United States: The recent declaration by the US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) revealed the dissemination of 239 current genetic sequences of the H5N1 avian flu virus sourced from poultry, wild birds, and dairy cows, providing vital insights for scientists delving into the virus’s propagation.
Recent occurrences over the preceding three days have seen APHIS documenting four additional H5N1 instances within dairy herds, coupled with further positive identifications within wild avian populations and domestic fowl. Additionally, the Centers for Disease Control and Prevention (CDC) issued a recent update outlining its strategies for identifying novel human infections.
The long-awaited genetic sequences, a pivotal element as the outbreak approaches its one-month milestone, have yet to elucidate the mechanism through which the 2.3.4.4b H5N1 clade is now capable of infecting bovine species nor the precise modalities of dissemination among dairy herds. Against the backdrop of the virus’s persistent proliferation across diverse global locales, veterinary specialists are fervently seeking solutions to safeguard both bovine and human welfare, according to the reports by cidrap.umn.edu.
Expressing discontent over the sluggish pace of genetic sequence dissemination and other investigatory particulars, some scientific circles highlight the scarcity of available genetic data preceding yesterday’s disclosure. Heretofore, only scant genetic sequences had surfaced from recent outbreaks, encompassing instances from select bovines and felines delineated within a recent preprint publication authored by a cohort from Iowa State University.
APHIS, in its official statement, elucidated its customary practice of publishing sequences via GISAID, the Global Initiative on Sharing All Influenza Data. However, in the interest of transparency and expediting research endeavors, it opted to furnish unprocessed sequence data via the National Institutes of Health National Center for Biotechnology Information. Emphasizing the diverse array of species from which the sequences derive—encompassing bovines, felines, gallinaceous birds, skunks, raccoons, grackles, blackbirds, and geese—APHIS affirmed its commitment to sustained data availability on a rolling basis.
Dr. Louise Moncla, Assistant Professor of Pathobiology at the University of Pennsylvania School of Veterinary Medicine, extended a welcomed reception to the disclosure of raw genetic sequences. However, she underscored the time-intensive nature of subsequent analysis steps, such as data retrieval and mapping, intimating that the elucidation of inter-viral relationships remains a protracted endeavor.
Further reports issued over recent days by APHIS underscore the burgeoning incidence of H5N1 detections among bovines, poultry, and avian wildlife. Notably, four additional H5N1 occurrences within dairy herds have been documented, bringing the cumulative tally to 32. The latest positive samples emanate from bovine populations in Kansas, Michigan, and Texas, as reported by cidrap.umn.edu.
Additionally, APHIS unveiled two fresh H5N1 detections within poultry collectives, encompassing a previously disclosed outbreak at a commercial turkey farm in Michigan’s Newaygo County and a third hatchery in New Mexico’s Roosevelt County. Moreover, the agency reported approximately 30 supplementary H5N1 sightings within wild avian cohorts, spanning waterfowl, shorebirds, corvids, and birds of prey, with the preponderance situated within the eastern precincts of the nation.
Turning to ancillary developments, the CDC, on April 19, disseminated an update delineating its responsive measures, inclusive of laboratory inquiries aimed at refining the understanding of antiviral efficacies and candidate vaccine strains.
Confirmatory testing for seasonal influenza antivirals has recently culminated, with assessments on the H5N1 variant from the recent human case in Texas affirming susceptibility to all commercially available neuraminidase inhibitors. Concomitantly, scrutiny to corroborate susceptibility to baloxavir marboxil—a distinct antiviral agent—remains ongoing, owing to the protracted duration requisite for comprehensive evaluation.
The CDC further divulged ongoing endeavors to assess the protective efficacy of extant candidate vaccine viruses against the H5N1 strain isolated from the Texas patient, leveraging serological analyses of vaccinated individuals. Preliminary genetic scrutiny suggests the suitability of the CDC’s extant candidate vaccine strains in conferring immunity against the subtype encountered in the Texas patient, cidrap.umn.edu outlined.
In concert with these initiatives, the CDC has embarked on the formulation of an epidemiological field study to glean deeper insights into the outbreak’s dynamics. Thus far, surveillance efforts encompassing emergency department surveillance and flu testing data in locales where H5N1 incursions have been identified in dairy bovines or other fauna have yielded no anomalous trends.