Common disease in cats is cat flu, a general name for viral infection of the upper respiratory tract. Not usually fatal in healthy adult cats it can that be life-threatening to unvaccinated cats and kittens, immuno-suppressed and older cats. Most commonly this disease seen in situations where cats are kept in large groups because it’s a very contagious disease and can spread quickly from cat to cat, rarely it can also be seen in pet cat households.
The virus spreads with contact from the discharge from the nose and eyes, from the cat sneezing, like a cold is spread in humans. The virus can live outside the cat's body for a period of time and infection can be transmitted via anything your cat comes into contact with. Due to the disease being very contagious infected cats should be kept isolated from other cats. Cat flu cannot be spread to humans. Although vaccination helps to reduce the risk of cat flu, this disease can still be seen in vaccinated cats. Cats who have recovered from cat flu may become symptomless carriers of the virus, shedding the virus to the other cats especially at times of stress. The Feline Herpes Virus carrier state lasts the lifetime of the cat, and Feline Calicivirus the carrier state lasts from 1to 18 months after infection.
It is known that a number of infectious agents have been found to cause cat flu, but the vast majority of cases are caused by one of two viruses: Feline Herpes Virus-1 (FHV-1) or Feline Calicivirus (FCV). Feline Herpes Virus-1 (FHV-1) and Feline Calicivirus (FCV) are responsible for 80% cases of cat flu. Feline Herpes Virus (Feline Virus Rhinotracheitis) is the more serious of the two. This virus infects the membranes of the eyes, sinuses, the lining of the nose, pharynx, and throat. Feline Herpes Virus symptoms usually last for about 7 -14 days, and the virus can live outside the cat's body for approximately 24 hours. Calicivirus symptoms usually last for about 7 - 10 days; it may survive up to 7-10 days outside the cat.
Symptoms and diagnostics:
Feline Herpes Virus (FHV-1) infection: Severe and potentially life-threatening illness. Affected cats develop a clear discharge from the nose and eyes. The virus affects the membranes of the eyes causing conjunctivitis, eyes become swollen and red with a discharge that is often filled with pus if a secondary bacterial infection takes place, sometimes corneal ulcers may develop. Sneezing is one of the most common symptoms.The virus causes rhinitis, inflammation of nasal linings. The nasal discharge is a clear fluid at the beginning, and then turns thick and green as the disease progresses. Cats may lose their sense of smell. Cats tend to be dull and depressed; they have a raised temperature and generally feel unwell. Cats often lose their appetite and sometimes become dehydrated; although they are dehydrated they may refuse to drink.A secondary bacterial infection of damaged tissue can cause chronic conjunctivitis, sinusitis and bronchitis. Antibiotic treatment usually only provides temporary relief of these symptoms. Coughing and sneezing is common. A pregnant cat may abort the kittens; if they are born then they have high probability to catch the infection from their mother. The majority of infected cats make a full recovery, but recovery takes several (2-3) weeks and some cats are left with permanent effects of infection such as chronic rhinitis. Cats with chronic rhinitis are usually healthy in other ways but have a persistent discharge from the nose and sneeze.
Feline Calicivirus (FCV) infection: Usually a milder form of cat flu with less dramatic nasal discharges. A number of different strains exist and signs can be variable depending on the strain involved. The most prominent symptom of Feline Calicivirus is ulceration of the mouth and tongue, palate, lips and sometimes the tip of the nose, also the gingivitis may affect gums. Sometimes mouth ulcers may be the only sign of infection. Depending on the severity of the mouth ulcers drooling can occur. The virus causes cold like symptoms; affected animal has runny nose and eyes, it can affect the membranes of the eye but does not cause eye ulcers. The cat may or may not have a fever. The cat sometimes finds it too painful to eat because of the mouth ulcers, and may lose the appetite. The infection becomes more serious if secondary bacterial infections invade. There are some strains that affect animals joints, these strains may cause lameness and fever in young kitten. Cats recover over a few days although they may need pain killers through this time. Recently more virulent strains of FCV have been identified in the USA and UK. These strains often cause severe swelling of the face and paws, skin ulcerations on the head and limbs, jaundice, hemorrhage in addition to other FCV symptoms. They have mortality rate up to 67%. These strains are currently under investigation.
Diagnosis is based on symptoms and laboratory tests. Testing for flu viruses requires taking a mouth or eye swab which is then submitted to a specialized laboratory where the virus and/or bacterium can be grown and identified.