The US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) today confirmed more H5N1 avian flu detections in poultry from three states, including on a second commercial broiler farm in Delaware's Kent County.

Also, officials confirmed an outbreak at a backyard farm in Michigan's Oakland County that has 100 birds, an event first announced by Michigan's agriculture department yesterday.

APHIS also confirmed a detection in Missouri, which involves poultry at a backyard farm housing 20 birds in Perry County.

Meanwhile, APHIS confirmed one more H5N1 detection in dairy cattle, which involves another herd in California. The latest addition lifts the national total to 924 in 16 states and puts California's total at 707 since the end of August 2024.

In other federal developments, the Centers for Disease Control and Prevention (CDC) revised its interim guidance for employers to reduce exposure to influenza A (including H5N1) in people working with animals. Changes were made to improve the readability and organization of the guidance, which now covers workers in a wider range of settings, including zoos and sanctuaries.

Preliminary positive in Maryland poultry

Separately, the Maryland Department of Agriculture (MDA) today announced that preliminary tests have identified avian flu at a broiler operation in Caroline County, which is located on the state's eastern border with Delaware.

MDA officials said the outbreak is the first in Maryland's commercial poultry since 2023 and the third in the Delmarva region, a recently affected part of Delaware.

A 28-year-old man from Kampong Cham province in Cambodia has died from an H5N1 avian flu infection after being exposed to and possibly consuming sick chickens, according to a statement translated and posted today by Avian Flu Diary, an infectious disease news blog.

This is the 19th human H5N1 case identified in Cambodia since early 2023. Most recently, in September 2024, the country reported a fatal H5N1 case in a teen girl, caused by a novel reassortant that included internal genes from the newer 2.3.4.4b clade. The 15-year-old girl had handled sick birds in her village in the week prior to her death. 

Tale of 2 clades

The older 2.3.2.1c clade has been has been implicated in poultry outbreaks in Asia for years. Clade 2.3.4.4b is currently being transmitted globally and causing outbreaks among cattle and dairy workers in the United States, as well as infecting birds. 

In the new Cambodian case, the patient died on January 10 after suffering fever, difficulty breathing, cough, and fatigue. According to the statement, the patient's family raises chickens, and the man is the caretaker and cooked sick chickens for food.

Cambodian officials have not yet released details on what clade is implicated in this case. 

Three countries reported new polio cases this week, according to the latest update from the Global Polio Eradication Initiative (GPEI).

In Pakistan, one wild poliovirus type 1 (WPV1) case was reported Kyhber Pakhtunkhwa province, with onset of paralysis occurring on November 9. The case brings Pakistan's 2024 case count to 68.

Newly-reported polio cases in Nigeria and Indonesia were both caused by circulating vaccine-derived poliovirus type 2 (cVDPV2). In Nigeria, three cVDPV2 cases with onset of paralysis in late October were reported in Kebbi and Kano provinces, bringing the country's 2024 total to 93 cases. In Indonesia, a cVDPV2 case with paralysis onset on May 15 was reported in Maluku Utara province, bringing the country's 2024 total to 7.

Meanwhile, the United Kingdom reported another cVDPV2-positive environmental sample, which was collected on December 15. In late 2024, the country reported similar wastewater detections in samples collected in November from London, Leeds, and East Worthing.

In 2022, cVDPV2 detections in 19 London sewage samples prompted UK health officials to offer a booster dose of inactivated polio vaccine to children ages 1 through 9 in all London boroughs.

A 3.5-year-old white-tailed doe on a high-fence ranch in Brown County in central Texas has tested positive for chronic wasting disease (CWD), marking the first case of the fatal neurodegenerative disease in the county, the Texas Parks and Wildlife Department (TPWD) reported today.

"The detection occurred on a ranch registered as a deer breeder release site and identified as having received deer from a CWD-positive breeding facility reported in 2024," TPWD said in a news release. "Testing hunter-harvested deer allows animal health officials to assess disease presence and was required as part of the quarantine issued for this property epidemiologically traced to a facility with a CWD-positive detection."

Sound wildlife-management practices urged

CWD is a slow, progressive disease that affects cervids such as deer, elk, and moose. It's caused by infectious misfolded proteins called prions, which spread through direct contact or environmental contamination. While the disease hasn't been observed in people, hunters are advised not to eat meat from a sick cervid and to use precautions when handling the carcass.

Landowners and hunters are encouraged to implement sound wildlife management practices, such as adequate deer harvest and management of healthy native habitat.

"Landowners and hunters are encouraged to implement sound wildlife management practices, such as adequate deer harvest and management of healthy native habitat, to help mitigate disease impacts on the deer populations, especially in areas where CWD has been detected," TPWD wrote.

The disease was first identified in Texas in 2012 in free-ranging mule deer in the Hueco Mountains near the border with New Mexico. Since then, it has since been detected in Texas captive and free-ranging cervids, including white-tailed deer, mule deer, red deer, and elk.