Dispersal of influenza virus populations within the respiratory tract shapes their evolutionary potential.

Viral infections are characterized by dispersal from an initial site to secondary locations within the host. How the resultant spatial heterogeneity shapes within-host genetic diversity and viral evolutionary pathways is poorly understood. Here, we show that virus dispersal within and between the nasal cavity and trachea maintains diversity and is therefore conducive to adaptive evolution, whereas dispersal to the lungs gives rise to population heterogeneity.

Chlamydial infections in free-ranging raptors presenting to a university veterinary medical teaching hospital (1993-2022).

Objective: To describe the prevalence, clinical findings, lesions, and risk factors associated with chlamydial infections in free-ranging raptors presented to a university veterinary medical teaching hospital.

Methods: Medical records retrospectively searched for raptors admitted from January 1993 through April 2022 were tested for Chlamydia spp infections using quantitative PCR (qPCR), immunohistochemistry, culture, and sequencing. Findings were collected and analyzed.

Modulation of human-to-swine influenza a virus adaptation by the neuraminidase low-affinity calcium-binding pocket.

Frequent interspecies transmission of human influenza A viruses (FLUAV) to pigs contrasts with the limited subset that establishes in swine. While hemagglutinin mutations are recognized for their role in cross-species transmission, the contribution of neuraminidase remains understudied. Here, the NA's role in FLUAV adaptation was investigated using a swine-adapted H3N2 reassortant virus with human-derived HA and NA segments.

Mass vaccination with reassortment-impaired live H9N2 avian influenza vaccine.

Avian influenza poses a severe threat to poultry production and global food security, prompting the development of vaccination programs in numerous countries. Modified live virus (MLV) vaccines, with their potential for mass application, offer a distinct advantage over existing options. However, concerns surrounding reversion, recombination, and unintended transmission have hindered the progress of MLV development for avian influenza in poultry.