People in 21 states have been confirmed with Salmonella infections, with seven out of 10 of them reporting they handled birds in backyard flocks before becoming ill, according to an outbreak alert from the CDC.

Five of the 52 confirmed patients have been so sick they had to be admitted to hospitals, according to the Centers for Disease Control and Prevention. Four of the Salmonella Salmonella Braenderup and Salmonella Montevideo strains detected in the ill people are resistant to some antibiotics that are commonly used to treat such infections. Five isolates from ill people did not show evidence of antibiotic resistance.

State public health officials have reported to the CDC that the first confirmed patient became ill on Jan. 12. The most recent was confirmed on April 29. Salmonella is easily transferred to hard and soft surfaces. It is particularly easy to contaminate kitchen counters, cooking utensils, pots and pans.

Source: CDC

But, proper handwashing and careful handling of backyard chickens and ducks can eliminate much of the risk. Also, state health departments are increasingly working with hatcheries and other businesses that sell live chicks to consumers to raise public awareness about the risks of infection.

Click on image to view video. Video by James Andrews

As with outbreaks detected in recent years, many of the patients in the current outbreak reported handling live birds in the days before becoming ill.

In interviews, ill people answered questions about animal contact in the week before they became ill. Of 33 people interviewed, 23 (70%) reported contact with backyard poultry before becoming ill. Ill people reported buying poultry from various sources, including agricultural stores, websites, and hatcheries.

Backyard poultry from multiple hatcheries are the likely source of these outbreaks. Regardless of wher 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.

Public health investigators are using the PulseNet system to identify illnesses that may be part of these outbreaks. PulseNet is the national subtyping network of public health laboratories coordinated by CDC. 

DNA fingerprinting is performed on Salmonella bacteria isolated from ill people by using techniques called pulsed-field gel electrophoresis (PFGE) and whole genome sequencing (WGS). CDC PulseNet manages a national database of these DNA fingerprints to identify possible outbreaks. 

WGS gives a more detailed DNA fingerprint than PFGE. WGS performed on Salmonella from ill people in this outbreak showed that they are closely related genetically. This means that the ill people are more likely to share a common source of infection.