Season One, Episode 13: The Longest Night
Jill goes to Nunavut to pursue the source of the new flu outbreak. Mayko goes to Denver in attempt to find patient zero. Daisy returns to Toronto and identifies Vascily Popov as the person who infected her baby with the Miranda virus.
Is it possible that avian flu can combine with Spanish Flu?
What is avian flu?
Flu viruses that infect birds are called “avian influenza viruses.” Influenza A viruses are the only type of flu virus that infects birds. There are different subtypes of influenza A and different strains within each subtype.
Different subtypes and strains of avian influenza viruses can be categorized as low or high pathogenic, depending on how sick they make the birds they infect. While all subtypes of influenza A can infect birds, some subtypes can also infect other species, including humans.
How do avian influenza viruses spread among birds?
Avian influenza viruses circulate among birds around the world. Infected birds can spread the virus via saliva, nasal secretions and feces. Fecal-to-oral transmission is the most common mode of transmission between birds.
Wild birds generally do not get sick, but can spread the virus to other birds. Domesticated birds can catch the virus through exposure to contaminated materials such as dirt, cages, water or feed. Highly pathogenic strains of avian influenza virus can cause disease and death among some species of domesticated birds – more than 90 percent of poultry can die from infection by high pathogenic avian virus.
How does bird flu transmit to people?
Influenza A viruses are found in many animals including birds, pigs, whales, horses and seals. While certain subtypes of influenza A virus are specific to certain species, birds can be hosts to all subtypes of influenza A.
Influenza A viruses normally found in one species can sometimes cross the species barrier and infect another species. Avian influenza viruses can be transmitted to humans in two ways: directly from birds or from bird environments to people; or through an intermediate host species such as pigs.
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Patient Zero A scientist tagging a hawk is presumed to have caught a virulent form of influenza virus from the bird. |
How can the influenza virus mutate?
Influenza viruses contain eight separate genes. If a person or animal is infected with two different viruses at the same time, the viruses can mix and “swap” genes. For example, if a pig were infected with a human influenza A virus AND an avian influenza A virus at the same time, genes from the two viruses could be exchanged to create a new virus that contains some genes from the human virus and some genes from the avian virus. This new virus might then be able to infect humans and would have characteristics not seen in human viruses before. This swapping of genes could also take place in a human infected with two different viruses, again resulting in a new virus.
Can avian flu spread directly to humans?
Usually, avian influenza A viruses do not infect humans. However, several instances of human infection of avian influenza have been reported in the last eight years. In most cases, humans are thought to have had direct contact with infected poultry. Thus far, these direct bird-to-human transmissions have not resulted in widespread human-to-human transmission of influenza A. This remains an area of active research and monitoring because of the potential pandemics that may result.
So…
Although it is possible for two different influenza virus strains to combine and form a new virus, it requires that one animal is infected by both viruses at one time. Since there is no intact virus from the 1918 Spanish Flu, it’s not possible for a person to be infected with that virus. Therefore, it is not possible that avian influenza can combine with the Spanish Flu.
Is it probable to stave off a new flu epidemic with drug treatment?
How do antiviral drugs work?
Antiviral drugs, when taken early during infection, can affect the ability of the virus to reproduce, but do not provide immunity against infection. Generally, there are two types of antiviral drugs used to treat influenza infections: M2 ion channel inhibitors and neuraminidase inhibitors.
M2 is a protein that spans the membrane encapsulating the influenza virus. It is thought to play a critical role in removing the membrane from the virus upon infection which then allows the virus to replicate itself. When M2 ion channel inhibitor drugs are used, the virion is not completely removed from the membrane and the virus is unable to make more copies of itself. Blocking the M2 channel can also change the acidity within the cell, which also affects the success of infection of some strains of influenza virus.
Neuraminidase is a protein found on the surface of influenza virus; it breaks the chemical bonds that hold new virus particles to the outside of an infected cell. Once these bonds are broken, the new viruses are liberated to infect other cells. Neuraminidase inhibitors block the ability of this protein to release new virus particles, thereby limiting the spread of infection.
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Treating flu patients with antiviral drugs At NorBAC’s suggestion, doctors in Colorado treat flu patients with known antiviral drugs, with no great success. |
Are antiviral drugs effective against Spanish Flu?
A group of American researchers has engineered influenza viruses in the lab that contain genes from the virus that caused 1918 Spanish Flu. They find these new viruses are able to infect both cultured human cells and live mice. The researchers also found that currently available M2 ion channel inhibitors and neuraminidase inhibitors can inhibit the engineered virus from reproducing. They conclude that the existing drug regimen would likely be effective in curbing a new, 1918-like influenza virus.
So…
Yes, if caught and treated early enough, antiviral drugs may be effective in preventing a flu epidemic.
- Audrey M. Huang, Ph.D.
Want to read and learn more?
To read more about avian influenza, visit the link:
http://www.who.int/csr/disease/avian_influenza/en/
To read more about antiviral drugs used to fight the flu, visit the link:
http://www.phac-aspc.gc.ca/media/nr-rp/2005/2005_3bk1_e.html
