Dysentery outbreak in Oregon leaves at least 40 sickened: What to know
FILE - Shigella dysenteriae, bacteria which causes bacillary dysentery or shigellosis, seen under a microscope. (Photo by DeAgostini/Getty Images)
Two dozen new cases of Shigella, which can cause dysentery, have been reported in Oregon since the start of the new year, according to health officials.
Cases have been on the rise since 2012 and the illness has spread to the Portland Metro areas. Health officials say the increase "is concerning."
What is Shigella?
Dig deeper:
Shigella bacteria cause shigellosis, which is an illness that impacts the intestines, according to the Mayo Clinic.
Shigella can cause a range of systems, including, but not exclusively, dysentery.
Other symptoms can also include:
- Fever
- Stomach pain
- Diarrhea
Where did the outbreak begin?
The backstory:
Shigella cases have been rising in Multnomah County, Oregon, since 2012, according to a county official.
"High case counts throughout 2024 reflected two separate outbreaks of different strains of Shigella. The cases that we are seeing in 2025 are the result of transmission of a strain of Shigella sonnei strain that was introduced into Oregon in the spring of 2024," the spokesperson told FOX TV Stations.
The disease eventually spread to the Portland Metro area in the summer of 2024 and has spread within and between housed and unhoused populations in the region since then, they added.
How many cases are in Oregon?
By the numbers:
There are 197 total cases nationally with this particular strain.
Sixty-one percent of the cases have been in Multnomah County.
There are at least 14 distinct subclusters, which means that there are several pathways of transmission within different groups of people.
In 2024, there were 158 confirmed cases in Multnomah County.
What we know:
As of January, 40 new cases were reported.
What we don't know:
Data for February is not finalized.
However, preliminary data shows that there are six confirmed cases and "three cases without culture-confirmed illness developed illness and were reported in February."
"Even though the data are not yet finalized, the number of cases in February 2025 appears to represent a decline from the number of cases in January," the spokesperson said.
What caused the outbreak in Multnomah?
Dig deeper:
Health officials said there are several ways the Shigella bacteria spread throughout the county.
- Some cases are contracted through international travel to lower-resource countries (less than 20%).
- Among cases without international travel, fecal-oral spread through intimate (including sexual) contact may account for between half and more than two-thirds of all cases.
- About one-third to half of cases in the past year have been in people experiencing either homelessness or housing instability.
- We have also identified spread among housed and unhoused social groups who use drugs.
The cases of Shigella are being spread between people rather than from one outbreak source, such as a restaurant, the spokesperson explained.
How to stop the spread
Since the most common source of transmission for Shigella is human to human among several subgroups, "there is no single, easy answer to stop all illness from spreading," according to the spokesperson.
What's next:
The Multnomah County Health Department provides educational resources to teach people about avoiding the transmission of any disease.
"They counsel people to avoid preparing food, limit sexual contact, and stay out of pools and other communal water bodies for at least two weeks after symptoms stop. People who work in food, childcare or healthcare facilities are restricted from work until they test negative," the spokesperson said.
For unhoused people, the department can provide additional support through short-term housing, which health officials explained is the "best intervention for reducing spread."
Other prevention tips include:
- Frequent handwashing
- Throw away soiled diapers in a covered, lined garbage bin
- Disinfect diaper-changing areas right after use
- Avoid ingesting water from ponds, lakes or untreated pools
- Avoid sexual contact with anyone who has been suffering from diarrhea or recently recovered
Who is at risk?
Most people are able to recover from dysentery within a few days. However, if it goes untreated for a prolonged period, it can be fatal, according to the Cleveland Clinic.
The people who are most at risk of suffering from serious complications of dysentery include:
- Young children
- People over 50
- Dehydrated or malnourished people
The Source: Information for this report was gathered from an email received from the Multnomah County press office on March 6, 2025, the Mayo Clinic and the Cleveland Clinic. This story was reported from Los Angeles.