A veterinary science student’s harrowing experience with leptospirosis, a potentially deadly bacterial disease, has highlighted new research indicating its growing prevalence across Australia. Sylvia Morris, then in her second year of studies in Townsville, fell seriously ill with what initially seemed like a common cold. However, her condition rapidly deteriorated, progressing to pneumonia before she was diagnosed with leptospirosis.
This bacterial infection, transmitted through the urine and faeces of infected animals and contaminated soil, carries significant health risks, including severe illness and even death. Humans can contract leptospirosis through various means, such as direct contact with animals, engaging in gardening, swimming in freshwater, or even wading through floodwaters.
A Rising Tide of Infection
New research has sounded an alarm, revealing that this once-rare disease is becoming more common throughout Australia. Rural and agricultural communities are identified as particularly vulnerable, with cases often going undetected due to a lack of comprehensive surveillance.
Dr. Morris recounted the difficulty in pinpointing the exact source of her infection, given her work and the presence of multiple pets at home. “But it can be just a muddy puddle or having a cut that becomes an issue,” she explained, underscoring the insidious nature of the disease. Her own recovery involved a two-week course of antibiotics and a challenging six-month battle with extreme fatigue. “My liver was pretty unhappy at the time and I had pneumonia which took a little while to bounce back from,” she shared. Her university, James Cook, found no evidence of an outbreak at the time, and no other students were infected.
Global Threat, Local Impact
Globally, leptospirosis is recognised as a leading cause of zoonotic disease-related illness, according to the US Centre for Disease Control. It’s estimated that approximately one million cases occur worldwide each year, resulting in nearly 60,000 fatalities.
The recent research, spearheaded by the University of New England, advocates for increased public testing for leptospirosis. It also calls for greater vigilance beyond Australia’s tropical north and urgent further investigation into the disease. Outbreaks globally are reportedly becoming more frequent and severe, with new subtypes of the Leptospira bacteria continually emerging.
Associate Professor Jacqueline Epps, a rural General Practitioner affiliated with the University of New England, noted that the disease is migrating into regions previously untouched by it. “We have seen over time more outbreaks heading further south, particularly in New South Wales,” Dr. Epps stated. The research links the increasing incidence of leptospirosis to more frequent storms and flooding, exacerbated by climate change, leaving Australia’s rural communities potentially unprepared.
While leptospirosis is a notifiable disease, its human symptoms often mimic those of influenza or COVID-19, leading to frequent misdiagnoses or cases going entirely undiagnosed. Early and precise diagnosis is paramount to avert severe complications, such as organ failure and meningitis. Although dairy farmers commonly vaccinate their cattle against the disease, there is no vaccine available for humans, and treatment hinges on the prompt administration of specific antibiotics.
Rod Martin, president of the Australian College of Rural and Remote Medicine, observed that cases are spreading from coastal areas into central Queensland, territories where the disease was previously unheard of. “We may need to educate doctors in emergency departments and patients in rural areas as the weather keeps heading south and the tropics spread beyond Rockhampton,” Dr. Martin advised.
The Rodent Connection: Superspreaders in Our Midst
One of the most significant recorded leptospirosis outbreaks occurred on a berry farm in New South Wales in 2018, affecting up to 84 workers. The contamination was traced back to rats urinating on crops. Dr. Epps highlighted a concerning trend: “The most common form of transmission is from mice and rats and that’s new.” She added that the bacteria can persist in the environment for months, complicating efforts to identify infections in livestock. Dr. Epps urged for immediate investment in diagnostic capabilities, noting that Australia has not conducted human prevalence studies since 2011. She stressed the importance of public awareness, advising people to avoid floodwaters, protect cuts, minimise exposure to rodents, and adopt precautions in high-risk occupations.
Agriculture on High Alert
Alison Colvin, a co-author of the report and a member of UNE’s Animal Science Discipline, emphasised the escalating threat to agricultural communities. “A large range of mammals can carry the disease, and it can lead to some animals continuing to be carriers and shedders for their lifetime,” Dr. Colvin explained. She pointed to the dairy industry as a prime example, where the bacteria can trigger devastating abortion storms in herds. Dr. Colvin cited a New Zealand report that estimated the annual cost to its cattle, sheep, and deer industries at US$8 million, with an additional US$6 million spent on preventative cattle vaccinations. The findings of this critical research were published in the Australian and New Zealand Journal of Public Health.
