Parvovirus in dogs

Parvovirus is contagious and can spread through direct contact via the fecal-oral route. A dog that sniffs the anus of an infected dog, or sniffs infected dog poop can contract the virus. The virus can also spread indirectly if a dog licks or comes in contact with a surface that has been in touch with an infected animal. Shoes that have been in an area that has CPV can also track in the virus and act on canines. 

Canine parvovirus Type II causes CPV. It was first reported in 1976 when an epidemic unleashed severe gastrointestinal and cardiac conditions in young dogs. Since then the virus has been found to affect coyotes, wolves, foxes, as well as raccoons. It is similar to feline panleukopenia virus (FPV) that has been known since the 1920s and affects cats; in fact, parvovirus is a mutation of FPV. 

Not every dog that contracts CPV falls sick - it depends on the dog’s immune system and the number of virus particles involved.

There is an incubation period of three to seven days before the onset of symptoms. The virus initially penetrates the lymph nodes and tonsils. Here, the virus invades lymphocytes (a variety of infection-fighting white blood cells) and makes millions of copies of compromised lymphocytes and enters the bloodstream. 

The virus then attacks the epithelium lining of the gut that is responsible for the absorption of nutrients from food and also acts as a barrier against microorganisms introduced to the body through eating or drinking. This vulnerability also hinders the ability of the gut to retain water and excess fluid loss leads to dehydration. 

The weakening of the stomach’s lining causes severe diarrhoea and makes the body susceptible to a host of secondary infections. The virus also invades the bone marrow and compromises the body’s ability to manufacture immunity and further exacerbates any secondary infections.

The intestinal lining can grow vulnerable enough to break down, causing the infection to spread throughout the body in the bloodstream. Widespread sepsis along with dehydration makes CPV a deadly disease.

Symptoms include severe and bloody diarrhoea, loss of appetite, sudden onset of high fever, nausea, lethargy and depression. The severity of diarrhoea and vomiting in a pup is a cause for concern and must prompt a visit to the veterinarian.

The faecal ELISA test is the most common diagnostic tool employed by vets. ELISA, or Enzyme Linked Immunosorbent Assay, consists of a plate containing antibodies to CPV. A stool sample of the dog is introduced to the plate and if the virus is present the colour changes suggesting that the dog is infected. 

The ELISA test is a quick and cheap diagnostic method that takes about 15 minutes to run. However, there is a possibility for false positives and negatives. The fecal PCR (Polymerase Chain Reaction) test is more accurate but takes a longer time to execute - and there may not always be enough time to go through it.

A white blood cell count confirms the diagnosis. If levels of WBCs are low it is an indication of a weakened immune system.

There is no cure for CPV, so treatment focuses on symptom management and supportive care. Dogs with severe symptoms are likely to be admitted to hospital for treatment since it is a labour-intensive and life-saving process. 

Fluids containing nutrients are administered intravenously to rehydrate the salts lost to severe diarrhoea and malabsorption. It is done intravenously so the fluids are directly absorbed by the blood. Potassium and dextrose may be added to maintain electrolyte and blood sugar levels. Antibiotics may also be infused to tackle any secondary diseases and step in for the compromised immune system. Symptom-relieving drugs such as antiemetics can also bring relief. 

The entire process can take up to a week before the situation is stabilized. Deworming drugs are also administered to rule out the possibility of parasitic infections. 

Parvovirus should not be treated at home since chances of survival are substantially lowered due to opportunistic infections and intestinal abnormalities. While CPV can sometimes be fatal, the good news is that 70 percent of dogs that receive timely treatment make it out of the disease and even develop immunity against it.

Dogs that survive parvovirus continue to be vulnerable up to at least two months after recovery, as their immune systems are weakened and must be kept in a secure environment, and fed a nutritious diet recommended by the vet. Your dog may be extremely hungry after recovering from the disease but keep the diet light initially. Home cooked food such as boiled chicken and rice will be easy on the stomach. Shifting from the diet recommended by the vet may cause diarrhoea to return and undo the treatment. 

Virus shed from an infected dog can live for 10 days, so if you have other dogs it’s a good idea to keep the sick dog quarantined for a while even after the initial disease is treated.

Parvovirus vaccination makes up the ‘core’ group of vaccinations that all dogs must get. Called the DHPP vaccine, it covers canine distemper, infectious hepatitis, parainfluenza and parvovirus. The vaccine is administered three times between the ages of six and 16 weeks. A booster shot is also recommended after a year of the final shot followed by an injection every three years.

While the vaccine cannot provide total protection from the virus, other methods of prevention are futile. The virus occurs commonly and the best defence is following the vaccine schedule. Those exposed to the vaccine have a reduced chance of contracting the disease.

There are some steps that can be taken indoors to mitigate the effects of the virus. While it is a resilient and hardy virus, bleach is known to lower its potency. Cleaning surfaces that have come in contact with an infected dog with bleach can reduce the chances of it spreading. Contact for at least 10 minutes with bleach kills the virus. Also dispose of any rags, clothes or loose material that directly came in contact with faeces or vomit of an infected dog.

If your dog is less than 16 weeks old, it is not recommended to take it out to public parks or interact with other dogs until the vaccine regimen is complete. The immune system may still be weak and an undesired reaction may occur. 

Additionally, it may be a good idea to not get a pup into a house that witnessed parvovirus for at least two months. Studies have shown that the virus can live up to a month indoors. If you are living in a neighborhood with other dogs it is a good idea to inform your neighbours of your dog’s condition so they may get their dog checked as well.