Central Hawke's Bay dog owners are being warned of a parvovirus outbreak in the district, which the SPCA says could be the worst in a decade.
Karen Phillips, from CHB Vets in Waipukurau, said a number of dogs had died recently after contracting Parvoviral enteritis - a severe, sometimes fatal, infection of the intestinal tract in dogs and cats.
"Between Vet Services Hawke's Bay and us, we have seen about 30 cases. We have had five deaths in our clinic alone."
Dr Phillips said parvo was a nasty virus that was very contagious and especially severe in puppies. Symptoms included vomiting, diarrhoea, appetite loss, dehydration, and depression.
"If a pup comes in with vomiting and diarrhoea it is one of the first things we look for.
"Owners should be looking for a normally lively dog that goes quiet and vomits. They vomit continually - several times a day and not even related to eating - and then develop bloody diarrhoea as the lining of their gut strips off."
Parvo can be prevented with regular yearly vaccinations.
Dr Phillips said a common misconception among owners was that the virus could only be spread through direct contact with infected animals.
However pets could contract the virus simply by walking in areas where infected dogs had been, and visitors could also bring the virus into homes on the bottoms of their shoes.
"We've had reports of parvo in pups that have never even left their property before," she said.
Treatment of parvovirus infection could require animals to be hospitalised for days while they received fluid therapy and antibiotics, and even blood transfusions, while waiting for the virus to run its course.
Prevention of parvo was the key, she said.
"Treatment of parvovirus infection is expensive and not always successful. So, if your pet has not been vaccinated against canine parvoviral infection, you should discuss yearly vaccinations with your veterinarian."
CHB SPCA shelter manager Renee Hickey said her rescue dog Travis was lucky to survive parvo.
"The only reason he made it was because he had been vaccinated - they only get a milder case."
She said while most of instances of parvo had been confined to Waipukurau, it was still the highest number of cases she had seen.
"It's the worst I've seen it in my 10 years," she said.
A simple test can be done at the vet on the first visit to determine if a dog has parvovirus.
There are 5034 known dogs in CHB, according to council figures.