Parvoviral enteritis

In recent months there has been an outbreak of canine parvoviral enteritis (parvovirus). Parvovirus mainly affects puppies up to six months of age, but older, unvaccinated dogs can also be affected. The virus targets rapidly dividing cells such as those in the intestines - damaging and killing them faster than they can replace themselves. This causes significant damage to the intestinal tract. Parvovirus can also result in blood clotting issues, especially when sepsis develops.

Signs include severe vomiting, diarrhoea, lethargy, inappetence, and sepsis (infection crossing into the blood and travelling around the body via the bloodstream). Diarrhoea often has blood in it and is quite liquid and high-volume. Parvovirus lasts approximately one week with an incubation period of seven to fourteen days.

Parvo is transmitted by accidental ingestion of virus particles that are shed in dog faeces – it is important not to let dogs (especially if not fully vaccinated) sniff around unknown dog faeces. The virus can last for months to years in certain places (longer in cold and damp areas) so eradicating it from the environment is basically impossible. Parvovirus can also be transmitted from a pregnant mother to her unborn pups.

Testing for parvovirus is relatively straightforward – almost exactly like a covid test – except with the sample taken from a different location! This allows us to have a result in ten minutes. False negatives can occasionally occur, but false positives do not.

Parvovirus requires intensive treatment. This involves hospitalisation in an isolation area with barrier nursing – foot baths, gowns, and gloves to prevent transmission of the virus to other dogs in the hospital. A vet and nurse are assigned to parvo patients and these staff members will avoid contact with other dogs as much as possible. As well as isolation, patients are placed on intravenous fluids to correct dehydration and replace electrolytes lost by vomiting and diarrhoea. Injectable antibiotics, pain relief, and antinausea medication are given daily. Gut protectants are given orally. The animal is syringe fed or a feeding tube is placed if they are not able or willing to eat on their own – giving a highly digestible gastrointestinal recuperation diet is critical to help the intestinal cells repair and replace themselves. The animal’s vitals including temperature, heart rate, respiratory rate and effort, gum colour, hydration, blood pressure, and oxygenation are checked at least once daily to make sure the patient is stable and not developing sepsis. Blood testing is often required to measure white blood cell count, check for electrolyte abnormalities and glucose levels – issues with these can cause abnormal heart rhythms, seizures, coma, and death. Sometimes, an abdominal ultrasound is needed as it is possible for aggravated intestines to telescope inside each other (intussusception), which can cause a blockage or even death of the affected piece of intestine. In severe cases that develop clotting issues, a plasma transfusion may be required.

For patients where the disease is caught early, it is sometimes possible to treat them as an outpatient. This involves oral antibiotics and antinausea, as well as giving electrolyte powder in water. If the patient is not eating or drinking, or is still vomiting, it can make it difficult to get these medications in and keep them in. It also puts a lot of extra strain on the already damaged intestinal lining to absorb these medications well. We also give fluid under the skin to help maintain hydration, however if the patient is already somewhat dehydrated, the fluid may not be absorbed well. Outpatient treatment requires extremely close monitoring, and the dog may still require intensive treatment in the clinic if they do not improve within the first 24 hours.

In general, most dogs that survive the first three to four days of illness will survive. There is a higher chance of survival when intervention is early, especially in hospitalised animals.

Parvovirus can be a very expensive and difficult disease to treat. The best prevention for parvovirus is vaccination. A course of three vaccinations is generally given at eight, twelve, and sixteen weeks of age, with a booster given at six to twelve months of age. After this, threeyearly vaccination is recommended. The vaccination is a modified live vaccine, meaning the live parvovirus has been altered so that it cannot cause disease following vaccination but causes a strong immune response to occur. As we know that not all dogs will develop the exact same duration of immunity, it is possible to test antibody levels at the lab. This allows us to see if a dog still has enough antibodies for protection, and, if not, vaccination is recommended.

Please note, vaccinations for leptospirosis and canine cough are annual so a yearly vet check to receive these vaccines is still recommended.

If you think your dog may have parvovirus, contact the clinic as soon as possible for an appointment. Please leave the dog in the car – the vet will do a parvo test and then do an examination and make a plan with you from there.

At Tauranga Veterinary Services we can see you and your beloved pet 7 days per week at our Tauranga Clinic and 6 days at our Te Puna, Katikati, Papamoa and Mount Maunganui Clinics. Book online at www.bopvets.co.nz or call 0800 838 7267 now to organise a booking convenient to you.