Parvo - What is it...and what do you do for it?

Goliath at 5 months on his way home after an 8 night stay at the vets with parvo

Canine parvovirus type 2 (CPV2, colloquially parvo) is a contagious virus mainly affecting dogs. The disease is highly contagious and is spread from dog to dog by direct or indirect contact with their feces. It can be especially severe in puppies that are not protected by maternal antibodies or vaccination. It has two distinct presentations, a cardiac and intestinal form. The common signs of the intestinal form are severe vomiting and dysentery. The cardiac form causes cardiovascular failure in young puppies. Treatment often involves veterinary hospitalization. Vaccines can prevent this infection, but mortality can reach 91% in untreated cases. Canine parvovirus will not infect humans.

How is it treated??

Survival rate depends on how quickly CPV is diagnosed, the age of the dog and how aggressive the treatment is. Treatment usually involves extensive hospitalization, due to the severe dehydration and damage to the intestines and bone marrow. A CPV test should be given as early as possible if CPV is suspected in order to begin early treatment and increase survival rate if the disease is found.

Treatment ideally also consists of crystalloid IV fluids and/or colloids, antinausea injections (antiemetics) such as metoclopramide, dolasetron, ondansetron and prochlorperazine, and antibiotic injections such as cefoxitin, metronidazole, timentin, or enrofloxacin.[25] IV fluids are administered and antinausea and antibiotic injections are given subcutaneously, intramuscularly, or intravenously. The fluids are typically a mix of a sterile, balanced electrolyte solution, with an appropriate amount of B-complex vitamins, dextrose and potassium chloride. Analgesic medications such as buprenorphine are also used to counteract the intestinal discomfort caused by frequent bouts of diarrhea.

In addition to fluids given to achieve adequate rehydration, each time the puppy vomits or has diarrhea in a significant quantity, an equal amount of fluid is administered intravenously. The fluid requirements of a patient are determined by the animal's body weight, weight changes over time, degree of dehydration at presentation and surface area.

A blood plasma transfusion from a donor dog that has already survived CPV is sometimes used to provide passive immunity to the sick dog. Some veterinarians keep these dogs on site, or have frozen serum available. There have been no controlled studies regarding this treatment.  Additionally, fresh frozen plasma and human albumin transfusions can help replace the extreme protein losses seen in severe cases and help assure adequate tissue healing.

Once the dog can keep fluids down, the IV fluids are gradually discontinued, and very bland food slowly introduced. Oral antibiotics are administered for a number of days depending on the white blood cell count and the patient's ability to fight off secondary infection. A puppy with minimal symptoms can recover in 2 or 3 days if the IV fluids are begun as soon as symptoms are noticed and the CPV test confirms the diagnosis. If more severe, depending on treatment, puppies can remain ill from 5 days up to 2 weeks. However, even with hospitalization, there is no guarantee that the dog will be cured and survive.

Tamiflu reduces disease severity and hospitalization time in canine parvovirus infection. The drug may limit the ability of the virus to invade the crypt cells of the small intestine and decrease gastrointestinal bacteria colonization and toxin production.[26] However, due to the viral DNA replication pattern of parvovirus and the mechanism of action of oseltamivir, this medication has not shown to improve survival times or shorten hospitalization stay. Lastly, recombinant feline interferon omega (rFeIFN-ω), produced in silkworm larvae using a baculovirus vector, has been demonstrated by multiple studies to be an effective treatment. However, this therapy is not currently approved in the United States

A recent 2012 study(not yet published) has shown good results with an intensive at-home treatment using Maropitant and Convenia, two drugs newly released by Pfizer. The treatment would cost $200 to $300, a fraction of the $1,500 to $3,000 that inpatient care cost. In the study, survival rate for the new treatment group was 85%, compard to the 90% survival for the conventional inpatient treatment

Prevention and decontamination

Prevention is the only way to ensure that a puppy or dog remain healthy because the disease is extremely virulent and contagious. The virus is extremely hardy and has been found to survive in feces and other organic material such as soil for over a year. It survives extremely cold and hot temperatures. The only household disinfectant that kills the virus is bleach.

Puppies are generally vaccinated in a series of doses, extending from the earliest time that the immunity derived from the mother wears off until after that passive immunity is definitely gone. Older puppies (16 weeks or older) are given 3 vaccinations 3 to 4 weeks apart. The duration of immunity of vaccines for CPV2 has been tested for all major vaccine manufacturers in the United States and has been found to be at least three years after the initial puppy series and a booster 1 year later.

A dog that successfully recovers from CPV2 generally remains contagious for up to three weeks, but it is possible they may remain contagious for up to six. Ongoing infection risk is primarily from fecal contamination of the environment due to the virus's ability to survive many months in the environment. Neighbours and family members with dogs should be notified of infected animals so that they can ensure that their dogs are vaccinated or tested for immunity. The vaccine will take up to 2 weeks to reach effective levels of immunity; the contagious individual should remain in quarantine until other animals are protected.