Canine parvovirus enteritis can be an unaffordable and devastating disease for pet owners. The inability to pay for conventional in-hospital care can result in the heartbreak of relinquishment or euthanasia. Three recent studies have broken new ground by reporting the results of outpatient treatment for parvo.1–3 The justification for this approach? “We were tired of sending dogs away who had nowhere else to go, no other options.”3
- Standard of care for parvo enteritis is hospitalization, intravenous fluids and supportive care including antemetics, antibiotics, analgesia, deworming, correction of hypoglycemia and electrolyte imbalances and early enteral nutrition.
- Parvo has a mortality rate as high as 90% in untreated patients, and approximately 9% for aggressively treated patients.
Outpatient Treatment Studies
- The “Colorado Study”1 was a prospective, randomized study and therefore provides the best evidence. However, it was a kind of “inpatient outpatient” set-up where outpatient treatment was simulated and the level of care was higher than it would be in a true outpatient setting. The Sarpong study was retrospective and incorporated selection bias, in that it only included patients that had been deemed suitable for outpatient treatment. There was no control or comparison group. The Penn SPCA study was also retrospective and non-comparative, and is as yet unpublished, therefore representing the weakest evidence at this point.
- All treatment protocols included IV or SQ fluid therapy, antibiotic cover, antemetics and early enteral nutrition.
- The Colorado study included regular monitoring and specific correction of glucose and potassium, while the other two studies did not.
Main Data and Findings
Patient Selection: The sickest animals were excluded or removed from the outpatient protocols.
Survival: In the Colorado study, 90% of inpatients and 80% of outpatients survived; the difference was not statistically significant. Outpatient survival was 75% for the Sarpong study and 85% for the Penn study.
Risk factors for mortality: Weight ≤ 4kg and age ≤ 4 months characterized non-survivors in the Colorado study.
Enteral nutrition: Interestingly, mortality was 19% (vs overall 25%) in dogs fed Nutrical every 2-4 hours.2 This was statistically significant. Nutrical is a high-calorie supplement (4kcal/mL vs standard recovery diets of 1kcal/mL). Typically, high-protein supplements are recommended.
Antibiotic selection: There was no difference in survival between standard intravenous antibiotics and cefovecin.
Resources: The Penn SPCA study was time- and labour-intensive, requiring students or staff to be constantly available to respond to client calls, as well as twice-daily visits for SQ fluids and assessment.
Diagnostics and monitoring: Diagnostics and monitoring in the Colorado study were more typical of an intensive care setting, while the Penn study pared these down to physical exam, with emphasis on mentation, mucous membrane colour, CRT, skin tent, HR, RR and PCV/total solids/blood smear.
Fluid rates: The Colorado study used a base fluid rate of 120mL/kg/day for inpatients, and the same base rate divided QID for SQ administration to outpatients. These rates were adjusted for dehydration and ongoing losses, and SQ fluids were reduced or withheld if the previous SQ fluids had not been absorbed.
Ontario Experience: East Village Animal Hospitals
The East Village Animal Hospitals in London and Kitchener, whose clientele include exclusively low-income citizens and animal rescue organizations, routinely use an outpatient Colorado State-type protocol for treating hemorrhagic gastroenteritis, including parvovirus, because of their clients’ financial constraints. Dr. Martha Harding learned of this method on the Veterinary Information Network, where many veterinarians in the low-income regions of the US devised similar outpatient treatments for parvovirus when the disease first evolved in the early 1980s, and continue to this day.
Due to the risk of contamination, patients do not enter the hospital, according to Dr. Harding, but rather EVAH technicians obtain the history, preliminary physical examination and fecal swab using appropriate PPE, with the dog outside still in the vehicle. If parvovirus is confirmed by “SNAP test”, a “cocktail” bag of fluids is prepared and the veterinarian goes to the vehicle to discuss the parvovirus diagnosis.
In contrast with the Colorado and Pennsylvania studies, preliminary intravenous fluids are not administered. Rather, the veterinarian or technician administers a first bolus of “cocktail” fluids, teaching the client how to administer subsequent fluids every 4 – 6 hours at home. Clients are also instructed to administer a syringe of chicken or vegetable broth every 15 – 30 minutes during daytime hours during the first 24 hours, and then offer small meals of a soup-consistency chicken and rice mixture or gastro-enteric wet food beginning on day 2. Dogs typically require “subcutaneous cocktail” treatment for 48 – 72 hours, after which time, appetite, vomiting and diarrhea are improving, and dogs no longer allow owners to treat subcutaneously. Antibiotics and anti-emetics are then continued per os. Using this protocol, EVAH’s efficacy rate has been 100% in over a dozen cases for confirmed parvovirus cases, and a parvovirus-negative hemorrhagic enteritis case was also successfully treated using the same methods. Clients are asked to contact all neighbours with dogs to inform them of the parvovirus diagnosis, and suggest that owners review their dogs’ vaccination status.
The details of the subcutaneous cocktail can be found in the members’ section of the website.
Considerations for Shelters
Costs for the Colorado outpatient dogs were reduced by an estimated two-thirds compared with the in-patient protocol. This is a major advantage compared with admission to a private veterinary hospital.
For shelters, the time commitment for the outpatient protocol may or may not be resource-effective, depending on what model is used and on the shelter’s internal and financial resources. Using models such as the EVAH protocol, true outpatient treatment is definitely feasible. A thorough initial assessment is essential, as is the ability to reach veterinary medical staff with questions and concerns and protocolized decision points at which inpatient treatment or euthanasia are recommended.
There’s an irony in the way North American shelters manage medical surrenders, in that substantial resources may be used to remove an animal from its loving home, treat it, house it and then place it in a different home. If only we could work to keep that animal with the family who love it… Here’s one of the many ways we can!
With grateful thanks to guest co-author Dr. Martha Harding DVM, East Village Animal Hospitals, London and Kitchener Ontario.
- Venn EC, Preisner K, Boscan PL, et al. Evaluation of an outpatient protocol in the treatment of canine parvoviral enteritis. J Vet Emerg Crit Care 2017; 27: 52–65.
- Sarpong KJ, Lukowski JM, Knapp CG. Evaluation of mortality rate and predictors of outcome in dogs receiving outpatient treatment for parvoviral enteritis. J Am Vet Med Assoc 2017; 251: 1035–1041.
- Stupine J. PSPCA Outpatient Parvo Clinic. Maddie’s Fund Webinar 2016. https://www.youtube.com/watch?v=xT9Er7jpsfc