Parvo in Dogs
There is good news and bad news about Parvo. Canine Parvovirus Type 2 (CPV) is a highly-contagious incurable viral illness and, sadly, the bad news is that around nine in ten puppies that contract it and do not receive prompt treatment will die.
The good news is that 85% of infected puppies who are treated go on to survive although treatment can be drawn-out and distressing.
The even better news is that parvovirus in dogs can be virtually eliminated by a simple vaccine given every two to four weeks until 16 weeks of age. Is it really worth the risk not to vaccinate?
There most common form of parvo dog disease hits the intestine and is characterised by vomiting, diarrhoea, lethargy, weight loss, and lack of appetite. Much rarer is cardiac parvovirus, which attacks the heart muscles of very young puppies, often leading to death. It’s usually found in puppies under six weeks old who contracted from their mothers in the womb. It can be difficult to spot, and often the only indication is the death of the puppy. If they survive the infection, signs of long term cardiac damage may not surface for several years, but its victims can later suffer from congestive heart failure.
With intestinal Parvo, it is not the virus itself which kills the patient, but the effects of dehydration and secondary infection.
Dogs of any age can be affected, but most acute cases of Parvo are seen in puppies aged between six weeks and six months simply because they have less developed immune systems.
The scary thing is that your cherished puppy could become infected by simply being walked through your local park or even down the street where you live. It is spread by direct – or indirect – contact with dog faeces. High concentrations of the virus are found in the stool of infected animals, so it only takes a sniff to contract parvo, but even soil on a shoe is all that is needed. This is because Parvovirus can live in the ground for several months, so dogs can still be infected even if the stool is no longer present.
Within two days of the virus entering your dog's body, it moves to the lymphoid tissues, where it can then enter the bloodstream and move to the digestive system and bone marrow. This results in visible symptoms within 7 to 10 days.
Certain dog breeds seem more prone to CPV infection including Rottweilers Doberman Pinschers, Pit Bulls, Labrador Retrievers, German Shepherds, English Springer Spaniels and Alaskan sled dogs.
Since CPV is a viral infection and so cannot be cured, treatment is focused the symptoms and preventing secondary bacterial infections, which is why the best thing to do prevent it in the first place with proper vaccination.
Puppies get some natural protection from antibodies passed on by their mothers but should be vaccinated at six, nine and 12 weeks, and should be kept away from strange dogs until at least two weeks after the final jab. If your dog is one of the at-risk breeds, he will need jabs for up to 22 weeks.
What are common parvo symptoms?
Since the most common form of CPV is the intestinal form known as enteritis, parvo symptoms include often severe vomiting, diarrhoea, dehydration, dark or bloody stool, and in severe cases, fever. Blood tests may also reveal lowered white blood cell counts.
While most cases are seen in puppies younger than 12 weeks old, parvovirus enteritis can be seen in dogs of any breed, sex, or age. Death can occur a matter of hours after the end of the incubation period which can be between 4 to 14 days, so it is vital to spot parvo symptoms in dogs as soon as possible and seek your vet’s assistance.
Bloody diarrhoea – with or without vomiting – are not necessarily signs of parvo and so if you present your dog at the vets, expect them to carry out diagnostic CPV tests to rule out other causes. A full physical exam and further lab tests can determine the severity of the disease.
As an incurable viral infection treatment is directed at supportive therapies. Because severe dehydration is the real killer, replacing lost fluids is probably the single most important treatment, usually by intravenous electrolyte solution. However, in milder cases, subcutaneous or oral fluids may be used for several days.
At the other end of the spectrum, really severe cases may require treatment with blood transfusions, and in almost all cases, antibiotics are used to help control secondary bacterial infections.
CPV was first observed in the Seventies and within two years of its discovery it had spread worldwide. Today it ranks among the most infection diseases among canines. Without intervention it can kill its victims within a few hours or a few days depending on the strain and the strength of the animal: smaller breeds have a lower survival rate and so you should react quicker at the first signs of severe vomiting and/or bloody stool.
Parvo itself does not directly cause pain but the symptoms can be distressing and uncomfortable. Your vet will administer pain relief if required while treatment progresses.
Indeed, if your pet ever shows sign of pain for any cause consult your vet immediately. It may be a visible sign of something seriously wrong. While dogs who survive Parvo generally go on to lead long and happy lives, cell death in the intestines and bone marrow of a puppy can stunt their growth, although it may be hard to tell if the eventual size is unknown, but it can also cause long-term kidney or liver damage and permanently weaken the immune system, leaving him more susceptible to other diseases in later life.
If your dog has survived parvo – and the prospects are good – be aware that he will still have the virus in his faeces for up to three weeks, so for the sake of other puppies out there be extra careful to remove the offending poos and dispose of them safely.
And as Parvo survivors become carriers of the virus they will continue to sporadically poop out the virus at various points for the rest of their lives. Bag it and bin it.