The US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) today announced a new federal order that spells out a national strategy for testing milk in the wake of ongoing H5N1 avian flu outbreaks on dairy farms.

A handful of states have already adopted bulk milk tank testing policies, but the new federal order expands the approach to the national level. The order, developed with stakeholder input, requires raw unpasteurized milk samples to be collected and shared with the USDA for testing. The USDA also posted guidance on the new order.

APHIS said the order is designed to provide a more uniform testing system that quickly identified infected herds and sheds light on how the virus is spreading. The three-part order covers sharing of raw milk samples, requires owners of affected herds to share epidemiological information, and requires private and state veterinary labs to report positive tests to the USDA.

H5N1 strikes more California poultry and dairy farms

The US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) today confirmed more avian flu outbreaks in poultry flocks from two states, including three layer farms in California’s Merced County, one of which has more than 1.7 million birds. 

APHIS also confirmed the virus at a duck meat producer in California’s San Joaquin County that has 13,000 birds.

Elsewhere, tests confirmed outbreaks at three commercial turkey farms in South Dakota, affecting flocks in Charles Mix, Mcpherson, and Spink counties. Taken together, the farms have nearly 185,000 birds.

In other avian flu developments, APHIS confirmed two more outbreaks in dairy cattle, both from California. The latest outbreaks push California’s total since the virus first turned up in Central Valley dairy cows in late August to 506. The national total is now 720 from 15 states.

Though US flu activity is still low, markers such as test positivity and emergency department (ED) visits show more rises, the Centers for Disease Control and Prevention (CDC) said today in its latest weekly update.

In its monitoring of outpatient visits for flulike illness, Louisiana and the District of Columbia are at the high and very high level, respectively, with Georgia and Arizona at the lower tier of the high level. Most detections are influenza A, and subtyping last week at public health labs shows nearly 62% of influenza A viruses were H3N2 and 36% were 2009 H1N1. Nationally, outpatient visits are highest in the youngest children, followed by patients ages 5 to 24 years old.

No pediatric flu deaths were reported this week, keeping the season’s total at two.

Overall respiratory activity rises to moderate level

In its overall respiratory virus snapshot today, the CDC upgraded the overall situation from low to moderate, noting that flu activity continues to slowly increase and that it expects COVID activity to rise in the coming weeks. Respiratory syncytial virus (RSV) activity is moderate and continues to rise across most of the country, and illnesses caused by Mycoplasma pneumoniae (“walking pneumonia”) remain elevated in young children.

In COVID-specific updates, the CDC said COVID activity remains low. Wastewater SARS-CoV-2 detections, considered an early indicator, remain low but are highest and gradually rising in the Midwest.

In its latest variant proportion estimates today, the CDC said levels of the XEC variant, now at 44%, continue to rise and are now outpacing the KP.3.1.1 variant, which had been dominant the last several months. XEC is a hybrid of two JN.1 variants.

A systematic review and meta-analysis of randomized controlled trials (RCTs) found that audit and feedback (A&F) interventions improved antibiotic prescribing across four outcome metrics in primary care settings, an international team of researchers reported yesterday in Clinical Infectious Diseases.    

The reviewers identified 56 RCTs that directly compared antimicrobial stewardship interventions with A&F versus those without A&F and used random-effects meta-analysis to evaluate the evidence across four outcomes: total antibiotic prescribing volume, unnecessary antibiotic initiation, excessive prescription duration, and broad-spectrum antibiotic selection. They also looked at how the effects of A&F interventions varied by study and intervention characteristics.

Reductions of 11% to 23%

They found that A&F was associated with an 11% relative reduction in antibiotic prescribing volume (rate ratio [RR], 0.89; 95% confidence interval [CI], 0.84 to 0.95), a 23% relative reduction in unnecessary antibiotic initiation (RR, 0.77; 95% CI, 0.68 to 0.87), a 13% relative reduction in prolonged duration of antibiotic course (RR, 0.87; 95% CI, 0.81 to 0.94), and a 17% relative reduction in broad-spectrum antibiotic selection (RR, 0.83; 95% CI, 0.75 to 0.93).

Larger reductions were found in low-income compared with high-income countries, and in countries with higher antibiotic use compared with lower antibiotic use. In addition, studies providing monthly feedback, compared with quarterly or annual feedback, also appeared to have greater effect.

Although the study authors caution that heterogeneity was substantial, outcome definitions were not standardized across trials, and intervention fidelity was not consistently assessed, they say the similarity across outcomes is striking.

"Our results contribute to the growing evidence base for the effectiveness of A&F interventions to modify prescribing behaviours for antibiotics in primary care settings," they wrote.

Germany has become the latest European country to find poliovirus during routine wastewater surveillance, joining Spain and Poland who have also reported such detections in recent months. 

According to the Global Polio Eradication Initiative (GPEI), German officials found four circulating vaccine-derived poliovirus type 2 (cVDPV2) environmental samples in October and November, from four major cities: Munich, Bonn, Cologne, and Hamburg.

Poliovirus has been detected through routine surveillance of wastewater systems in three countries in the WHO European Region (Germany, Poland and Spain) since September this year.

"Poliovirus has been detected through routine surveillance of wastewater systems in three countries in the WHO European Region (Germany, Poland and Spain) since September this year," GPEI said. "While no cases have been detected to date, the presence of the virus underscores the importance of vaccination and surveillance, as well as the ongoing risk that any form of poliovirus poses to all countries everywhere."

The European region has been free of polio since 2002. Last week the European Centre for Disease Prevention and Control (ECDC) urged countries to be cautious and proactive with routine vaccination. 

"While the public health impact and significance of wastewater sample findings is yet to be determined, the priority actions remain the same: effective surveillance and high vaccination coverage across all communities,” the ECDC said. “Europe continues to have a high capacity to achieve both these goals.”

More polio in Pakistan 

In other polio news, in the past 2 weeks Pakistan has reported seven new wild poliovirus type 1 (WPV1) cases. The total number of cases for 2024 is 56.

Afghanistan also detected a WPV1 case, bringing the country’s total this year to 25. 

Finally, Niger has three new vaccine-derived cases. The country has seen 14 cVDPV2 cases in 2024.

• Sierra Leone yesterday launched a preventive Ebola vaccination campaign to protect frontline workers against future threats from the virus, the World Health Organization (WHO) said today. The campaign is targeting 16 districts with the Ervebo vaccine, developed in Canada and made by Merck. Gavi, the Vaccine Alliance, and other partners are supporting the effort. Immunization will include people likely to be some of the first involved in an outbreak response, including healthcare workers, traditional healers, community health and social workers, laboratory personnel, motorcycle taxi drivers, and security forces. Sierra Leone was one of the hardest hit countries in West Africa’s 2014-2016 outbreak. 
• Since August, three more Americas countries and one new territory have reported their first local Oropouche virus cases of the year, the Pan American Health Organization (PAHO) said yesterday in an update. They include Ecuador, Guyana, Panama, and Cayman Island. The new confirmations push the number of Americas countries reporting either local or imported cases this year to 10, plus one territory. The illness total for the year is currently 11,642, including 2 deaths. Brazil has been the hardest hit country, and cases involving transmission from pregnant women to their babies have been reported from Brazil and Cuba. 
• The Administration for Strategic Preparedness and Response (ASPR) within the US Department of Health and Human Services (HHS) said yesterday that it has partnered with SLI Medical to airlift 40,000 cases of critically needed intravenous (IV) fluid from South Korea. The move is the latest to address an ongoing shortage that has resulted from damage to Baxter’s IV fluid manufacturing plant in North Carolina during Hurricane Helene. Officials said the airlift operation can expand to 21,000 cases per week, if needed. The move follows earlier airlift operations of IV products from Baxter’s international facilities, but certain IV fluids remain in short supply.