by JC Campbell

Created on: February 07, 2009

Influenza is an airborne disease which is liable to affect all breathing creatures whether they be animal or human. Many of the flu viruses that have plagued mankind throughout the years have had animals as their source, so like humans, animals can catch and pass on the flu. Though it is unusual for animals to pass on the flu directly to humans, there have been cases where humans have been adversely affected such as in the recent "bird flu" scare.

Ducks, chickens, pigs, horses and seals are among the numerous animals that are susceptible to the flu virus and in some cases, there is a crossover between species which exacerbates the problem. The result of such crossover is that new flu virus strains are created causing further misery.

The respected Centers for Disease Control and Prevention discussed this problem flu viruses in animals that become mixed or "reassorted" and explained how this could impact on humans. Their website included this comment:

"Pigs can be infected with both human and avian influenza viruses in addition to swine influenza viruses. Infected pigs get symptoms similar to humans, such as cough, fever and runny nose. Because pigs are susceptible to avian, human and swine influenza viruses, they potentially may be infected with influenza viruses from different species (e.g., ducks and humans) at the same time. If this happens, it is possible for the genes of these viruses to mix and create a new virus. For example, if a pig were infected with a human influenza virus and an avian influenza virus at the same time, the viruses could mix (reassort) and produce a new virus that had most of the genes from the human virus, but a hemagglutinin and/or neuraminidase from the avian virus. The resulting new virus would likely be able to infect humans and spread from person to person, but it would have surface proteins (hemagglutinin and/or neuraminidase) not previously seen in influenza viruses that infect humans. This type of major change in the influenza A viruses is known as antigenic shift. Antigenic shift results when a new influenza A subtype to which most people have little or no immune protection infects humans. If this new virus causes illness in people and can be transmitted easily from person to person, an influenza pandemic can occur." www.cdc.gov

The pig, it is believed, can be a host for viruses that infect such birds as chickens and ducks. But it can also be the host for other viruses that infect humans. Therefore, if a pig becomes infected by both types of virusesone sort that infects animals and another sort common to humansthe genes of the two strains can get mixed together. The result can be a totally new strain of influenza, one to which humans have no immunity. Some feel that farming communities where poultry, swine, and people live in close proximityas is often the case in Asia, for exampleare likely sources of new flu strains.

The Avian Flu is one of the most recent examples of the concern over viruses carried by other creatures. The Wall Street Journal in 2005 made this comment: "The bird-flu virus currently active in Asia is known as H5N1 and was first spotted in Hong Kong's poultry markets in 1997. It is unusual for its virulenceit kills as many as 80% of those who catch it."

This flu virus can reportedly infect people who come in close contact with infected animals. Yes the flu is as much a disease that affects animals as it does humans. The strength of the virus depends on the type of strain and as we observe when we catch the flu personally, can produce a wide variety of symptoms. The simple fact is that the flu is an airborne ailment that animals are prone to catch just like humans.

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