if exposed. Kittens, especially strays, are very susceptible and should be vaccinated starting at 6 - 8 weeks. Isolate cats with flu from other cats and use separate feeding bowls etc. and disinfect the area they have been in. Avoid letting kittens have contact with unvaccinated cats.

FELINE CHLAMYDIAL DISEASE

Chlamydia psittaci is a bacteria that predominantly causes conjunctivitis. It is thought to be one of the most important feline ocular pathogens and has been isolated from approximately a third of cases of conjunctivitis in household cats. The prevalence in Australian cats is believed to be between 0 - 20%.

Although this disease is not thought to transmit to humans sensible care should be taken if your cat is infected with this bacteria.

Symptoms

This disease generally causes conjunctivitis; red sore eyes, often with a discharge. The infection usually starts in one eye but will spread to both over a few days. A mild cough and snotty may also occur. Your cat can be feverish and the lymph nodes might enlarge so that you might feel lumps under your cat's chin. Abortion, arthritis and pneumonia can occur are uncommon.

Two distinct types of conjunctivitis have been noted.

• Kittens that are between 7 - 10 days of age develop "sticky eye" where the lids are stuck together with a mucky discharge.
• Conjunctivitis in cats between 6 - 12 weeks up to 5 - 9 months. Adult cats can also develop Chlamydial conjunctivitis but the disease tends to be less severe and of shorter duration due to better immunity.

The incubation period from infection to symptoms is between 3 - 14 days. The clinical signs diminish somewhere between 2 - 6 weeks with quicker recovery in older cats. Some cats develop persistent conjunctivitis and may lose weight with a decreased appetite and general illness. Some cats will become carriers and continue to shed the bacteria for up to 18 months.

What immunity that develops from exposure to Chlamydia is usually short-lived and cats don't become completely immune to this disease even if they recover naturally.

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