Feline herpes virus, or cat flu, is an upper respiratory virus that affects the nose, throat, eyes and larynx. Symptoms of the feline herpes virus include nasal discharge, listlessness, fever, loss of appetite, lethargy and sneezing. Depending on the cat’s vaccination status and immune system health, the severity of the infection can range from mild (sneezing and tearing) to severe.
Predisolone is an immunospressive drug used to treat a variety of conditions in cats, including feline herpes, when the immune system is overactive, causing pain, inflammation or severe itching.
Feline herpes virus is transmitted via cat-to-cat contact or by coming into contact with live virus particles in the environment. The feline herpes virus is rarely fatal in cats, though secondary bacterial infections or complications, such as dehydration due to loss of appetite, can be fatal if not treated. Many cats that contract the feline herpes virus are treated with a regimen of antibiotics to prevent a secondary bacterial infection from occurring, though the antibiotics will have no effect on the virus whatsoever. Supportive care is recommended to ensure that the cat is receiving water and nutrients during its illness to prevent dehydration and sharp drops in blood glucose levels.
Predisolone and the Immune System
Cats who have received regular annual vaccinations against the feline herpes virus can still become infected, especially if they are on prednisolone therapy. Prednisolone is a glucocortico steroid used to suppress the immune system and inflammation response in many traditional treatments for cats. Conditions such as autoimmune diseases, allergies and osteoarthritis are all treated with prednisolone. It is because of the drug’s immunosuppressive characteristics that it is advised to keep cats receiving the treatment indoors for a period of up to one month after the last treatment is taken in order to allow the immune system to recover.
If a cat has previously had the feline herpes virus, the virus can lurk in the cat’s system, dormant, for years after the infection. If, at any time, the cat takes prednisolone, the virus can become active and reinfect the cat, regardless of exposure precautions. Since the cat’s immune system is suppressed, the severity of the symptoms of the virus are usually greater than normal, so proactive antibiotic therapy is a must to prevent complications such as pneumonia. It is advisable to have the cat hospitalized in order to receive intravenous fluid therapy, injectable antibiotics and regular blood glucose monitoring. Oxygen therapy may also be indicated if the cat is showing signs of having difficulty breathing.
Cats who are on chronic prednisolone treatments for more severe conditions may have recurring herpes infections caused by a dormant virus. There is no cure for this situation, and many animals in this situation will have a shortened life span because of it.
If your cat is currently taking prednisolone, take extra precautions to avoid exposing your cat to herpes or any other virus by keeping him indoors and isolated from other cats in the house. If you suspect that your cat has developed herpes symptoms caused by a dormant virus, take him to the veterinarian for an evaluation and monitoring.