obÌåÓý

obÌåÓý 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).

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. obÌåÓý 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. obÌåÓý 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.