Investigation Details
Posted November 10, 2022
This year’s investigation of outbreaks linked to backyard poultry is over. However, any backyard poultry can carry Salmonella germs that can make you sick. Always take steps to stay healthy around your flock.
CDC and public health officials in many states investigated 13 multistate outbreaks of Salmonella infections with seven serotypes: Enteritidis, Hadar, I 4,[5],12:i:-, Indiana, Infantis, Typhimurium, and Mbandaka.
Epidemiologic, laboratory, and traceback data showed that contact with backyard poultry made people sick.
As of November 10, this outbreak investigation is over.
Epidemiologic Data
A total of 1,230 people infected with one of the outbreak strains were reported from 49 states, the District of Columbia, and Puerto Rico (see map). Illnesses started on dates ranging from February 12, 2022, to October 18, 2022 (see timeline).
Sick people ranged in age from less than 1 to 102 years, with a median age of 36 years, and 253 (21%) were children under 5 years. Of the 1,202 people with sex information available, 661 (55%) were female. Of the 726 people with health outcome information available, 230 (32%) were hospitalized. Two deaths were reported, one from Tennessee and one from Wyoming.
The true number of sick people in these outbreaks was likely much higher than the number reported, and the outbreaks may not have been limited to the states with known illnesses. This is because many people recover without medical care and are not tested for Salmonella.
State and local public health officials interviewed people about the food they ate and the animals they came into contact with in the week before they got sick. Of the 737 people interviewed, 433 (59%) reported contact with backyard poultry before getting sick. Of the 507 people with dietary information available, 146 (29%) reported eating eggs from backyard poultry and 14 (3%) reported eating meat from backyard poultry before getting sick.
Traceback Data
Of the 289 people with purchase information available, 216 (75%) people reported purchasing backyard poultry since January 1 of this year, and 41 people purchased poultry from more than one location. Purchase locations included feedstores, a flea market, an auction, a 4H event, and directly from hatcheries. Fifteen patients purchased poultry directly from seven hatcheries. Of purchases made from feedstores, 195 retail locations owned by 50 companies were reported. These feedstores were supplied by at least 10 hatcheries. One common poultry supplier was not identified across all 13 outbreaks.
Laboratory Data
Public health investigators used the PulseNet system to identify illnesses that were part of these outbreaks. 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 were closely related genetically. This means that people in these outbreaks likely got sick from the same type of animal.
Public health officials in North Dakota, New Mexico, Tennessee, and Wisconsin identified several of the outbreak strains in samples collected from poultry and poultry enclosures, in stores, and at people’s homes.
Whole genome sequencing (WGS) was also used to identify any predicted antibiotic resistance for bacteria from 1,225 sick people’s samples, 15 animal samples, and 14 environmental samples. Of the total 1,254 samples, 538 (42.9%) were predicted to be resistant to one or more of the following antibiotics: amoxicillin-clavulanic acid (0.2%), ampicillin (1.8%), cefoxitin (0.2%), ceftiofur (0.2%), ceftriaxone (0.2%), chloramphenicol (0.1%), ciprofloxacin (16.4%), gentamicin (0.8%), kanamycin (0.2%), nalidixic acid (16.4%), streptomycin (22.1%), sulfamethoxazole (2.1%), tetracycline (23.1%), and trimethoprim-sulfamethoxazole (1.4%). Analysis of bacteria from 694 sick people’s samples, 8 animal samples, and 14 environmental samples did not predict resistance to any antibiotics. Testing of bacteria from 5 sick people’s samples using standard antibiotic susceptibility testing methods by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) confirmed these results (streptomycin, kanamycin, and ceftiofur were not tested by this method).
Most people with Salmonella illness recover without antibiotics. However, if antibiotics are needed, some illnesses in these outbreaks may be difficult to treat with some commonly recommended antibiotics and may require a different antibiotic choice.
Public Health Action
CDC always advises everyone to take steps to stay healthy around backyard poultry. CDC continues to work with hatcheries and stores that sell poultry to educate new poultry owners and control the spread of Salmonella.
CDC and public health officials in many states are collecting different types of data to investigate multistate outbreaks of Salmonella infections with serotypes Enteritidis, Hadar, Indiana, Infantis, Typhimurium, Mbandaka, and I 4,[5],12:i:-.
Epidemiologic and laboratory data show that contact with backyard poultry is making people sick.
Epidemiologic Data
Since the last update on August 12, 2022, 307 more illnesses have been reported. As of September 12, 2022, a total of 1,191 people infected with one of the outbreak strains have been reported from 50 states, the District of Columbia, and Puerto Rico (see map). Illnesses started on dates ranging from February 3, 2022, to September 1, 2022 (see timeline).
Sick people range in age from less than 1 to 102 years, with a median age of 36 years, and 249 (21%) are young children under 5 years. Of the 1,164 people with sex information available, 635 (55%) are female. Of the 681 people with health outcome information available, 211 (31%) have been hospitalized. Two deaths have been reported, one from Tennessee and one from Wyoming.
The true number of sick people in an outbreak is likely much higher than the number reported. 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.
State and local public health officials are interviewing people about the food they ate and the animals they came into contact with in the week before they got sick. Of the 685 people interviewed, 399 (58%) reported contact with backyard poultry before getting sick, 119 (17%) reported eating eggs from backyard poultry, 14 (2%) reported eating meat from backyard poultry, and 257 (38%) reported that at least one of their household members had contact with backyard poultry.
Laboratory and Traceback Data
Of the 386 people with purchase information available, 199 (52%) people reported purchasing backyard poultry since January 1 of this year, and 36 people purchased poultry from more than one location. People have reported buying poultry from 199 retail locations across 42 states and territories. Traceback of these purchases has not identified a single, common source of backyard poultry. At least nine hatcheries supplied backyard poultry to these purchase locations.
Whole genome sequencing (WGS) was used to identify any predicted antimicrobial resistance for bacteria from 1,186 sick people’s samples, 8 animal samples, and 14 environmental samples. Of the total 1,208 samples, 538 (44.5%) were predicted to be resistant to one or more of the following antibiotics: amoxicillin-clavulanic acid (0.2%), ampicillin (1.8%), cefoxitin (0.2%), ceftiofur (0.2%), ceftriaxone (0.2%), chloramphenicol (0.1%), ciprofloxacin (21.7%), gentamicin (0.7%), kanamycin (0.2%), nalidixic acid (21.7%), streptomycin (19.5%), sulfamethoxazole (2.2%), tetracycline (20.4%), and trimethoprim-sulfamethoxazole (1.5%). Testing of bacteria from 5 sick people’s samples using standard antimicrobial susceptibility testing methods by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) confirmed these results (streptomycin, kanamycin, and ceftiofur were not tested by this method).
Most people with Salmonella illness recover without antibiotics. However, if antibiotics are needed, some illnesses in these outbreaks may be difficult to treat with some commonly recommended antibiotics and may require a different antibiotic choice.
Public Health Actions
CDC always advises everyone to take steps to stay healthy around backyard poultry. CDC is working with hatcheries and stores that sell poultry to educate new poultry owners and control the spread of Salmonella at hatcheries.
CDC and public health officials in many states are collecting different types of data to investigate multistate outbreaks of Salmonella infections with serotypes Enteritidis, Hadar, I 4,[5],12:i:-, Indiana, Infantis, Typhimurium, and Mbandaka.
Epidemiologic and laboratory data show that contact with backyard poultry is making people sick. Since the previous update on July 13, 2022, two additional strains (I 4,[5],12:i:- and Indiana) and 312 new illnesses have been reported.
Epidemiologic Data
As of August 1, 2022, a total of 884 people infected with one of the outbreak strains have been reported from 48 states and the District of Columbia (see map). Illnesses started on dates ranging from February 3, 2022, to July 23, 2022 (see timeline).
Sick people range in age from less than 1 to 102 years, with a median age of 32 years, and 191 (22%) are young children under 5 years. Of the 866 people with sex information available, 475 (55%) are female. Of the 503 people with health outcome information available, 158 (31%) have been hospitalized. Two deaths have been reported, one from Tennessee and one from Wyoming.
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 2 to 4 weeks to determine if a sick person is part of an outbreak.
State and local public health officials are interviewing people about the food they ate and the animals they came into contact with in the week before they got sick. Of the 430 people interviewed, 269 (63%) reported contact with backyard poultry before getting sick. Of the 311 people with dietary information available, 80 (26%) reported eating eggs from backyard poultry and 12 (4%) reported eating meat from backyard poultry before getting sick.
Of the 303 people with purchase information available, 169 (56%) people report purchasing backyard poultry since January 1 of this year, and 31 people purchased poultry from more than one location. People have reported buying poultry from 177 retail locations across 41 states.
Laboratory Data
Public health officials in North Dakota, New Mexico, Tennessee, and Wisconsin identified several of the outbreak strains in samples collected from poultry and poultry enclosures, in stores and at people’s homes.
Whole genome sequencing (WGS) was also used to identify any predicted antibiotic resistance for bacteria from 882 sick people’s samples, 10 animal samples, and 12 environmental samples. Of the total 904 samples, 367 (40.6%) were predicted to be resistant to one or more of the following antibiotics: amoxicillin-clavulanic acid (0.3%), ampicillin (2.3%), cefoxitin (0.3%), ceftiofur (0.3%), ceftriaxone (0.3%), chloramphenicol (0.1%), ciprofloxacin (17.4%), gentamicin (0.8%), kanamycin (0.2%), nalidixic acid (17.4%), streptomycin (19.2%), sulfamethoxazole (2.5%), tetracycline (20.4%), and trimethoprim-sulfamethoxazole (1.9%). Testing of bacteria from 3 sick people’s samples using standard antibiotic susceptibility testing methods by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) confirmed these results (streptomycin, kanamycin, and ceftiofur were not tested by this method).
Most people with Salmonella illness recover without antibiotics. However, if antibiotics are needed, some illnesses in these outbreaks may be difficult to treat with some commonly recommended antibiotics and may require a different antibiotic choice.
Public Health Action
CDC always advises everyone to take steps to stay healthy around backyard poultry. CDC is working with hatcheries and stores that sell poultry to educate new poultry owners and control the spread of Salmonella at hatcheries.
CDC and public health officials in many states are collecting different types of data to investigate multistate outbreaks of Salmonella infections with serotypes Enteritidis, Hadar, Infantis, Typhimurium, and Mbandaka.
Epidemiologic and laboratory data show that contact with backyard poultry is making people sick. Since the previous update on June 9, 2022, one additional strain (Mbandaka) and 353 new illnesses have been reported.
Epidemiologic Data
As of July 5, 2022, a total of 572 people infected with one of the outbreak strains have been reported from 48 states (see map). Illnesses started on dates ranging from February 3, 2022, to June 22, 2022 (see timeline).
Sick people range in age from less than 1 to 102 years, with a median age of 32 years, and 130 (23%) are young children under 5 years. Of 559 people with information available, 304 (54%) are female. Of 278 people with information available, 92 (33%) have been hospitalized. Two deaths have been reported, one from Tennessee and one from Wyoming.
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 2 to 4 weeks to determine if a sick person is part of an outbreak.
State and local public health officials are interviewing people about the animals they came into contact with in the week before they got sick. Of the 279 people interviewed, 196 (70%) reported contact with backyard poultry before getting sick. Of 175 people with information available, 42 (24%) reported eating eggs from backyard poultry before getting sick. Of 176 people with information available, 5 (3%) reported eating meat from backyard poultry before getting sick.
Of 195 people with information available, 125 (64%) people report purchasing backyard poultry since January 1 of this year. Nineteen of those people purchased poultry from more than one location. People have reported purchasing poultry from 130 different retail locations across 36 states.
Laboratory Data
Public health officials in North Dakota, Tennessee, and Wisconsin identified outbreak strains in testing of poultry and poultry environments in stores and at people’s homes.
Whole genome sequencing (WGS) was also used to identify any predicted antibiotic resistance for bacteria from 571 sick people’s samples, 3 animal samples, and 9 environmental samples. Of the total 583 samples, 204 (35.0%) were predicted to be resistant to one or more of the following antibiotics: amoxicillin-clavulanic acid (0.5%), ampicillin (3.1%), cefoxitin (0.5%), ceftiofur (0.5%), ceftriaxone (0.5%), ciprofloxacin (8.9%), gentamicin (0.9%), kanamycin (0.2%), nalidixic acid (8.9%), streptomycin (22.6%), sulfamethoxazole (3.1%), tetracycline (22.5%), and trimethoprim-sulfamethoxazole (2.4%). Testing of bacteria from 3 sick people’s samples using standard antibiotic susceptibility testing methods by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) confirmed these results (streptomycin, kanamycin, and ceftiofur were not tested by this method).
Most people with Salmonella illness recover without antibiotics. However, if antibiotics are needed, some illnesses in these outbreaks may be difficult to treat with some commonly recommended antibiotics and may require a different antibiotic choice.
Public Health Action
CDC always advises everyone to take steps to stay healthy around backyard poultry. CDC is working with hatcheries and stores that sell poultry to educate new poultry owners and control the spread of Salmonella at hatcheries.
CDC and public health officials in many states are collecting different types of data to investigate multistate outbreaks of Salmonella infections with serotypes Enteritidis, Hadar, Typhimurium, and Infantis.
Epidemiologic data show that contact with backyard poultry is making people sick.
Epidemiologic Data
As of June 2, 2022, a total of 219 people infected with one of the outbreak strains have been reported from 38 states (see map). Illnesses started on dates ranging from February 15, 2022, to May 19, 2022 (see timeline).
Sick people range in age from less than 1 to 89 years, with a median age of 29 years, and 56 (26%) are young children under 5 years. Of 213 people with information available, 116 (54%) are female. Of 95 people with information available, 27 (28%) have been hospitalized. One death has been reported from Tennessee.
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 2 to 4 weeks to determine if a sick person is part of an outbreak.
State and local public health officials are interviewing people about the animals they came into contact with in the week before they got sick. Of the 87 people interviewed, 61 (70%) reported contact with backyard poultry before getting sick. Of 56 people with information available, 16 reported eating eggs from backyard poultry and 2 reported eating meat from backyard poultry.
Laboratory Data
Public health investigators are using the PulseNet system to identify illnesses that may be part of these outbreaks. 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 these outbreaks likely got sick from the same type of animal.
WGS was also used to identify any predicted antibiotic resistance for bacteria from 219 sick people’s samples. Of the 219 samples, 72 (33%) were predicted to be resistant to one or more of the following antibiotics: ampicillin (0.9%), kanamycin (0.5%), streptomycin (30.6%), sulfamethoxazole (0.9%), tetracycline (31.5%), and trimethoprim-sulfamethoxazole (0.9%). Testing of bacteria from 2 sick people’s samples using standard antibiotic susceptibility testing methods by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) confirmed these results (streptomycin and kanamycin were not tested by this method).
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.
Public Health Action
CDC always advises everyone to take steps to stay healthy around backyard poultry. CDC is working with hatcheries and stores that sell poultry to educate new poultry owners and control the spread of Salmonella at hatcheries.