Description

Canine parvovirus (CPV) is very contagious and causes primarily

a gastrointestinal (GI) disease. The disease can be prevented

by vaccination.

Cause

CPV is highly concentrated in the feces of infected animals. It persists

in the environment under a variety of conditions and is resistant

to many common disinfectants. CPV is inactivated by sodium

hypochlorite (a 1:20 dilution of common household bleach) after

10 minutes of contact time. All organic material must be removed

first, so that the bleach can reach the virus. Because parvovirus is

so resilient, the virus can be carried on inanimate objects (fomites)

such as shoes, clothing, and other materials that touch infected substances.

Transmission commonly occurs by swallowing the virus.

Clinical Signs

The primary signs are GI and include diminished appetite, vomiting,

lethargy, and diarrhea. Vomiting is often severe, and diarrhea

may be profuse and bloody. Fever may be present, and animals

can become severely dehydrated very quickly. Affected dogs are

often very weak, and shock may develop in some dogs from the

dramatic loss of body fluids. Rarely, the heart is affected, which

can cause sudden death.

Diagnostic Tests

Because CPV causes many infected dogs to become seriously ill, a

number of tests may be recommended to assess its effects on various

organs and to confirm the presence of the virus:

• A complete blood count may show low numbers of certain

white blood cells and platelets (needed for blood clotting).

Anemia may be detected and is sometimes severe.

• A serum biochemistry panel may show low blood protein levels

and electrolyte imbalances (such as low potassium) from

the vomiting and diarrhea.

• X-rays of the abdomen help rule out other causes of GI signs.

• Specific tests for parvovirus are done on fecal samples. These

tests are rapid, may be done in the veterinary clinic, and are

very reliable. However, false-positive tests are possible 5-12

days after vaccination for parvovirus, because noninfective

virus is shed in the feces after vaccination. False-negative tests

are also possible.

• Tests may also be done for antibodies to the virus in the blood

but may not be needed.

• Changes typical of CPV may be seen in biopsies of the GI

tract. Biopsy is not commonly done to diagnose the disease in

a living animal, but it may be useful to determine the cause of

death in dogs that do not survive.

Dogs with suspected CPV infection should be isolated from other

animals because of the highly contagious nature of the virus.

Special precautions are needed to prevent transmission to other

dogs. Hospitalized animals are commonly quarantined in an isolation

ward. To decrease spread of the disease, owners may not be

allowed to visit animals that are in isolation.

Treatment of CPV is largely supportive, with intravenous

fluids, sometimes plasma transfusions, antivomiting medications,

and possibly medications to decrease stomach acid production

(to protect the stomach). If anemia is severe, blood

transfusions may be administered. Antibiotics may be given for

secondary bacterial infections.

Severely ill dogs may develop sepsis, a widespread bacterial

infection that occurs when bacteria normally confined to the GI

tract are released into the bloodstream as a result of severe damage

caused by CPV. When sepsis occurs, it can adversely affect many

other organs and usually requires intensive therapy.

Food and water are commonly withheld until no vomiting

has occurred for 12-24 hours. Then small amounts of water or

ice chips may be offered, and if that is tolerated well, bland

food is reintroduced very slowly. Small portions are fed every

2-4 hours initially, after which the amount of food is gradually

increased and the time between feedings is gradually

lengthened.

Dogs with parvovirus infection may also be treated with

deworming medications, because the animals most susceptible

to CPV (especially young puppies) are also the ones most

susceptible to intestinal parasites. The heart disease caused by

CPV often progresses very rapidly, so treatment is not often

possible.

Follow-up Care

Dogs that recover from parvovirus disease usually have long-lasting

protection from reinfection. Regular vaccination is recommended

to maintain good immunity, however.

Prognosis

Dogs that survive the first 2-4 days of treatment are most likely to

recover fully. Prognosis is guarded (uncertain) for dogs with prolonged

illness. Prognosis is poor for dogs with sepsis. Dogs with

CPV-related heart disease often die from the condition.

Treatment Options