Vets say they're concerned over the growing anti-vaccine lobby among pet owners, and food fads such as raw and grain-free diets for animals are gaining popularity.
British vets Danny Chambers and Zoe Belshaw raised the issue in a recent opinion piece published in New Scientist.
In it, they say alternative therapies for animal diseases have become widespread, including homeopathy, Chinese medicine and even pet psychics offering therapy via Facebook messenger.
Chambers, from Langford Vets at University of Bristol, tells Nine to Noon's Kathryn Ryan it's an interesting development that mirrors what's happening in human medicine.
"One of the best parts of being a vet is obviously treating animals and making them better but equally satisfying is the relationship you have with the owners," he says.
"What we’re discovering now is that there’s quite a few people who believe that vaccines do more harm than good or believe that many pet foods are actually dangerous and they’d rather opt for disproven alternative therapies - for example homeopathy.
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"And they’d rather get advice from Facebook groups from other people who also believe that vets aren’t best placed to advise on animal health, and this group of people does seem to be growing."
He says it's a trend that has a not insignificant, growing number of people ascribing to it.
"For instance, a raw feeders group in the UK - a closed group where they discuss raw feeding - is over 40,000 people.
"I think it's 45,000 people are in a group called 'Canine health, dog vaccinations, what vets don't tell you' and they certainly believe that vets and pharmaceutical companies are profiting out of making your animals sick and they believe that vaccines do more harm than good and that vets promote vaccines and dog food in order to make animals sick so that they then make more profit from them.
"So they’re a small number of owners when you look at the total number, but they’re not an insignificant number and they do seem to be growing, and they’re very ... determined to spread their message."
He says it's a concern because of the potential health effects of not vaccinating.
"It’s just exactly the same as you see in human medicine," he says.
"Measles in Europe has hit a record high, they’re talking about how more than 41,000 people have been infected with measles in the first six months of this year, 37 people have died from it.
"And the main reason for that is people have stopped vaccinating. Two years ago there was only 5000 cases of measles and now there’s 41,000 this year so far.
"Vaccines are a sort of victim of their own success because once a lot of the population is vaccinated and then you don’t see the disease anymore people forget how serious the diseases are and they start to believe that the vaccinations are more dangerous than the disease itself."
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He says the raw feeding trend is also a concern.
"I’ll stress that If you do it properly, and you’re very well informed and you’re very careful it is possible to feed dogs a raw diet and it can be very healthy.
"But, dogs are prone to the same illnesses that humans are and if meat has been slaughtered at an abattoir and then taken to a supermarket and then bought and then fed raw, it could … be contaminated with E coli or salmonella, just exactly the same way as if humans were eating it without cooking it. "
He says some dogs affected will not get sick, but others will and there's also a follow-on risk to humans.
"If the dog is eating raw chicken and then licking the toddlers’ faces or even licking the owners faces … that has a very high chance of infecting humans as well and there are reports of people getting sick from their dogs’ raw food."
While the raw diet may seem natural and healthy for dogs, that's not entirely true either.
"Wolves I guess are the wild type of dog: they don’t eat meat that’s just been through a supermarket, they eat meat that they catch," he says.
"And domestic dogs are very different to wolves. They’ve got different digestive tracts, they’ve been domesticated for around 15,000 years, they’ve been through the agricultural revolution and they’re adapted to eat the diets that we feed them."
New Zealand Veterinary Association chief veterinary officer Helen Beattie says they're aware of anti-vaccination sentiment among some pet owners and a growing interest in raw food diets in Aotearoa too.
"I think the same processes are driving it here as Danny’s speaking of in the UK," she says.
She says the vaccines used in New Zealand are very similar to those used in the UK.
It's important to remember that the people who are not vaccinating their animals are doing so with good motives.
"I think the reason people engage in alternative or different ways of feeding animals or treating them and different therapies and views is all actually born out of the fact that they do really want to do the best for their pet.
"Purely dismissing it is totally unhelpful I think, because they are doing it for the same reasons."
She largely agrees with Danny however, about raw food and alternative diets.
"It can be done in any number of ways and it can be done very well if you want to feed a raw food diet but it does take a whole lot of engagement and knowledge and extracting information from the right people and taking advice and we’d strongly suggest that people engage with their veterinarian around that.
"Possibly a specific person who has knowledge in and around nutrition who can give really robust advice about how to do this well if you’re going to go down that track."
Danny says a healthy diet for pets is similar to gauge as for humans.
"We need a balanced diet with all the vitamins and minerals that you require but you need it in the right amount of energy.
"I’m from a farm and we used to feed our dogs a working dog diet because they’re sheepdogs and they’re working running around for eight, nine, ten hours a day. If you gave exactly the same diet to a pug that never really got walked and was very much a house dog they'd be very obese.
"One of the biggest health problems that we see in dogs in the UK is obesity, about a third of dogs are overweight so I’d probably argue that eating too many calories is probably the biggest health issue for dogs in the UK at the moment.
Helen agrees, and says it’s also about life-stage nutrition.
"What’s good for a puppy isn’t necessarily good for a geriatric - and yes, some of that will be around calories because our geriatric may be spending a lot more time sitting down but we need them lean so they can get up and keep moving."