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Showing posts from May 21, 2025

#Pathogenicity and #transmissibility of bovine-derived HPAI #H5N1 B3.13 virus in #pigs

Abstract Since the first emergence of highly pathogenic avian influenza (HPAI) H5N1 viruses in dairy cattle , the virus has continued to spread, reaching at least 17 states and at least 950 dairy herds in the United States. Subsequently, spillovers of the virus from dairy cattle to humans have been reported. Pigs are an important reservoir in influenza ecology because they serve as a mixing vessel in which novel reassortant viruses with pandemic potential can be generated. Here, we show that oro-respiratory infection of pigs resulted in productive replication of a bovine-derived HPAI H5N1 B3.13 virus . Infectious virus was mainly identified in the lower respiratory tract of principal infected pigs, and sero-conversion was observed in most of the principal pigs at later time points, suggesting limited replication of the bovine-derived HPAI H5N1 B3.13 virus in pigs. In one animal, we detected the emergence of a mutation in hemagglutinin (HA) previously associated with increased affinity ...

#Bulgaria - High pathogenicity avian #influenza #H5N1 viruses (#poultry) (Inf. with) - Immediate notification

  On the 19th of May, an official veterinary doctor was called to the farm due to suspected influenza, as there was an increase in mortality within the animals. On the same day, samples were taken and sent to the Bulgarian National Laboratory for Avian Influenza, where, on the 20th of May, it was confirmed that the farm was affected by a highly pathogenic avian influenza virus. Source: WOAH,  https://wahis.woah.org/#/in-review/6490 ____

A protective and broadly binding #antibody class engages the #influenza virus #hemagglutinin head at its stem interface

ABSTRACT Influenza infection and vaccination impart strain-specific immunity that protects against neither seasonal antigenic variants nor the next pandemic . However, antibodies directed to conserved sites can confer broad protection. Here, we identify and characterize a class of human antibodies that engage a previously undescribed, conserved epitope on the influenza hemagglutinin (HA) protein. Prototype antibody S8V1-157 binds at the normally occluded interface between the HA head and stem. Antibodies to this HA head–stem interface epitope are non-neutralizing in vitro but protect against lethal influenza infection in mice. These antibodies bind to most influenza A subtypes and seasonal human variants, and are present at low frequencies in the memory B cell populations of multiple human donors. Vaccines designed to elicit these antibodies might contribute to “universal” influenza immunity. IMPORTANCE Antibodies to the influenza virus hemagglutinin (HA) protein confer the strongest p...

Characterization of emerging #H3N3 avian #influenza viruses in #poultry in #China

Abstract Avian influenza viruses continue to challenge poultry and human health ; therefore, careful surveillance and evaluation of emerging viruses are important for animal disease control and human influenza pandemic preparedness . In this study, we detected a series of H3N3 subtype avian influenza viruses in chickens , pigeons, and ducks during our routine surveillance and diagnosis between September 2022 and May 2023. We performed extensive analyses to fully understand the origins of these viruses and their risk to animals and humans. We found that the viruses were complex reassortants ; the viruses from chickens and pigeons carry genes mainly derived from H3N8 viruses and H10N3 viruses , whereas the two duck viruses were reassortants of duck and wild bird viruses. The chicken and pigeon , but not duck, viruses replicated in multiple organs of chickens and were shed for up to 13 days, but none caused disease or death. Six of the viruses tested all bound to both avian- and human-typ...