Canine Kennel Cough is actually better termed as Kennel Cough Syndrome (KC) as it refers to a series of upper respiratory infections which tend to produce a hacking, retching cough. Other signs seen include a running nose-which can be watery or snotty and eyes signs such as conjunctivitis. They are spread by droplet infection in the air and also direct contact. Clothing can carry infections but close attention to hygiene and changing clothes will reduce the possibility. The infections can last up to 6 weeks in some cases but in any case, the dogs should be kept isolated until several days after they stop coughing. Any dog can catch any infection but young and old dogs are at risk of severe complications including fatality. It is important that in contact dogs are isolated as well as the obviously infected ones as they may transmit KC to other dogs they meet. Thus leaving the coughing dog at home and taking out the others will not prevent spread.
There are many causes of KC but the main ones in the UK are Bordatella bronchispetica (Bb) which can also be transmitted to other species such as cats, Canine parainfluenza virus (CPi), Canine adenovirus 1 and 2 (CAV 1, CAV2), and Canine herpesvirus (CHV). Bb can be shed by infected dogs for up to 4 months after infection. This is the most common cause and the one which is responsive to antibiotics. It is commonly combined with CPi in KC nasal vaccines and most injectable vaccines contain the CPi. The injectable KC vaccines are not available in the UK as the licensing authorities do not consider it efficacious enough to warrant a license. CPi on its own produces a mild cough and watery runny nose but combined with Bb the signs are more severe and the dog is more likely to be off its food and appear unwell.
CAV 1 and 2 are not often seen in fully vaccinated dogs as CAV 1 is the cause of canine hepatitis and most dogs who have puppy vaccinations and at least the first booster will have adequate immunity as there is some cross-reaction giving immunity to both viruses.
One major worry here is the CHV as this only produces mild symptoms in normal adults of a runny nose and coughing but if it affects pregnant bitches is the cause of “fading puppy” syndrome. It also causes other problems with breeding depending on what stage of pregnancy the bitch is infected. CHV is similar to the Herpes simplex virus in humans (causing cold sores) and Feline Herpesvirus (cat flu) in that once infected the dog becomes a carrier and during periods of stress the virus will come back out. Thus if a bitch has once had the infection it may come back out when she is pregnant and infect puppies. During pregnancy the puppies maybe just born in lower litter sizes than expected or a litter may fail-some born dead or some born undeveloped. In puppies, under two weeks they may die as “fading puppies”. There is a vaccine available to use during pregnancy that stops the virus affected the puppies. It needs to be used during every pregnancy as previously mentioned the virus can activate every time. A bitch that has once been infected can go on to produce normal puppies but may also be a risk to the other bitches in the kennel. She would need the CHV vaccine during pregnancy-two doses given; one during the beginning of the season or a week after mating and one given one week before the bitch is due to whelp.
The nasal vaccines mentioned earlier for KC can be used from 3 weeks of age and will give good protection with 72 hours for Bb and CPi. Thus in an outbreak in a kennel with young puppies, it is worth considering vaccinating all the in-contact dogs.
I hope this discussion underlines the need to take KC seriously as the symptoms of each infection are similar but the consequences of the different infections vary. I have seen a litter of Borzois that died of Bb and also personally experienced a litter that died due to CHV. Having a litter of dead and decomposing puppies was an experience I would not wish on anyone. The condition can lead to fatal bronchopneumonia in the old or debilitated animal and in dogs with an underlying heart condition can lead to heart failure. Please think of other people when your dogs have “the cough” as it is more serious than often known.