An ongoing outbreak of Salmonella infections traced to backyard poultry flocks has now infected 1,135 people across 48 states, the District of Columbia and Puerto Rico, according to an update from the CDC.

Two deaths have been confirmed but the ages of the victims were not reported. A fourth of the patients have been children younger than 5 years old. Twelve percent of the patients have been children younger than 1 year old, according to an update from the Centers for Disease Control and Prevention.

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“The true number of sick people in these outbreaks is likely much higher than the number reported, and these outbreaks may not have been limited to the states with known illnesses,” according to the CDC.

The first person became ill on Dec. 15, 2020, and the most recent person documented as being infected becoming sick on Oct. 10 this year. More people are expected to be added to the patient count because backyard flocks continue to be popular and it can take a month or more for a patient to be added to the list because of the time it takes to confirm and report infections.

Age information is available for 1,132 people. Patients’ ages have ranged from less than 1 to 97 years old, with a median age of 37 years. Many were young children: 268, or 24 percent, were younger than 5 years, and 140, or 12 percent, were younger than 1 year.

Of 1,107 people with gender information available, 646 were female. Of 829 people with information available, 273, or one third, were hospitalized. That is a higher than usual rate of hospitalization for Salmonella outbreaks.

State and local public health officials interviewed people about the animals they came into contact with the week before they got sick. Of the 677 people interviewed, two-thirds reported contact with backyard poultry before getting sick.

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Of 293 people who reported contact with backyard poultry and who provided more information, 212 reported that they bought backyard poultry this year. Purchase locations included feedstores, auctions, and directly from hatcheries.

Traceback of these purchases did not identify a single, common source of backyard poultry. Out of the 293 reports, a total of 264 separate purchases from more than 150 purchase locations of 70 different companies were reported. At least 17 hatcheries supplied backyard poultry to these purchase locations.

DNA fingerprinting was 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 from several states found two of the outbreak strains — Hadar and Enteritidis — from sick people’s backyard poultry and the backyard poultry environment. For example:

  • On April 15, public health officials in Ohio found the outbreak strain of Salmonella Hadar from a sick person’s ducklings.
  • On May 7, local public health officials in California found the outbreak strain of Salmonella Hadar from a sick person’s duck environment including the ground, duck droppings, and duck’s sleeping area).
  • On June 1, public health officials in Arizona found the outbreak strain of Salmonella Hadar from a sick person’s chickens and the chicken environment including the chickens’ roost and water source.
  • On June 15, public health officials in Maryland found the outbreak strain of Salmonella Enteritidis from a sick person’s chickens.

About Salmonella infections
Animals and foods that are contaminated with Salmonella bacteria usually do not look, smell or taste spoiled. Animals usually do not appear sick. Anyone can become sick with a Salmonella infection, but infants, children, seniors and people with weakened immune systems are at higher risk of serious illness because their immune systems are fragile, according to the CDC.

Anyone who has had contact with backyard flocks or farm animals — such as those at petting zoos — and developed symptoms of Salmonella infection should seek medical attention. Sick people should tell their doctors about the possible exposure to Salmonella bacteria because special tests are necessary to diagnose salmonellosis. Salmonella infection symptoms can mimic other illnesses, frequently leading to misdiagnosis.

Symptoms of Salmonella infection can include diarrhea, abdominal cramps, and fever within 12 to 72 hours after eating contaminated food. Otherwise healthy adults are usually sick for four to seven days. In some cases, however, diarrhea may be so severe that patients need to be hospitalized. 

Older adults, children, pregnant women and people with weakened immune systems, such as cancer patients, are more likely to develop a severe illness and serious, sometimes life-threatening conditions.

It is possible for some people to be infected with the bacteria and to not get sick or show any symptoms, but to still be able to spread the infection to others.

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