Parvovirus or "cat flu" in dogs
Dr W J Grobler BVSc
1. INTRODUCTION
The name "Cat flu" is misleading because even though cats suffer from a similar disease, the disease is not contracted from cats. The symptoms in dogs are due to intestinal involvement and very unlike flu symptoms. Dry, windy weather sees more cases which occur mostly in puppies, but previously unexposed, unvaccinated adult dogs are also at risk. Even with the best treatment available some animals still don't survive, so vaccination is of paramount importance in the prevention of this terrible disease.
2. CAUSE
This serious disease is caused by one of the smallest viruses known to man called Canine Parvovirus (CPV).(Parvo is the Latin for small). As many as 300 000 virus particles will fit into a millimeter!
Albeit so small the virus is extremely tough and will survive most disinfectants. It may stay alive in the environment for as long as two years if conditions are favourable. In 1978 when the first cases of Parvovirus in dogs were seen, the virus spread all over the world in a matter of months, often without the involvement of dogs in the transmission.
Massive numbers of virus occur in the stool of a sick dog. One gram of faeces may contain enough virus to infect 10 million susceptible dogs!
The virus need certain enzymes to grow. These enzymes are found in rapid growing cells like the ones lining the intestinal tract. These cells grow quickly enough so that the intestinal lining is renewed every two to three days. If the virus grow inside these cells they break up leaving large areas of damaged lining that lead to severe loss of body fluids. The normal intestinal flora which under ordinary circumstances are pretty harmless, can now invade the body through the damaged areas.
3. SYMPTOMS
- Often a high fever
- Listlessness
- No appetite
- Continuous vomiting or foaming at the mouth
- Very smelly diarrhoea that frequently becomes blood-tinged
- White or bluish gums
- Abdominal pain
- Dehydration — animals appear to have lost weight overnight
The symptoms usually appear very suddenly and susceptible pups may die within a few hours. Pups with large numbers of antibodies wil show much lighter symptoms. In rare instances animals may develop infection of the heart muscles with fatal results.
A bitch with good immunity against parvo will transfer these antibodies to her pups in the uterus. They will then be protected to a large degree for a period of six to twelve weeks. Exposure to the virus, whether naturally or through vaccination wil enhance this immunity. Healthy puppies, like the one on the left should thus be vaccinated at six weeks of age, again four weeks later and preferably a third time another four weeks later. It is very unlikely that a pup that has had three properly administered vaccinations will contract the disease. It is however important to stress that puppies must be healthy and free from worms before they can be vaccinated.
Because Parvovirus is one of the most frustrating diseases a vet has to put up with, vaccination remains the only efficient way of saving the puppy owner a lot of tears and regret.
4. TREATMENT
At present there are no affordable injectable drugs that kill viruses in the body, thus no specific treatment exists once the virus is inside the body. Treatment is aimed at curbing secondary bacteria, stopping vomiting and replenishing body fluids.
- Antibiotics
- Anti-emetics
- Intravenous fluid administration
- Inteflora or similar probiotics to replenish gut flora (beneficial bacteria in the intestines)
- Activated charcoal to bind toxins in the gut
- Oral electrolytes if animals are still drinking and not vomiting
- Small quantities of bland food eg. rice and cooked chicken
- Blood transfusion in very severe cases