Feline viruses – list, overview, discussion.

As feline viruses can be confusing to the average cat caretaker and I put myself in that category, I thought an overview page might help. The intention is to stand back and try and make sense of all the long words and slightly confusing names such as “feline distemper”, a misleading description. This is not meant to be a detailed look at this subject but I do include links to other pages on this and my blogger site.

Feline viruses, as infectious agents, need to be distinguished from other infectious agents: bacterial infections and fungal and protozoan diseases.

Feline herpes
Feline herpes virus. Photo: asmscience.org
Two useful tags. Click either to see the articles:- Toxic to cats | Dangers to cats

Feline Upper Respiratory Disease

The most common infectious disease diagnosed in domestic cats1. Eight out of ten cases are caused by one of two highly contagious feline viruses:

  1. rhinotracheitis virus- feline herpesvirus (Feline herpes virus type 1 – FHV-1)
  2. feline calcivirus (FCV)

Transmission is through intimate contact between cats from virus particles shed in:

  • sputum (spit)
  • nasal/eye discharges

Most common form of transmission:

  • grooming, licking
  • sharing food bowls

Symptoms appear after 2 to 17 days and are:

  • inflammation of mucus membrane
  • sneezing
  • ulceration of mouth (sometimes) leading to under eating and weight loss
  • corneal lesions

FCV infections produce less severe inflammation that FHV-1. About 80% of cats that have recovered can be carriers of FHV-11. Cats also carry FCV once infected.

Feline Herpes Virus

3 Dec 2008 Viral Rhinotracheitis (RHV), which is an upper respiratory infection (URI) and a feline viral respiratory disease. Incidentally, the other major cause of feline viral respiratory disease is the Calicivirus group.


This disease is also called “feline distemper”, confusingly, I think and “feline infectious enteritis” as it causes enteritis (inflammation of the small intestine), which is often fatal in kittens. The panleukopenia virus is so called because the infection causes a severe reduction in white cell count. The word “pan” means “all” and “leukopenia” means reduced white blood cells.

Pablo and Bones suffer from ataxia due to cerebellar hypoplasia
Pablo and Bones suffer from ataxia due to cerebellar hypoplasia which is caused at birth by the mother passing on feline panleukopenia. Photo in public domain.

RELATED: Feline panleukopenia puts hundreds of cats from Central California SPCA at risk including at PetSmart

This is a hardy virus that can survive in the environment under harsh conditions.  It is a highly contagious feline virus. Primary source of transmission is from the faeces. Transmission also takes place through: vomit, urine, saliva. Contact with contaminated objects spreads the disease.

Infection primarily take place in the womb and in young kittens (post-natal). Infected adults can carry the virus showing no symptoms.

Symptoms – post natal in kittens:

  • abdominal pain
  • diarrhoea
  • vomiting
  • fever
  • crying
  • collapse
  • fatal

Symptoms – infected in the womb – kittens born with:

  • cerebral hypoplasia (politically incorrect term: spastic cat)

Feline Distemper Symptom – acute and occurring quickly

Feline Panleukopenia (“Panleukopenia” means depression of the various kinds of white blood cells); Feline Infectious Enteritis (FIE); FPV; FIE

Feline Leukemia Virus

A feline virus that causes cancer. Known as FeLV. It is an RNA retrovirus for the technically minded.  The virus can only survive for minutes outside the body.

FeLV Chart
FeLV Chart. MikeB.

RELATED: Feline Leukemia Virus (FeLV) in Plain Language

Transmission is through contact between cats, the virus secreted in saliva. Mutual grooming comes to mind. Transmission also takes place from mother to offspring in utero.

Symptoms: Feline Leukemia Symptoms

Testing: Feline Leukemia Test

Adoption: Adoptable FeLV cats

Signs Of Feline Leukemia

Before setting out the signs of feline leukemia a little background information may help. I am also making the presumption that people searching for

Feline Coronavirus – not Covid

This virus is labelled: FCoV. It causes two separate diseases in domestic cats:

  1. feline enteric infection – mild infection – caused by a strain of coronavirus called FECV – symptoms: small % of cats have vomiting, diarrhoea, low grade fever, recover in 5-7 days, fatalities are rare.
  2. feline infectious peritonitis (FIP) – severe and always fatal – caused by a stain called FIPV – symptoms: See below:
  • Feline FIP

    6 Sep 2008 The Coronavirus (FCoV) is so called because the virus is circled by a Half of the cats that contract vasculitis develop Feline FIP.

  • My puppy has just eaten my cat’s poo and my cat has FIP

    1 Apr 2010 Addie DD, Jarrett, O: Use of a reverse-transcriptase polymerase chain reaction for monitoring the shedding of feline coronavirus by healthy

  • A victim of FIP

    4 Sep 2009 Last year I lost my Ivanhoe, who succumbed to FIP (feline infectious because back then many believed that Coronavirus meant FIP.

    Feline Immunodeficiency Virus

    This feline virus is labelled FIV. It belongs to the same family of feline viruses that include FeLV mentioned above. Unlike FeLV it does not cause cancer, however. There is no evidence that links it to human disease.

    Squirt. She’s about 11 years old. She was thrown outside to fend for herself after her elderly owner died. Squirt’s the neediest of all and needs a special human for her golden years. She is a senior with arthritis and is FIV-positive, and she really deserves a forever home to call her own again. Squirt will paw at you for attention—she’s desperate to be someone’s lap cat and best friend.

    Thought to infect 1-3% of all USA domestic cats. Infection is for life. Transmission is through saliva and bite wounds.  Also from mother to kitten, either in utero or in colostrum (mother’s milk).

    Occurs mainly in adult free roaming male cats. Mean age of infection is between 5 and 6 years.

  • FIV cats colloidal silver

    Today, the strides in FIV cats colloidal silver treatment are slowly becoming an increasingly known possibility for combating the scary health threat that

  • Pictures of Cats org Blog: Feline Aids

    21 Aug 2008 The feline immunodeficiency virus was discovered in California in 1986 (or 1987?). In research work carried out at the University of Florida

    Man infected with rabies
    Omar Zouhri – the last photo. Photo: Mirrorpix.


    We know that rabies is an invariably fatal feline virus. It is a worldwide health problem still. Of course, it infects other animals including the human animal.

  • Cat Rabies Symptoms

    It is probably worth recognizing cat rabies symptoms as rabies does occur in cats in many countries and in the United States,

  • Feline Rabies

    Feline rabies may be the savior of the feral cat in Asia at least in respect of the cat meat and fur market, although I doubt it. There will still be cat.

  • Zoonotic Disease Carried by Cats

    25 Mar 2009 Rabies is by far the most serious. As I understand it, rabies is eliminated in the UK so their is almost no risk (except rabies that is

  • Cat Drooling

    In the UK rabies is eradicated but in the USA, the biggest domestic cat market, rabies exists albeit rarely as far as I am aware. Shots are commonly given

    Picture of a throat swab taken by 2 veterinary staff at a Cairo clinic to test for Covid-19
    Picture of a throat swab taken by 2 veterinary staff at a Cairo clinic to test for Covid-19 as it a requirement for travel.


    Cats can get Covid from their owner. We know that. It is rare and the symptoms are nearly always mild based on the limited data that we have. The symptoms are similar to those of humans. Please click on the link below to recognise Covid symptoms in your cat.

    RELATED: How do I know if my cat has Covid?


    Vaccinations are important but cat caregivers should vaccinate wisely. When kittens are born, they inherit protective antibodies from the milk they suckle from their mothers but this lasts around 6-10 weeks. You can vaccinate against feline infectious enteritis. This is extremely effective and provides prolonged protection. Vaccinations against cat flu i.e. feline herpesvirus and feline calicivirus are the norm. And you can vaccinate against feline leukaemia virus and rabies. Dr. Bruce Fogle vaccinates all kittens against feline infectious enteritis, feline herpesvirus, and feline calicivirus. For outdoor cats that might meet a feral cat he vaccinates against feline leukaemia virus.

    Distracting a domestic cat during vaccination jab with a very tasty paste from a tube.
    Distracting a domestic cat during vaccination jab with a very tasty paste from a tube. Photo: Screenshot.

    A disadvantage of going outdoors is contracting a life-threatening viral infection. Although if one is lucky you might live in an area where a high percentage of indoor/outdoor cats are vaccinated which creates a protective bubble by preventing transmission.

    Feline viruses – Note:

    1. page 191 The Cat, Its Behavior, Nutrition & Health by Linda P Case. Other sources: myself and Dr. Bruce Fogle: Complete Cat Care.

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