Past Outbreaks in Wisconsin

Archived Outbreaks and Investigations

Below is a list of past outbreaks and investigations with wide impact in Wisconsin.

For current outbreaks and investigations, please visit our Outbreaks in Wisconsin page.

Stack of folders full of paper documents

2019 Outbreaks

Outbreak of E. coli O157 Infections Linked to Fresh Express Sunflower Crisp Salad Kits
Final Update 1/15/2020

Fresh Express Sunflower Crisp chipped lettuce kit

Campus Outbreaks of Adenovirus
Final Update 12/4/2019

  • The Wisconsin Department of Health Services (DHS) is working with local health departments, the Centers for Disease Control and Prevention (CDC), and college and university health services directors in our state to track multiple outbreaks of respiratory illness caused by adenoviruses and to provide prevention information to students and staff.
  • People usually get sick with adenoviruses when they spend time with large groups of people (for example, at universities, hospitals, or schools). There are over 50 different types of adenoviruses. Usually adenoviruses cause mild illness, but sometimes they can be serious. The types of symptoms you have depend on which type of adenovirus you have and the part of the body that the virus is affecting.
    • Adenoviruses most commonly cause respiratory illness, which can range from cold and flu-like symptoms to bronchitis and pneumonia.
    • Some adenoviruses can cause diarrhea or pink eye, and in rare cases, inflammation of the bladder or severe neurological disease.
    • Anyone can get sick from an adenovirus. People with a weakened immune system, or those who have lung or heart problems are more likely to become very sick from an adenovirus.
    • Antibiotics do not work against adenoviruses.
  • There are a number of ways you can get an adenovirus:
  1. Breathing in adenovirus from the air: someone with the virus coughs or sneezes and the virus gets into the air. It is then breathed in by someone around them.
  2. Having direct contact with someone who has an adenovirus: touching or shaking hands with someone who has the virus on their skin and then touching your hands to your mouth, nose, or eyes.
  3. Touching surfaces with adenovirus: touching a surface (for example, a door knob, counter top, or phone) with adenovirus on it and then touching your hands to mouth, nose, or eyes. NOTE: Adenoviruses are able to survive on surfaces for a long time. It is important to wash toys, towels, and other surfaces often to make sure it doesn't spread to others.
  4. Having contact with poop: Some adenoviruses can spread through poop, for example, during diaper changing.
  5. Having contact with water that has adenovirus: Adenoviruses can also spread through water, such as swimming pools, but this is less common.

NOTE: Sometimes the virus can be shed (released from the body) for a long time after you recover from an adenovirus, especially if you have a weakened immune system. Usually you do not have any symptoms during this time of “virus shedding,” even though you can still spread adenovirus to others.

Outbreak of E. coli Infections Linked to Romaine Lettuce
Final Update 12/19/2019

  • The Wisconsin Department of Health Services (DHS) is working with local health departments, the Wisconsin Department of Agriculture, Trade, and consumer Protection (DATCP), the Centers for Disease Control and Prevention (CDC), and the U.S. Food and Drug Administration (FDA) to investigate a multistate outbreak of E. coli O157:H7 infections linked to romaine lettuce.
    • As of December 19, 2019, the CDC reports that 138 people in 25 states are infected with the outbreak strain of STEC. There have been 72 people hospitalized and 13 cases of hemolytic uremic syndrome (HUS), a type of kidney failure. No deaths have been reported.
    • As of December 19, 2019, Wisconsin has 33 confirmed cases linked to this outbreak. Of these, 14 people have been hospitalized and 2 have developed HUS.
  • Epidemiologic, laboratory, and traceback evidence collected so far shows that romaine lettuce from the Salinas, California, growing region is a likely source of this outbreak.
    • On November 21, 2019, a list of salad products were recalled after laboratory testing found the same strain of E. coli that was making people sick in Maryland in romaine lettuce harvested from the Salinas, California growing region.
    • On December 6, 2019, Wisconsin health officials found E. coli O157 in an unopened bag of chopped Fresh Express® brand Leafy Green Romaine salad from Salinas, California that was collected from an ill person’s home. On December 13, 2019, specialized laboratory testing called whole genome sequencing showed that the E. coli O157 strain found in the romaine matches the outbreak strain of E. coli that has made people in Wisconsin and other states sick.
    • While E. coli O157 was found in a bag of chopped Fresh Express® brand romaine, not all ill people in Wisconsin included in this outbreak report eating Fresh Express® brand romaine. No single brand, product, or type of romaine lettuce has been reported by all ill individuals. The investigation is ongoing to determine the source of contamination and if additional products are linked to illness.
  • Wisconsin DHS, the CDC, and FDA are advising people not to eat, sell, or serve any romaine lettuce harvested from Salinas, California, until more information is available.
  • While certain romaine-containing products were recalled, many romaine lettuce and romaine-containing products are still available on store shelves.
  • Advice to Consumers, Retailers, and Restaurants:
    • Most romaine lettuce products are labeled with a harvest location showing where they were grown. This advice includes all types of romaine lettuce harvested from Salinas, California, such as whole heads of romaine, hearts of romaine, and packages of precut lettuce and salad mixes which contain romaine, including baby romaine, spring mix, and Caesar salad.
    • Restaurants and retailers should check the label on bags or boxes of romaine lettuce, or ask their suppliers about the source of their romaine lettuce.
    • Suppliers, distributors, and others in the supply chain should not ship or sell romaine harvested in Salinas, California.
  • If you have romaine lettuce at home:
    • If the packaging has “Salinas” on the label in any form (whether alone or with the name of another location), don’t eat it, and throw it away.
    • If it isn’t labeled with a growing region, don’t eat it, and throw it away.
    • If you don’t know if the lettuce is romaine or whether a salad mix contains romaine, don’t eat it, and throw it away.
    • Wash and sanitize drawers or shelves in refrigerators where romaine lettuce was stored. Follow these five steps to clean your refrigerator.
  • If you are buying romaine lettuce at a store:
    • If the packaging has “Salinas” on the label in any form (whether alone or with the name of another location), don’t buy it.
    • If it isn’t labeled with a growing region, don’t buy it.
    • If the packaging has “Salinas” on the label in any form (whether alone or with the name of another location), don’t sell or serve it.
    • If it isn’t labeled with a growing region, don’t sell or serve it.
  • About Shiga toxin-producing E. coli (STEC):
    • People with STEC usually get sick with bloody diarrhea and stomach cramps 3-4 days after eating food contaminated with the germ. Contact your doctor if you think you ate romaine lettuce from the Salinas region of California and are having any symptoms.
    • Remember to wash your fresh fruits and vegetables before eating them, even if they have been “pre-washed.”
  • Additional information can be found on the following websites:

Hepatitis A Infection in a Mondovi Hansen's IGA Food Worker
Final Update 11/21/2019

  • The Wisconsin Department of Health Services (DHS) is working with the Buffalo County Health Department, the Department of Agriculture, Trade, and Consumer Protection (DATCP), and the Centers for Disease Control and Prevention (CDC) regarding a confirmed case of hepatitis A virus infection in a food handler.
    • A food handler with hepatitis A infection is concerning because of the potential for food contamination.
    • This individual worked at the Mondovi Hansen’s IGA store deli while they were able to spread Hepatitis A, from October 28 through November 17, 2019.
    • Health officials are advising people who shopped at the Mondovi Hansen’s IGA during October 28 and November 17, 2019 and ate produce or deli items to call their doctor. They should ask about their risk of exposure to hepatitis A virus and options for vaccination (if not already vaccinated).
    • There is no risk of exposure outside of these dates.
  • Symptoms of hepatitis A infection can include abdominal pain, nausea, vomiting, diarrhea, dark urine, clay-colored stool, fever, chills, and yellow skin and eyes (jaundice).
    • Hepatitis A symptoms occur between 15 and 50 days after exposure and can last for several weeks to months. Most people recover from hepatitis A on their own, but occasionally patients may need to be hospitalized. Hepatitis A is rarely fatal.
    • Antibiotics do not work against hepatitis A virus.
  • The best ways to prevent the spread of hepatitis A virus are:
    • Get the hepatitis A vaccine. A single shot of the hepatitis A vaccine can help prevent an infection if given within two weeks of being exposed to hepatitis A virus.
    • Always wash your hands with soap and water after using the bathroom or changing a diaper. Hand sanitizer is NOT effective against Hepatitis A virus.
    • Thoroughly wash your hands with soap and water before and during food preparation and before eating food.
  • Additional information can be found at the following websites:

Hepatitis A Cases Linked to Blackberries
Final Update 12/11/2019

  • The Wisconsin Department of Health Services (DHS) is working with local health departments, Centers for Disease Control and Prevention (CDC), and the U.S. Food and Drug Administration (FDA) to investigate a multistate outbreak of hepatitis A that may be linked to fresh, non-organic blackberries. These blackberries were sold at Fresh Thyme Farmers Market and Woodman's Market stores during September 9 through September 30, 2019.
  • A single, common supplier of these berries has not been identified and no recall has been issued at this time.
    • Ill patients reported eating fresh, non-organic blackberries from Fresh Thyme Farmers Market or Woodman's Market stores in Indiana, Michigan, Minnesota, Missouri, Nebraska, and Wisconsin.
    • As of December 11, 2019, the CDC reports that 18 people in six states are infected with the outbreak strains of hepatitis A.
    • Wisconsin has five confirmed cases linked to this outbreak. Three cases in Wisconsin have been hospitalized.
    • Ill patients reported their illnesses starting between October 15 and November 5, 2019.
  • If you purchased any blackberries from a Fresh Thyme or Woodman's location between September 9 and September 30, 2019, do not eat them and throw them away.
    • Check your freezer for these blackberries. If you froze them to eat later, do not eat them and throw them away.
    • If you ate any of these blackberries within the last two weeks and are not vaccinated against hepatitis A, contact your doctor or local health department to discuss vaccination options.
  • Symptoms of hepatitis A infection can include abdominal pain, nausea, vomiting, diarrhea, dark urine, clay-colored stool, fever, chills, and yellow skin and eyes (jaundice).
    • Hepatitis A symptoms occur between 15 and 50 days after exposure and can last for several weeks to months. Most people recover from hepatitis A on their own, but occasionally patients may need to be hospitalized. Hepatitis A is rarely fatal.
    • Antibiotics do not work against hepatitis A virus.
  • Additional information can be found on the following websites:

Salmonellosis Associated with Consuming Beef Tartare at Restore Public House in La Crosse
Final Update 9/6/2019

Fresh, paper-thin sliced raw beef

  • The Wisconsin Department of Health Services (DHS), in collaboration with the La Crosse County Health Department, investigated an outbreak of salmonellosis associated with consuming beef tartare served at Restore Public House in La Crosse between July 10 and July 12, 2019.
  • 35 restaurant patrons were interviewed during the investigation. Seven confirmed and 10 probable (ill but not tested) cases were linked to this outbreak.
  • Restore Public House voluntarily removed the beef tartare dish from their menu once they were notified of the illnesses.
  • See the DHS salmonellosis fact sheet for more information on common symptoms of salmonellosis. If you have any symptoms of salmonellosis, please contact your doctor.
  • Consumption of raw or undercooked meat, poultry, or eggs can increase your risk of foodborne illness. See the DHS food safety webpage for more information on safe food practices.
  • Additional information can be found on the following websites:

Multistate Outbreak of Multidrug-Resistant Salmonella Infections Linked to Contact with Pig Ear Dog Treats
Final Update 10/30/2019

Dried pig ears.

  • The Wisconsin Department of Health Services (DHS) and local health departments worked with the Centers for Disease Control and Prevention (CDC) and the U.S. Food and Drug Administration (FDA) to investigate a multistate outbreak of salmonellosis linked to contact with pig ear dog treats.
    • 154 people in 34 states were infected with the outbreak strains of Salmonella.
    • 35 people were hospitalized, with no deaths reported. Children younger than 5 years accounted for 19% of illnesses.
    • In Wisconsin, 4 laboratory-confirmed cases were linked to this outbreak.
  • CDC and FDA have dropped their warning to avoid buying or feeding any pig ear treats, except for treats that have been recalled. Consumers should not give recalled pig ears to their pets. Consumers should always wash their hands right after feeding any pig ear treats to their dogs.
    • Several companies recalled pig ear products because they might have been contaminated with Salmonella. No single supplier, distributor, or common brand of pig ear treats has been identified that could account for all the illnesses.
    • Details on pig ear products involved with the outbreak can be found on the FDA webpage.
  • See the DHS salmonellosis fact sheet for more information on common symptoms and treatment of salmonellosis. If you have any symptoms of salmonellosis, please contact your doctor.
  • Additional information can be found on the following websites:

Salmonellosis Linked to Consuming Foods from Outpost Natural Foods
Final Update 1/16/2020

  • The Wisconsin Department of Health Services (DHS) and local health departments investigated an outbreak of salmonellosis linked to consuming food from Outpost Natural Food locations.
  • On August 23, 2019, the Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) and the City of Milwaukee Health Department suspended meat and food processing at Outpost Natural Foods located in Milwaukee at 2826 S. Kinnickinnic Ave. due to insanitary conditions. DATCP suspended the cooperative's meat establishment license and the City of Milwaukee suspended the cooperative's retail food processing activities.
  • Insanitary conditions were discovered during a routine inspection and ready-to-eat products tested positive for Salmonella.
  • Four people infected with the outbreak strains of Salmonella found at Outpost Natural Foods; three were available for interview and each reported consuming food from one of the Outpost Natural Food locations.
  • Known patient onset dates ranged from March 20-May 6, 2019.
  • All licenses have been re-instated and Outpost Natural Food is operating under Voluntary Compliance Agreement’s on each license.

Multistate Outbreak of Salmonella Infections Linked to Contact with Backyard Poultry
Final Update 11/1/19

Chickens feeding on the grass in the backyard

Salmonellosis Linked to Vegetable Trays
Final Update 7/11/19

Store bought vegetable tray

  • The Department of Health Services (DHS), the Wisconsin Department of Agriculture, Trade, and Consumer Protection (DATCP), Minnesota Department of Health and local health departments worked with the Centers for Disease Control and Prevention (CDC), and the U.S. Food and Drug Administration (FDA) to investigate a multi-state outbreak of salmonellosis linked to consumption of certain Del Monte vegetable trays.
  • All ill patients associated with this outbreak, four in Wisconsin and one in Minnesota, reported eating a Del Monte vegetable tray purchased from a Wisconsin or Minnesota Kwik Trip location before they became ill.
  • The Del Monte vegetable trays associated with the investigation contain broccoli, cauliflower, carrots, and dill dip. It is not likely that the trays that made people sick are still on the market or still in people’s homes.
  • See the DHS salmonellosis fact sheet, P-42088 for more information on common symptoms and treatment of salmonellosis.
  • Additional information can be found on the following websites:

Salmonellosis Linked to Cut Melons
Final Update 6/19/19

Fresh melon cut up and ready to eat

  • The Wisconsin Department of Health Services (DHS) in collaboration with the Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP), the Centers for Disease Control and Prevention (CDC), and the U.S. Food and Drug Administration (FDA) alerted Wisconsin consumers to a multistate outbreak of Salmonella Carrau infections linked to eating pre-cut melons sold by Caito Foods LLC.
  • One case was reported in Wisconsin and 137 people infected with the Salmonella strain were reported in nine other states.
  • On April 12, 2019, Caito Foods LLC recalled pre-cut watermelon, honeydew melon, cantaloupe, and pre-cut fruit medley products containing one of these melons supplied at the Caito Foods LLC facility in Indianapolis, Indiana.
  • Additional information can be found on the following websites:

Salmonellosis Linked to Ground Turkey
Final Update 6/19/19

Raw ground turkey.

  • The Wisconsin Department of Health Services (DHS) and local health departments investigated four cases of salmonellosis affecting Wisconsin residents with the same strain (DNA fingerprint) of Salmonella.
  • All four of the Wisconsin patients were linked to Butterball raw ground turkey. Testing of leftover raw ground turkey received by the patients was positive for the outbreak strain of Salmonella.
  • These items were shipped to institutional and retail locations nationwide. The affected ground turkey product may have been distributed through food pantries.
  • As a result of this outbreak, Butterball recalled 78,164 pounds of raw ground turkey products. A complete list of products included in the recall can be found in the U.S. Department of Agriculture Recall notice. The products subject to recall bear establishment number “EST. P-7345” inside the USDA mark of inspection.
  • Additional information can be found on the following websites:
2018 Outbreaks

Legionnaires' Disease Associated with the University of Wisconsin (UW) Hospital in Madison
Final Update 6/4/19

Closeup of the front of a running shower head

  • The Wisconsin Department of Health Services (DHS), in collaboration with the Centers for Disease Control and Prevention (CDC), and Public Health Madison and Dane County, worked closely with UW Health on the investigation of nosocomial Legionnaires’ disease associated with the University Hospital in Madison, Wisconsin.
  • On Nov. 28, 2018, DHS was notified by a UW Health Infection Preventionist of confirmed cases of Legionnaires’ disease among patients admitted to their hospital since Oct. 31, 2018.
  • 14 cases of Legionnaires' disease were identified at University Hospital. Three patients who had been hospitalized for other serious health conditions died.
  • An environmental investigation at the hospital was completed.
  • Legionellosis in an infection caused by Legionella bacteria. There are two different types of legionellosis: Pontiac fever and Legionnaires' disease. Pontiac fever is a mild respiratory illness and Legionnaires' disease is a type of pneumonia.
    • Legionnaires' disease is not normally spread from person to person.
    • This CDC infographic outlines how Legionella bacteria is spread from water sources to people.
  • Additional information can be found on the following websites:

Salmonellosis Linked to Kellogg's Honey Smacks Cereal
Final Update 6/19/19

Bowl of dry breakfast cereal

Cyclosporiasis Linked to Salads Sold at McDonald's
Final Update 6/19/19

Bowl of salad lettuces

Salmonellosis Linked to Cut Melons
Final Update 6/19/19

Fresh melon cut up and ready to eat

  • The Wisconsin Department of Health Services (DHS) and the Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) alerted Wisconsin consumers to a multistate outbreak of Salmonella Adelaide infections linked to the consumption of pre-cut melons. No cases were identified in Wisconsin residents, but the recalled products were sold at locations in the state.
  • The FDA identified Costco stores in the following Wisconsin cities as having distributed the recalled pre-cut melon: Bellevue (Green Bay), Grafton, Grand Chute, Menomonee Falls, Middleton, New Berlin, Pewaukee, Pleasant Prairie, and Sun Prairie.
  • The full list of stores where this product was distributed is available on the FDA’s website.
  • No cases were reported in Wisconsin. Nationally, 77 people infected with the Salmonella strain have been reported.
  • Additional information can be found on the following websites:

Synthetic Cannabinoids (K2, Spice)
Final Update 6/19/19

  • Case counts in Wisconsin can be found on our synthetic cannabinoid webpage.
  • The CDC is investigated this outbreak across the nation.
  • If you have used any of these products, and start experiencing severe, unexplained bleeding or bruising, please have someone take you to the hospital immediately or call 911.

 

Acute Flaccid Myelitis (AFM) Investigation
Final Update 6/4/19

Digital illustration of a neuron

  • The Wisconsin Department of Health Services (DHS) and local health departments (LHDs) are actively working to identify potential cases of acute flaccid myelitis (AFM). DHS is working with health care providers and the Centers for Disease Control and Prevention (CDC) during this developing situation.
  • There were nine confirmed and three probable cases of AFM in Wisconsin.
    • AFM is also called “acute flaccid paralysis with anterior myelitis” or “polio-like syndrome.” It is rare and mainly found in children. It affects the body’s nervous system, specifically the spinal cord. AFM can be caused by some viruses, environmental toxins, and genetic disorders.
    • Viruses that can cause AFM include enteroviruses (polio and non-polio) and flaviviruses, such as West Nile Virus, Japanese Encephalitis virus, or St. Louis encephalitis virus. Other viruses that may cause AFM are herpesviruses (e.g., cytomegalovirus, Epstein-Barr virus) and adenoviruses.
  • See the DHS AFM webpage for more information on common symptoms and treatment of AFM. Seek medical care as soon as possible if you notice any symptoms of AFM in you or your child, for example if your child is not using their arm or leg normally.
  • Additional information can be found on the following websites:
    • AFM Fact Sheet, P-01298 (Multiple Languages): Educational fact sheet for the general public on AFM covering signs and symptoms, treatment, and prevention.
    • About AFM: CDC webpage including information on symptoms, diagnosis, possible causes of AFM, treatment, and prevention.

E. coli O157:H7 Linked to Romaine Lettuce - Fall 2018
Final Update 1/10/19

Romaine Lettuce on white background

  • The Wisconsin Department of Health Services (DHS), Centers for Disease Control and Prevention (CDC), U.S. Food and Drug Administration (FDA), and numerous other states investigated a multistate outbreak of E. coli O157:H7 infections.
  • This outbreak was not related to the multistate outbreak of E. coli O157:H7 infections linked to romaine lettuce that occurred earlier in 2018 (see below for Wisconsin-specific information).
  • Nationwide, 62 people from 16 states were infected with the outbreak strain of E. coli O157:H7. Illnesses started on dates ranging from Oct. 7 to Dec. 4, 2018.
  • There were 25 people hospitalized, with no deaths reported. One Wisconsin E. coli O157:H7 infection was linked to the outbreak.
  • This outbreak appears to be over as of January 9, 2019.
    • Contaminated lettuce that made people sick in this outbreak should no longer be available.
    • Epidemiologic, laboratory, and traceback evidence from the United States and Canada indicated that romaine lettuce harvested from the Central Coastal growing regions of northern and central California was the likely source of the outbreak.
  • Additional information on the following websites:

Bovine Tuberculosis (TB) Investigation
Final Update 11/2/18

  • The Wisconsin Department of Health Services (DHS) is working with the Wisconsin Department of Agriculture, Trade, and Consumer Protection (DATCP) to investigate bovine tuberculosis (TB) in a dairy herd located in Dane County. The Wisconsin TB Program is working with Public Health Madison and Dane County to complete a contact investigation on the farm and identify individuals who may need TB testing.
  • Precautions are being taken by DATCP and the farm to ensure the safety of both meat and milk. Consumers and the general public are not at risk of contracting TB infection from this herd. Food safety laws prevent meat from infected animals from entering the food chain and the pasteurization process destroys disease-causing organisms in milk.
  • People are not at risk if they have made only brief visits to the affected farm, have not consumed raw milk, or have not worked closely for extended periods of time with animals. Visiting the farm, living near the farm, or making deliveries to the farm does not pose a risk for becoming infected with bovine TB.
  • Additional information on bovine TB can be found on the following websites:

Cyclosporiasis Linked to Vegetable Trays
Final Update 9/7/18

Store bought vegetable tray

  • The Department of Health Services (DHS), the Wisconsin Department of Agriculture, Trade, and Consumer Protection (DATCP), and local health departments are working with the Centers for Disease Control and Prevention (CDC) and the U.S. Food and Drug Administration (FDA) to investigate an outbreak of cyclosporiasis linked to the consumption of Del Monte vegetable trays sold at Kwik Trip.
    • 177 cases report consuming a Del Monte vegetable tray purchased at a Kwik Trip location in Wisconsin. Most ill persons reported purchasing the tray on or after May 16, 2018. Kwik Trip voluntarily removed the trays from sale in their stores on June 8, 2018.
    • Consumers should not eat 6 oz. or 12 oz. Del Monte vegetable trays (containing broccoli, cauliflower, carrots, and dill dip) purchased at a Kwik Trip location.
    • Del Monte issued a recall of 6 oz, 12 oz, and 24 oz vegetable trays with dip. See the FDA website for full details.
  • As of Sept. 5, 2018, CDC was notified of 250 laboratory-confirmed cases of Cyclospora infection in people from 4 states who reported consuming pre-packaged Del Monte Fresh Produce vegetable trays containing broccoli, cauliflower, carrots, and dill dip.
  • Based on epidemiological data or traceback evidence, it was not possible to determine if an individual component of the vegetable trays was the likely vehicle of infection. Read the related statement from the FDA for additional information.
  • See the DHS cyclosporiasis fact sheet for more information on common symptoms and treatment of cyclosporiasis. If you have any symptoms of cyclosporiasis, please contact your doctor.
  • Additional information can be found on the following websites:

Multistate Outbreak of Salmonella Infections Linked to Contact with Backyard Poultry
Final Update 6/14/19

Chickens feeding on the grass

  • During 2018, the Wisconsin Department of Health Services (DHS) and local health departments worked with the Centers for Disease Control and Prevention (CDC) to investigate multistate outbreaks of Salmonella infections linked to contact with backyard poultry.
    • The CDC reported that 334 people from 47 states became ill with a strain of Salmonella linked to backyard poultry during 2018.
    • In Wisconsin, 33 laboratory-confirmed cases of Salmonella were linked to the 2018 national backyard poultry outbreak.
    • Nationally, illness onset dates ranged from Feb. 15 to Aug. 10, 2018. Children younger than 5 years accounted for 21% of illnesses.
  • Outbreaks of Salmonella infections linked to contact with backyard poultry happen every year in the U.S. Many of these infections are preventable.
  • More information about outbreaks associated with live poultry can be found at CDC's webpage U.S. Outbreaks of Zoonotic Diseases Spread between Animals and People.
  • More information about backyard poultry and safe handling can be found at the DHS backyard poultry webpage.

E. coli O157:H7 Linked to Romaine Lettuce - Spring 2018
Final Update 6/28/18

  • The Wisconsin Department of Health Services (DHS), the Centers for Disease Control and Prevention (CDC), U.S. Food and Drug Administration (FDA), and numerous other states investigated a multistate outbreak of E. coli O157:H7 infections.
  • Epidemiologic, laboratory, and traceback evidence indicated that romaine lettuce from the Yuma growing region was the likely source of this outbreak.
  • Nationwide, 210 people from 36 states were infected with the outbreak strain of E. coli O157:H7. Illnesses started on dates ranging from March 13, 2018, to May 12, 2018.
  • As of 6/28/2018, 96 people were hospitalized, with five deaths reported. Three Wisconsin E. coli O157:H7 infections have been linked to the outbreak.
2017 Outbreaks

Legionnaires’ Disease Associated with Christmas Mountain Village Resort in Wisconsin Dells
Final Update 1/16/20

Closeup of the front of a running shower head

  • The Wisconsin Department of Health Services (DHS), in collaboration with the Sauk County Health Department, and the Wisconsin Department of Agriculture, Trade, and Consumer Protection (DATCP), worked with Christmas Mountain Village on the investigation of three cases of Legionnaires’ disease associated with Christmas Mountain Village Resort in Wisconsin Dells, Wisconsin.
  • Legionnaires’ disease is a type of pneumonia caused by the bacteria Legionella, which can grow inside building water systems (pipes, hot water heaters, etc.).
    • Symptoms of Legionnaires’ disease can include cough, fever, chills, muscle aches, headache, and shortness of breath.
    • Legionnaires’ disease is more common in people aged 50 years and older, those who smoke, and among individuals who are at higher risk of infection, such as those with a chronic illness, respiratory disease, or a weakened immune system.
    • Legionnaires' disease is not normally spread from person to person.
    • People can get Legionnaires’ disease after breathing in small water droplets with Legionella. This CDC infographic outlines how Legionella bacteria is spread from water sources to people.
  • Christmas Mountain Village Resort is working with a water management company on testing the resort’s water for Legionella and remediation (removal of Legionella from the water system).
    • The resort is continuing to notify guests at the time of reservation and check-in.
    • Point-of-use filters have been installed on showerheads and faucets in all units of the resort. These point-of-use filters are a recommended risk-reduction measure and will stay in place until testing and completing remediation (removal of Legionella) of all units at the resort is complete.
  • People who are planning to visit Christmas Mountain Village should evaluate their risk of infection or talk to their doctor before their visit and may wish to consider postponing their visit until after remediation is complete.
  • DHS and the Sauk County Health Department continue to monitor for new cases potentially associated with the resort. People who become ill with symptoms of Legionnaires’ disease within 14 days of their stay should seek medical attention and mention the information above to their doctor.
  • Additional information can be found on the following websites:

Seoul Hantavirus
Final Update 05/26/2017

Three rats

  • During 2017, the Wisconsin Department of Health Services (DHS), Wisconsin local health departments, the Centers for Disease Control and Prevention (CDC), and other state health departments investigated an outbreak of illnesses caused by the Seoul virus, a rare type of hantavirus carried by Norway and black rats.
  • The outbreak was detected in January 2017 when two Wisconsin residents were diagnosed with Seoul hantavirus (SHV), which can cause hemorrhagic fever with renal syndrome. Norway and black rats are the only known reservoir. The investigation determined the affected individuals were in routine contact with pet rats, either owning rats as pets or operating a rattery where they regularly sold and exchanged rats with individuals and other ratteries.
  • The response efforts included tracking movement of rats between locations (ratteries, pet homes) with infected rats, coordination of hantavirus testing for rats linked to the outbreak, and follow-up with people exposed to infected rats or ratteries.
  • Nationwide, 17 laboratory-confirmed recent human cases of SHV infection were reported as part of this outbreak, including three cases in Wisconsin. Two additional Wisconsin residents were identified with evidence of past infection.
    • The outbreak investigation led to the identification of 31 infected ratteries in 11 states and Canada. This indicated that Seoul virus should be considered endemic in the U.S., and that pet rats in the U.S., including Wisconsin, can be carrying Seoul virus at any time.
    • Rat owners and breeders may wish to determine if a rat is infected prior to introducing it into their home or rattery. Commercial testing for Seoul virus is available through several laboratories. Contact your veterinarian for testing information.
  • See the DHS hantavirus fact sheet, P-42053 for more information on common symptoms and prevention of SHV. If you have any symptoms of SHV and a history of rat contact, please contact your doctor.
  • Additional information can be found on the following websites:
2016 Outbreaks

Multidrug-resistant Campylobacter Outbreak
Final Update 01/18/2018

Sleepy puppy rests in his owner's arm

  • The Wisconsin Department of Health Services (DHS), the Centers for Disease Control and Prevention (CDC), several other states, and the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (USDA-APHIS) investigated a multistate outbreak of multidrug-resistant (MDR) Campylobacter infections.
  • Nationwide, 113 people from 17 states were infected with the outbreak strain of MDR Campylobacter, including eight people in Wisconsin. Illnesses started on dates ranging from Jan. 12, 2016, to Jan. 7, 2018.
    • Of the 103 ill people with information available, 23 (22%) were hospitalized.
    • This outbreak was linked to contact with pet store puppies. Of those who became ill, 90% had a link to puppies at, or from, a Petland store, or had contact with with a person who became sick after contact with a puppy from a Petland store.
  • In Wisconsin, eight people became sick and two were hospitalized.
  • All puppies and dogs can carry Campylobacter bacteria. Because of this, it is especially important to wash your hands thoroughly with running water and soap for at least 20 seconds every time you touch dogs, their poop, or their food. Adults should supervise handwashing for young children. Please see our Handwashing After Animal Contact flyer, P-01699 for more information about how to prevent these infections.
  • See the DHS campylobacteriosis fact sheet, P-42045 for more information on common symptoms and treatment of campylobacteriosis. If you have any symptoms of campylobacteriosis, please contact your doctor.
  • Additional information can be found on the following websites:

Elizabethkingia anophelis
Final Update 05/03/2016

Elizabethkingia Anophelis - culture plate

  • The Wisconsin Department of Health Services (DHS) and the Centers for Disease Control and Prevention (CDC) investigated an outbreak of bacterial infections caused by Elizabethkingia anophelis.
  • There were 67 total cases reported to DHS during this outbreak. Of those cases, 63 were confirmed, and four tested positive for Elizabethkingia but will never be confirmed as the same strain of Elizabethkingia anophelis because the specimens were not available for testing.
  • The majority of patients who acquired these infections were over 65 and all patients had a history of at least one underlying serious illness.
  • Counties with confirmed cases include Columbia, Dane, Dodge, Fond du Lac, Jefferson, Milwaukee, Ozaukee, Racine, Sheboygan, Washington, Waukesha, and Winnebago.
  • There were 18 deaths among individuals with confirmed Elizabethkingia anophelis infections and an additional one death among possible cases for a total of 19 deaths. It was not determined if these deaths were caused by the infection or other serious, pre-existing health problems. Counties where deaths occurred are: Columbia, Dodge, Fond du Lac, Milwaukee, Ozaukee, Racine, Sheboygan, Washington, and Waukesha.
  • DHS quickly identified effective antibiotic treatment for Elizabethkingia, and alerted health care providers, infection preventionists, and laboratories statewide. Initial guidance was sent on January 15, 2016, and there was a rapid identification of cases and health care providers were able to treat and improve outcomes for patients.
  • Additional information can be found on the following websites:
2015 Outbreaks

Salmonella Heidelberg
Final Update 02/12/2018

Calf laying on hay

Last Revised: May 10, 2021