Outbreak of Drug-Resistant Shigellosis Hits Toronto’s Underhoused Community. Shigella bacteria in an illustration made available by the Centers for Disease Control and Prevention. (CDC)
Toronto is grappling with an outbreak of Shigellosis, a highly contagious and drug-resistant bacterial illness, that has primarily affected the city's underhoused population. On Wednesday, Toronto Public Health (TPH) confirmed the outbreak, with nine confirmed cases among individuals who are either experiencing homelessness or at risk.
Dr. Howard Shapiro, Associate Medical Officer of Health, noted that while the total number of Shigellosis cases in Toronto is not alarming—101 cases have been reported in 2024 so far, just slightly fewer than the 119 cases recorded for all of 2023—this outbreak is notable for its higher-than-usual incidence within the homeless community. TPH usually sees only one or two cases in this vulnerable population at any given time.
The first known case of the outbreak began showing symptoms in early September, though it's unclear where the affected individuals were residing. Despite the outbreak's focus in shelters and encampments, Dr. Shapiro reassured the public that the overall risk to the wider population remains low.
To combat the spread, TPH has been working closely with Toronto Shelter & Support Services, healthcare providers, and social service agencies. They are reinforcing infection prevention measures in shelters, such as the use of personal protective equipment, enhanced cleaning protocols, and regular symptom monitoring.
Shigellosis is caused by the Shigella bacterium, which spreads through fecal matter, often through contaminated food or water, or by direct contact with an infected person. The disease is particularly concerning for those in crowded environments like shelters, where sharing facilities and lack of sanitation make it easy for the infection to spread. Dr. Stephen Hwang, a researcher with the MAP Centre for Urban Health Solutions, highlighted how easily Shigella can be transmitted, noting that just 10 bacteria are enough to cause an infection.
For people living in shelters or encampments, the bacteria can spread quickly, with one infected person potentially passing it on to dozens of others. The absence of proper hygiene and sanitation in these settings makes it difficult to contain the illness. Dr. Hwang emphasized that this makes the homeless community especially vulnerable, as those with stable housing can more easily rest and recover, while those without may lack the resources to heal.
The symptoms of Shigellosis—diarrhea, fever, nausea, and abdominal cramps—typically resolve within a week, but severe cases can require hospitalization. In some instances, antibiotics may be needed, but certain strains of Shigella have developed resistance to common antibiotics, complicating treatment.
To help prevent further spread, health officials urge people to practice thorough handwashing, avoid sharing food or personal items with those who have diarrhea, and refrain from public swimming until fully recovered. For those with Shigellosis, it is also recommended to avoid sexual contact until at least two weeks after symptoms end.
The ongoing investigation aims to better understand how the outbreak began and how best to prevent its spread. With the holidays approaching, health authorities are closely monitoring the situation to protect both the underhoused community and the general public.
