WHAT IS IT?
Canine Parvovirus is a viral disease of dogs that was first
reported in early 1978. Parvovirus is capable of causing two
different sets of clinical problems. The first to be recognized,
and most common, is the "intestinal" form which is manifested by
diarrhea; often bloody vomiting, loss of appetite, depression,
fever, and sometimes death. The second syndrome, the "cardiac"
form, occurs in very young pups and is manifested by an acute
inflammation of the heart muscle.
Any age, breed or sex of dog could
be affected by Parvovirus. However, infection with Parvovirus does
not automatically mean illness. Several factors such as age,
environment, stress, parasites and general health status of each
individual dog infected could affect the severity of illness. The
degree of illness could range from very mild and not apparent, to
very severe, often resulting in death. The disease is usually more
severe in young dogs (less than 6 months of age) or old
dogs.
WHERE DID IT COME FROM?
Experts agree that canine Parvovirus is closely related to
Parvoviruses that affect other animals. Where the virus originally
came from remains unknown, but it is possible that it is a mutant
from another Parvovirus that affects other species of animals. Man
is not known to be affected by canine Parvovirus. Since its first
appearance in 1978, canine Parvovirus has spread to every continent
in the world, probably the result of the hardy nature of the virus.
It is resistant to extremes of temperature (i.e., it survives
freezing and extreme heat) and is unharmed by detergents, alcohol
and common disinfectants. Direct transmission occurs when an
infected dog comes in contact with a healthy dog. The virus is
found in heavy concentration in the infected dog's stool. The virus
particles can be easily spread on shoes, clothing and other
inanimate objects. Fleas, as well as people, can therefore act as
indirect sources of infection. Once it gets a foothold in a kennel,
it is difficult to eliminate.
Oral Phase: The disease process
begins with the oral ingestion of Parvovirus from the feces of an
infected dog. The virus initially invades the lymph glands of the
throat (lymph nodes and tonsils) where it multiplies. Following
multiplication in the lymph glands for l to 2 days, the virus then
enters the blood stream which causes the VIREMIA phase (virus in
the blood).
Viremia Phase: This phase is
characterized by massive amounts of virus in the dog's bloodstream,
which in turn is spread to all parts of the body, such as, the
intestine, bone marrow, spleen, other lymph nodes and the heart (in
young pups less than 8 weeks of age). As infection spreads, the
symptoms of illness become apparent. (See "symptoms" in next
section). The Viremia phase can last for approximately l to 9
days.
Contagious Stage: The final
phase in the cycle is the contagious or "shedding" phase. As many
as 30 billion Parvovirus particles can be shed from the intestines
of an infected dog in every ounce of stool. The highest
concentration of virus in the stool is seen when the infected dog
is showing signs of illness. A dog can, however, be a source of
infection to other dogs without having observable signs of illness.
Transmission can occur for at least 3 weeks after a dog becomes
infected with the virus. Chronic "carriers" are not know to exist
as in other virus disease. Parvovirus in the environment can infect
susceptible dogs for many months once shed in the stool.
What are the symptoms? The symptoms
below indicate a problem warranting medical attention. Early,
vigorous treatment of illness caused by canine Parvovirus infection
is imperative since vomiting and diarrhea can lead to dehydration
and chemical imbalance in the body. If your dog shows these signs,
see your veterinarian. Early treatment can save lives.
- Cardiac Form (less than 8 weeks of
age)
- Sudden death
- Crying, difficulty breathing,
gasping for breath
- Extreme depression
- Weakness
- Unwillingness to nurse
- Irregular heartbeat
- Intestinal Form (any age dog
affected, but more severe in puppies).
- Depression
- Loss of appetite
- Fever (above 103 degrees F)
- Vomiting
- Diarrhea with or without blood
(more serious if blood present)
- Low white blood count
- How is it controlled?
Control of Parvovirus by sanitation
measures alone extremely difficult because the virus is such a
resistant, hardy organism and because it is so easily spread.
Contact with other dogs and especially their stool, should be
minimized. Clorox diluted one part to 30 parts with water has been
effective in disinfecting inanimate objects such as clothing,
floors, kennels, etc. However, it is impractical, if not
impossible, to disinfect public streets, parts, etc. Isolation of
infected dogs is another method of control, although moderately
effective. Both of these measures will help reduce the amount of
contagious virus in the environment, but only vaccination will
control the actual source of infection, the contagious shedding
dog.
Vaccination is the most effective
control measure for canine Parvovirus disease. A properly immunized
dog will have circulating antibodies in the blood that will destroy
Parvovirus following exposure.
THE ROLE OF MATERNAL ANTIBODY IN PUPPY
IMMUNIZATION
Maternal antibodies are antibodies against Parvovirus which
are passed from the mother to the puppies through the "first milk"
or colostrum. They provide the puppy with an immediate temporary or
"passive" immunity. The mother obtains these antibodies from prior
vaccination or by natural exposure to Parvovirus. However, maternal
antibody is a two-edged sword; it protects the puppy against
disease early in life, but it also blocks active immunization. In
the case of Parvovirus, maternal antibody can interfere with
vaccination for as long as 14 to 16 weeks of age in some pups. A
refractory period can exist in some pups where very low, almost
undetectable levels of maternal antibody will inhibit the
vaccination process but will not prevent Parvovirus infection.
Since the level of maternal antibody varies from puppy to puppy, it
is important to begin vaccination at an early age and repeat every
3-4 weeks until the puppy is at least 16 - 18 weeks old.
Facts you should know about Parvo Virus:
1. It is contagious to dogs only -
not cats or people.
2. Signs include vomiting, fever,
and bloody diarrhea with a very foul odor.
3. The virus sometimes may attack
the HEART muscle causing myocarditis (inflammation). This may occur
for up to 3-6 weeks after apparent recovery from the intestinal
form of the disease. This "heart" form is ALWAYS FATAL!
4. The YOUNGER the dog, the GREATER
the chance it will NOT recover.
5. Dogs that recover from Parvo are
often weak, making them even more susceptible to other diseases,
such as DISTEMPER.
6. The virus is transmitted through
the FECES of an infected dog. It can be carried on dog's hair and
feet as well as live on contaminated rugs, bedding, shoes, and
other objects.
7. The most effective disinfectant
is 4 oz. Clorox in l gallon of water.
8. Dogs that recover from Parvo
continue to spread the virus in the feces for a month or longer.
(Carriers).
9. Dogs remain HIGHLY SUSCEPTIBLE to
Parvo until after the LAST injection of the immunization
series.
10. Death from Parvo Virus result
from:
- Dehydration.
- Overwhelming bacterial infection
resulting from the pet's lowered resistance.
- Blood loss from internal
hemorrhage.
- Heart attack from invasion of the
heart muscle by the virus.
11. Treatment is aimed at
maintaining the normal body composition and preventing secondary
bacterial infection. We have NO CURE for any animal virus, just as
there is NO CURE for any human virus.
12. The body normally is about 80%
water. Life is NOT possible when 12-15 % of the normal body fluids
are lost. With Parvo Virus, the pet often quickly becomes
dehydrated from the vomiting, diarrhea, and inability to consume
fluids. This is the reason fluid therapy is so important in Parvo
Virus Therapy.