Feline Upper Respiratory Infection Causes

By far, viruses are the most common causes of upper respiratory infections in cats. About 80%- 90% of infections are viral, while most of the rest are caused by bacteria.

The most common culprits often show up in shelters and multi-cat households:

• Feline herpesvirus. This is related to the virus that causes chickenpox and cold sores in people, but cats can’t give it to their owners.
  • Most cats that get feline herpesvirus will carry it for the rest of their lives.
  • They may be able to spread it even if they don’t seem sick.
  • That can include a mother cat with a new litter of kittens.
• Feline calicivirus. This highly contagious virus causes a mild to severe respiratory infection and oral disease.
• Chlamydia. Runny eyes are a typical sign of this bacterial infection.
• This bacterial infection is usually associated with stress and overcrowded living conditions.
  • It’s more common in dogs.
• Fungus. Cats can pick up fungal infections by being exposed to bird droppings and decaying plants.

Viruses are found in the saliva, tears, and nasal secretions of infected cats.

• They’re easily spread through direct contact, like touching and grooming, or when cats cough and sneeze on each other.
• Viruses can also live on surfaces cats share, like food and water bowls or litter boxes.
• People can spread them from one cat to another with contaminated hands or clothing.

Feline Upper Respiratory Infection Risk Factors

Upper respiratory infections are common for cats that live in crowded conditions, like shelters or breeding facilities. They’re also more likely in multi-cat households. Other risk factors include:

• Kittens and elderly cats are more likely to get infections.
• Vaccination status. Your cat’s vaccines can keep them from getting sick or cause an infection to be milder.
• Physical condition. Cats that have feline leukemia or feline immunodeficiency virus are more likely to get infections. Other illnesses or medications that suppress the immune system can put your cat at risk.
• Stress. It can make a cat more likely to pick up a virus in the first place and cause it to come back later in life.
• Breed. Persians and other flat-faced breeds are more likely to get upper respiratory infections because of their facial structure.
• Going outside. Outdoor cats are more likely to come in contact with infected cats or with fungi that can cause infections.

Are other cats in the household at risk of infection?

A cat with an acute upper respiratory infection will be infective to other cats during the incubation period and for up to three weeks after developing symptoms.

• A cat that is a carrier of an upper respiratory virus may always be infective to other cats.
• Cats that are unvaccinated, young, or that have chronic underlying conditions are more susceptible and may develop a serious illness.
• Adequately vaccinated adults will likely only develop a mild case of illness, which may resolve without treatment.
• It is always prudent to isolate a new cat from the other cats in your household for at least 1–2 weeks to minimize the risk of transmission of any infectious diseases.
  • During this time, the cat should be examined by a veterinarian to ensure it is safe for the cats to make contact.