DOG SMARTS: UNDERSTANDING CANINE INFLUENZA IN ADVANCE WITH DR. BOWEN

There have been no reported cases of canine influenza at The Watering Bowl or anywhere in Missouri, for that matter. However, we wanted to share some expert knowledge with you.

So, we asked Dr. Bowen, a graduate of the University of Missouri—College of Veterinary Medicine to tell us what she knows, so we are all well aware of what to look for.

Dr. Bowen practices at the Brentwood Banfield Pet Hospital, not far from our Hanley location. In fact her two dogs, Layla and Arnold enjoy spending some cage-free time with us at The Watering Bowl.

Prior to finishing her veterinary studies, Dr. Bowen worked as an assistant for the gerontology and public policy programs at UMSL before working as the assistant to the chairperson of the Department of Psychology.

An advocate of Pekingese dogs, Dr. Bown currently resides in Maplewood with two cats, Maggie and Taz, to go along with her two dogs. And in her limited free time, she enjoys powerlifting—even competing in meets from time to time.

And we’re thrilled to share what we learned from our very knowledgeable and well-rounded friend, Dr. Bowen.

 

What is canine influenza?

Canine influenza is virus capable of causing contagious respiratory infections in dogs. Prior to the 1990s-early 2000s, dogs were thought to be immune to getting “the flu.” The first reported cases of canine influenza occurred in 2004 when outbreaks occurred in groups of racing greyhounds in Florida. Those dogs were found to be infected with a subtype (or strain) of virus that was almost identical to an influenza virus of horses, known as H3N8. Canine influenza seemed to be a problem confined to racing greyhounds, but less than one year after the initial outbreaks in Florida, reports of canine influenza began showing up in pet dogs in Florida and New York City. Cases of canine influenza have since been reported in several states and also other countries with sporadic outbreaks being reported every few years.

Recently, canine influenza has made news headlines for causing “outbreaks of dog flu in Chicago and the Midwest.” There have been numerous confirmed cases of canine influenza during the latter part of March and early April, which we initially thought were caused by the H3N8 influenza strain. This past week, researchers at Cornell University in New York reported that the cases of canine influenza in Chicago and surrounding areas are actually caused by a strain of virus closely related to Influenza A H3N2, which was first identified in 2006 and is a widespread cause of canine influenza in dog populations in southern China and South Korea. H3N2 has never been detected in the United States until now. There are several strains of H3N2 circulating in dogs in Asia, most of which appear to have originated from birds. Canine H3N2 influenza virus has been shown to infect cats in Asia but not humans. The National Veterinary Services Laboratories in Ames, IA is working to further characterize the virus that has been isolated from dogs in Chicago.

 

How is canine influenza different from what my dog is already vaccinated for?

Canine influenza is an emerging (new) virus of dogs that has been present in the dog population for only about 20 years or less, and it has not been a common or widespread cause of illness in dogs. As a result, most dogs have never been exposed to the virus and are therefore considered naïve to the canine influenza virus. A dog (or a human, cat, horse, etc.) is considered naïve to an infectious agent if the immune system has never been exposed through vaccination or by contacting the infectious particle in the environment. Most of the dog population of the United States has no protection against the canine influenza virus and would become infected if exposed. Fortunately, most dogs are not at risk for coming into contact with the virus, and also not all infected dogs would show signs of illness (some dogs’ immune system would clear the virus without having obvious signs of infection.)

Vaccination against canine influenza has not been a common practice, because the likelihood of most dogs coming into contact with the virus is low. Dogs are considered “at risk” for contacting the virus if they are in frequently in contact with many dogs in a densely populated, community setting (e.g. shelters, kennels, day care, dog park, hospital waiting area, grooming, etc.).

 

What type of infection does canine influenza cause?

Canine influenza causes respiratory disease, and most upper respiratory illness in dogs is casually referred to as “kennel cough.” “Kennel cough” is the name we give to any cough in a dog that may be contagious in nature (often based on the history of recently being boarded). Most cases of “kennel cough,” however, are NOT caused by canine influenza virus; the most common infectious agents involved in kennel cough are the Bordetella bronchiseptica bacteria and the canine parainfluenza-3 virus. Other factors, including overall health of dogs (e.g. stress, nutrition) and environmental conditions (e.g. ventilation, overcrowding, etc) can factor in to causing kennel cough; sometimes the virus or bacteria just happens to be in the right place at the right time.

Most cases of canine influenza infections present looking like any other case of kennel cough, with a dry, hacking cough in an otherwise happy and healthy dog. The only way to know if your dog’s kennel cough is caused by the influenza virus and not from some other virus or bacteria requires laboratory blood testing or submitting a swab from the nasal passages to test for the virus, neither of which are cost-effective or practical to do. Most cases of kennel cough are mild and will respond to initial treatment, so it is extremely rare for special tests to be indicated. The main reason that we would want to identify a specific virus or bacteria is when there are outbreaks or dogs with respiratory illness that does not respond to the usual treatment.

As with kennel cough caused by other viruses and bacteria, the majority (80-90%) of canine influenza infections cause a mild infection of the upper respiratory tract (nose, mouth, throat, sinuses). It is much less common (10-20% of cases) for canine influenza infections to cause a more serious infection of the lower respiratory tract (lungs, bronchioles, trachea). Severe forms of infection are more likely to involve co-morbidities (two diseases occur when another virus or bacterial infection sets in). Canine influenza virus is just one of several pathogens (infectious agents) that can be involved in canine infectious respiratory disease complex. A rare but fatal syndrome of acute, hemorrhagic (bloody) pneumonia has been reported in only greyhounds.

 

What are the symptoms? 

Mild upper respiratory infections with canine influenza present with a loud, hacking cough that gets worse with exercise and can persist for several weeks up to a month, but dogs are otherwise healthy appearing. There is usually no nasal discharge, nor fever. Dogs with mild upper respiratory infection usually have normal activity levels but can be mildly lethargic (tired). They usually have a normal appetite with no vomiting or diarrhea. The cough can also be soft, wet, and semi-productive. Some dogs will develop a low grade fever, have a decreased appetite, decreased activity, and produce a yellow or greenish nasal discharge even with a mild form of upper respiratory infections. Severe respiratory infections usually cause a high fever, decreased appetite and energy, and rapid breathing; these dogs are usually found to be infected with more than one respiratory pathogen or have pneumonia that occurred secondary to the primary infection.

 

How contagious is the virus?

The canine influenza virus is highly contagious under certain circumstances. The virus is easily spread amongst dogs when they are housed in close contact with one another. Contagious virus particles are shed from the upper respiratory tract of infected dogs for 7-10 days and are present in all respiratory secretions (e.g. nasal discharge, saliva, even the aerosols that are produced from coughing and sneezing). Of significance is that dogs are contagious for 2-5 days before there are any symptoms of respiratory infection.

The virus can be transmitted between dogs through direct contact (nose-to-nose, nose-to-mouth, close proximity playing, etc)., and the virus is also spread by aerosolized respiratory secretions; a coughing dog can aerosolize and spread the virus up to 40 feet away. The virus may be able to survive on objects and remain in the environment for several days, and infectious respiratory diseases can then be spread by infected toys, bowls, leashes, collars, muzzles, and our shoes and clothing. The virus is easily killed with bleach and several common disinfectants.

 

How is a dog with canine influenza treated?

All newly coughing dogs should be examined by a veterinarian as soon as possible, as there are many possible causes for coughing.   Blood work and/or x-rays may be recommended to rule out severe respiratory disease or other, non-infectious causes for a cough. Mild respiratory infections can be treated as outpatients. Antibiotics are often prescribed to prevent secondary bacterial infections. Expectorants may be prescribed to break up secretions in the lower airways so they can be coughed up. A cough suppressant may be indicated in some instances to provide relief and rest from a harsh cough. Additional treatments prescribed for mild respiratory infections are rest, rehydration, anti-inflammatory medications, and proper nutrition.

More severe respiratory infections may require hospitalization with intravenous fluid therapy and antibiotics, oxygen therapy, bronchodilators, nebulization and coupage of the chest, and other treatments, depending on the severity of infection.

 

How common is influenza?

Canine influenza is currently not a common cause of infection in the general canine population, and for that reason vaccination against canine influenza virus is currently not indicated for most dogs. In the last ten years (2005-current) The Cornell University Animal Health Diagnostic Center has reported <3,000 positive test samples for canine influenza (the number of positive dogs would be less than positive tests due to paired testing or repeat testing; i.e. there have not been that many positive dogs identified in the last ten years). One of the makers of canine influenza vaccine reported that only 3% of coughing dogs in their study tested positive for canine influenza infection.

 

Why do we need to be concerned about influenza if Missouri has never had a case of it?

Canine influenza is highly contagious, and we should assume it is only a matter of time before Missouri sees its share of influenza-related kennel coughs. Dogs have no natural protection against the influenza virus, and there are now at least two strains of influenza virus capable of infecting dogs in the United States.

Vaccination against influenza may eventually be required for some pets the same way that bordetella is currently required. At this time the virus is not common enough that we require vaccination, but if your pet is “at risk” for exposure then you should talk to your veterinarian to decide if the influenza vaccine should be recommended for your dog.

 

Do I need to be concerned about putting my dog in day care or boarding it at a kennel?

The benefits of day care and boarding are tremendous to both dogs and their humans, and I am not aware of any immediate problems or increased risks that should prevent a healthy dog from being in day care or boarding at this time.

We do want you to be aware of and informed about canine influenza. There are currently no reported cases of canine influenza in Missouri, and I am also not aware of any outbreaks of canine respiratory disease in the area at this time.

The concern with canine influenza is that infected dogs are contagious and spreading virus for several days before they have any symptoms of respiratory infection. One asymptomatic dog therefore has the potential to infect many dogs in a large group setting, and most of those dogs will become symptomatic with a hacking cough. Some infected dogs may develop pneumonia and have more severe respiratory disease.

Although most infections result in mild symptoms, you should consult with your veterinarian to determine if your dog has any medical conditions that could put him or her at increased risk of developing more severe infection should exposure occur.

 

What is the best way to prevent canine influenza?

Keep your pet healthy from head to toe. Oral care, nutrition, weight management, parasite prevention and testing, routine blood work, and proper vaccinations based on lifestyle assessment are a few basic but important steps you can take to keep your dog as healthy as possible. A healthy pet will have a stronger immune system.

There is a vaccine available that protects against the canine H3N8 influenza virus. Similar to the human influenza vaccine, vaccination is not guaranteed to prevent illness but can lessen the severity and duration of symptoms. At this time we do not know if the vaccine provides any protection against the canine H3N2 influenza strain that appears to be in Chicago.

Vaccination against canine H3N8 influenza requires a series of two shots given 2-3 weeks apart. It will take another 1-3 weeks’ time for the vaccine to provide any protection. Because it takes at least one month from the initial vaccine to provide protection, it is recommended that you talk to your veterinarian asap to find out if the canine influenza vaccine is recommended for your dog. Also, find out when your dog’s other vaccines are due, specifically the ones that protect against respiratory infections (Bordetella with canine parainfluenza, and canine adenovirus-2), because vaccinating your dog the day of or just before boarding does not provide great protection.J Booster vaccines at least 2 weeks in advance of boarding, if not current, to allow for the greatest protection.

Also, do not allow your dog to make nose to nose contact with other dogs on the sidewalk or in pet stores if you see that they have nasal discharge or are actively coughing.

Ask questions!