Outbreak Investigation Updates by Date

Posted November 18, 2020 at 3:00 PM ET

September 23, 2020

Since the last update on July 29, 2020, 408 more ill people and one additional Salmonella serotype (Newport) were added to this investigation.

As of September 22, 2020, a total of 1,346 people infected with one of the outbreak strains of Salmonella have been reported from 49 states. A list of the states and the number of cases in each is on the Map of Reported Cases page.

Illnesses started on dates from January 14, 2020, to August 28, 2020. Ill people range in age from less than 1 year to 95 years, with a median age of 34. Fifty-eight percent are female. Of 698 people with information available, 229 (33%) have been hospitalized. One death in Oklahoma has been reported.

If antibiotics are needed, some infections related to these outbreaks may be difficult to treat with some commonly recommended antibiotics and may require a different antibiotic choice. Whole genome sequencing performed on Salmonella bacteria isolated from 1083 ill people and two environmental samples showed predicted antibiotic resistance to one or more of the following antibiotics for 718 isolates: amoxicillin-clavulanic acid (1.8%), ampicillin (4.1%), cefoxitin (1.8%), ceftriaxone (1.8%), chloramphenicol (0.8%), ciprofloxacin (0.2%), fosfomycin (2.6%), gentamicin (1.1%), kanamycin (0.4%), streptomycin (59.2%), sulfisoxazole (4.2%), tetracycline (59.3%), and trimethoprim-sulfamethoxazole (2.3%). There was no antibiotic resistance predicted for 367 (33.8%) isolates. Testing of 12 outbreak isolates using standard antibiotic susceptibility testing by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory showed resistance to streptomycin and tetracycline in 3 isolates and no resistance in 9 isolates (fosfomycin and kanamycin were not tested by this method).

Investigation of the Outbreaks

Epidemiologic and laboratory evidence shows that contact with poultry (such as chicks and ducklings) in backyard flocks is the likely source of these outbreaks.

In interviews, ill people answered questions about animal contact in the week before they became ill. Of 613 people interviewed, 416 (68%) reported contact with chicks and ducklings before becoming ill.

Testing of backyard poultry and their environments (such as backyard coops) in Kentucky and Oregon found three of the outbreak strains.

Ill people reported buying poultry from many sources, including agricultural stores, websites, and hatcheries. No single store chain or hatchery accounts for all of the illnesses.

Regardless of where backyard poultry are purchased, they can carry Salmonella germs that can make people sick. Backyard poultry owners should always follow steps to stay healthy around their flocks.

This investigation is ongoing, and CDC will provide updates when more information becomes available.

July 29, 2020

Since the last update on June 24, 2020, 473 more ill people and four additional Salmonella serotypes (Braenderup, Muenchen, Thompson, and Typhimurium) were added to this investigation.

As of July 28, 2020, a total of 938 people infected with one of the outbreak strains of Salmonella have been reported from 48 states. A list of the states and the number of cases in each is on the map of reported cases page.

Illnesses started on dates from January 14, 2020, to July 14, 2020. Ill people range in age from less than 1 year to 94 years, with a median age of 32. Fifty-six percent are female. Of 461 people with information available, 151 (33%) have been hospitalized. One death in Oklahoma has been reported.

If antibiotics are needed, some infections related to these outbreaks may be difficult to treat with some commonly recommended antibiotics and may require a different antibiotic choice. Whole genome sequencing performed on Salmonella bacteria isolated from 597 ill people predicted antibiotic resistance to one or more of the following antibiotics: amoxicillin-clavulanic acid (1.4%), ampicillin (4.0%), cefoxitin (1.4%), ceftriaxone (1.4%), chloramphenicol (0.8%), ciprofloxacin (0.1%), fosfomycin (2.8%), gentamicin (1.2%), kanamycin (0.4%), streptomycin (63.4%), sulfisoxazole (4.4%), tetracycline (63.5%), and trimethoprim-sulfamethoxazole (2.6%). There was no antibiotic resistance predicted for 249 (29.4%) isolates. Testing of 10 outbreak isolates using standard antibiotic susceptibility testing by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory confirmed these results (fosfomycin and kanamycin were not tested by this method).

Investigation of the Outbreaks

Epidemiologic and laboratory evidence shows that contact with poultry (such as chicks and ducklings) in backyard flocks is the likely source of these outbreaks.

In interviews, ill people answered questions about animal contact in the week before they became ill. Of 409 people interviewed, 303 (74%) reported contact with chicks and ducklings before becoming ill.

Testing of backyard poultry and their environments (such as backyard coops) in Kentucky and Oregon found three of the outbreak strains.

Ill people reported buying poultry from many sources, including agricultural stores, websites, and hatcheries. No single store chain or hatchery accounts for all of the illnesses.

Regardless of where backyard poultry are purchased, they can carry Salmonella germs that can make people sick. Backyard poultry owners should always follow steps to stay healthy around their flocks.

This investigation is ongoing, and CDC will provide updates when more information becomes available.

June 24, 2020

Since the last update on May 20, 2020, 368 more ill people and six additional Salmonella serotypes (Agona, Anatum, Enteritidis, Infantis, Mbandaka, and I 4,[5], 12:i:-) were added to this investigation.

As of June 23, 2020, a total of 465 people infected with one of the outbreak strains of Salmonella have been reported from 42 states. A list of the states and the number of cases in each is on the map of reported cases page.

Illnesses started on dates from January 14, 2020, to June 1, 2020. Ill people range in age from less than 1 year to 88 years, with a median age of 31. Fifty-six percent are female. Of 241 people with information available, 86 (36%) have been hospitalized. One death in Oklahoma has been reported.

If antibiotics are needed, some infections related to these outbreaks may be difficult to treat with some commonly recommended antibiotics and may require a different antibiotic choice. Whole genome sequencing performed on 225 samples of Salmonella bacteria isolated from ill people predicted antibiotic resistance to one or more of the following antibiotics: amoxicillin-clavulanic acid (2.2%), ampicillin (3.4%), cefoxitin (2.2%), ceftriaxone (2.2%), chloramphenicol (0.4%), fosfomycin (5.2%), gentamicin (0.7%), streptomycin (75.7%), sulfisoxazole (2.2%), tetracycline (76.4%), and trimethoprim-sulfamethoxazole (1.1%). There was no antibiotic resistance predicted for 42 (15.7%) isolates. Testing of four outbreak isolates using standard antibiotic susceptibility testing by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory confirmed these results (fosfomycin was not tested by this method).

Investigation of the Outbreaks

Epidemiologic evidence shows that contact with backyard poultry (such as chicks and ducklings) is the likely source of these outbreaks.

In interviews, ill people answered questions about animal contact in the week before they became ill. Of 226 people interviewed, 179 (79%) reported contact with chicks and ducklings before becoming ill. Ill people reported buying poultry from various sources, including agricultural stores, websites, and hatcheries.

Regardless of where poultry are purchased, they can carry Salmonella germs that can make people sick. Backyard poultry owners should always follow steps to stay healthy around their flocks.

This investigation is ongoing, and CDC will provide updates when more information becomes available.

May 20, 2020

CDC and public health officials in multiple states are investigating a multistate outbreak of Salmonella Hadar infections linked to contact with backyard poultry.

Public health investigators are using the PulseNet system to identify illnesses that are part of this outbreak. PulseNet is the national subtyping network of public health and food regulatory agency laboratories coordinated by CDC. DNA fingerprinting is performed on Salmonella bacteria isolated from ill people by using a standardized laboratory and data analysis method called whole genome sequencing (WGS). CDC PulseNet manages a national database of these sequences that are used to identify possible outbreaks. WGS gives investigators detailed information about the bacteria causing illness. In this investigation, WGS showed that bacteria isolated from ill people were closely related genetically. This means that people in this outbreak were more likely to share a common source of infection.

As of May 15, 2020, a total of 97 people infected with the outbreak strain of Salmonella Hadar have been reported from 28 states. A list of the states and the number of cases in each is on the map of reported cases page.

Illnesses started on dates from February 26, 2020, to May 1, 2020. Ill people range in age from less than one year to 87 years, with a median age of 37 years. Fifty-eight percent are female. Of 50 people with information available, 17 (34%) have been hospitalized. No deaths have been reported.

If antibiotics are needed, some infections related to these outbreaks may be difficult to treat with some commonly recommended antibiotics and may require a different antibiotic choice. WGS of 26 isolates from ill people predicted antibiotic resistance to one or more of the following antibiotics: amoxicillin-clavulanic acid (4%), ampicillin (4%), cefoxitin (4%), ceftriaxone (4%), gentamicin (4%), streptomycin (100%), sulfamethoxazole (4%), and tetracycline (100%). Testing of clinical isolates using standard antibiotic susceptibility testing methods by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory is currently underway.

Investigation of the Outbreak

Epidemiologic evidence shows that contact with backyard poultry (such as chicks and ducklings) is the likely source of this outbreak.

In interviews, ill people answered questions about animal contact in the week before they became ill. Of 44 people interviewed, 38 (86%) reported contact with chicks and ducklings before becoming ill. Ill people reported buying poultry from various sources, including agricultural stores, websites, and hatcheries.

Regardless of where poultry are purchased, these birds can carry Salmonella germs that can make people sick. Backyard poultry owners should always follow steps to stay healthy around their birds.

This investigation is ongoing, and CDC will provide updates when more information becomes available.