Animals – Vicious virus

Back as far as 1967, scientists had recognised there was a parvovirus that was causing ill-thrift (failure to thrive) in some newborn pups. This was CPV-1. In 1978, when I was a vet student in Palmerston North, scientists in America discovered that a severe vomiting and bloody diarrhoea syndrome in dogs was caused by a new parvovirus, known as CPV-2. The DNA of this new parvovirus was almost identical to the parvovirus that caused the well-recognised disease of domestic cats known as feline infectious enteritis or panleucopenia. It is generally accepted that the cat parvovirus, a virus incapable of causing disease in non-felines, mutated to become CPV-2, the cause of the dangerous disease in dogs, which we still see today.

Within two years the disease was being seen all over the world. The virus is very contagious and resilient. It can survive over a year in the environment, and the only household product that will kill it is bleach. The young family next to our student flat had a lovely Shetland sheepdog (Sheltie). It caught parvovirus and couldn’t be saved. In those early days, apparently, some vets tried using the cat parvovirus vaccine on dogs with mixed success. I took my dog, a three-month-old puppy, along to the Massey University veterinary clinical practice in March 1979 to get her first vaccination. My puppy was vaccinated against canine distemper and hepatitis. She got a booster for the same thing a year later, but still no dog parvovirus vaccine was available.

In January 1981, after I had left Massey, my dog got her first parvovirus vaccination. It was made by the Australian animal vaccination manufacturing company, Websters. If they weren’t the very first, they were certainly one of the first with a vaccine. Later that year, when I was now working for Oamaru Veterinary Services, I remember going with the boss, to a rural intersection to vaccinate heaps of working dogs. I remember seeing dozens of utes and farmers and what seemed like hundreds of Huntaways, Beardies and Border Collies that day.

Viruses are mainly classified on what they look like, their type of DNA or RNA, their mode of replication, what the host organism is and the type of disease they cause. Go back 100 years and we only knew about the last two of these. Viruses are too small to see under a light microscope. Louis Pasteur, a great advocate of the germ theory of disease, postulated that rabies was caused by a “germ” much smaller than bacteria. It wasn’t until the development of the electron microscope in 1931 that we got our first images of viruses. So if CPV-2 had first appeared 100 years ago, it might have been called  “Squitters” or “Dog Dysentery”. And if we didn’t have the microbiological developments of the last 100 years, Covid-19 might be known as “The Chinese Death” or “ Donald’s Folly” or “Boomer Remover”, depending on your perspective.

David Haugh, Wellsford Vet Clinic
www.vetsonline.co.nz/wellsfordvet