RETROVIRAL SCREENING
Dr. Ashly LaRoche
Feline retroviral screening is often recommended at a new kitten visit or yearly visit. This is a blood test that screens for two very
important diseases of the cat – Feline Leukemia and Feline Immunodeficiency virus. Both viruses can be transmitted from cat to cat contact and can lead to extensive medical needs and specific housing requirements. This Doc Talk will touch on both viruses a bit to better understand the veterinary testing recommendations. Outdoor cats and kittens are the most susceptible groups.
Feline Leukemia virus is a retrovirus that is easily passed by contact amongst cats. Sharing water bowls and mutual grooming are ways of transmission as the virus is passed in all body fluids. However, contact with saliva and respiratory secretions are the most common ways cats transmit it to each other. The virus can go into a latent stage in the cells of the bone marrow to persistently infect the cat. The virus may never activate in some cats once infected. These cats will test negative at this stage, but the virus can reactivate in months, years or never. Some cats with a healthy immune system can become exposed but fight off the virus, especially healthy older cats. Many exposed cats go on to initially become actively infected. Cats with active infection with the Feline Leukemia virus start getting infections such as respiratory infections as the virus compromises the immune system. In advanced stages, the cat often develops severe anemia as the bone marrow is destroyed.
Feline Immunodeficiency virus differs from Feline Leukemia in that aggressive cat to cat contact is needed. Typically, the virus is spread in the saliva and it takes a bite wound for transmission. All infected cats harbor the virus. It is not until the virus rapidly replicates that the cat begins to get sick. Many cats never get sick from infection. The virus destroys the immune system. Weight loss and infections are seen with active infection.
Young kittens and outdoor cats are the highest risk groups for infection. Outdoor cats often have a wandering lifestyle and come in contact with other infected cats. Therefore, keeping cats indoors is recommended. Screening all new cats and kittens is recommended in addition to yearly testing for cats that go outside or are exposed to cats that go outside. Retroviral positive cats should be kept indoors to prevent spread to the outdoor cat population and exposure of the infectious agents. Screening for retrovirus is important, as new owners need to be aware of additional medical care that may be needed in the life of the positive kitty, as well as a potentially shortened lifespan. Additionally, owners need to make commitment to proper indoor housing needs. Retroviral negative tested cats that have to be housed with a Feline Leukemia positive cat should be vaccinated for the virus to prevent infection.
Feline Leukemia and Feline Immunodeficiency virus can be devastating infections. Fortunately, with good wellness and monitoring, many cats can live good quality, if not long, lives. Testing helps identify the infected cats to allow an overall decrease of the disease in the cat population.