Parvo in Dogs
Written by Dirk Dekens, DVM of the
Parvo is a viral disease seen only in dogs and dog-like animals, such as wolves and coyotes. First detected in 1978 almost simultaneously in the
The Virus
The virus responsible shows great resemblance to the cat distemper virus (responsible for feline panleucopenia) and the mink enteritis virus. This has made some scientists believe that parvo may have resulted as a mutation of a modified live virus used in cat vaccines against distemper. The virus is very resistant and can survive for months in fecal material. Disinfectants such as bleach diluted in water (1:30) or formaldehyde can be used to inactivate the virus.
Contraction
Most dogs typically get the virus by means of direct contact with contaminated stool or other excretions. Indirect spreading of the virus is also possible through carriers such as people and contaminated bedding. Once the dog is infected, it takes several days to one week before clinical signs develop. Initially the virus will multiply in the throat area but later it will establish itself in the gastro intestinal tract, causing vomiting and diarrhea; other parts of the body such as the bone marrow, causing a decrease in the number of white blood cells, and the heart muscle in some cases.
Clinical Signs
The following clinical signs are typically observed in dogs with parvo. At first the animal will lose its appetite and become lethargic. Within hours frequent vomiting often accompanied by a fever will be seen. Over the course of the next 24 to 48 hours most animals develop severe diarrhea, eventually progressing to a bloody watery diarrhea. The clinical signs last for several days until the animal either dies or recovers completely. Parvo is mosr devastating in puppies, causing 50% or more to die compared to about 10% in older dogs. Death is usually caused by severe dehydration and hypothermia, or secondary bacterial complications because of a compromised immune system. Rarely, sudden death in very young puppies is seen, caused by severe damage to the heart muscle.
Diagnosis
A diagnosis of parvo is usually made based on the clinical signs such as the sudden onset of vomiting and bloody diarrhea. Confirmation can be obtained by performing a very specific fecal test. Bloodwork can also be useful to establish a diagnosis.
Treatment and Prevention
Because of its viral nature, treatment of parvo can only be symptomatic. Treatment often lasts several days to one week or longer. Hospitalization with intensive care at a veterinary facility is in most cases the only viable approach to this disease. Fluid therapy (subcutaneous or intravenous fluids) to replace lost fluids caused by vomiting and/or diarrhea, and to maintain a proper fluid balance is extremely important to avoid dehydration and gradual weakening of the animal. In addition, medications to control persistent vomiting, and antibiotics, to prevent or battle secondary bacterial complications, are regularly administered.
But despite the best veterinary care, some animals will still die. Therefore prevention of parvo, rather than treatment, is most important. Various vaccines are available through veterinary clinics that are very effective. A basic vaccination is required starting as early as 5 weeks of age, repeated every 3 to 4 weeks, and continued until about 18 to 20 weeks of age. Yearly booster vaccines are required afterwards. Dogs that have not received the complete basic vaccination are often still at risk despite the fact that they have received one or two vaccinations already. These animals have not yet built up a solid resistance against this disease. Extreme care should be taken to avoid any contact with other dogs or to eliminate direct exposure to the parvo virus until the animal has received its complete basic vaccination.
Conclusion
During the past few months many veterinarians have noticed an increase in the incidence of this disease in
Please contact your own veterinarian promptly if you observe clinical signs that could indicate parvo in your dog. The earlier the animal is treated, the better its chances will be for survival and the smaller the chance will be that your dog will spread the disease to other animals.
Reprinted with permission from Carol Mawer, Director - Calgary Humane Society.
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