Cat Respiratory Infections

Feline Herpes Virus

• Double stranded RNA virus.
• Glycoprotein lipid envelope.
• 1 serotype.

Generic 'flu' like symptoms. Also conjunctivitis and hypersalivation. Low mortality rates. Turbinate damage can lead to chronic disease. 

Pathogenesis:

• Oronasal infection.
• 2-6 day incubation period.
• Multiplication in oral/respiratory tissue. 

Diagnosis:

• Serology.
• PCR.
• Histopath.
• Viral isolate- OP swab in VTM cultured in cells can take up to two weeks.

Feline Calicivirus

• ssRNA with no envelope.
• Many strains.

Clinical Signs:

• 'Flu like symptoms.'
• Oral ulceration and chronic stomatitis- 80-100% cats shed coronavirus with acute faucitis with experiment infection.
• Pneumonia.
• Shifting lameness in young cats- pneumonia and respiratory disease. Spontaneous resolution.
• Virulent systemic disease. Vaccinated cats not protected. Clinical signs include:

1. Facial/paw oedema-> necrosis/ulceration.
2. Respiratory disease/pyrexia.
3. Haemorrhagic nose and faeces.
4. Jaundice.

Diagnosis:

• OP swabs-> viral isolate.
• Serology.
• PCR.

Epidemiology of Both

• Short lived outside the cat. Herpes <1 day. Calici < 1 week.
• Transmission- direct contact with infectious discharge and fomites. Aerosol transmission not major.
• Carriers. 

1. Herpes- Latency and reactivation. 100% carriers after infection. Latency and recrudescence after stress with shedding for 4-11 days. Latency again.
2. Calicivirus- persistent infection. Most cats shed for 30d post infection with 50% still shedding 75 days post infection. Colony and show cats biggest shedders. Long life infection/self limiting.