Key points
Public health officials are investigating multistate outbreaks of Salmonella illnesses linked to contact with backyard poultry. Any backyard poultry can carry Salmonella germs that can make you sick. Always take steps to stay healthy around your flock.
Investigation details
CDC and public health officials in several states are collecting different types of data to investigate multistate outbreaks of Salmonella Mbandaka and Salmonella Enteritidis infections.
Epidemiologic, traceback, and laboratory data show that contact with backyard poultry is making people sick.
Epidemiologic data
Since the last update on May 5, 2025, 97 new people, 29 new states, and one new Salmonella serotype were added to the investigation. As of May 19, 2025, a total of 104 people who were infected have been reported from 35 states. Illnesses started on dates ranging from February 9, 2025, to May 3, 2025. Of 83 people with information available, 25 (30%) have been hospitalized. One death has been reported from Illinois.
The true number of sick people in an outbreak is likely much higher than the number reported, and the outbreak may not be limited to the states with known illnesses. This is because many people recover without medical care and are not tested for Salmonella. In addition, recent illnesses may not yet be reported as it usually takes 3 to 4 weeks to determine if a sick person is part of an outbreak.
Public health officials collect many different types of information from sick people, including their age, race, ethnicity, other demographics, and the animals they had contact with in the week before they got sick. This information provides clues to help investigators identify the source of the outbreak.
The table below has information about sick people in this outbreak ("n" is the number of people with information available for each demographic).
Demographics
Information
Age
(n=103)
Range from <1 to 85 years
Median age of 18 years
32% under 5 years
Sex
(n=103)
48% female
52% male
Race
(n=76)
92% White
4% African American/Black
4% Native American or Alaska Native
Ethnicity
(n=76)
83% non-Hispanic
17% Hispanic
State and local public health officials are interviewing people about the animals they had contact with during the week before they got sick. Of the 71 people with information about animal contact, 58 (82%) reported contact with backyard poultry before getting sick.
Traceback data
Of 33 people who reported owning backyard poultry, 27 (82%) reported purchasing or obtaining poultry since January 1 of this year. People reported obtaining poultry from agricultural retail stores. Investigators continue to collect information about where sick people obtained poultry and what hatcheries supplied the retail stores that ill people purchased poultry from.
These outbreak strains have been linked to two hatcheries. CDC is working with state partners to notify these hatcheries of these links and assess any links to upstream suppliers. Additional hatcheries may be linked to these outbreaks as the investigation continues.
Laboratory data
Investigators in Ohio collected samples from the inside of boxes used to ship poultry from hatcheries to retail stores, including the box liner and bedding. WGS showed that the Salmonella Mbandaka found in these samples was the same strain as the one found in sick people. This sample was linked to a hatchery that was also identified by traceback data.
Based on WGS analysis, bacteria from 67 people's samples and one environmental sample had no predicted resistance; two people's samples predicted resistance to gentamicin, streptomycin, and tetracycline, while 35 people's samples predicted nonsusceptibility to ciprofloxacin. Most people with Salmonella illness recover without antibiotics. However, if antibiotics are needed, some illnesses in this outbreak may not be treatable with some commonly recommended antibiotics and may require a different antibiotic choice. More information is available at the National Antimicrobial Resistance Monitoring System (NARMS) site.
Previous updates
Investigation details
CDC and public health officials in several states are collecting different types of data to investigate a multistate outbreak of Salmonella Mbandaka infections.
Epidemiologic, traceback, and laboratory data show that contact with backyard poultry is making people sick.
Epidemiologic data
As of April 24, a total of 7 people infected with the outbreak strain of Salmonella Mbandaka have been reported from 6 states. Illnesses started on dates ranging from February 9, 2025, to March 24, 2025.
The true number of sick people in an outbreak is likely much higher than the number reported, and the outbreak may not be limited to the states with known illnesses. This is because many people recover without medical care and are not tested for Salmonella. In addition, recent illnesses may not yet be reported as it usually takes 3 to 4 weeks to determine if a sick person is part of an outbreak.
Public health officials collect many different types of information from sick people, including their age, race, ethnicity, other demographics, and the animals they had contact with in the week before they got sick. This information provides clues to help investigators identify the source of the outbreak.
The table below has information about sick people in this outbreak ("n" is the number of people with information available for each demographic).
Demographics
Information
Age
(n=7)
Range from <1 to 55 years
Median age of 5 years
43% under 5 years
Sex
(n=7)
57% female
43% male
Race
(n=5)
100% White
Ethnicity
(n=6)
83% non-Hispanic
17% Hispanic
State and local public health officials are interviewing people about the animals they had contact within the week before they got sick. Of the 7 people with information about animal contact, 5 (71%) reported contact with backyard poultry before getting sick.
Traceback data
Of 4 people with information available, 2 (50%) reported purchasing or obtaining poultry before getting sick. People reported obtaining poultry from agricultural retail stores. Investigators continue to collect information about where sick people obtained poultry and what hatcheries supplied the retail stores that ill people purchased poultry from.
This outbreak strain has been linked to two hatcheries in past outbreaks, including one which is also linked to the poultry shipping material sample in the current outbreak. CDC is working with state partners to notify this hatchery of these links and assess any links to upstream suppliers. Additional hatcheries may be linked to the outbreak as the investigation continues.
Laboratory data
Public health investigators are using the PulseNet system to identify illnesses that may be part of this outbreak. CDC PulseNet manages a national database of DNA fingerprints of bacteria that cause gastrointestinal illnesses. DNA fingerprinting is performed on bacteria using a method called whole genome sequencing (WGS). WGS showed that bacteria from sick people's samples are closely related genetically. This means that people in this outbreak likely got sick from the same type of animal.
Investigators in Ohio collected samples from the inside of boxes used to ship poultry from hatcheries to retail stores, including the box liner and bedding. WGS showed that the Salmonella Mbandaka found in these samples was the same strain as the one found in sick people.
WGS analysis of bacteria from 6 people's samples and one environmental sample did not predict resistance to any antibiotics. One person's sample predicted resistance to gentamicin, streptomycin, and tetracycline. More information is available at the National Antimicrobial Resistance Monitoring System (NARMS) site. Most people with Salmonella illness recover without antibiotics. However, if antibiotics are needed, this resistance is unlikely to affect the choice of antibiotic used to treat most people.