Title: CORONAVIRUSES
1CORONAVIRUSES
- PETER H. RUSSELL, BVSc, PhD, FRCPath, MRCVS
- Department of Pathology and Infectious Diseases,
The Royal Veterinary College, - Royal College Street,
- London NW1 OTU.
- E-mail Web site
2LEARNING OBJECTIVESStudents should be able to
- Compare the pathogenesis and epizootiology of
enteric coronaviruses of calves and pigs. - Discuss the diagnosis of and problems
associated with the control of feline infectious
peritonitis virus. - Explain how infectious bronchitis virus of
chickens is controlled.
3FAMILY CHARACTERISTICS
4TRANSMISSIBLE GASTROENTERITIS VIRUS (TGEV)
5TRANSMISSIBLE GASTROENTERITIS VIRUS (TGEV)
6TRANSMISSIBLE GASTROENTERITIS VIRUS (TGEV)
- EPIZOOTIOLOGY Faecal-oral transmission
chronic carriers may harbour infection in the
respiratory tract (TGEV replicates in the lung
also). Common in the U.S. In Europe, sporadic
outbreaks occur. In the UK, TGE is often absent
for several years.
7TRANSMISSIBLE GASTROENTERITIS VIRUS (TGEV)
8TRANSMISSIBLE GASTROENTERITIS VIRUS (TGEV)
9PORCINE RESPIRATORY CORONAVIRUS
10BOVINE ENTERIC CORONAVIRUS
- DISEASE PATHOGENESIS Infects the small
intestinal colonic enterocytes causing villus
stunting and a malabsorption diarrhoea. Also
infects respiratory tract. One of the pathogens
found associated with calf scour.
11FELINE INFECTIOUS PERITONITIS (FIP)FIP is a
fatal disease which occurs in around one tenth of
cats infected with the feline coronavirus (FCoV).
Therefore most cats infected with FCoV do not
develop FIP.
- DISEASE A slow death. Some weeks, months or
years after a localized primary infection with
FCoV, cats who have failed to eliminate the virus
can develop FIP.
12FELINE INFECTIOUS PERITONITIS (FIP)
- ANTIGENICITY The virus associated with FIP is
indistinguishable antigenically from the common
enteric FCoV.
13FELINE INFECTIOUS PERITONITIS (FIP)
- HOST RANGE Domestic wild cats.
14FELINE INFECTIOUS PERITONITIS (FIP)
- CONTROL
- A vaccine (Primucell) is available outside the
UK. It will not protect cats already incubating
FIP and kittens have to be isolated to prevent
infection with FCoV before they are old enough to
be vaccinated at 16 weeks. Problems with
vaccination Antibodies do not protect from the
disease and probably make it worse.
15 INFECTIOUS BRONCHITIS VIRUS (IBV) of CHICKENS
- ANTIGENICITY At least 8 serotypes in two
antigenic groups.
16 INFECTIOUS BRONCHITIS VIRUS (IBV) of CHICKENS
- EPIZOOTIOLOGY World-wide infection.
Transmission by infectious droplet inhalation or
faecal/oral. Persistent infections may occur for
several months following recovery.
17OTHER CORONAVIRUSES
18Summary
- The pathogenesis of the gastroenteritis caused
by TGEV in pigs and BCV in calves is similar but
TGEV is epizootic or enzootic in pigs while BCV
is enzootic. - Feline Infectious Peritonitis is a fatal disease
of cats (effusive/non-effusive forms). Diagnosis
is difficult no vaccines in the UK. - Infectious Bronchitis Virus is controlled by
aerosol vaccination of chicks with attenuated
vaccines.