After floods and mouse plagues, GPs are advised to consider leptospirosis when they see patients with fever, severe headaches, muscle aches, chills, vomiting and red eyes, experts say.
The key to clarifying a diagnosis of leptospirosis versus multiple differential diagnoses, such as influenza, lies in a history of contact with suspicious animals.
Professor Ben Adler, a 40-year-old microbiologist with experience with the Victorian Infection and Immunity Network and the Department of Microbiology at Monash University, told InSight + that the initial symptoms of leptospirosis were largely not specific “.
“But if there is no history of contact with [relevant] animals, it will not be lepto, ”he said.
Leptospirosis is caused by the bacterium Leptospira, of which there are many strains. It is found in the urine of mice, rats, cattle, pigs and dogs. Initial symptoms appear 5 to 14 days after infection and last from a few days to 3 weeks. If left untreated, depending on the strain, serious illness can lead to pulmonary hemorrhage, acute kidney failure, and acute liver failure, meningitis, and even death.
Humans can catch Leptospira through contaminated water, mud and soil, through cuts and abrasions and mucous membranes of the nose, mouth and eyes. Human-to-human transmission is rare.
With mouse pests in the states of Eastern and Western Australia, as well as flood events in Queensland and New South Wales this year, leptospirosis is on the rise.
A spokesman for the federal Department of Health said human cases of the notifiable disease had increased last year. He said there were 201 reports of leptospirosis in the 12 months to April 17.
“This is above the 5-year average for the same period, which is 129 cases,” he told The Medical Republic. “Most cases in the last year have occurred in Queensland and NSW.”
Fortunately for Australians, the most nasty strains of Leptospira are not endemic here, according to Professor Adler.
“We have a limited range of serovars here,” he said. “And they’re not the ones who cause the really serious disease. In other countries it’s a different story, and leptospirosis is largely a disease of inequality.”
The other good news for Australians is that while there is no human vaccine, treatment with standard antibiotics such as doxycycline (100 mg twice a day), amoxicillin and erythromycin is effective because resistance is non-existent.
“In humans, lepto is a dead end infection,” said Professor Adler.
“There is no human-to-human spread, so a human gets infected and that’s the end of it. Even if resistant leptos were to emerge, they wouldn’t spread to anyone else.”
The key is early treatment, with recommended antibiotics being started even before the diagnosis is confirmed by pathological testing and continued for at least 7 days.
As the number of floods increases, at least in some states, what role will climate change play in the incidence of leptospirosis outbreaks?
“There is good evidence that he has already done so,” Professor Adler told InSight +.
“There have been outbreaks of extreme weather events around the world, especially when there are sudden floods.
“The last big cyclone in Fiji, there were big floods and what followed was an increase in lepto cases. The same goes for India, Sri Lanka, Indonesia, Thailand and the Philippines.”
Some recreational activities may increase the risk of infection, according to the Federal Department of Health:
“People can also get sick after swimming, wading, washing or taking part in water sports on polluted waterways. Going through the woods and camping near areas of polluted rivers and swamps is also a risk. Leptospira bacteria can survive in in soil and fresh water for many weeks, extreme weather events can resurface these bacteria, especially in flood waters. “
Resources for leptospirosis:
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