New research examined influenza viruses circulating among different groups of birds using data to determine which species of birds are engaged in viral transmission.
This study comes at a time when a highly virulent strain of avian influenza is sweeping across North America.
The outbreak of avian influenza
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The science-based population has been increasing familiarized with discussing influenza viruses in birds as a group, but birds are an incredibly diverse taxon of animals with distinct natural histories, physiology, and anatomy, according to Jonathan Runstadler, professor and chair of the Department of Infectious Disease & Global Health at Tufts University's Cummings School of Veterinary Medicine.
Runstadler is one of the authors of a new research article published in the journal PLOS Pathogens that examined influenza viruses spreading among separate categories of birds and identifies which sorts of birds are engaged in viral transmission.
This research comes at an ideal time since a highly virulent form of avian flu has been spreading across North America.
This strain of avian flu initially appeared in a domestic goose in China about 1996.
The virus evolved and spread, and the first large wild bird epidemic occurred in a significant wetland in Central Asia around 2005.
Subsequent viral modifications resulted in an introduction to the United States via the Pacific Northwest in 2014, severely damaging the poultry sector and necessitating the culling of around 40 million turkeys and chickens as a control measure.
Geese are land grazers that flourish in urban and agricultural areas, which might be an ecological issue.
Many geese species are considered pests in North America and Europe.
"They are the ideal overflow host because they can utilize a human-altered environment," said Nichola Hill, lead author of the paper and an assistant professor of biology at University of Massachusetts Boston, as per ScienceDaily.
Furthermore, knowing which birds are responsible for long-distance propagation may impact how or when the virus enters a new geographic location.
For example, the 2014 epidemic likely arrived in the United States via the Pacific, whereas the current outbreak arrived via the Atlantic, and ducks may not have been as involved.
The majority of avian influenza subtypes that have caused human illnesses are H5, H7, and H9 viruses.
The Asian strains H5N1 and H7N9 have caused the majority of human cases of avian influenza, although other forms have also produced some human illnesses.
In wild birds, avian influenza infections are frequently asymptomatic, but in farmed poultry, they can be fatal.
Marine animals can also become infected with avian influenza viruses (for example, H10N7 in harbor seals), with human illness occurring as a result.
People could become contaminated with avian influenza viruses by inhalation or direct contact with infected birds' fluids (saliva, mucus, or excrement).
When avian influenza viruses acquire mutations that allow them to bind to human-specific receptor sites in the respiratory tract, they are likely to cause influenza in humans.
Because all influenza viruses are susceptible to fast genetic change, avian strains may be able to transmit more easily from person to person by direct mutation or reassortment of genome components with human strains during replication in a human, animal, or avian host.
An influenza pandemic might occur if these strains have the capacity to travel efficiently from person to person.
Avian influenza symptoms are similar to seasonal influenza symptoms; however, illness severity and case fatality rates are greater, but this varies greatly depending on the virus strain.
China is running active poultry vaccination campaigns for the H5 and H7 influenza viruses to help prevent the virus from spreading from wild to domestic birds, who are more likely to come into touch with the virus and carry it to humans.
The spread of the disease is being controlled by detecting and eliminating affected flocks of domestic birds.
If public health officials judge it essential, an H5N1 bird flu vaccination is available for distribution.
Regular influenza vaccination does not protect against avian flu.
