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CORONAVIRUSES. 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. LEARNING OBJECTIVES Students should be able to:.
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CORONAVIRUSES PETER H. RUSSELL, BVSc, PhD, FRCPath, MRCVS Department of Pathology and Infectious Diseases, The Royal Veterinary College, Royal College Street, London NW1 OTU. E-mailWeb site
LEARNING 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.
TRANSMISSIBLE GASTROENTERITIS VIRUS (TGEV) DISEASE & PATHOGENESIS
TRANSMISSIBLE GASTROENTERITIS VIRUS (TGEV) HOST RANGE : pigs
TRANSMISSIBLE 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.
TRANSMISSIBLE GASTROENTERITIS VIRUS (TGEV) DIAGNOSIS:
BOVINE 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.
FELINE 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.
FELINE INFECTIOUS PERITONITIS(FIP) ANTIGENICITY: The virus associated with FIP is indistinguishable antigenically from the common enteric FCoV.
FELINE INFECTIOUS PERITONITIS(FIP) HOST RANGE: Domestic & wild cats.
FELINE 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.
INFECTIOUS BRONCHITIS VIRUS (IBV) of CHICKENS ANTIGENICITY : At least 8 serotypes in two antigenic groups.
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.
Summary • 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.