Enteritis (Diarrhea, Vomiting)
Dogs are at risk of enteritis (intestinal disease) caused by two common viruses, canine parvovirus and canine coronavirus. Canine parvovirus enteritis is generally considered to be more severe than coronavirus enteritis. However, parvovirus enteritis may be more serious if coronavirus is also present. Diarrhea and vomiting caused by these viruses can range from mild to severe and are accompanied by depression and loss of appetite. Unvaccinated puppies and young dogs are most commonly affected because they have not been previously exposed or vaccinated and are susceptible to infection. Viral enteritis is easily spread because of the large volume of virus in feces, which contaminates the environment and is readily spread from one animal to another. Severe cases of viral enteritis can be fatal due to dehydration and loss of appetite. Puppies are at greatest risk of death because of their limited body reserves.
Additional Information About Enteritis/Parvovirus
What is “parvo”?
Canine
parvovirus (CPV) infection is a relatively new disease that appeared
for the first time in dogs in 1978. Because of the severity of the
disease and its rapid spread through the canine population, CPV has
aroused a great deal of public interest. The virus that causes this
disease is very similar to feline panleukopenia (feline distemper) and
the two diseases are almost identical. Therefore, it has been
speculated that the canine virus is a mutation of the feline virus.
However, that has never been scientifically proven.
Are there different strains of canine parvovirus?
Two
slightly different strains of canine parvovirus, named CPV-2a (1980)
and CPV-2b (1984), are recognized. They cause the same disease and
vaccines give protection against both. CPV-2b is associated with the
most severe disease. A distinct type of parvovirus (CPV-1) has been
found in pups with diarrhea and also in normal dogs. CPV-1 is not
thought to be an important cause of disease.
How does a dog become infected with parvovirus?
The
main source of the virus is from the feces of infected dogs. The virus
begins to be shed just before clinical signs develop and continues for
about ten days. Susceptible dogs 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, alcohol, and many disinfectants. A 1:30
bleach solution will destroy the infective virus. CPV has been
recovered from surfaces contaminated with dog feces 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 or areas contaminated by infected feces.
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 six to ten days of the initial infection.
What are the clinical signs of parvo?
The
clinical signs and symptoms of CPV disease can vary, but generally they
include severe vomiting and diarrhea. The diarrhea often has a very
strong smell, may contain lots of mucus and may or may not contain
blood. Additionally, affected dogs often exhibit a lack of appetite,
marked listlessness and depression, and fever. It is important to note
that many dogs may not show every clinical sign, but vomiting and
diarrhea are the most common and consistent signs; 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 usually the most severely affected, and the most difficult to
treat. Any unvaccinated puppy that has vomiting or diarrhea should be
tested for CPV.
How is it diagnosed?
The
clinical signs of CPV infection can mimic many other diseases that
cause vomiting and diarrhea; consequently, the diagnosis of CPV is
often a challenge for the veterinarian. The positive confirmation of
CPV infection requires the demonstration of the virus or virus antigen
in the stool, or the detection of anti-CPV antibodies in the blood
serum. Occasionally, a dog will have parvovirus but test negative for
virus in the stool. Fortunately, this is an uncommon occurrence. A
tentative diagnosis is often based on the presence of a reduced white
blood cell count (leukopenia) and clinical signs. If further
confirmation is needed, stool or blood can be submitted to a veterinary
laboratory for additional tests. The absence of a leukopenia does not
mean that the dog does not have CPV infection. Some dogs that become
clinically ill may not have a low white blood cell count.
Can parvo be treated successfully?
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, and destroys some blood cell elements.
The intestinal damage results in severe dehydration (water loss),
electrolyte (sodium and potassium) imbalances, and infection in the
bloodstream (septicemia). When the bacteria that normally live in the
intestinal tract are able to get into the blood stream, it becomes more
likely that the animal will die. The first step in treatment is to
correct dehydration and electrolyte imbalances. This requires the
administration of intravenous fluids containing electrolytes.
Antibiotics and anti-inflammatory drugs are given to prevent or control
septicemia. Antispasmodic drugs are used to inhibit the diarrhea and
vomiting that perpetuate the problems.
What is the survival rate?
Most
dogs with CPV infection recover if aggressive treatment is used and if
therapy is begun before severe septicemia and dehydration occur. For
reasons not fully understood, some breeds, notably the Rottweiler,
Doberman pinscher and English springer spaniel, have a much higher
fatality rate than other breeds.
Can parvo be prevented?
The
best method of protecting your dog against CPV infection is proper
vaccination. Puppies receive a parvo vaccination as part of their
multiple-agent vaccine given at 8, 12, and 16 weeks of age. In some
situations, veterinarians will give the vaccine at two-week intervals
with an additional booster at 18 to 22 weeks of age. After the initial
series of vaccinations, all dogs should be given a booster vaccination
at one year. Thereafter your veterinarian will discuss with you an
appropriate schedule of revaccination. Dogs in high exposure situations
(i.e., kennels, dog shows, field trials, etc.) may be better protected
with a booster every six to twelve months. Pregnant females might be
boostered with a killed parvo vaccine within two weeks before whelping
in order to transfer protective antibodies to the puppies. Adult dogs
considered to be at low risk for contracting the disease may be
vaccinated every two to three years. Your veterinarian and you should
make the final decision about the vaccination schedule that best fits
your pet’s lifestyle.
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 is best accomplished by cleaning
food bowls, water bowls, and other contaminated items with a solution
of 1/2 cup of chlorine bleach in one gallon of water (133 ml in 4
liters of water). It is important that chlorine bleach be used because
most disinfectants, even those claiming to be effective against
viruses, will not kill the canine parvovirus.
Does parvovirus pose a health risk for me? How about for my cats?
It is important to note that there is no evidence to indicate that CPV is transmissible to cats or humans.
