The US Centers for Disease Control and Prevention (CDC) today confirmed another human H5N1 avian flu case in California, which likely reflects follow-up testing of a presumed positive involving a San Francisco child. The latest confirmation puts the national total since early 2024 to 67 cases, of which 38 are from California.

San Francisco health officials announced the presumed-positive case, which involved a child with fever and conjunctivitis who was not hospitalized and has fully recovered, on January 10. Though most of California’s cases involve people with occupational exposure to sick dairy cows, the state has reported two illnesses in people with undetermined exposure sources, both of them children. The California Department of Public Health (CDPH) also updated its H5N1 total to 38 today, which adds a second illness from an undetermined exposure source.

In an updated risk assessment today, the CDC said the H5N1 risk to the general public remains low, but is higher in farm workers exposed to sick animals or their byproducts, backyard bird flock owners, animal care workers, and animal health and public health responders.

The CDC also spelled out the factors that would cause it to raise its risk assessment, including more efficient virus transmission, increased disease severity, more widespread cases, and great impacts from genetic changes in the virus. 

USDA confirms more detections in poultry and dairy cattle

In other developments, the US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) confirmed more H5N1 outbreaks in poultry from three states. They include a broiler farm in Maryland’s Caroline County that has nearly 229,000 birds and two commercial turkey farms in Ohio, one in Darke County and the other in Mercer County, that, taken together, have about 15,000 birds. APHIS also confirmed the virus in a backyard flock in Phillips County, Kansas.

Also, APHIS confirmed 2 more H5N1 detections in dairy cattle, both in California, which pushes the national total to 927 and California’s total to 710.

A randomized clinical trial in the United Kingdom found that a procalcitonin-guided algorithm did not reduce the duration of intravenous (IV) antibiotics in hospitalized children compared with usual care, researchers reported last week in The Lancet Child & Adolescent Health.

The BATCH (Biomarker-guided duration of Antibiotic Treatment in Children Hospitalised) trial, led by investigators from UK universities and hospitals, enrolled children aged 72 hours to 18 years who were treated with IV antibiotics for suspected or confirmed bacterial infection at 15 hospitals. Of the 15,282 children screened from June 11, 2018, to October 12, 2022, 1,949 (median age, 3.1 years; 54% male) were randomly assigned to receive procalcitonin-guided therapy (977 children) or usual care (972). The co-primary outcomes were duration of antibiotic use (assessed for superiority) and a composite safety measure (assessed for non-inferiority).

The aim of the trial was to investigate whether the use of procalcitonin, a biomarker for bacterial infection, would safely reduce antibiotic duration compared with usual care, in which C-reactive protein is used to guide antibiotic therapy. The investigators hypothesized that because procalcitonin is a more specific host-response biomarker for bacterial infection, it might better facilitate decisions to de-escalate antibiotic therapy.

No evidence of treatment effect

But the results did not support that theory. The median IV antibiotic duration was 96 hours in the procalcitonin group and 99.7 hours in the usual care group (hazard ratio, 0.96; 95% confidence interval [CI], 0.87 to 1.05), providing no evidence of a treatment effect. Comparison of safety outcomes showed 9% of children in the procalcitonin group and 9% in the usual-care group had at least one event covered by the composite safety outcome measure (estimated adjusted risk difference, -0.81), indicating procalcitonin-guided therapy was non-inferior to usual care. 

Investigators also found that total costs were higher in the procalcitonin group, and that adherence to the protocol was low.

"Our results suggest that in hospitalised children treated with intravenous antibiotics for suspected or confirmed serious bacterial infection, a procalcitonin-guided algorithm is not effective in reducing intravenous antibiotic duration, especially where robust antimicrobial stewardship programmes are already implemented," they concluded.

An international study of cancer patients with Clostridioides difficile infection (CDI) found recurrence rates were significant and severe CDI episodes were common, but newer treatments were underused, researchers reported yesterday in the International Journal of Infectious Diseases.

The study of CDI cases reported at three Australian hospitals and one Spanish hospital from 2020 through 2022 focused on cancer patients because they are particularly vulnerable to CDI, owing to prolonged hospitalizations and exposure to antibiotics. In addition, while newer treatments such as fidaxomicin, bezlotoxumab, and fecal microbiota transplantation (FMT) have shown promise for reducing CDI recurrence in clinical trials, and fidaxomicin is now recommended as a first-line treatment for CDI, cancer patients have been underrepresented in those studies.

A total of 547 episodes of CDI among cancer patients were documented over the study period, primarily in patients with lymphoma (19.2%), acute myeloid leukemia (16.6%), and colorectal cancer (7.9%). Of these patients, 57.4% had been hospitalized before developing CDI, and 66.5% had received antibiotics within the preceding 30 days. Fifty percent of the episodes were classified as either severe or severely complicated.

Significant recurrence rate

The most commonly prescribed CDI therapy was vancomycin (81.5%), followed by metronidazole (15%) and fidaxomicin (9.1%). The 90-day recurrence rate was 15.6% and overall 90-day mortality was 22.3%, but CDI-attributable mortality was 4.9%. Independent risk factors for CDI recurrence were female sex (odds ratio [OR], 2.26; 95% confidence interval [CI], 1.13 to 4.52), age >75 years (OR, 2.69; 95% CI, 1.30 to 5.59), dialysis (OR, 5.15; 95% CI, 1.45 to 18.27), vomiting at presentation (OR, 0.06; 95% CI, 0.01 to 0.55), colonic wall thickening in the CT abdomen (OR, 2.42; 95% CI, 1.06 to 5.49), and vancomycin therapy (OR 4.60, 95% CI 1.34-15.84). 

The authors say they hope their findings encourage higher uptake of fidaxomicin, bezlotoxumab, and FMT in cancer patients with CDI.

"Although recurrence rates among these patients are significant, the use of fidaxomicin and other preventive measures was rare," they wrote. "Importantly, we identified factors that may guide the initiation of such strategies in cancer patients."

A hunter-harvested mule deer in the Hog Heaven Management Zone of Montana's Flathead Indian Reservation was confirmed positive for chronic wasting disease (CWD) on January 6, the Confederated Salish and Kootenai Tribes (CSKT) Division of Fish, Wildlife, and Recreation and Conservation (DFWRC) announced yesterday.

The reservation is located in the western part of the state on the Flathead River.

"The CSKT Wildlife Program is implementing the initial response protocol from the Tribe’s CWD Surveillance and Management Plan," the CSKT news release said. The response will include the collection of samples from 150 mule deer harvested from Hog Heaven and Irvine herds to determine CWD prevalence.

The CSKT Wildlife Program is implementing the initial response protocol from the Tribe’s CWD Surveillance and Management Plan.

"It is extremely important for the health of our Tribal people and our big game herds that any deer, elk or moose harvested from this area is tested for Chronic Wasting Disease before consumption," CSKT said. "There currently no vaccine for CWD, and if it were to spread to humans it would likely be through consuming infected meat."

CDC advises against eating meat from infected animals

CWD is a fatal neurodegenerative disease caused by infectious misfolded proteins called prions, which spread among cervids such as deer, elk, and moose and through environmental contamination. 

The disease isn't known to infect people, but experts fear it could cause illness similar to the prion disease bovine spongiform encephalopathy ("mad cow" disease). The US Centers for Disease Control and Prevention warn against eating meat from infected animals.