LEPTOSPIROSIS SPIKE KILLING DOGS IN FLOOD-RAVAGED NORTHERN QUEENSLAND

At least six dogs in North Queensland have died from leptospirosis, a bacterial disease, in recent days, following a sharp rise in cases linked to recent flooding.

Leptospirosis, caused by the Leptospira bacteria, is a potentially fatal infection that is primarily found in northern Australia. It spreads through water or soil contaminated by the urine of infected animals such as rats, cattle, pigs, and dogs.

The disease can lead to kidney and liver failure in both humans and animals, and it can be fatal, even with treatment.

Graham Lauridsen, director of Tropical Vets, which operates clinics across north Queensland, explained that the recent floods have contributed to a significant surge in dog infections.

“In the last two days, it’s gotten really bad,” Lauridsen said.

“Normally, during a wet season, we see one or two cases a week during the worst periods. But right now, Innisfail has seen three or four cases, Ingham over 10, and Tully has had a couple recently. They’re now seeing new cases every day.”

Symptoms ‘unfortunately’ vague

Dr. Lauridsen confirmed that at least six dogs brought to his clinics in the past few days had succumbed to leptospirosis.

“Once the dogs are severely affected, about eight out of ten won’t survive,” he explained.

He also noted that while early treatment improves a dog’s chances of survival, the symptoms of the disease are often “unfortunately vague,” making it difficult to diagnose in the early stages.

“It’s generally just a sick dog, maybe off its food, a little bit of vomiting, sometimes diarrhoea, sometimes just lethargic, and then they’ll go jaundiced,” he said.

Vaccine available for dogs

Dogs can be protected against leptospirosis with two doses of a vaccine but supplies have been disrupted in recent years.

Australia experienced a nationwide shortage of leptospirosis vaccines from late 2022.

Then in late 2023, a manufacturer voluntarily recalled the Treidlia Auslepto vaccine following the death of a dog and several others suffering adverse reactions.

A new vaccine — Nobivac Lepto 2 manufactured by MSD Animal Health — became available in late 2024 which Dr Lauridsen described as “very good and effective”.

“We’ve had it since October. We’ve vaccinated literally thousands of dogs but obviously there’s still plenty out there that haven’t been vaccinated as yet,” he said.

No increase in human cases yet

Leptospirosis can also affect humans, typically through contact with infected animals or contaminated water or soil. However, Queensland Health has reported no noticeable increase in human cases of the disease in North Queensland following the recent flooding.

The Townsville Public Health Unit, which oversees the flood-impacted Ingham area, has recorded just one case so far this year, while the Cairns Public Health Unit has reported four cases. Between 2019 and 2023, Queensland averaged 99 cases of leptospirosis annually.

A 2022 journal article estimated that Australia sees around 2,400 severe cases and over 100 deaths from leptospirosis each year.

Unlike dogs, there is no vaccine for humans, but preventative measures such as frequent handwashing, covering wounds with waterproof dressings, and using protective equipment, particularly in high-risk professions like agriculture, can help reduce the risk of infection.