This page is dedicated to summarizing the most common infectious diseases we see in cats. Fortunately, we can vaccinate for many of these diseases, so talk to us if you are concerned!
Feline Distemper aka Panleukopenia
What is the cause? Feline distemper is caused by a feline-specific parvovirus What does it target? This virus targets the intestinal tract and bone marrow How is it spread? This virus is airborne. It is most often spread in places where an infected animal has been (such as a shelter) or by direct contact with an infected animal What are the symptoms? This virus causes acute infection with diarrhoea, vomiting, fever and dehydration as the most common symptoms. What is the outcome of infection? This virus has a high mortality rate, especially in young kittens 2 – 6 months of age. Kittens are most susceptible when they have lost maternal immunity and/or have yet to be vaccinated How is it diagnosed? History, physical exam, and blood work findings of low white cell count (panleukopenia) can be suggestive of parvovirus infection. Historically, canine parvovirus test kits were used to detect virus in feces however newer lab tests can be used to isolate virus in tissue (PCR testing) or antibody levels. Is there a vaccine? There are very effective vaccines for panleukopenia. Vaccinations should be given starting at 6/8 weeks of age and is given as an initial series of 2 vaccines, followed by a booster 1 year later then every 3 years.
What is the cause? Feline leukemia is caused by a retrovirus (Feline Leukemia Virus or FeLV). FeLV is a relative of Feline Immunodeficiency Virus (FIV; more below). What does it target? Like FIV, this virus also targets the immune system. Unlike FIV, FeLV infection tends to occurs in kittens and young cats. How is it spread? The virus lives in bodily fluids so it requires “direct transmission” to be spread including cat fight/bite wounds, close casual contact (such as grooming) or shared dishes, and from infected queens (either in utero or via infected milk). What are the symptoms? Affected cats are generally between 1 and 6 (average 3) years of age at time of diagnosis. The symptoms of infection can depend on the type of disease present (i.e. cancer vs non-cancer form) but are most often vague and include depression, intermittent fever, jaundice, dehydration, muscle wasting, anorexia, anaemia, swollen lymph nodes, and recurrent infection. It is important to note that cats can be infected for long periods of time before clinical signs develop. What is the outcome of infection? There is no cure for FeLV so treatment is supportive but is most often fatal, especially if the cat is clinical at time of diagnosis. How is it diagnosed? FeLV infection is diagnosed by detecting virus antigen in the blood stream. False-negative results are possible if the virus is localized in tissue such as bone marrow. In this case, additional testing, such as immuno-fluorescence antibody (IFA) testing can be done on blood smears. There is an in-clinic antigen ELISA test available that can provide FeLV results 10 minutes. This screening test is usual done in conjunction with FIV. Is there a vaccine? There are very effective vaccines to protect your cat against FeLV. Vaccination is done as an initial series of two vaccines 3 – 4 weeks apart followed by annual boosters. As infection happens in kittens, it is important to vaccinate young cats as opposed to older ones.
Feline Immunodeficiency Virus
What is the cause? Feline Immunodeficiency Virus (FIV) is caused by a retrovirus and is a member of the same genus that causes HIV in people. What does it target? Like HIV, this virus targets the cat’s immune system specifically the body’s lymphocytes and macrophages. How is it spread? The virus lives in bodily fluids so it requires “direct transmission” to be spread. The most common mode of transmission in cats is through bite wounds. It is considered a disease of older cats (>5years at the time of diagnosis). It is more common in male cats then female cats but this is likely because they have more “at risk behaviour” such as roaming and aggression that will get them bitten by an infected cat. What are the symptoms? The symptoms of FIV are often vague and are associated with the immunosuppressive nature of this virus. The most common complaints are chronic GI, skin or upper respiratory disease. As the immune system is target, cats infected with FIV can present with immune-system cancer, such as lymphosarcoma or generalized lymph node enlargement. What is the outcome of infection? Many cats can live to their geriatric years with FIV presuming that we are able to control the consequences of immunosuppression. It is important to keep an FIV positive cat indoors to decrease the risk of exposure to other cats. How is it diagnosed? FIV infection is diagnosed by detecting antibodies in the blood stream. Identification of the virus itself through techniques such as PCR are often not successful as the body is very good at keeping the level of circulating virus low. The challenges with diagnosing infection from antibodies include (a) false positive results from previous vaccination or maternal antibodies and (b) false negatives from an exhausted immune system or insufficient time between infection and testing. There is an in-clinic test available that can provide FIV results 10 minutes. This screening test is usual done in conjunction with FeLV. Is there a vaccine? There is a vaccine available for FIV but there are some concerns with its use including (a) false positive results on conventional antibody tests, (b) not effective against all strains of FIV. It is for this reason that there are so many challenges for developing an HIV vaccine in people – this virus loves to mutate so developing a vaccine that covers all mutations is very challenging. The vaccine is given as a series of 3 initial vaccines followed by an annual boosters.
Feline Infectious Peritonitis
What is the cause? FIP is caused by coronavirus; however, the mode of infection is not that simple. Coronaviruses are very common and most cats are exposed to them during their lifetime. In most cats, coronavirus causes short-term diarrhoea but in a small % of cats, it takes on the horrible systemic form known as FIP. For FIP to occur, it requires (a) mutation of normal intestinal cell-loving coronavirus into a macrophage-loving coronavirus and (b) a poor host immune system that cannot get rid of infected macrophages. What does it target? Coronaviruses normally target intestinal cells but in FIP they target macrophages, one of the cells of the immune system. How is it spread? Although coronaviruses are very common and easily spread via fecal-oral contact FIP is not “spread” like other infections as it requires specific mutations within an infected cat to turn into FIP. That said, FIP may appear to “spread” though a cattery or litter of kittens but this is more likely because they share the same genetics rather than the type of coronavirus in the environment. What is the outcome of infection? Currently there is no successful treatment for FIP so the infection is always fatal. Cats with the dry form of FIP can linger for a long time with infection but eventually the virus will win. What are the symptoms? FIP is considered a kitten disease with the age of incidence <3 years of age. FIP is divided into two types: wet form and dry form. Wet form FIP is often fast progressing and hallmarked by diarrhoea, rapid weight loss, dehydration, loss of body condition, and a very large distended belly full of straw-yellow fluid. Thedry form FIP is more challenging to diagnose as the dry form is often slow to progress and the symptoms can be vague but generally include weight loss, anorexia, depression, poor growth, jaundice, enlarged lymph nodes, neurological signs, uveitis (eye disease), etc. How is it diagnosed? Diagnosing FIP is very challenging as short of isolating virus within tissue macrophages there is no reliable one test to diagnose FIP. Faced with these challenges, FIP becomes a diagnoses based on clinical signs and suggestive lab results. High globulins, low white cell count, anemia, and a high titre count has a very high predictive value for diagnosing FIP Is there a vaccine? Although a vaccine was developed it is no longer used nor advocated by feline practitioners and the AAFP as FIP infection is based, not only on exposure of the virus, but how each individual cat’s immune system responds to infection.
What is the cause? Rabies is caused by a Lyssavirus. It is very important to note that all warm blooded species, including humans, are at risk of contracting rabies. What does it target? The virus targets the central nervous system How is it spread? This virus is spread through direct contact including bite wounds or pushing infected saliva into open wounds. Carrier species in Alberta is bats, however foxes, racoons, and skunks can be carrier species in endemic areas of North America. What are the symptoms? There are two phases of virus infection including a excitatory/furious phase characterised by restless, irritable behaviour, unprovoked biting, and noise sensitivity. The paralytic/dumb form of rabies is characterised by paralysis, cramps, stupor behaviour, and swallowing difficulties. What is the outcome of infection? Infection is always fatal. How is it diagnosed? Rabies should be considered in any unvaccinated animal showing unusual mood or behaviour changes or unaccountable neurological signs in endemic areas. Diagnosis is done on brain tissue using a special staining technique called “direct fluorescence antibody” Is there a vaccine? There are very effective vaccines against rabies. Because this virus can affect people and is fatal, all cats with any possible exposure to the outside including balconies, enclosed pens, “supervised outdoor time” should be vaccinated against rabies. Indoor cats with a history of aggression should also be vaccinated (for liability reasons). We use a cat-specific recombinant vaccine (so as to minimize side effects) that requires annual boosters. There are some killed virus vaccines that can provide immunity for 3 years.
Upper Respiratory Diseases
What is the cause? The classic sneezing, runny eye, runny nose cat “colds” are caused by (a) feline herpes virus, (b) feline calicivirus, and/or (c) Chlamydia. Chlamydia is the least common cause in our area so we will focus on the viral causes of URD. What does it target? These viral diseases target the upper respiratory system including the eyes, nose, sinuses, nasal passages, and trachea. How is it spread? These viruses are airborne. It is most often spread in places where an infected animal has been (such as a shelter) or by direct contact with infected material (fomites). What are the symptoms? The symptoms of URD are generally flu-like (fever, malaise) with sneezing, runny eyes, and runny nose being the most common. Ulcers of the eye are associated with herpes virus infection whereas ulcers of the mouth are generally associated with calicivirus. What is the outcome of infection? With supportive care, most cats will overcome infection of URD. That said, once a cat has been exposed to herpes virus, the virus lives forever in them (think about people with cold sores), so recurrent infection is possible. How is it diagnosed? Symptoms are used to diagnose URD. To differentiate between herpes virus and calicivirus infection, however, one must isolate virus in tissue (generally done through PCR testing). Is there a vaccine? There are vaccines that protect against all three infectious agents. However, just like human flu vaccines, they may not guarantee 100% immune protection, but will help minimize the severity of disease. Vaccination is done as an initial series of two vaccines 3 – 4 weeks apart followed by an annual booster. After the one-year booster, further vaccines will be given every 1 – 3 years depending on the type of vaccine used and the risk of the cat.