Disease Overview

Feline viral upper respiratory tract disease is typified by signs of rhinosinusitis, conjunctivitis, lacrimation, salivation, and/or oral ulcerations. The principal causative agents are feline herpesvirus type 1 (FHV-1) and feline calicivirus (FCV).

FAST FACTS

• FCV is widespread in the general cat population, ranging from 10% for household pets kept in small groups up to 40% in some large colonies.
• After FHV-1 infection, virtually all cats will remain latently infected, becoming lifelong carriers of the virus.

TRANSMISSION

FCV

• Hypersalivation
• Oral ulcerations
• Sneezing
• Nasal discharge
• Fever
• Anorexia
• Dyspnea
• Depression

FHV-1

• Conjunctivitis
• Ocular ulceration
• Ocular discharge
• Sneezing
• Nasal discharge
• Salivation
• Pharyngitis
• Lethargy
• Fever
• Anorexia

CLINICAL SIGNS

• Retching
• Sneezing
• Watery nasal discharge
• Coughing
• Pneumonia, inappetence, fever, and lethargy in severe cases

MORBIDITY THREATS

FCV

Occasionally signs of lameness due to acute arthritis (synovitis) will manifest. This usually only lasts a few days, and there will often be signs of respiratory disease at the same time.

Rarely, outbreaks of more severe strains have been manifested. Infection with these strains can result in severe pneumonia, hepatitis, pancreatitis, skin swelling and ulceration, and bleeding from the nose and intestine. In these outbreaks up to 50% of affected cats can die.

FHV-1

Acute upper respiratory tract disease is the most common manifestation of FHV infection.

A less common manifestation of chronic FHV infection is conjunctivitis and keratitis. FHV infection causes the development of multiple small branching corneal ulcers (called ‘dendritic keratitis’). Rarely, chronic FHV infection can result in skin inflammation and ulceration. This is most commonly seen around the nose and mouth but can affect other areas such as the front legs.

SPREADING DISEASE

FCV is relatively resistant to environmental conditions and can potentially survive up to a month in the environment, although in most cases probably does not survive more than 7-14 days.

Viral excretion of FHV-1 may last for 1 to 3 weeks. After infection, virtually all cats will become lifelong carriers of the virus. Some of these cats will intermittently shed virus again, commonly following episodes of stress or immunosuppression.

DIAGNOSIS

In most cases, a specific diagnosis of FCV or FHV-1 infection will not be required. The presence of typical upper respiratory signs is enough for a presumptive diagnosis of FCV and/or FHV-1 infection. Signs of oral ulceration and milder respiratory signs tend to suggest the involvement of FCV whereas more severe respiratory illness and signs of keratitis in may suggest the involvement of FHV-1.