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Canine Parvovirus
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Canine
Parvovirus
http://www.sheltermedicine.com
Introduction
Parvovirus is highly contagious, incredibly durable in the environment,
and capable of producing severe or life-threatening disease in dogs. It
is critical to prevent transmission of the disease and rapidly identify
infected animals in order to provide medical care as deemed appropriate
and protection to other dogs in the shelter. Inevitably, Parvovirus
will be introduced
into shelters from the surrounding community from time to time. If this
occurs where preventive medicine is not practiced, in a crowded, busy
shelter
where staff is already stretched to the maximum, the response to the
epidemic
is a crisis mode, which is inefficient, very expensive, and much less
effective at protecting animals from this deadly disease.
Parvovirus facts
Parvovirus is very durable in the environment and can persist for
months or years.
Bleach or potassium peroxymonosulfate (Trifectant or Virkon-S) have
been proven to kill parvovirus if used correctly. For more information
on
parvocidal disinfectants, click here.
There is no way to completely
disinfect contaminated dirt and grass, although sunlight and drying has
some effect. Mechanical decontamination through irrigation may also be
helpful, but the area must be allowed to dry thoroughly between
applications. Potassium peroxymonosulfate has relatively good activity
in the face of organic matter, and can be sprayed on contaminated areas
using a pesticide sprayer or other applicator. To be on the safe side,
contaminated areas should be off limits to puppies for 1-6 months
(choose the longer end of the waiting interval for moist, dark areas,
if area can not be heavily irrigated or if it can not be sprayed with
potassium peroxymonosulfate).
Parvovirus can be spread on hands, feet, clothing, tools, rodents and
flies traveling from kennel to kennel! Dogs may carry the virus on
their fur and feet even if they themselves do not get ill. The virus
enters the dog through the nose or mouth and has an incubation period
of 3 days to 2 weeks (usually 5-7 days).
Puppies under 6 months old are most likely to get severe disease.
Rottweilers, Dobermans, pit bulls and mixes of these breeds are
especially vulnerable. Adult dogs may get mild disease that is
indistinguishable from diarrhea of any other cause. Affected dogs have
mild to severe diarrhea, may be
dehydrated and lethargic, have vomiting, or can develop severe to fatal
secondary bacterial infections.
Vaccination usually prevents disease in adult dogs that have received a
vaccine at least 1-2 weeks before exposure, but does not prevent them
from carrying virus on fur if exposed. Puppies up to 16 weeks of age
may not be protected fully by vaccination.
Diagnosing Parvovirus
There are three ways to "test" for parvo: clinical, by complete blood
count (CBC), and by fecal antigen tests. Read the " parvo
cheat sheet" for a quick summary of diagnosis.
Clinically: Dogs with
parvoviral enteritis typically have vomiting and diarrhea which
typically is severe but may be mild. Lymph nodes may be enlarged and
the dog may
have a fever. Other diseases may mimic parvo, so a clinical diagnosis
made
without the aid of diagnostic testing is not precise.
CBC: Dogs with parvo typically have very few white blood cells.
If the normal lower limits for white blood cell counts on the CBC is
6000 cells/microliter, a dog with parvo may have less than 1000.
Although this also does not confirm parvo, it is strong evidence and a
dog with some
other disease and such a low white cell count requires aggressive
treatment
or euthanasia regardless.
Fecal antigen test: The fecal tests used in clinics and shelters are
assaying for antigens of the virus itself. If the dog has the virus in
its feces, the test should be positive. Always keep in mind that:
Tests must be performed exactly as the literature indicates or the
test is invalid.
Tests should be performed on any dog with diarrhea that is also
exhibiting signs of systemic disease: vomiting, lethargy, fever, loss
of appetite, dehydration, or dogs with unusually copious, smelly/bloody
diarrhea, or
any dog with known exposure to parvo within the preceding 14 days who
then
develops diarrhea.
Interpreting test results
Some vaccinated dogs may have a false-positive test, i.e. the virus in
their feces is vaccine strain. The vaccine-positive result can happen
within about 3-14 days of vaccination. A study in kittens suggests this
is uncommon with some tests - only 1/64 recently vaccinated kittens
tested weakly positive on the Idexx brand test. However, 13/64 kittens
tested positive,
some strongly positive, on the Synbiotics brand test. (Levy, J. K.
(2006).
Impact of Vaccination on Parvovirus Testing in Kittens. International
Veterinary
Vaccines and Diagnostic Conference, Oslo, Norway.) Equivalent data is
not
available for puppies, however all puppies testing positive should be
carefully
isolated regardless of recent vaccine history.
Some dogs with parvo have negative tests, either because it is very
early in the course of the disease or late in the course (most puppies
will
test negative by the time they've had clinical signs for 2-3 days).
Tests
should be repeated on dogs that are strong suspects or used in
conjunction with a CBC or blood smear.
Parvovirus is very uncommon in dogs over four months of age vaccinated
at least 1-2 weeks prior to exposure. Positive test results in these
dogs should be verified by another test, such as a CBC (or necropsy if
the
dog dies or is euthanized). If multiple cases of apparent parvovirus
are
observed in vaccinated dogs over four months old, please contact the UC
Davis Shelter Medicine Program.
Each shelter should have a decision tree about which tests to use and
what to do with a dog once tests are performed. One example: if
sufficient facilities exist, have a transitional area for dogs that
have suspect parvovirus but things do not add up (a dog who has a
positive test result but who also appears well, a dog with bloody
diarrhea that has negative test results). Attempt to clarify the status
of such dogs with a CBC. Carefully isolate, retest and monitor
"transitional" dogs daily until they are clearly not
infected with parvo and then place them up for adoption or they clearly
have parvo and then euthanize or treat them.
Limiting the Spread of Parvovirus
Vaccination against parvovirus is very effective and is the cornerstone
of prevention. Vaccinate all dogs and puppies over 4-6 weeks of age
immediately on intake, and repeat vaccinations in puppies every 2-4
weeks. Go with
the low end of the age range and short end of the vaccination interval
in shelters where parvo risk is high.
Use a known parvocidal disinfectant, correctly applied at the correct
concentration. This is particularly important following a known parvo
exposure. For more information on disinfection, see our Cleaning
and Disinfection information sheet. For more information on parvo
disinfection FAQS, click
here.
Train staff in recognition of
parvovirus, including correct use of the fecal antigen test. Create
a written plan for what to do if a parvo case is identified.
Ensure availability of protective gear such as gloves, protective
jumpsuits (long sleeves are a must!), and boots or shoe covers.
Puppies and at-risk dogs
exposed to parvovirus should be isolated and quarantined for two weeks.
For more information on quarantine and risk assessment, see notes on panleukopenia
control. The considerations for quarantine in the face of parvo
are the same, as these two viruses are very closely related.
Perform routine shelter maintenance to minimize the spread of infection
in the event that infection does occur
Cleaning should be performed routinely (typically daily for tasks like
cages and weekly for floors, walls, vehicles etc.) with a know
parvocidal disinfectant.
All areas of the shelter are to be cleaned and disinfected routinely
(except carpeted areas). This includes vehicles, front lobby, all
walkways and common areas, after hours receiving, etc.
Areas of animal transport vehicles where dogs are kept should be
cleaned and sprayed with a parvocidal disinfectant between each use.
Scrapers and scrub brushes should be designated for each kennel and
used only for that kennel to minimize cross contamination.
Remove all gross organic matter from runs prior to disinfection. Scrape
or scrub as needed to remove dried on debris.
If necessary, use degreasing solution to clean the kennel.
Rinse with water.
Spray with parvocidal disinfectant. Avoid splashing as much as possible
(splashing can spread the virus). Do not use power washers or high
pressure hoses during a parvo outbreak unless all animals have been
removed from the area.
Allow to air dry, or squeegee if necessary.
Ideally wait ten minutes before letting dogs back into that area.
Spray walkways with parvocidal disinfectant after cleaning runs.
Do not allow puppies from unknown backgrounds into play yards, carpeted
offices, or other hard to clean areas until they have been in the
shelter at least two weeks.
Perform routine surveillance and keep track of trends.
Maintain a logbook for staff to record parvo test results in a
convenient location and ensure that staff uses it! It should include
the Parvo test date, animal number, and initials of the person running
the test (which
also allows supervisors to figure out who does not runs tests).
Monitor for severe or bloody diarrhea, vomiting, depression or other
signs of illness. Also observe for dogs that are found dead in run or
any incoming puppy that has an unthrifty appearance. If there is any
doubt, that animal should be tested.
Balancing parvovirus risk and puppy socialization
It's easy to see the consequences when a puppy is exposed to parvovirus
before vaccination has a chance to protect. This motivates us to
carefully protect puppies from possible exposure to this deadly virus.
However, the consequences of poor socialization are less immediately
apparent, but may be equally severe. A puppy that has been isolated
from other animals, people and a wide variety of experiences may grow
up fearful or even aggressive. As we know in shelters, this may lead to
fatal consequences if the dog is later surrendered due to these
behaviors. We need to balance the risk of parvo with the very real risk
of poor socialization, and do our best to
provide puppies with the best of both worlds: a variety of experiences
in
a relatively safe and clean environment. For more on providing puppies
with
socialization opportunities while protecting them from parvo, please
see
our information sheet on "parvovirus
and puppy socialization".
Client Information
Parvovirus is highly infectious and causes diarrhea (sometimes bloody),
vomiting, lethargy, weakness, and fever. The virus also attacks white
blood cells, leaving the infected dog much more susceptible to other
bacterial infections.
Diarrhea can be mild or severe fatal. Diarrhea in an otherwise bright,
alert, eating, drinking dog is more likely due to diet change, stress,
parasites, or diet change, than to parvovirus.
The virus is very contagious and is spread by exposure to feces.
Unfortunately, dogs from shelters often have been exposed to parvovirus
and should be
observed for 14 days after adoption to be sure they are not incubating
the virus.
There is some risk that a dog incubating parvovirus will infect other
dogs. The new dog and its feces should be kept away from puppies and
unvaccinated dogs for 2 weeks. Dogs that have had at least two
vaccines, with the last one at least 2 weeks prior to exposure to an
infected dog are fairly protected.
If you suspect your dog has parvo, call your vet as soon as possible.
The earlier the infection is diagnosed and treated with fluids,
antibiotics, and nursing care, the more likely it is to do well.
Communicating with the general public when parvoviral infections occur
in your shelter
The presence of cases of parvovirus in the shelter should be
communicated to local veterinarians and to the public.
Adopters should be informed of the exposure status of their new dogs
with a copy of any relevant medical records, and should sign an
adoption with medical waiver form.
All adopters should be given a parvo information handout which should
include a description of the disease and the associated clinical signs
of an infected animal.
As always people who have recently adopted an animal should be strongly
advised to have the animal examined by a veterinarian. In the event
that the adopted animal had been kept in an area where there was even a
remote chance that it could have been exposed to parvo the adopter
should be informed and it should be made clear to them that they should
notify their veterinarian so that they may examine the dog, perform any
necessary diagnostic tests, and properly advise the owner on the care
of their newly adopted animal.
This protocol is from the UC Davis Koret Shelter
Medicine Program's website
and is republished with kind permission from Mike
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June 2005
What is canine parvovirus?
Canine parvovirus is a highly contagious and serious disease caused
by a virus that attacks the gastrointestinal tract of puppies, dogs,
and
wild canids. It was first identified in 1978 and is seen worldwide. It
also
can damage the heart muscle in very young and unborn puppies.
How is parvovirus spread?
Puppies and dogs usually become infected when they ingest virus that is
passed in the feces (stool) of an infected dog. Canine parvovirus is
resistant to changes in environmental conditions and can survive for
long periods
of time. Trace amounts of feces containing parvovirus may serve as
reservoirs of infection and the virus is readily transmitted from place
to place on
the hair or feet of dogs or via contaminated cages, shoes, or other
objects.
What dogs are at risk?
All dogs are at risk, but puppies less than four months old and dogs
that have not been vaccinated against canine parvovirus are at
increased risk of acquiring the disease. Certain breeds (e.g.
Rottweiler and Doberman Pinscher) appear to have a high risk of
experiencing severe disease.
What are some signs of parvovirus infection?
Canine parvovirus causes lethargy; loss of appetite; fever; vomiting;
and severe, often bloody, diarrhea. Vomiting and diarrhea can cause
rapid dehydration, and most deaths from parvovirus occur within 48 to
72 hours following onset of clinical signs. If your puppy or dog shows
any of these signs, you should contact your veterinarian promptly.
How is canine parvovirus diagnosed and treated?
Veterinarians diagnose canine parvovirus on the basis of clinical
appearance and laboratory tests. No specific drug is available that
will kill the virus in infected dogs. Treatment should be started
immediately and consists primarily of efforts to combat dehydration by
replacing electrolyte and fluid losses, controlling vomiting and
diarrhea, and preventing secondary infections.
Sick dogs should be kept warm, receive good nursing care, and be
separated
from other dogs. Proper cleaning and disinfection of contaminated
kennels
and other areas where infected dogs are housed is essential to control
the
spread of parvovirus. Canine parvovirus is not easily killed, so
consult your
veterinarian for specific guidance on cleaning and disinfecting agents.
How is parvovirus prevented?
Vaccination and good hygiene are critical components of canine
parvovirus prevention.
Vaccination—Vaccination is important. Young puppies are very
susceptible to infection, particularly because the natural immunity
provided
in their mothers' milk may wear off before the puppies' own immune
systems
are mature enough to fight off infection. If a puppy is exposed to
canine
parvovirus during this gap in protection, it may become ill. An
additional
concern is that immunity provided by a mother's milk may interfere with
an effective response to vaccination. This means even vaccinated
puppies
may occasionally succumb to parvovirus. To narrow gaps in protection
and
provide optimal protection against parvovirus during the first few
months
of life, a series of puppy vaccinations are administered.
To protect their adult dogs, pet owners should be sure that their dog's
parvovirus vaccination is up-to-date. Ask your veterinarian about a
recommended vaccination program for your canine companion.
In spite of proper vaccination, a small percentage of dogs do not
develop protective immunity and remain susceptible to infection.
Hygiene—Until a puppy has received its complete series of vaccinations,
pet owners should use caution when bringing their pet to places where
young puppies congregate (e.g. pet shops, parks, puppy classes,
obedience classes, doggy daycare, and grooming establishments).
Reputable establishments and training programs reduce exposure risk by
requiring vaccinations, health examinations, good hygiene, and
isolation of ill puppies and dogs. Contact with known infected dogs and
their premises should always be avoided.
Finally, do not allow your puppy or dog to come into contact with the
fecal waste of other dogs while walking or playing outdoors. Prompt and
proper disposal of waste material is always advisable as a way to limit
spread
of canine parvovirus infection.
Although this brochure provides basic information about canine
parvovirus, your veterinarian is always your best source of health
information. Consult your veterinarian for more information about
canine parvovirus and its prevention.
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CANINE
PARVOVIRUS
Note
for Pet Owners:
This
information is provided by Provet for educational purposes only.
You should seek the advice of your veterinarian if your pet is ill as
only he or she can correctly advise on the diagnosis and recommend the
treatment that is most appropriate for your pet.
Topics on this Page
Description
Cause
Breed Occurrence
Signs
Complications
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Diagnosis
Treatment
Prognosis
Long-term problems
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Description
Canine parvovirus only emerged during the 1970's as a serious
infectious disease which causes acute gastrointestinal disease or heart
disease in young dogs. In the most serious cases it can be rapidly
fatal.
Cause
The cause of Canine Parvovirus disease is a highly contagious
DNA-containing virus of which there are two types CPV-1 and CPV-2 . The
virus is transmitted through the mouth or nose from faeces. CPV-2 is
responsible for the most serious outbreaks of parvovirus enteritis and
it can be passed by out in the faeces of a dog within 3-4 days after
infection and before clinical signs are seen.
Breed Occurrence
Canine parvovirus (CPV-2) affects all breeds of domesticated dog, as
well as wild dogs (including bush-dogs, coyotes, maned wolves) and the
virus
may also be transmitted to cats, ferrets and mink. CVP-1 appears to
only
affect domesticated dogs..
Puppies aged 6weeks-6months in some breeds of dog have been reported to
have a higher risk of developing canine parvovirus (CPV-2)
disease than others, including :
Alaskan sled dogs
Doberman Pinschers
German Shepherd Dogs
Labrador Retrievers
Rottweilers
Staffordshire Terriers (American)
Signs
Some dogs can be infected with canine parvovirus and show no signs at
all or just a mild gastroenteritis. Clinical signs are first seen after
an incubation period of about 4-5 days. There are two main organ
systems
involved in canine parvovirus disease (CVP-2):
Gastrointestinal tract - parvoviral enteritis
Vomiting
Bloody diarrhoea
Rapid dehydration
High fever
Depression
Death
Heart disease - can be seen in pups born to unvaccinated mothers
Heart muscle inflammation (called myocarditis)
Heart failure - listless
Distressed pups - crying, difficulty breathing
Diarrhoea
Death
Canine parvovirus disease due to CVP-1 affects the same organs
in young puppies up to 3 weeks of age and causes :
mild diarrhoea
vomiting
difficulty breathing
Death - "fading puppy" syndrome
In adult bitches CPV-1 infection may cause :
fading puppy syndrome in her litters
abortion
foetal abnormalities
Complications
Secondary infections including septicaemia and giardia occur in some
patients following recovery from the disease.
Diagnosis
Diagnosis of CPV-2 infection can be made by testing faeces with an
ELISA antigen test up to 1 week after clinical signs are seen. After
this time the dog is no longer shedding virus in its faeces. NB This
test does not detect CPV-1
Diagnosis of both CPV-2 and CPV-1 can be made from histopathological
examination of infected tissue samples or faeces for virus
particles.
Treatment
There is no specific treatment for canine parvovirus, so puppies should
be vaccinated against according to the local veterinary
practice's normal protocol - usually at least 2 doses from 6 weeks of
age. Some pups have strong immunity from the mother and they need to be
vaccinated much
later. Protection from a vaccine may only last for up to 15 months, so
regular
boosters are needed. The vaccine is only effective against CPV-2
and
there is no vaccine available against CPV-1.
For clinical cases fluid therapy is essential to reverse dehydration
and electrolyte abnormalities. Other drugs may also help such as
antibiotics and antiemetic drugs (eg metoclopramide) to prevent
vomiting. Puppies should be kept warm and in isolation when being
treated. Dietary management is important in the recovery of parvovirus
patients because the gastrointestinal tract may take some time to
recover from the damage caused by the virus. A highly digestible, low
fibre ration is usually recommended.
CPV-2 is responsible for the most serious disease outbreaks and it can
survive in the environment on inanimate objects for up to 5 months.
Unfortunately the virus is resistant to many disinfectants - but
it is sensitive to bleach (sodium hypochlorite) at a dilution rate
of 1:30 bleach:water and this should be used to clean areas in
which an infected dog has been kept.
Prognosis
Puppies that survive CPV-2 infection usually do so within 7 days, but
the younger the pups are when they succumb to the disease the poorer
the prognosis
Puppies with CPV-1 infection usually die despite treatment, but they
should be kept warm and given nutritional support as well as pups with
CVP-2
infection.
Long term problems
Copyright
(c) 1999 - 2007 Provet. All rights reserved. mailto: info@provet.co.uk
reprinted with kind permission from Mike Davies
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The above information is simply
informational. It's intent is not to replace the advice of a
veterinarian nor to assist you in making a diagnosis of your pet.
Please consult with your own veterinarian for confirmation of any
diagnosis. Your pets life may depend on it.
