Introduction

Canine parvovirus is a highly infectious pathogen affecting rapidly dividing cells: principally gastrointestinal, bone marrow and myocardial. Treatment is therefore aimed at minimising spread of infection, while administering supportive treatment to a severely debilitated puppy with a severe haemorrhagic gastroenteritis and sepsis. Canine parvovirus myocarditis, occurring in puppies <8 weeks old, carries an extremely guarded prognosis and will not be covered here.

Nursing Management

Strict hygiene requirements required to control the source of the disease and prevent disease transmission are best achieved with isolation facilities.

Isolation facilities should be totally self-contained with restricted access and a separate air handling system. Equipment for feeding, nursing (treatment table and medical supplies) and cleaning (sink, range of effective and appropriate disinfectants, clinical waste bags) should be available. Any bleach-containing disinfectant will be effective against parvovirus.

Isolation Rules, Nurses

Only one nurse should be allocated to isolation facilities, who ideally should have no other animal duties. Strict personal and environmental hygiene should be maintained with protective disposable clothing (gloves, apron, overshoes), antiseptic hand washes, foot bath and disposable paper towels.

Isolation Rules, Animals

No contact should be allowed with other animals. Soiled material should be removed quickly (bedding, bathing animal, tail bandages etc.) thereby minimising the presence of infectious agents and keeping the patient clean, warm and comfortable.

Monitoring

Monitoring should be performed frequently and nursing treatments amended according to changing parameters. A recommended protocol is given in Figure 1.

Figure 1. Monitoring puppy with parvovirus.

Treatment

Antibiosis

Antibiosis is needed to treat neutropenia (<2 x 10⁹/l), to protect against gastrointestinal tract (GIT) ulceration and bacterial translocation, fever and sepsis. A broad-spectrum antibiotic effective against aerobes and anaerobes should be selected, e.g., ampicillin/potentiated clavulanic acid with metronidazole and enrofloxacin (N.B. large-breed puppies and enrofloxacin risk/ benefit) or ampicillin/potentiated clavulanic acid with an aminoglycoside (N.B. nephrotoxicity). Antibiotics should be administered via the intravenous route initially.

Fluid Therapy

This is based on the ever-changing hydration status and ongoing losses (vomiting/diarrhoea amounts). Hydration status is estimated from Figure 2 or if animal's normal weight is known from the percentage difference in actual weight.

Fluid requirements per day are therefore a total of:
Maintenance requirements (approx 50 mls/kg/d)
plus
ongoing losses (estimate of vomit/diarrhoea amounts/weight)
and
fluid deficits (body weight x dehydration % (hydration status))

Shock doses of 90 ml/kg may be needed over the first hour. Deficits should be replaced over the next 24-36 hours. Fluid requirements will change and should be adjusted accordingly based on regular reexaminations to include clinical signs, weight, packed cell volume (PCV)/total protein (TP), vomiting/diarrhoea and urine output (aim 1-2 ml/ kg/hr). Administration should be via the intravenous route (peripheral/central) or intraosseous route if venous access is not possible. Fluid type depends on laboratory parameters such as electrolytes, glucose and albumin levels (Figure 3).

Hypokalaemia should be treated based on the level of animal potassium blood results and appropriate veterinary supplementation to 0.9% saline fluids. Rates should not exceed 0.5 mmol/kg body weight/hr. Potassium is monitored two to three times/day

Figure 2. Hydration status.

Figure 3. Recommended fluids.

Control of Vomiting and Oesophagitis Complications

Anti-emetics can be used in an attempt to control vomiting (metoclopramide, maropitant citrate). Antacids (H2 receptor antagonist (cimetidine/ ranitidine) or proton pump inhibitors (omeprazole)) and sucralfate are given as gastric protectants (sucralfate should be given on an empty stomach).

Nutritional Support

In general practice parenteral nutrition is difficult to achieve and risks of sepsis may exclude its use. Tube feeding is compromised due to the severe degree of vomiting occurring in these patients. Therefore food should be withheld for 12-24 hours until vomiting has ceased. Providing a bland diet will help GIT recovery. Various diets are available for convalescent support. Glutamine-containing oral rehydration solutions may provide limited nutrition of the GIT lining early in the disease and may be given as ice cubes initially to avoid vomiting. Meals should be little and often so as not to overwhelm the compromised GIT.

Other Medications

 Selemectin-type spot-on anti-parasitic agent

 Probiotics may help GI flora recovery once vomiting has stopped

 B vitamins can be added to intravenous fluid

 Interferon injections may aid recovery

 Vaccination should be recommended for in-contact and local canine population

Prognosis

Persistent diarrhoea may occur secondary to intussusceptions (ultrasound/barium impregnated polyethylene spheres (BIPS) study/endoscopy may be required) or dietary sensitivities (endoscopy/food trials). However, most cases can expect to recover in 4-5 days.

References

1.  Dallas S, Wiggins K. Management of the inpatient. In: Moore, M; Simpson, G. eds. BSAVA manual of veterinary nursing. Gloucester: BSAVA, 2003; 1-10.

2.  Holt D, Brown D. Acute abdominal and gastrointestinal emergencies. In: King L.; Hammond R. BSAVA manual of canine and feline emergency and critical care. Cheltenham: BSAVA, 1999; 127-131.

3.  Nelson RW, Couto CG. Disorders of the intestinal tract. In: Nelson, RW.; Couto CG. eds. Small animal internal medicine (third edition). St Louis: Mosby, 2003; 433-435.

4.  Oxley L, Kane M, et al. Nursing the emergency patient. In: Moore, M; Simpson, G. eds. BSAVA manual of veterinary nursing. Gloucester: BSAVA, 2003; 50-59.