Should Canada's rattiest cities worry about leptospirosis? Symptoms to know after New York reports rising cases

While the disease is rare in Canada, here are the symptoms and risks you should know about.

Karla Renic
·Lifestyle Editor
·4 min read
leptospirosis canada cases new york rat problem. Leptospirosis is rare in Canada, but New York City is reporting rising cases. Here's what you need to know about symptoms and risks of the disease. (Image via Canva)
Leptospirosis is rare in Canada, but New York City is reporting rising cases. Here's what you need to know about symptoms and risks of the disease. (Image via Canva)

New York City is facing "a real problem" with rats. The rodents have caused a public health concern due to rising cases of leptospirosis, a bacterial illness linked to rat urine. According to an expert, the disease is more common in animals and very rare in humans in Canada, but cases do occasionally pop up.

There were 24 cases of leptospirosis were reported in New York City last year, a sizeable increase compared to its average of three annual cases over the last decade. New York City Mayor Eric Adams is now leading initiatives to curb the rat population in the city by eliminating food sources like plastic garbage bags from city streets, People reported.

In Canada, a 76-year-old Quebec man was hospitalized this past winter with a severe fever, a headache and abdominal pain. A Canadian Medical Association Journal report said that 18 days before admission, the patient had "found a rat in his toilet bowl and it had bitten him on two fingers as he tried to remove it." The Montrealer ended up with sepsis, a severe response to an infection, and subsequent tests found leptospirosis. He was treated with antibiotics and recovered.

Montreal isn't even on Orkin's list of the top 25 "rattiest" cities in Canada. The top 10 list includes:

  1. Toronto

  2. Vancouver

  3. Burnaby

  4. Kelowna

  5. Mississauga

  6. Richmond

  7. Victoria

  8. Ottawa

  9. Scarborough

  10. Moncton

But what exactly does leptospirosis look like in humans? And should Canadians in the "rattiest" cities worry about the U.S. cases? Here's what you need to know.

What is leptospirosis?

Leptospira bacteria, computer illustration. Leptospira is one of a group of helical bacteria known as spirochaetes, which contains many serious pathogens. Leptospira cells have many small coils and an overall C- or S-shaped form. One or both ends of Leptospira are usually hooked. The parasitic species L. icterohaemorrhagiae is the main causative agent of leptospirosis (Weils disease), but many other Leptospira species cause similar symptoms, attacking the liver (jaundice) or the meninges of the brain (meningitis). Infection occurs through contact with rodents, dogs and farm animals, so farmers, sewage workers and veterinary surgeons are particularly susceptible. Treatment is with penicillin.
Leptospira is a bacteria that causes leptospirosis, with infection often happening through contact with infected rodents, dogs and farm animals. (Image via Getty)

Leptospirosis is a disease caused by a bacteria called Leptospira. "The disease is spread through contact with water, soil or food contaminated by urine from infected animals," according to Health Canada.

Dr. Isaac Bogoch, a Canadian infectious diseases specialist, said leptospirosis is rare in Canada and is not a reportable disease; "it's not well tracked."

You can get infected through accidental ingestion or exposure through the skin, Bogoch said in an interview with Yahoo Canada. For example, you can become infected "if (infected animals) urinate in a stream or a river, and you're swimming in that stream or river, and water splashes into your eye or into your mouth, or into a cut on your skin."

What are the symptoms of leptospirosis?

While very rare in humans, leptospirosis can cause severe problems. Key symptoms include:

  • Fever and flu-like symptoms

  • Headache and muscle aches

Leptospirosis can also lead to more severe illnesses, including multi-organ involvement of the kidney and liver, Bogoch said. These symptoms describe Weil's disease and can include:

  • Jaundice (yellowing of the skin and eyes in severe cases)

  • Renal failure (kidney damage)

  • Hemorrhagic rash (bleeding under the skin)

  • Meningitis-like symptoms

Bogoch added that the disease might affect people differently, with some having mild or no symptoms and others having severe forms of the infection. It can also lead to complications like sepsis.

Bogoch emphasized that testing for leptospirosis takes longer than most infections. "If you strongly suspect someone has leptospirosis, you wouldn't necessarily wait for that test to come back," he claimed. Treatment with antibiotics usually starts based on symptoms and suspected exposure.

Do Canadians need to worry about leptospirosis?

Blood sample tube with laboratory requisition form for Leptospirosis test. Bogoch claimed that Canadians should not be overly concerned about leptospirosis
The Canadian expert claimed Canadians should not be overly concerned about leptospirosis. (Getty)

Leptospirosis is more prevalent in tropical and subtropical regions, so those who travel to those areas are at a greater risk than the general Canadian population.

According to Health Canada, specific risk factors include:

  • Travel to high-risk areas, like tropical regions

  • Participating in freshwater activities such as rafting, canoeing, swimming

  • Occupational exposure, for example, farm employees

Despite some Canadian cities being labelled as the country's "rattiest," Bogoch claimed that Canadians should not be overly concerned about leptospirosis. "The risk of contracting leptospirosis in Canada is extraordinarily small," he reassured, even with the slight increase in cases in places like New York City.

Bogoch recommended that Canadians seek medical advice before they travel to mitigate risks not only from leptospirosis but also from other infectious diseases, especially if they're traveling to the tropics.

So, while leptospirosis is becoming an issue in areas like New York City, the risk in Canada is minimal. "Maybe the relative risk is a little bit higher now. But the absolute risk is extraordinarily small," Bogoch said.

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