The County of San Diego has announced 11 new shigella cases associated with an ongoing outbreak, bringing the total to 15 confirmed and three probable among individuals experiencing homelessness.

The continuing investigation shows onset of illness dates between Aug. 16 and Oct. 14. The 18 cases in this outbreak represent 6.8 percent of the 266 total cases reported to date in San Diego County.

The cases are all among individuals experiencing homelessness who resided at multiple locations in central San Diego. No source of the outbreak has currently been identified.

The County is working closely with the City of San Diego to:

  • Identify potential exposure sites.
  • Promote good hygienic precautions among homeless service providers and food providers.
  • Identify additional cases.
  • Connect ill individuals to treatment and housing.

Other steps include:

  • Relocation of currently deployed handwashing stations to areas frequented by homeless individuals and evaluation of need for additional stations.
  • Increased cleaning of portable and fixed public bathrooms.
  • Increased sidewalk sanitization from twice weekly to seven days per week for the time being. Frequency will be continually assessed.
  • Notification by the County Department of Environmental Health and Quality about the outbreak – and precautions – to food facilities in the downtown area, charitable feeding operators, the California Restaurant Association, Downtown San Diego Partnership and Gaslamp Quarter Association.
  • Public health nurses conducting outreach at shelters.
  • Homeless Outreach Teams distributing Shigella information as part of hygiene kits given to persons experiencing homelessness, including an extra 600 the week of Oct. 18.

Shigella is a contagious infection typically spread by contaminated surfaces, food or water, or person-to-person. Those at increased risk include young children (especially those in daycare), people who are experiencing homelessness, travelers to locations with poor sanitation, and men who have sex with men. In 2020, a total of 240 shigellosis cases were reported in San Diego County residents while the 426 cases reported in 2019 was the highest since 1995.

Typical symptoms include diarrhea (sometimes bloody), fever and stomach cramps. While most people will recover fully without antibiotic treatment, some individuals with poor immune systems can develop life-threatening disease and may need further treatment.  People with symptoms that resemble shigella should contact their medical care provider. The provider may order stool testing to help with the diagnosis.

Strategies to avoid getting or spreading shigella include frequent hand washing and not preparing food while ill with diarrhea.

The County of San Diego Health and Human Services Agency is monitoring an outbreak of at least six cases of shigellosis in individuals experiencing homelessness since Sept. 30, 2021.

The cases were found after the individuals were hospitalized. They are expected to recover.

The County has notified the City of San Diego and will work with the city and potential exposure sites and homeless service providers to ensure good hygienic precautions, identify any additional cases and connect ill individuals to treatment and housing.

A health advisory to local providers also has also been issued.

“Shigellosis isn’t usually serious, but in the wrong circumstances it can spread, and we want to ensure this vulnerable population is kept safe,” said Seema Shah, M.D., medical director of HHSA’s Epidemiology and Immunization Services branch.

Shigellosis is a contagious infection typically spread by contaminated surfaces, food or water, or sometimes person-to-person such as men who have sex with men (MSMs). In 2020, the County identified 243 total cases; to date in 2021, the County has identified 220.

Although only a small number of organisms can make a person sick, casual contact is not the main way shigellosis bacteria are spread. Typical symptoms include diarrhea (sometimes bloody), fever and stomach cramps.

The infection is diagnosed with stool testing. Most people will recover fully without antibiotic treatment, though individuals with poor immune systems can develop life-threatening disease. If you have symptoms that resemble shigellosis, contact your primary care physician for assistance.

Recognized worldwide as the most common cause of dysentery, the Shiga bacillus—or Shigella—is a gram-negative rod belonging to the family Enterobacteriaceae, so named because many of its members live in the intestines of humans and warm-blooded animals. 

Shigellosis is the clinical syndrome caused by Shigella species and is most typically associated with diarrhea and other gastrointestinal symptoms. Shigella species are transmitted by the fecal-oral route, and most infections are transmitted from person to person, reflecting the low infectious dose. Because of its quite common person-to-person spread, shigellosis has long been associated with outbreaks in daycare centers, nursing homes, institutional settings (e.g., prisons), and cruise ships. Shigella infections also may be acquired from eating contaminated food; studies estimate that approximately one-third of U.S. shigellosis cases annually might be caused by the consumption of contaminated food. 

Most people who are infected with Shigella develop diarrhea, fever, and stomach cramps after being exposed to the bacteria. Symptoms may start 12 to 96 hours after exposure, usually within one to three days. Reactive arthritis can develop after a Salmonella infection. The other relatively rare complication that can occur with a Shigella infection is the development of hemolytic uremic syndrome (HUS). This rare complication is more commonly caused by E. coli O157:H7, and it can lead to a low red blood cell count (hemolytic anemia), low platelet count (thrombocytopenia), and acute kidney failure. It is more common to develop HUS after being infected with S. dysenteriae.

Seattle & King County is reporting an increase in shigellosis cases since mid-December in King County. Since the end of October, Public Health has received 40 total reports of Shigella infection, with 22 of those reported since December 14th. This compares to an average of 2-3 cases reported during a typical week this year. Public Health has had 173 reported cases of Shigella in 2019 and 129 cases in 2020 from preliminary data.

Shigella germs (bacteria) spread easily from one person to another because it takes as few as 10 germs to make you sick. Symptoms of shigellosis include diarrhea, fever and stomach cramps. Most people get better after about one week but can be sick longer or become dehydrated and need medical care. People can also be contagious even after feeling better. The germs can spread when someone with Shigella does not wash their hands well after using the toilet then contaminates objects, food or water. Shigella also spreads easily through sexual contact. Handwashing with soap and water is the best way to protect yourself and others against Shigella infections.

Among the recent infections, 28 cases occurred among people who reported experiencing homelessness or unstable housing or who accessed homeless services. These cases have occurred across multiple settings and no common source among the cases has been identified. Typically, in the U.S., those considered at highest risk for getting Shigella are travelers to developing countries, men who have sex with men, young children, and those with weakened immune systems. However, we know people experiencing homelessness are at increased risk for a wide range of health problems, including outbreaks caused by infectious diseases.

“Outbreaks of Shigella among people living homeless are often a reflection of the lack of access to medical care, basic hygiene and sanitation resources,” said Elysia Gonzales, Medical Epidemiologist, Public Health – Seattle & King County. “Shigella is highly contagious. It’s important that anyone with symptoms of Shigella contact a healthcare provider for potential testing and treatment to help decrease the spread of preventable illnesses among our most vulnerable residents.”

Public Health has identified at least 20 different homeless service sites that were visited by someone while infectious or just prior to illness. The public health team has been contacting homeless service providers at these sites, which include emergency shelters, day centers, supportive housing, food services, and encampments, to assess for any other known diarrheal illnesses and to provide infection control guidance.

Public Health has also been working with partners who conduct outreach to homeless service providers and homeless communities to assess for any possible cases of Shigella and to reinforce the importance of access to hand washing resources.

People who have Shigella usually get better with fluids and rest and do not typically require antibiotic treatment. Those with weakened immune systems can get a more serious illness. It is important to contact a healthcare provider if you have signs or symptoms such as diarrhea, fever, stomach cramps or dehydration, especially if these symptoms continue for more than a few days or become severe. Antibiotics can be an important part of controlling transmission in outbreak settings or among those living in crowded and unsanitary conditions and can shorten the duration of fever and diarrhea in individuals. However, there is also growing concern about antibiotic-resistant Shigella infections, so healthcare providers should do laboratory testing of stool samples to make sure they are prescribing the right antibiotic.

Homeless service sites who suspect any clusters of diarrheal illness should contact Public Health at 206-296-4774. The Sanitation and Hygiene Guide for Homeless Service Providers has information about special cleaning and disinfection practices for vomit, diarrhea, or blood.

More information about Shigella is available at King County’s shigellosis page and CDC’s shigellosis page.

The Multnomah County Health Department ordered the immediate closure of the Small Pharaoh #1 food cart in downtown Portland (SW 5th and Stark) late Tuesday, Aug. 11, 2020 after linking the business to an outbreak of shigellosis. This is the first food cart closure in Multnomah County in many years due to health concerns. Food carts are inspected, regulated and scored the same as brick and mortar restaurants.

Shigellosis is caused by a type of bacteria known as shigella that can cause severe gastrointestinal illness in people, including diarrhea, fever and cramps. It can also lead to more severe illnesses such as sepsis and kidney injury. Local data indicate that one out of three diagnosed infections typically require hospitalization.

Shigella is spread through food, through water, or person to person by swallowing fecal matter. Most people recover without treatment, and  this particular strain is highly resistant to the most common antibiotics used to treat shigellosis.

Health officials took the unusual step of ordering the closure of the food cart at 5th and SW Stark after several individuals from different households were confirmed to have shigellosis after eating food from the facility. Four cases have been confirmed with three additional presumptive cases with symptoms who have not been tested. Shigella is a very contagious bacteria and can spread after swallowing a very small amount of the bacteria.

Anyone with symptoms of shigellosis who ate at the downtown location of Small Pharaoh between July 27 and August 11 should contact their care provider or seek medical care as needed.

In general, anyone ill with diarrhea should stay home from work, especially if they prepare food or work in child care or a long-term care facility. Shigella can spread easily among people who live together. To prevent spread in a household: wash hands well before eating and after using the bathroom, and avoid sex until the diarrhea is completely gone.

Health care providers who believe someone is ill enough to need antibiotics should consult with an infectious disease specialist and Multnomah County Health Department about the details of drug resistance.

For consultation or to report possible illness associated with this outbreak, call 503-988-3406.

Shigella is a reportable illness, and 47 cases have been reported to the Health Department in 2020. Historically, the majority of shigella infections in the Portland area are acquired during international travel or through intimate contact among men who have sex with men. Since 2015, Multnomah County has identified cases among persons experiencing homelessness that were caused by shigella strains that had been previously circulating in the area among housed individuals. In other parts of the United States, shigella frequently causes outbreaks in childcare and long-term care facilities

The Texas Department of State Health Services is reminding people to take precautions following 27 cases of shigellosis in Fort Stockton and Pecos County. Shigellosis is a diarrheal illness caused by bacteria that can spread through the stool of sick people or animals or by consuming contaminated food or water.

In addition to diarrhea, shigellosis can cause fever, nausea, vomiting and stomach cramps. Anyone with some of those symptoms should contact their health care provider and be tested for shigellosis by stool sample. People who are sick should stay home from work or school until they are diarrhea and fever free for at least 24 hours.

The best way to avoid spreading the illness is to wash hands frequently, especially before preparing or serving food, before eating, after using the bathroom, after changing a diaper, and after cleaning areas where pets or livestock live. People should also refrigerate leftovers right away, avoid thawing foods on counters or in sinks, and avoid swallowing untreated water such as from ponds and lakes.

The initial patients involved in the outbreak first got sick in October, and three patients have required hospitalization. Public health is investigating the outbreak, and no single source has been identified at this time.

The City of Lubbock Health Department has reported an increase in cases of shigellosis, a diarrheal illness that can last from four to seven days.

Between September and October 21 cases were reported. That is a sharp increase from 2018, when only three cases of shigellosis were reported, according to the City of Lubbock.

The bacteria that causes the illness, called Shigella, is spread person-to-person through the unwashed hands of an infected person.

City officials recommend always washing hands before eating or handling food, after using the toilet, after infant diaper changes and frequently during the day.

Symptoms include diarrhea, abdominal cramping, fever, nausea and vomiting. Once a person is exposed symptoms usually develop within one to three days.

People with diarrheal illnesses of any kind, which include shigellosis, should not attend work, school or daycare until they are free from symptoms for at least 24 hours.

A significant increase in acute frequent diarrhea is being reported in Amador County. Heathcare providers have reported Shigellosis in several individuals. Amador County Environmental Health and Public Health are completing an investigation and have enforced food safety practices at a lone establishment associated with reports of this illness.

Shigellosis is a disease caused by a group of bacteria called Shigella. Most who are infected with Shigella develop diarrhea, fever, and stomach cramps starting a day or two after they are exposed to the bacteria. Shigellosis usually resolves in 5 to 7 days. Some people who are infected may have no symptoms at all, but may still pass the Shigella bacteria to others.

The spread of Shigella can be stopped by frequent and careful handwashing with soap and water. Shigella germs are easily spread. The most common way people become ill is by eating food prepared by someone who is infected with Shigella. This illness can also be spread by touching contaminated surfaces.

Though most individuals do not require medical attention and begin recovery within a few days, Shigella illness can be serious in young children, the elderly, and people with other health conditions. Dehydration is a key concern. Symptoms of dehydration include a decrease in urination, a dry mouth and throat, and feeling dizzy when standing up. If you think you or someone you are caring for is severely dehydrated, contact your healthcare provider.

Food service workers who are experiencing these symptoms, as with any illness, should stay home, and should not engage in food preparation or food service while they are ill. They should be especially diligent about handwashing and use of gloves after they return to work. Healthcare and daycare workers who are ill should also not go to work.


  • Consumers who recently experienced symptoms of foodborne illness after eating raw oysters
  • Restaurants that sell raw oysters in California, Nevada, New York, and Arizona


  • Oysters harvested from Estero El Cardon, Baja California Sur, Mexico
  • Oysters were distributed primarily to California, Nevada, New York, and Arizona
  • Oysters were sold to wholesale distributors with direct sales to restaurants and not to grocery retail outlets.


Consumers should not purchase oysters marketed as being harvested from Estero El Cardon, in Baja California Sur, Mexico from restaurants. Consumers who have recently experienced symptoms of foodborne illness should contact their healthcare provider and report their symptoms and receive care.

Restaurants and retailers should not serve oysters from the Estero El Cardon harvest area in Baja California Sur, Mexico. Restaurants and retailers should dispose of any products with harvest tags that indicate a growing area of Estero El Cardon by throwing them away.

Symptoms of Shigella Illness (Shigellosis)

Shigella is a bacterium that spreads from contaminated feces. It often spreads through unclean water that an infected person has been in. Food can become contaminated when handled by an infected person who did not use proper hand hygiene after going to the bathroom, or if contaminated water is used in the process of growing or preparing the food.

Symptoms of shigellosis generally develop within 8 hours or up to about 2 days. Although shigellosis is often mild and goes away by itself in a week or less, it can become very serious in some cases. Severe cases can be treated with certain antibiotics. Symptoms of shigellosis may include watery stool that may have blood, pus, or mucus in it, vomiting, cramping, and fever. Young children, the elderly, and people with a weak immune system are more likely than others to develop severe illness.

If you suspect you have symptoms of shigellosis, contact a health professional.

Summary of Problem and Scope

The FDA is investigating a subset of a larger outbreak investigation being conducted by the Centers for Disease Control and Prevention. Between the harvesting dates of February 12, 2019 and April 9, 2019, five ill patients reported eating raw oysters shortly before becoming ill with Shigella flexneri. One of the five patients was hospitalized; there have been no deaths. The last illness onset was April 17, 2019. Laboratory analyses were used to confirm the reported clinical illnesses and traceback information indicated the implicated shellfish were harvested from Estero El Cardon, in Baja California Sur, Mexico.

The FDA confirmed that oysters harvested in Estero El Cardon, Baja California Sur, Mexico, were distributed to California, Nevada, New York, and Arizona with illnesses reported in California, Nevada and New Hampshire. The New Hampshire case reported eating at a restaurant in California shortly before becoming ill. It is possible that additional states received these potentially contaminated oysters either directly from Mexico or through further distribution within the U.S.

On May 7, 2019, the Mexican Shellfish Sanitation Program authorities voluntarily closed the growing area of Estero El Cardon and halted oyster harvesting in response to the reported illnesses. The shelf-life of fresh, raw oysters is limited. All raw oysters from this growing area are no longer expected to be available to consumers. For more information please see

Recommendations for Consumers

Consumers who have symptoms should contact their health care provider to report their symptoms and receive care.

To report a complaint or adverse event (illness or serious allergic reaction), you can

Visit for additional consumer and industry assistance.

Recommendations for Retailers

In the event that retailers and/or other food service operators are found to have handled recalled or other potentially contaminated food in their facilities, they should:

  • Contact their local health department and communicate to their customers regarding possible exposure to Shigella.
  • Wash the inside walls and shelves of the refrigerator, cutting boards and countertops, and utensils that may have contacted contaminated foods; then sanitize them with a solution of one tablespoon of chlorine bleach to one gallon of hot water; then dry with a clean cloth or paper towel that has not been previously used.
  • Wash and sanitize display cases and surfaces used to potentially store, serve, or prepare potentially contaminated foods.
  • Retailers that have sold bulk product should clean and sanitize the containers used to hold the product.
  • Wash hands with warm water and soap following the cleaning and sanitation process.
  • Conduct regular frequent cleaning and sanitizing of cutting boards and utensils used in processing to help minimize the likelihood of cross-contamination.

FDA Actions

Mexican health officials closed the Estero El Cardon growing area on May 7, 2019. The FDA continues to work with Mexico’s health authorities, and state and local partners continue to verify that this product has been successfully removed from commerce and to ensure that the raw oysters were not further distributed.

“Shigella at a Wedding” – Instead of “I do,” should be “Hell No.”


On August 14, 2018, the Oregon Health Authority (OHA) and Yamhill County Health and Human Services (YCHHS) independently received reports of persons with gastrointestinal illness days after attending a wedding and reception in Yamhill County on August 11. Over the next two days, additional wedding attendees reported gastrointestinal illness. OHA notified the Multnomah County Health Department (MCHD), and the agencies initiated an investigation to determine the cause of the outbreak and to prevent additional cases. YCHHS contacted the Oregon Department of Agriculture (ODA), which regulates some food-service establishments in Oregon.

By August 15, 10 cases had been reported to OHA. A Health Alert Network notice was sent to the ORCD1 group,1 advising them to ask patients with gastrointestinal illness whether they had attended a wedding in Yamhill County and, if they were willing, to submit a stool sample. Fecal samples from patients were cultured and isolates serotyped at the Oregon State Public Health Laboratory. On August 20, Shigella flexneri type 3a was first identified from a patient specimen. OHA consulted with subject matter experts at the Centers for Disease Control and Prevention (CDC) for information on this Shigella serotype.


Methods YCHHS public health investigators obtained contact information for attendees and the caterer. The caterer is based in Multnomah County. MCHD officials contacted the caterer to obtain a menu of foods served at the wedding. Using this information, on August 16 OHA epidemiologists emailed to wedding attendees a link to an online survey asking them to identify foods they had eaten and to determine whether they had illnesses meeting the case definition.

Information from the first survey indicated that there was a cocktail hour between the wedding ceremony and the reception. Because S. flexneri infections have been associated with international travel,2 and there were additional food exposures, OHA invited wedding attendees to complete a second online survey on August 20. OHA asked respondents about their illness on this survey, too.

A confirmed case had S. flexneri cultured from a clinical specimen. A presumptive case was defined as self-reported diarrhea or vomiting in a person who attended the wedding reception.

An ODA environmental health specialist inspected the venue, collected water samples and leftover strawberries and cucumbers, and examined general biosecurity. Yamhill County environmental health specialists collected leftover potatoes. Well-water samples were tested using the Colilert test for total coliforms. Food samples were tested for Shigella species using polymerase chain reaction testing. Multnomah County environmental health specialists inspected the caterer. They observed hygiene practices and asked that people who prepared food for the reception submit stool samples for testing.


Among 263 wedding attendees and reception venue staff, 192 were represented on the first survey and 128 on the second survey; some people completed the survey for their children, spouses, or other relatives. In total, 200 people were represented by the two surveys combined.

One hundred seven cases were identified, of which 23 (21%) were confirmed. Eighty-two (77%) of the cases were Oregon residents; the remainder were residents of 11 other states. Oregon cases resided in 11 different counties.

Cases by time of illness onset are shown in Figure 1. Of the 93 cases with onset information, 89 (96%) were reported to have started on the two days between midnight on August 12th and midnight August 14th.

The median age of ill people was 30 years. Of 111 female attendees, 60 (54%) became ill. Of 88 male attendees, 47 (53%) became ill. Of 18 persons <18 years of age, 5 (28%) were ill.  Of 181 person >18 years of age, 102 (56%) were ill (Table 1). Persons < 18 years of age were significantly less likely to become ill (p = 0.03).

Of ill people, 74/105 (70%) missed school or work, 57/106 (54%) saw a clinician, 38/105 (36%) visited the emergency room, and 10/106 (9%) were hospitalized overnight.

Among the 48 cases whose illness had resolved when they completed the survey, illness duration ranged from 3 to 15 (median, 11) days. Forty-two cases were still ill when they completed their survey. No deaths were reported.

Persons (n = 55) who attended the rehearsal dinner were no more likely to become ill than those who did not attend it (RR 1.1, p= 0.54); therefore, the epidemiologic investigation focused on food exposures at the wedding reception. Food was served buffet-style. Five food items were each associated with a significantly increased risk of illness: asparagus, butter, bread, au gratin potatoes, and the aioli that was served with the asparagus. Asparagus was most strongly associated with illness: of those who ate asparagus, 64% became ill, compared to 12.5% of those who denied eating asparagus (RR 5.1, 95% CI 2.0–12.9). Asparagus consumption also accounted for a higher percentage of cases (96%) than any other exposure (Table 3). In a reanalysis of the other implicated foods, stratifying by asparagus consumption, only bread remained significantly associated with illness (RR 1.6, 95% CI 1.1–2.6).

There was a children’s buffet. Some persons under 10 ate food from the rest of the buffet, and some adults ate food from the children’s buffet. Persons under 10 were significantly more likely to have eaten from the kid’s buffet (p < 0.01) and significantly less likely to have eaten any adult food (p < 0.01).

Asparagus consumption differed by age: it was consumed by 150/172 (87%) of persons >10 but by none of 10 children <10 years old (p < 0.001) Bread consumption did not differ significantly by age.

When visiting the caterer, Multnomah County inspectors did not observe any food-handling violations. Stool samples were submitted by some of the food-handling staff; none were positive for Shigella. Food preparers were primarily responsible for specific dishes. When analyzing attendees’ exposures by who was responsible for the foods they consumed, illness rates did not differ significantly by food preparer. Catering records revealed that the caterer served some of the same foods, including the grilled asparagus dish, at multiple events that same weekend. The asparagus was sourced domestically. No illnesses related to those other events were reported to OHA.

The ODA inspector concluded that biosecurity on the venue’s water supply was sufficient to protect against intentional contamination. The water tested negative for bacterial contamination. The leftover strawberries, cucumbers and potatoes tested negative on bacterial culture; no asparagus had been left over for testing.


An outbreak of Shigella flexneri type 3a infections was most likely caused by contaminated asparagus consumed by people who attended a wedding reception in Yamhill County on August 11, 2018. Bread was also associated with illness, but it is less likely to be the cause of the outbreak. Asparagus accounts for a higher proportion of cases, and the age breakdown of illness is better explained by asparagus consumption patterns.

This is the second-largest foodborne outbreak of S. flexneri infections reported in the U.S. since 1988. The source of the contamination was not definitively identified. Because humans are the natural reservoir for Shigella species, and there were no concurrent outbreaks to suggest upstream contamination, poor food-handler hygiene is the most likely cause.

Outbreak 2018-4979 Shigellosis at a Wedding

See also,