Multistate Salmonella outbreak linked to backyard poultry flocks

News brief

Backyard chickens — Emilia Kohn / iStock

An outbreak of Salmonella linked to backyard poultry flocks has sickened 109 people in 29 states, Centers for Disease Control and Prevention (CDC) officials said yesterday.

While no deaths have been reported, the CDC said 33 people have been hospitalized. The median age of case-patients is 10 years, with 43% of those sickened under 5 years. Illnesses started on dates ranging from February 24 to April 30. Epidemiologic, traceback, and laboratory indicate backyard poultry is the source.

Of the 70 people interviewed by state and local public health officials, 51 reported contact with backyard poultry in the week before they got sick. Of the 28 people with information available, 18 reported buying poultry from multiple retail stores and a hatchery. No common poultry supplier has been identified.

The outbreak involves multiple Salmonella serovars, including Altona, Indiana, Infantis, Mbandaka, and Typhimurium. Whole-genome sequencing conducted by CDC PulseNet—the national subtyping network for foodborne bacterial disease surveillance—on isolates from case-patients shows they are closely related genetically. In addition, sequencing of samples collected from boxes used to ship poultry from hatcheries to retail stores in Indiana and Utah found that the Salmonella Altona and Salmonella Mbandaka isolates were the same strain as those found in case-patients.

Some antibiotic resistance detected

Further testing of isolates from 101 case-patients and 4 environmental samples found no predicted antibiotic resistance, but seven people's samples predicted resistance to one or more of the following antibiotics: amoxicillin-clavulanic acid, ampicillin, cefoxitin, ceftiofur, ceftriaxone, chloramphenicol, ciprofloxacin, gentamicin, kanamycin, streptomycin, sulfisoxazole, and tetracycline.

While most people recover from Salmonella infections without antibiotics, the CDC says some illnesses in the outbreak may be difficult to treat with commonly recommended antibiotics. Young children, adults over 65, and people with weakened immune systems have a higher risk of becoming severely ill.

The CDC advises people to wash their hands after touching backyard poultry and their eggs, supervise children around flocks, and to refrain from kissing or snuggling backyard poultry.

H5N1 traces found in muscle from culled dairy cow; Michigan reports 3 more affected herds

News brief

Lisa Schnirring

As part of its food safety testing in the wake of H5N1 avian flu circulation in dairy herds, the US Department of Agriculture (USDA) Food Safety Inspection Service (FSIS) announced today that viral particles were detected in tissue samples, including muscle, from 1 of 96 cows that were tested.

raw meat — Christine & Eric Mahler/Flickr cc

Meat from the culled dairy cows did not enter the food supply. At select FSIS-inspected facilities, the agency collected multiple tissues from the culled animals, including muscle samples from the diaphragm. Polymerase chain reaction (PCR) testing, which can detect virus fragments but not live virus, on the sample was done by the USDA's Animal and Plant Health Inspection Service (APHIS).

Postmortem examination of the animal that tested positive revealed signs of illness, and traceback activities are under way, along with notification of the producer to get further information.

USDA said the actions are part of its routine operations and provide further confidence in the US food safety system.

Virus strikes herd in 10th Michigan county

The Michigan Department of Agriculture and Rural Development (MDARD) today announced that H5N1 has been detected in three more dairy herds, including the first from Calhoun County. The other two farms are in Clinton and Ionia counties.

Samples from the cows tested positive for the virus at the Michigan State University Veterinary Diagnostic Laboratory. MDARD said the USDA's National Veterinary Services Laboratory (NVSL) has already confirmed findings from the outbreak in the Ionia County herd and that the NVSL's confirmation tests are still pending on samples from the Calhoun and Clinton county herds.

MDARD's line list for the outbreak now reflects 21 affected dairy herds from 10 counties, the most of any state.

Quick takes: US FLiRT variant proportions rise, first polio case in Angola, norovirus and raw oysters

News brief

Lisa Schnirring

In updated variant proportion estimates today, the US Centers for Disease Control and Prevention (CDC) reported steady rises in SARS-CoV-2 variants that have the FLiRT mutation, which may give them more immune-evasive properties but aren't known to cause more severe COVID illness. KP.2 and KP.3, which are offshoots of JN.1, currently make up 41.2% of sequenced viruses. (FLiRT stands for F for L at position 456 and R for T at position 346.) FLiRT viruses are fueling rises in cases in some countries such as Singapore. In the United States, the main COVID markers show no sign of a wave, but early indictors are up very slightly from very low levels, including test positivity and emergency department visits. Wastewater levels, another early indicator, remain at the minimal level.
Angola has reported its first infection from circulating vaccine-derived poliovirus type 2 (cVDPV2), which involved a patient from Lunda Norte province, which borders the Democratic Republic of Congo (DRC), Reliefweb reported today, citing a situation report from the International Federation of Red Cross and Red Crescent Societies. In late February, Angola's government had declared an outbreak after the detection of environmental samples in two other provinces, Luanda and Huambo. In other polio developments, three African countries reported more polio cases, all involving cVDPV2, the Global Polio Eradication Initiative (GPEI) said in its latest weekly update. They include Ethiopia, Guinea, and Nigeria.
The US Food and Drug Administration (FDA) today warned consumers, retailers, and restaurants not to eat or serve certain raw, half-shell oysters sourced from South Korea due to potential norovirus contamination and illness reports in people from Utah. JBR, based in Tongyeong, recalled oysters with the lot number B231227, which were distributed by a California company to restaurants and retailers in California, Colorado, Nevada, New Jersey, and Utah. Investigators are still working to determine other locations that received the products. In April, the FDA issued a similar warning after products from the same company were linked to norovirus illnesses in California.