Introduction
“Dog flu” is a relatively recent phenomenon. In early 2004, a group of racing greyhounds in Florida came down with cases of mild to severe respiratory disease, with 36% of affected dogs dying. After this outbreak, the Canine Influenza Virus (CIV) was identified, classified and intensively studied. It evolved from and remains strikingly similar to an equine influenza virus, but now is an emerging species-specific pathogen that – at least so far - infects and causes illness only in dogs. Fortunately, the mortality rate associated with canine influenza is very low, and supportive treatments are highly successful. Early diagnosis and treatment can dramatically improve the chances of a successful recovery in affected animals and can also help minimize further spread of the disease.
Canine Influenza - Treatment
Much like viral flu in people, canine influenza cannot be “cured” but instead must simply “run its course.” As for most viral diseases, treatment is largely supportive. Initially, affected animals should be isolated or otherwise closely managed for at least 7 to10 days after the onset of clinical signs, to prevent or at least minimize infection of other dogs. In mild cases, dogs should be managed at home rather than hospitalized, not only for comfort and cost considerations but also to prevent contaminating the veterinary hospital environment. Uncomplicated outpatient cases should be managed by enforced rest for at least 2 to 3 weeks. The dogs should be kept in a quiet, calm and familiar environment, and their activity should be restricted to going outside to “potty” only as necessary. They must be kept well-hydrated, with free access to fresh water, and should be fed a nutritious, palatable diet. Broad-spectrum antibiotics may be prescribed for dogs to prevent or control secondary bacterial infections. In mild cases involving a productive cough, cough suppressants normally are not recommended, because coughing is a normal and effective bodily mechanism for eliminating excessive respiratory secretions. Cough suppressants commonly are used for dogs with dry, non-productive coughs.
In more severe cases, where bronchopneumonia or other respiratory infection occurs, it may be appropriate to hospitalize the animal and provide intravenous antibiotic and fluid support. Dogs suffering from pneumonia may need enforced rest for several months and antibiotic therapy for several weeks after radiographic resolution of disease signs.
Some drugs are available and approved to treat viral influenza, but only in people. Use of such drugs in dogs is highly controversial, as their efficacy, side effects and safety in companion animals are unknown at this time.
Canine Influenza – Prevention and Control
The canine influenza virus seems to be easily killed by common disinfectants like ammonium compounds and bleach solutions. Good hygiene should be practiced by all dog owners, and especially by veterinary clinics, boarding and rescue facilities where a number of dogs are regularly in close contact. Dogs showing clinical signs of respiratory disease should be isolated from other dogs until those signs resolve; dogs that have been exposed to sick dogs should also be segregated for several weeks. Owners of dogs that are coughing should restrict their own contact with other dogs and should not pet or participate in activities bringing them in contact with healthy animals.
The first canine influenza virus vaccine was approved for licensure by the USDA in May of 2009. An inactivated whole-virus vaccine developed by Intervet/Schering Plough Animal Health Corporation, it is intended to help control rather than prevent disease caused by CIV infection. While it may not prevent illness in every case, clinical trials have shown this vaccine to be highly effective in reducing the incidence, severity and duration of disease. It also reduces the volume and duration of viral shedding by infected animals, which in turn makes them less contagious to other dogs.