alphainfluenzaviruses

Alphainfluenzaviruses are a genus of viruses within the family Orthomyxoviridae. This genus currently comprises two species: Alphainfluenzavirus influenzae and Alphainfluenzavirus avium. The most well-known member of this genus is the influenza A virus, species Alphainfluenzavirus influenzae. Influenza viruses are known for their ability to cause seasonal epidemics of respiratory illness in humans, as well as more severe pandemics.

The virions of alphainfluenzaviruses are typically spherical and enveloped, with a diameter of about 80 to 120 nanometers. Their genetic material is segmented and consists of single-stranded negative-sense RNA. The genome is divided into eight RNA segments, each encoding one or more viral proteins. Key surface glycoproteins, hemagglutinin (HA) and neuraminidase (NA), play crucial roles in viral entry and release from host cells, respectively. These glycoproteins are also important targets for the host immune system and are responsible for the genetic diversity observed within alphainfluenzaviruses, particularly through antigenic drift and shift.

Alphainfluenzaviruses infect a wide range of hosts, including birds, mammals (such as humans, pigs, and horses), and occasionally other vertebrates. Avian influenza viruses, belonging to the species Alphainfluenzavirus avium, are particularly significant as they are considered the natural reservoir for many influenza A subtypes. These viruses can occasionally transmit to humans and other mammals, leading to sporadic outbreaks and, in some cases, global pandemics. Research into alphainfluenzaviruses is vital for understanding influenza pathogenesis, developing vaccines, and implementing effective public health strategies to control influenza outbreaks.