Can Influenza Spread Between Species?

Have a question about science, health, fitness, or diet? Get cited, evidence-based insights: Consensus is an AI-Powered Academic Search Engine.

Try for free
Written by Consensus AI
6 min read

Check out this answer from Consensus:

Influenza viruses, especially Influenza A, have a remarkable ability to cross species barriers and adapt to new hosts. This adaptability is facilitated by a combination of viral evolution, host-virus interactions, and ecological factors. Understanding these mechanisms is crucial for predicting and preventing future influenza outbreaks and pandemics.

Influenza viruses, particularly Influenza A, are known for their ability to infect a wide range of host species and adapt to new hosts. This cross-species transmission is a significant concern for both human and animal health.

Key Insights

  • Diverse Host Range and Adaptability:
    • Influenza A viruses can infect a variety of species including birds, swine, humans, horses, dogs, cats, whales, and seals. They have a unique capacity to evolve and adapt after crossing species barriers, allowing them to replicate and spread within new host species .
  • Mechanisms of Cross-Species Transmission:
    • The ability of influenza viruses to cross species barriers involves several factors, including virus-host interactions, viral evolution, and the ability to bind to host cell receptors. These interactions determine the virus’s ability to infect and transmit between new hosts .
  • Examples of Cross-Species Transmission:
    • Specific subtypes of Influenza A, such as H5N1, H9N2, and H3N2, have successfully transmitted from birds to humans and other mammals. These examples highlight the complexity and variability of influenza virus epidemiology .
  • Ecological and Evolutionary Factors:
    • The spread of influenza viruses is influenced by ecological factors such as the diversity of avian hosts and their migratory patterns. Wild birds, particularly ducks, geese, and gulls, play a crucial role in the global transmission and spillover of influenza viruses.
  • Risk Factors for Transmission:
    • Proximity to infected animals, ingestion of infected material, and association with species known to carry influenza viruses are significant risk factors for cross-species transmission. However, there is a lack of comprehensive data on the epidemiological risk factors for such transmissions.

 


Can influenza spread between species?

Anne Moore has answered Near Certain

An expert from University College Cork in Immunology, Vaccines

Absolutely. Birds are the main reservoir for all influenza strains. They can transmit new viruses to pigs, horses, seals, humans. Pigs are a great “mixing vessel” where a bird-derived & a pig- or human-derived virus can reassort to create a new influenza virus which, as it’s new, has strong pandemic potential. The animal reservoir of influenza makes it far more difficult to eradicate compared to other viruses that just infect person-to-person; eg, SARS-CoV-2, polio, HIV etc….

 

Can influenza spread between species?

Maria Sundaram has answered Near Certain

An expert from Marshfield Clinic Research Institute in Epidemiology

Yes. Influenza can spread between species, and this is sometimes how influenza pandemics or new influenza strains come to be. The list of animals that can get influenza and spread it to each other is very long, and includes birds, pigs, cats, dogs, seals, whales, horses, and bats.

 

Can influenza spread between species?

Stephen Kissler has answered Near Certain

An expert from Harvard University in Epidemiology

Yes absolutely, and we see this all the time. Flu spreads very well in both domesticated and wild birds, and can also infect a whole range of other animals. When an influenza pandemic happens, it’s often due to a flu strain jumping over from an animal host into humans. It’s important to remember that flu also spreads in the other direction – we can infect animals with flu just as easily as they can infect us.

 

Can influenza spread between species?

Patricia Foster has answered Near Certain

An expert from Indiana University Bloomington in Biology, Genetics

Absolutely, it can and does.  Two strains of flu virus, A and B, commonly infect humans.  Versions of A are found in many different animal species, whereas B mostly infects only humans, although it has also been found in seals.  The natural hosts of influenza A strains are wild waterfowl, in which the virus can acquire genetic changes that let it jump to domestic birds.  From there new strains can jump to humans, from humans to birds or to pigs, and then back to humans.  The 1968 “Hong Kong flu” pandemic was caused by a jump from birds and the 2009 “swine flu” pandemic was caused by a jump from pigs.  This mixing up of the different strains in animals and humans allows genetic exchanges among the viruses, producing new, potentially dangerous, variants.  But a pandemic will only erupt if one of the variants acquires the ability to efficiently transmit from person to person.  Currently several avian influenza A strains that have already infected some humans are being closely monitored by world health organizations for their potential to cause a new pandemic.

 

Can influenza spread between species?

Patricia Foster has answered Near Certain

An expert from Indiana University Bloomington in Biology, Genetics

Absolutely, it can and does.  Two strains of flu virus, A and B, commonly infect humans.  Versions of A are found in many different animal species, whereas B mostly infects only humans, although it has also been found in seals.  The natural hosts of influenza A strains are wild waterfowl, in which the virus can acquire genetic changes that let it jump to domestic birds.  From there new strains can jump to humans, from humans to birds or to pigs, and then back to humans.  The 1968 “Hong Kong flu” pandemic was caused by a jump from birds and the 2009 “swine flu” pandemic was caused by a jump from pigs.  This mixing up of the different strains in animals and humans allows genetic exchanges among the viruses, producing new, potentially dangerous, variants.  But a pandemic will only erupt if one of the variants acquires the ability to efficiently transmit from person to person.  Currently several avian influenza A strains that have already infected some humans are being closely monitored by world health organizations for their potential to cause a new pandemic.

 

Can influenza spread between species?

Ian Frazer has answered Near Certain

An expert from University of Queensland in Vaccines, Vaccinology

Yes: birds (seabirds, chickens) are a major vector for spreading the flu viruses that make humans sick, and pigs are a common intermediary between birds and humans, allowing the flu viruses to adapt to infecting mammals.

 

Can influenza spread between species?

William  Rawlinson has answered Near Certain

An expert from UNSW Sydney in Virology, Microbiology, Molecular Biology

Yes, there is documented spread between birds (Avian influenza), mammals including pigs, and humans. Mutation and recombination events may occur during this and lead to new flu viruses. The 1918-1919 flu pandemic, sometimes called the Spanish flu outbreak, was due to a strain of flu (H1N1) known to infect humans, but most likely in this case derived from birds. It continues to be discussed, but most likely it was the avian derivation of the strain that contributed to the severe symptoms and signs, including pneumonia and death, seen in people with this particular strain during the pandemic.

Have a question about science, health, fitness, or diet? Get cited, evidence-based insights: Consensus is an AI-Powered Academic Search Engine.

Try for free