Following suspected outbreaks at three Central Valley dairy farms, the California Department of Food and Agriculture (CDFA) on August 30 announced that the herds in preliminary tests were positive for highly pathogenic avian influenza, and that the US Department of Agriculture (USDA) National Veterinary Services Laboratory confirmed the findings.

The herd started showing clinical signs consistent with H5N1 on August 25, and the dairy owners worked with veterinarians and the CDFA to submit samples for state lab testing. The CDFA added that no human cases have been detected and that the California Department of Public Health (CDPH) is working with the CDFA to monitor people who were exposed to the sick cows.

The CDFA said it and the CDFA have been preparing for possible outbreaks and that, earlier this summer, the CDPH supported the distribution of personal protective equipment to dairy farms, workers who handle raw milk, slaughterhouse workers, and those working on poultry farms.

The USDA Animal and Plant Health Inspection Service (APHIS) yesterday added the three herds to its list of confirmed H5N1 outbreaks in dairy cows, lifting the nation's total to 197 in 14 states.

A Centers for Disease Control and Prevention (CDC) analysis finds that overall US teen vaccination uptake was similar in 2022 and 2023, with a decline in up-to-date human papillomavirus (HPV UTD) vaccination by age 13 among adolescents born in 2010 versus 2007.

CDC investigators used the 2015 to 2023 iterations of the National Immunization Survey-Teen of 16,658 participants aged 13 to 17 years (born from January 2005 to December 2010) to estimate 2023 coverage, recent patterns by birth year, and trends by eligibility for the no-cost Vaccines for Children (VFC) program.

The results were published in Morbidity and Mortality Weekly Report.

Expanding opportunities to vaccinate

In 2023, 89.0%, 88.4%, 76.8%, and 61.4% of 13- to 17-year-olds had received one or more doses of tetanus, diphtheria, and pertussis (Tdap), quadrivalent (four-strain) meningococcal conjugate (MenACWY), HPV, and HPV UTD vaccines, respectively. From 2022 to 2023, receipt of the serogroup B meningococcal and hepatitis A vaccines rose 3.0 and 1.9 percentage points, respectively.

Vaccinations can also be administered through school-based clinics, pharmacies, and back-to-school health events, which can provide expanded opportunities for adolescents to receive recommended vaccines.

Receipt of at least one vaccine dose against Tdap, MenACWY, and HPV by age 13 among VFC-eligible teens born from 2008 to 2010 was comparable to that of those born in 2007. But the proportions of VFC-eligible and -ineligible adolescents current with HPV vaccination were 10.3 and 7.1 percentage points lower, respectively, among those born in 2010 than those born in 2007. 

Of teens born from 2003 to 2008, uptake of at least one dose of the Tdap and MenACWY vaccines by age 13 was lower among VFC-eligible than -ineligible adolescents, while coverage was similar for both groups born in 2009 and 2010.

"Health care providers should make strong recommendations for all routine vaccines and verify if adolescents, particularly those eligible for the VFC program, are up to date with all recommended vaccines," the authors wrote.

"Vaccinations can also be administered through school-based clinics, pharmacies, and back-to-school health events, which can provide expanded opportunities for adolescents to receive recommended vaccines," they added.

Diagnostics company ID-Fish Technology announced today that the US Food and Drug Administration (FDA) has cleared its new Lyme disease test.

The iDart Lyme IgG ImmunoBlot Kit is a stand-alone test for detecting Lyme-specific immunoglobulin G (IgG) antibodies that includes 31 Lyme antigen bands, more than any other Lyme test on the market. The company says the inclusion of 31 antigens will improve the sensitivity of Lyme disease diagnosis in suspected patients without sacrificing specificity. 

"The R&D team at ID-FISH has worked tirelessly on making sure that we deliver the most accurate test possible for the detection of Lyme disease," ID-Fish Technology Chief Scientific Officer Jyotsna Shah, PhD, said in a company press release. "We look forward to working with partners to get these tests to patients who need a correct diagnosis." 

Around 475,000 Americans annually are diagnosed with Lyme disease, which is caused by Borrelia burgdorferi, a type of bacteria carried by black-legged (deer) ticks.

Faster antimicrobial susceptibility test also cleared

In other diagnostic news, the Biomedical Advanced Research and Development Authority (BARDA) announced last week that the FDA has cleared bioMerieux's new antimicrobial susceptibility test (AST) for gram-negative pathogens commonly associated with bloodstream infections (BSIs).

The Vitek Reveal GN AST works with bioMerieux's Vitek Reveal AST System, which uses a metabolomic signature technology to produce phenotypic AST results from positive blood cultures within 5.5 to 6 hours—75% faster than traditional AST methods.

Fast and accurate AST results for gram-negative BSIs are considered crucial for reducing inappropriate antibiotic use and improving patient outcomes.

The test was developed by bioMerieux in partnership with BARDA.

The World Health Organization (WHO) yesterday shared more details from Cambodia about its latest fatal H5N1 avian flu case, including that it involves the older 2.3.2.1c clade but noting that the virus that infected the girl is a novel reassortant that include internal genes from the newer 2.3.4.4b clade.

Investigators found that poultry died in the girl's Prey Vent province village and that her family was given some of them to eat and that the girl was exposed to the chicken while preparing food. Her symptoms began on August 11, and, when her condition worsened, she was hospitalized about a week later in Phnom Penh and treated with oseltamivir (Tamiflu). She died on August 20.

Sequencing of the patient's virus sample at the Pasteur Institute in Cambodia found that the hemagglutinin gene from the 2.3.2.1c clade that has been circulating in Cambodia and Southeast Asia since 2013. The internal genes, however, belonged to the newer 2.3.4.4b, which is circulating globally.  "This novel reassortant influenza A(H5N1) virus has been detected in human cases reported in Cambodia since late 2023," the WHO said.

Cambodian health officials have tracked and monitored the girl's contacts, and no related cases have been found. The country has reported an uptick in human H5N1 infections since 2023, reporting 6 cases last year and 10 this year, of which 2 were fatal.

Reassortant circulating in poultry, found in earlier human cases

In April, animal health officials in Vietnam and the United Nations Food and Agriculture Organization (FAO) warned of the new reassortant circulating in chickens and muscovy ducks. 

The scientists said the virus has been circulating in the Greater Mekong subregion since 2022. Also, they noted that the reassortant had been linked to recent human cases and that the development shows the adaptive capacity of the virus and the risk of new, potentially more virulent strains.

A single-center study found that prolonging antibiotic treatment beyond 8 days did not improve outcomes in patients who had healthcare-acquired pneumonia caused by multidrug-resistant (MDR) Pseudomonas aeruginosa, researchers reported today in BMC Infectious Diseases.

In the retrospective study, researchers at Jackson Memorial Hospital in Miami compared outcomes in two groups of patients who had been treated for hospital-acquired/ventilator-associated pneumonia (HAP/VAP) caused by MDR P aeruginosa from 2017 through 2020. One group received 8 days or less of antibiotic therapy, which is roughly in line with the duration recommended by Infectious Diseases Society of America (IDSA) guidelines (7 days), and the other group received more than 8 days' worth. 

The primary outcome was clinical success at the end of therapy, defined as resolution of signs and symptoms of infection and no need for additional antibiotic treatment. Secondary outcomes included 30-day and 90-day mortality and relapsed pneumonia within 30 days of index culture. Relapse is one of the concerns when treating HAP/VAP caused by MDR P aeruginosa with a short course of antibiotics, particularly in immunocompromised patients.

No difference in clinical outcomes

Of the 85 patients (median age, 65.5 years) who met the inclusion criteria, 30 (35.3%) received 8 days or less of antibiotics and 55 (64.7%) received more than 8 days. Most patients in both groups were in the intensive care unit. 

Compared with those who received 8 days or less of antibiotics, no difference was seen for clinical success in patients treated for more than 8 days (80.0% vs 65.5%; odds ratio [OR], 0.47; 95% confidence interval [CI], 0.16 to 1.36). Similarly, no difference was found in 30-day and 90-day mortality among treatment groups, nor did patients who received shorter therapy have a higher relapse rate within 30 days of index culture.

"This result favors the approach of treating patients with MDR P. aeruginosa HAP/VAP for ≤8 days, instead of a longer duration, to prevent the development of resistance and adverse drug events," the study authors wrote.