Ch200 - Coronavirus

Question 1

What is Feline Coronavirus (FCoV) and what two biotypes are there

Answer 1

• FCoV is a pathogen of wild and domestic cats and is endemic in multi-cat environments
• FECV (feline enteric coronavirus) is proposed to cause mild self-limiting enteritis
• FIPV (feline infectious peritonitis virus) causes systemic inflammation and death.

Question 2

How does FIPV occur

Answer 2

• FIPVs arise from FECVs by mutations that occur spontaneously within each affected cat
• A mix of host and viral factors that dictate whether FIPVs will arise and what form the disease will take

Question 3

How many serotypes of FCoV have been identified and how are they separated

Answer 3

• Two distinct serotypes of FCoV have been identified, separated by the antigenic and genetic properties of their viral spike (S) protein
• Feline coronavirus serotype 1 (FCoV-1) and feline coronavirus serotype 2 (FCoV-2) have evolutionarily distinct S proteins that, in many ways, make them behave like different viruses

Question 4

What is the purpose of the viral spike (S) protein

Answer 4

S is a crucial mediator of infection responsible for both receptor binding and membrane fusion

Question 5

Describe the differences between FCoV-1 and 2.

What is the clinical outcome

Answer 5

FCoV-1
- more prevalent clinically, grows poorly in cell culture, and is less studied.
- The receptor is unidentified
- FCoV-1 S contains a notable insertion of a proteolytic cleavage site (S1/S2) that plays an important role in infection.

FCoV-2
- easily propagated in cell culture but accounts for a smaller proportion of natural infections
- Aminopeptidase N (APN) has been identified as the receptor for FCoV-2

Clinical outcome of infection appears to be the same: both FCoV-1 and FCoV-2 can result in FECV or FIPV in an infected cat.

Question 6

Describe the pathogenesis of FCoV

Answer 6

• FECV is ubiquitous amoung multicat environments
• It replicates in the intestinal epithelium
• within 24hrs of infection it can be detected in the tonsils and SI
• It then spreads systemically
• Monocyte associated viremia is common
• the virus is shed in the deces and transmitted oronasally

Question 7

How long does primary infection with FCoV last do cats clear the virus

Answer 7

• Primary infection can last several months.

Question 8

Do cats clear FCoV virus and is re-infection possible

Answer 8

• Some cats clear the virus, but many continue to shed at low levels for up to 2 years
• Colonic columnar epithelial cells appear to serve as a reservoir for persistent infection and shedding.
• Immunity is not long-lasting and reinfection may occur

Question 9

How long can FECV be detected post infection and in which organs

Answer 9

• FECV can be detected in all major organs, including the central nervous system
• Can be detcted for up to 80 days post-infection with no clinical signs

Question 10

How long can FCoV survive in the environment

Answer 10

• FCoV can survive 1 to 2 days on surfaces.
• As long as 7 weeks in dried feces