Lepto dog losses mounting in the north

The Leptospira australis vaccine, specifically used to protect against the disease in northern Australia, was recalled in December 2022, reportedly because a handful of dogs in Australia had a severe reaction to it, and it's not known if or when it will become available again.

There is only one company in Australia that makes the vaccine, Treidlia Biovet, based in Sydney, and they have declined to respond to North Queensland Register's questions.

Dog owners and veterinary professionals alike are concerned by a rise in leptospirosis cases seen during the past wet season, and are reverting to prevention advice from yesteryear to try and contain cases until a vaccine is again in circulation.

Graham Lauridsen from Tropical Vets at Tully said there were different strains of Leptospira bacteria and it was unfortunate that the vaccine for the strain in southern parts of Australia, which is still available, wasn't effective for the strain that occurs in northern Australia.

He helped prove the vaccine's effectiveness in the 1990s, working with the World Health Organisation and Queensland Health on collecting samples from sick dogs and undertaking a lot of trial work, and said the vaccine that had resulted had been used very successfully for a long period of time.

"It was as good a vaccine as you can get," he said, adding that about 12 months ago, it was just not available any more.

"In our practices it was standard practice to give puppies both parvo and lepto injections when they came in, because it's always there in the environment.

"Now we've had to go back to the 1990s."

The only way to prevent dogs from contracting the disease then, and now, was to advise people to keep dogs out of creeks and drains and floodwaters.

"But of course, dogs love playing in the water," Dr Lauridsen said.

Small mammals such as rodents are the most common carriers and shed the bacteria in their urine, which can contaminate water, soil, mud, bedding, and food.

Dogs are usually infected by ingesting stagnant water that has been contaminated with rat or mouse urine.

"It's worse in the wet season," Dr Lauridsen said.

"We see it from about Sarina all the way up the Cape and into the Northern Territory.

"The organism can live in the water for some length of time, and any working dogs that are out and about, especially on cane and banana farms, are at risk."

The Tully-based vet said it was common to see the disease mostly in puppies and dogs up to about five years.

"Once the vaccine wasn't available, all of a sudden we started seeing more cases," he said.

Of their six clinics, Dr Lauridsen said they weren't seeing as many cases at Townsville and Ayr, but at Ingham, Innisfail, Tully and Atherton they were getting one or two cases a week whereas they used to have one or two cases a season.

Once a dog contracts the disease, the prognosis is poor, with different sources quoting mortality rates of between 70 and 90 per cent.

A prolonged hospitalisation stay of 7-14 days is also common.

"It's expensive to treat infected dogs, between $1800 to $2000, and sometimes they don't live," Dr Lauridsen said.

He expected that without a vaccine, leptospirosis in the tropics would become more of a problem, partly because more people were moving to acreage for a rural lifestyle and partly because more people were getting dogs as pets.

He said there was talk of a new vaccine being developed, but the process of getting it registered and approved could take a minimum of two years.

"I don't know if it's being worked on or where it might be up to," he said.

The manufacturers, Treidlia Biovet were contacted to discuss the issue but said no-one was available for comment.

Leptospirosis can cause kidney failure and liver failure, and occasionally severe lung disease and bleeding disorders in animals.

Signs of leptospirosis may include fever, lethargy, sore muscles and a reluctance to move, shivering, increased drinking and urination, and jaundice or yellowing of the gums and whites of the eyes.

People with dogs with these symptoms should take them to a veterinarian immediately.

Dr Lauridsen said that being a zoonotic disease, people could also catch leptospirosis, known as Weil's disease, saying it was common in sugarcane regions when cane was cut by hand and was the primary reason why farmers started burning their cane prior to harvest.

According to Queensland Health, it's an occupational hazard for many people who work outdoors or with animals including farmers, veterinarians, meat workers, dairy farmers, and military personnel.

"It is a recreational hazard for campers, or those who participate in outdoor sports in contaminated areas, and has been associated with swimming, wading, and white water rafting," a fact sheet states.

"Humans become infected through contact with water, food, or soil containing urine from these infected animals.

"This may happen by swallowing contaminated food or water or through skin contact, especially with mucosal surfaces such as the eyes or nose, or with broken skin."

People who develop the severe form of leptospirosis, Weil's disease, find symptoms usually come on suddenly one to three days after milder, flu-like symptoms have passed