posted 05-29-2003 02:23 PM         

Also saw your pictures, he is so cute!

VETERINARY INFORMATION SERVICE

Parvo virus

Canine Parvovirus

Prior to 1977-78, parvovirus did not exist in the dog. The virus is a
close relative of feline panleukopenia (feline distemper) and in fact,
may have mutated from the cat and infected the dog in the late 1970ıs.
The virus is extremely hardy and survives for long periods outside its
host. The virus will live in the environment up to 6 months and survives
winter nicely under a blanket of snow where the temperature is usually
around 25-28 degrees F. Extremely cold temperatures prior to snow fall
will kill the virus. Sodium hypochlorite (bleach) is the only effective
disinfecting agent.

The virus is transmitted by oral ingestion of viral contaminated feces.
Upon ingestion by the new host it infects local lymph nodes, quickly
multiplies and then via the blood moves to the small intestine where
signs of the disease begin in approximately 5-6 days. The virus is
extremely deleterious to the lining (mucosa) of the small intestine. The
surface of the mucosa is stripped away upsetting crucial barriers and
interfering with normal balance of digestive enzyme secretion and
nutrient absorption. Additionaly, the normal bacterial flora of the small
intestine which aid in digestion are now exposed to ulcerated mucosa,
providing a direct route into the blood stream. Fluid loss from both
vomiting and diarrhea is dramatic and dehydration ensues. The onslaught
of bacteria and toxins into the blood will ultimately cause death.
Precipitous drops in white blood cell (WBC) counts are common and relate
directly to the prognosis and outcome of the infection. Ominous drops in
white blood cells are attributed to overwhelming degradation of WBCıs and
the direct depressive viral effect on WBC production in the bone marrow.

The incidence of the disease is highest in young dogs and tends to start
some time after the puppy has lost its maternal protection passed on at
birth with the first milk (colostrum). Any age can be infected but, most
dogs are infected between the ages of 2-6 months when maternal antibody
decreases below a protective level in the puppy. Signs of the disease
usually are mild to nonexistent. However, a full blown case of parvovirus
untreated can easily be fatal. Certain breeds seem to be more sensitive
to the disease; possibly related to their immune system. They include
rottweilers, Doberman Pinschers, and possibly black Labrador retrievers.

Generally, a diagnosis is made on the signs of the disease and falling
white blood cell counts. Good rapid diagnostic tests are also available
at veterinary clinics. Additionally, the virus can be found in the feces
by commercial labs using electron microscopy.

Treatment for the disease is primarily supportive although recently
immunotherapy has become important. Historically, dogs were supported by
aggressive intravenous fluid therapy to combat hydration and antibiotics
given to reduce secondary bacterial infection. Food is withheld until
vomiting has ceased. Many veterinarians employ antiemetics to lessen the
signs and aid in the control of dehydration. Blood transfusions have been
employed to increase the level of globulins, red blood cells and serum
protein being lost via the bowelıs bloody diarrhea. Most recently,
antitoxins and antiparvo serum are showing results. With hospitalization
and vigorous support most dogs will survive severe cases of parvo virus.
Early detection and aggressive therapy are the key to success.

Prevention of parvo virus is by vaccination. Modified live vaccines are
the most effective and continue to be safe. Producing and effective level
of protection requires frequent vaccination starting at 8 weeks of age
and repeating every 3-4 weeks until the puppy is sixteen weeks old. Some
investigators have suggested extending the protocol until 20-26 weeks
because of the persistence of maternal antibody in the puppy which
neutralizes the vaccine. Currently, annual revaccination is recommended.
Recently, it has been suggested that repeated annual vaccination may also
produce persistent antibody interference to the vaccination. After the
initial puppy series and first annual revaccination, boosters in the
future may be recommended triennial or less frequent. A change in
vaccine protocol, until further research is done, is not recommended.