What is Canine Parvovirus disease?
Canine parvovirus is a very contagious viral infection that occurs globally. Disease typically affects unvaccinated puppies (< 6 months of age) but can occur in unvaccinated dogs of any age. Clinical signs often include depression, not eating, vomiting and profuse diarrhea which is often blood tinged. Severe disease can result in death. Testing and subsequent treatment need to be initiated immediately; mortality is high and prognosis worsens as dogs develop more severe illness. Vaccination is highly effective at protecting against parvovirus. The virus is extremely hardy; contaminated environments can remain a source of infection for months.
How does a dog become infected with parvovirus?
The causative agent of CPV disease is a virus. The main source of the virus is the faeces of infected dogs. . Susceptible animals become infected by ingesting the virus. Subsequently, the virus is carried to the intestine where it invades the intestinal wall and causes inflammation. Unlike most other viruses, CPV is stable in the environment and is resistant to the effects of heat, detergents, and alcohol. CPV has been recovered from dog faeces even after three months at room temperature. Due to its stability, the virus is easily transmitted via the hair or feet of infected dogs, contaminated shoes, clothes, and other objects. Direct contact between dogs is not required to spread the virus. Dogs that become infected with the virus and show clinical signs will usually become ill within 7-10 days of the initial infection.
How does this disease affect the dog?
The clinical signs of CPV disease are somewhat variable, but generally take the form of severe vomiting and diarrhoea. The diarrhoea may or may not contain blood. Additionally, affected dogs often exhibit a lack of appetite, depression, and fever. It is important to note that many dogs may not show every clinical sign, but vomiting and diarrhoea are most common ; vomiting usually begins first. Parvo may affect dogs of all ages, but is most common in dogs less than one year of age. Young puppies less than five months of age are often the most severely affected and the most difficult to treat.
How is parvovirus diagnosed?
The clinical signs of CPV infection can mimic other diseases causing vomiting and diarrhoea; which can make the diagnosis of CPV a challenge for the veterinary surgeon. The positive confirmation of CPV infection requires the testing for antigens to the virus in the faeces. This is achieved by taking a swab of the patient’s rectum and using a simple test kit that takes a total of around 10 minutes to perform. Occasionally, a dog will have parvovirus but test negative for antigens to the virus in the faeces. Fortunately, this is not a common occurrence.
Can it be treated successfully?
As with any virus disease there is no treatment to kill the virus once it infects the dog. However, the virus does not directly cause death; rather, it causes loss of the lining of the intestinal tract. This causes severe dehydration, electrolyte imbalances, and infection in the bloodstream (septicaemia). It is when the bacteria that normally live in the intestinal tract are able to get into the blood stream that it becomes more likely that the animal will die.
The first step in treatment is to correct dehydration and electrolyte imbalances. This requires hospitalisation and the administration of intravenous fluids . Antibiotics and antiinflammatory drugs are given to prevent or control septicemia. Antispasmodic drugs are used to control the diarrhoea and vomiting .
What is the survival rate?
Most dogs with CPV infection recover if aggressive treatment is used and if therapy is begun before severe septicaemia and dehydration occur. For reasons not fully understood, some breeds, notably the Rottweiler, have a much higher fatality rate than other breeds.
Can it be prevented?
The best method of protecting your dog against CPV infection is vaccination. Puppies receive a parvo vaccination as part of the vaccines given at 6, 10 and 14 to 16 weeks of age. After the initial series of vaccinations when the dog is a puppy, all dogs should be boosted at least once a year. Bitches should be boosted before mating or immediately before whelping in order to transfer protective antibodies to the puppies.
Is there a way to kill the virus in the environment?
The stability of the CPV in the environment makes it important to properly disinfect contaminated areas. This can be accomplished by cleaning food bowls, water bowls, and other contaminated items with a solution of 250 mL of chlorine bleach in 5 litres of water. It is important that chlorine bleach or glutaraldehyde based disinfectants be used because many other “viricidal” disinfectants will not kill the canine parvovirus.