Already fighting a global pandemic, doctors in Vancouver are now facing an outbreak of dysentery in the Downtown Eastside, the poorest neighbourhood in the city.
The disease, called shigellosis, is caused by a highly contagious bacterium known as shigella, which causes symptoms of dysentery: profuse mucous or even bloody diarrhea, low-grade fevers and abdominal cramps. Shigellosis usually occurs in developing countries where sanitation is poor, making an outbreak in urban Vancouver, where I work as a resident emergency doctor, highly unusual.
“I don’t ever remember there being a previous outbreak… in the Downtown Eastside,” says Dr. Daniel Kalla, head of the emergency department at St. Paul’s Hospital in downtown Vancouver.
The local medical health officer for Vancouver Coastal Health was contacted for an interview but was unavailable.
There are four subtypes of shigella, with shigella flexneri being identified as the species behind Vancouver’s current outbreak. The bacteria are usually spread via contaminated hands or sexual contact, and patients can become infected from exposure to only 10 organisms, compared with 1,000 to 100,000 required to transmit salmonella. Patients can remain contagious for up to four weeks, long after initial symptoms resolve.
“If someone has shigella and doesn’t clean their hands well enough, even a small amount could lead to transmission,” says Dr. Victor Leung, medical director for Infection Prevention and Control at St. Paul’s Hospital.
“And even cases that resolve may still be transmitting,” he says, especially when there are shared washrooms.
Leung says he first heard about cases in downtown Vancouver on Feb. 20. “We got a call from the clinical teaching unit saying, ‘We’re noticing some cases of infectious (diarrhea) in patients who are homeless... and it looks like it’s shigella,’” he says.
Over the next few days, as new cases were confirmed, there seemed to be an emerging pattern of patients being homeless or living in single-room occupancies, a form of low-income housing.
Beyond that, it was difficult to identify a specific source of the outbreak.
“Each individual didn’t seem to have a common shelter or SRO and their food situations were different. And... one of the patients was recently diagnosed with COVID and was at a COVID isolation hotel,” says Leung, adding that the timeline of the patient’s symptom onset suggests the infection could have been acquired there.
Approximately 20 cases of shigellosis have been reported to the BC Centre for Disease Control, according to Dr. Linda Hoang, a medical microbiologist for the organization with a focus on public health. The rate of new cases seemed to slow down this week, says Hoang.
But because most cases have mild symptoms, says Leung, there may be more people unknowingly infected if patients aren’t seeking medical care. The pandemic may exacerbate this, because of restrictions limiting access to clinics as well as fear of possible COVID-19 exposure.
“COVID has used a lot of resources in the whole health system,” says Leung. “People are afraid to access care.”
Treatment and followup
Most mild infections don’t need antibiotics, and overusing antibiotics for diarrhea can increase bacterial resistance. But Leung notes that during an outbreak, pre-emptive treatment may help control spread by decreasing the duration of bacterial shedding, which transmits the infection.
The current strain of shigella flexneri is resistant to the preferred treatment, the antibiotic ciprofloxacin, as well as others such as ampicillin and trimethoprim/sulfamethoxazole. Vancouver Coastal Health is advising physicians to treat suspected patients with azithromycin or cefixime.
In the emergency room, ensuring that patients complete treatment and followup is a major consideration for those being discharged home, especially when “home” doesn’t have a fixed address.
“Azithromycin is a three-day course, so we give patients their first dose in hospital and then we give them two tablets to go so they’re more likely to have it and take it,” says Kalla. As for testing, he notes that “Compliance wouldn’t be good if we sent stool [testing] kits to go... [so] I like to keep patients until they produce a stool sample for culture.”
When it’s time for discharge, Kalla says, all patients are referred to social workers who notify shelters so they can be aware and make preparations for them.
Deciding whom to admit to hospital can be a difficult question, he says, but admission is usually reserved for high-risk patients who are very frail or significantly dehydrated.
Leung says this outbreak is the result of years of marginalization occurring in the Downtown Eastside.
“You have an increasing number of evictions due to rent increases, forcing a lot of people into homelessness in parks like Strathcona or Oppenheimer, where you have no hygiene measures.… You expect to see dysentery in places in the world that are underdeveloped. It’s less common in developed countries except in crowded places with poor living conditions.”
And Leung is not surprised that one of the cases may have been transmitted at a COVID-19 isolation hotel.
“The people going to a COVID isolation hotel are those who have no ability to have supported isolation — people living in SROs with mental illness exacerbated by substance use disorders,” he says.
The most effective method of prevention is thorough and frequent hand washing with soap and water, says Leung.
“But when you have people who are homeless and marginalized, how do you promote adherence? This is a disease of destitution.”