Parvo Outbreak, Ocean Shores, NSW

Scattered around the environment, like deadly confetti, Parvovirus is a hardy, virulent and highly contagious virus that strikes down hundreds of dogs each year. With a mortality rate up to 90%, it’s one disease that fully justifies canine vaccination.  Here’s a sad story of puppy-lives lost, and the consequences of vaccination complacency.

Introducing Parvovirus: viral confetti. Millions of virions per gram of poo.

The Local Story

The recent outbreak of Parvovirus in Casino, unreported on The Disease Watchdog,  was close, but didn’t rouse too much local concern.  One month later a 10 week-old puppy, recently rehomed to Ocean Shores from The Channon, came down with gastro symptoms. Within 5 days he was dead, despite veterinary support.

His social sphere consisted of 4 other young dogs:  one presented in such dire condition, he was immediately euthanased;  two others, both a few months older, were similarly unwell and hospitalised on IV fluids, but their prognosis is poor.  Another milder case is being managed as an outpatient. None of the puppies were fully vaccinated.

17/5/10 -  The 2 hospitalised cases made it through the weekend, but are still seriously unwell, and prognosis is guarded.  The puppy from the Channon was an only child, with minimal social contact, so may not be the source. The other puppy, euthansed on presentation, came from a litter in the Tweed area and may be the originator.

24/5/10 -  The cluster seems to have been contained for now. Total: 5;  the 2 youngest died; 2 survived with basic veterinary support; 1 survived with home care alone. As Parvo can persist in the environment for long periods, vets will need to be vigilant for at least another few months.

12/6/10 -  2 more cases diagnosed. One had contact with the environment of one of the original 3 survivors, the other lived in Ocean Shores but it’s uncertain where it contracted the disease. Both these dogs survived with hospital support.

29/6/10 – One more case diagnosed. This one had no direct contact with any infected dogs, but was handled by a human who visited the house of a dog that survived the original outbreak. The disease was transmitted by human hands, touching a surface contaminaed with virus 2 months ealier!

Until we get some hot, dry weather, the outbreak will continue to smoulder, as the virus will persist in the environment, on the ground, floors, in soil, and on shoes.

Follow up post: Parvo Transmission by Human Hand

The Virus

Canine Parvovirus, CPV2, suddenly appeared on viral centre-stage in 1978.  Mutation of only a few genes allowed the virus to jump the species barrier from feline, mink, or other wild carnivore. Within 2 years it had spread around the globe, killing millions of dogs.

Shed in massive quantities in the faeces of infected dogs, the virus is robust, surviving extreme temperatures, and can live for up to 2 years in moist soil.  It’s not bothered by most houshold and medical disinfectants including alcohol and iodine; desiccation and bleach are it’s main enemy.  With a low infective dose and environmental persistence, Parvo continues to reappear in sudden outbreaks, despite availability of a highly effective vaccination.

Pups and young dogs are most susceptible, but adults can also be affected.  Immunisation protocols recommended for puppies, at 8, 12 and 16 weeks, are designed stimulate immunity as maternal protection, conferred via placenta and milk,  wanes. Annual boosters have been recommended throughout adulthood, but immune response to vaccination is strong and this frequency is under negotiation.  Speak with your regular vet about this.

Disease outbreaks and treatment

The tendency for dogs to indiscriminately vacuum-up rotten things makes tummy upsets common. Most pet owners and vets aren’t too alarmed if a dog suffers a bit of gastro, with vomiting, diarrhoea, and loss of interest in play and food.  Tragically, in it’s early stages, Parvo may be indistinguishable from milder, non-contagious, gastro upsets, and it’s not unusual for an outbreak to be triggered by a single crook dog.

Unlike humans, who hygienically flush their Hep A-laden poo down a toilet, a Parvo-infected dog may stroll the paths, beaches and parks,  scattering virus like confetti, near and far.  If just 1 or 2 other unvaccinated dogs lick faecal residue, contamination of the suburb or town can amplify and ignite an epidemic.

Within a week or two the local vet hospital is cancelling all routine procedures, and turning people away.  The isolation ward overflows, spilling Parvo cases into the regular hospital wards, and the clinic starts to look like a doggy version of a scene from M.A.S.H.

Without veterinary attention mortality is about 90%.  If treated, however, the odds of survival are good enough for most dog owners give supportive therapy a go.  Success rates range from about 50%, for inexpensive supportive therapy alone (IV fluids, electrolytes, antibiotics, etc),  to above 80% if owners are willing to invest.

Expensive but potentially life-saving are close monitoring of electrolyte and fluid balance, and  transfusions of fresh serum, preferably collected from an immunised dog.   And for a freakish-sounding technological leap into the future: Experimental use of recombinant feline interferon omega (rFeIFN-ω), created by using a baculovirus to insert a feline gene into silkworm larvae, has been proven to be highly effective, but is unlikley to be in clinical use any time soon.

Patients may take 7 to 10 days before they choose life or move-on to their next encarnation.

The Incidence

279 cases have been reported, nationwide, this year to date. This figure will understate true incidence, as notification is voluntary.

Geographic distribution reveals clustering around metropolitan and rural centres, associated with canine population density and lower vaccination rates.  In NSW, larger outbreaks were Narrabri, 22 cases; Moree, 15; St Mary’s, in western Sydney, 40; and Dubbo, 12.  These epidemics may be a cluster at one site, (eg puppyfarm, greyhound facility etc), or a more dispersed, community-wide event.

Most cases occurred in isolation, or clusters of 2-3, rather than epidemics.  Solitary cases may be recrudescence of a latent environmental reservoir,  nascent epidemic, and cases diagnosed and quarantined early,  often after recent transportation of an infected dog between breeder, kennel,  holiday destination and home.

Local occurence, on the Northern Rivers: there were recent anectodal reports of an outbreak at Casino, and a solitary case at Pottsville. Local vets I have spoken to haven’t seen a confirmed case in Mullumbimby, Ballina, Byron or Ocean Shores, for the last 5 years.

Copyright Disease WatchDog and Virbac 2010

Cases of canine parvovirus, SE Australia,  Janurary to May 12th, 2010

Why do vets always bang-on about immunising?

For vaccination sceptics, who believe vets are conflicted by commercial self-interest and talk of epidemics is just drumming-up business, please understand: we would make heaps more money by leaving dogs unvaccinated and waiting for epidemics. We don’t do this for several reasons, relating to quality-of-life, both ours and your pets:

  • Managing a clinic, full of patients squirting highly contagious diarrhoea, with the quarrantine obsessions of foot baths, gloves, aprons and hand sprays, and the constant fear of infecting other hospital patients, is a major headache we would prefer to live without.
  • Dogs with Parvo suffer miserably, for many days, and may die, making them saddening cases to tend, even for the most calous and businesslike of vets.
  • High mortality rate and lack of miracle cure makes Parvo’s one of the less rewarding diseases to treat. Prognosis, time-course, and cost of treatment are highly variable and difficult to predict, and informing owners of pet death, after considerable investment, is workplace stress most vets dread.
  • Preventative vaccination is the only real solution. Losing a dog to Parvo is so much more costly to the pet owner, both finacially and emotionally, than the very rare hazards of vaccination.

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RECOMMENDATION

  • Ensure your puppy gets their complete puppy series, on time, and at least a one annual vaccination before you even start to think about relaxing, or stretch out vaccination intervals.
  • During outbreaks: ensure vaccinations are up to date; boosters aren’t protective for about 2 weeks. Felines are safe, but canines and ferrets should avoid any areas where large numbers of dogs congregate.  I have not yet seen a case contracted on a beach, but there is no reason why it wouldn’t be possible.  Alert hospital staff if you’re planning to arrive with a suspected case, so we can lay the newspaper red carpet. Make sure the mobile vet removes his shoes before he enters the house.
  • How you cope with clinical risks will determine your response to this information. Putting it in perspective: if, say, 2000 dogs died of Parvo each year, and there are 3.6 million dogs in Australia, then the current annual chance of losing your dog to this disease is approximately a 0.05%.   If we all stop vaccinating, however, that 2000 could easily blow out to 100,000.  For more information on the impact of falling vaccination rates on the whole community, pet and human, see Herd Immunity, Whooping and Kennel coughs
  • For more information on the many and varied causes of gastro problems, and ways to guage their severity see Tummy Trouble, What to do?

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One Response to “Parvo Outbreak, Ocean Shores, NSW”

  1. Toni says:

    Thanks for this information. I live on the mid north coast and have found it really useful. It was what I needed to find out whether or not the triennial booster was suitable for my dog. I think I will go with the annual booster.

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