The bird flu virus that affects birds has at least 15 different subtypes and usually only affects the bird population. The most dangerous subtype is the H5N1 subtype. When the virus is found in humans, it is said to have "jumped the species barrier. Because humans have no natural protection or immunity to the virus, they are likely to become ill very quickly and possibly die due to complications of the bird flu. Bird to human transmission: Birds such as turkeys, geese, and domestic chickens come in contact with the virus from food, water, or particles contaminated with the virus.
The virus can be shed in the droppings of migratory birds since they are natural carriers and is able to survive for 3 months in cool temperatures. Transmission of the virus from birds to humans occurs when a person working closely with these animals inhales dust particles containing the virus or by other means. In countries where live birds e. This is because both human and avian viruses can infect pigs. If a pig is infected with both viruses at the same time, different parts of the avian and human viruses can mix with each other.
Later, the avian virus that has picked up some genes from the human form of the influenza virus is able to more easily cause the condition in humans. Human to human transmission: Although the vast majority of human cases of bird flu are the result of direct contact with an infected bird, rare cases of direct human-to-human spread have been reported. Symptoms of the condition in birds depend on the pathogenicity of the virus that infects a bird. A virus that is not highly pathogenic causes mild illness.
This form of the condition produces ruffled feathers or a decrease in egg production in infected birds. Humans who have close contact with sick birds are at risk of infection with bird flu. For example a person may handle a sick bird, contaminate their hands with chicken faeces, and forget to wash their hands before eating.
They will then ingest the infected bird faeces. This is the most common way for a human to catch the bird flu. The virus can also survive in raw poultry meat but is destroyed during normal cooking.
There is no evidence that the current circulating H5N1 strain of bird flu can be spread easily from human to human. Although there have been too few human cases to determine the exact incubation period of bird flu, it would be expected to be from three to 10 days. The symptoms of bird flu in humans are similar to those of regular influenza and include:. If you have recently returned from a country that had an outbreak of bird flu and you get flu symptoms, see your doctor immediately.
When making the appointment, tell the clinic staff about your travel including any visits to markets, farms or anywhere else where birds were present. Influenza viruses that infect animal species can mutate and infect humans. The human immune system may have no defences against viruses that previously only infected animals. Health experts are concerned that the current bird flu affecting parts of Asia, the Middle East, Africa, and Europe could become a worldwide pandemic if the virus does mutate.
The worst influenza pandemic in modern history was the Spanish flu, which occurred in —19 and killed up to 50 million people. Measures to contain the spread of the current bird flu virus include identifying and culling affected poultry flocks, research into tests and vaccines, and rigorous quarantine practices. Federal and state governments have been working together to plan their response to an outbreak of bird flu. An episode of bird flu in Australia would trigger the Australian Action Plan for Pandemic Influenza, a federal government plan.
Victoria also has a Pandemic Influenza Plan, which details the steps that will be used by state government agencies and health services to manage an outbreak. A separate federal government plan, the Australian Veterinary Emergency Plan , is designed to manage bird flu outbreaks among bird populations such as poultry farms. Key measures to prevent an outbreak of bird flu include keeping wild birds and domesticated birds apart, and making sure that domesticated birds have a safe supply of drinking water.
Several antiviral medications used to treat human influenza are also effective for bird flu. These could be used if a person developed symptoms after possible exposure to avian influenza, or to prevent illness in a person who was in close contact with avian influenza. At present people living in Australia, or people making short visits to affected countries, do not need to have antiviral medications.
However Australians living in countries affected by avian influenza should consider having access to a supply of antiviral medication, to be used on medical advice. This can happen when virus is in the air in droplets or possibly dust and a person breathes it in, or when a person touches something that has virus on it then touches their mouth, eyes or nose.
Rare human infections with some avian viruses have occurred most often after unprotected contact with infected birds or surfaces contaminated with avian influenza viruses. However, some infections have been identified where direct contact was not known to have occurred. People who work with poultry or who respond to avian influenza outbreaks are advised to follow recommended biosecurity and infection control practices; these include use of appropriate personal protective equipment and careful attention to hand hygiene.
Additionally, CDC recommends that people responding to poultry outbreaks should get a seasonal influenza vaccination every year, preferably at least two weeks before engaging in an outbreak response. Seasonal influenza vaccination will not prevent infection with avian influenza A viruses, but can reduce the risk of co-infection with human and avian influenza A viruses.
They typically include:. Gastrointestinal symptoms such as nausea, vomiting, and diarrhea are more commonly seen in people who have the H5N1 infection; conjunctivitis is more commonly seen in people who are affected by H7 forms of the virus. Bird flu is spread through contact with both wild birds and domestic poultry, such as chickens, turkey, and ducks, per the Mayo Clinic. There have, however, been some instances in which a person has become infected without making direct contact with a bird.
More rarely, the virus has spread from person-to-person, but this type of transmission has been limited, and does not seem to happen easily, notes the CDC. Open-air markets can also be a source of bird flu, since eggs and birds can be sold in unsanitary conditions. Some people are more at risk than others for being very sickened with bird flu, including pregnant women, adults over the age of 65, and people with weakened immune systems.
It may be possible, however, to find antibodies that a person has produced to fight off the virus. While symptoms may be mild, more severe cases of bird flu can be deadly. For those patients hospitalized with avian influenza, mortality is more than 50 percent for all of the strains combined. The mortality rate for H5N1 has been estimated to be 60 percent, according to Stat Pearls. The average incubation period of bird flu H5N1 is two to five days, though it can last up to 17 days.
The World Health Organization says that people with bird flu should be treated with antiviral medications for at least five days, but can continue taking them until their symptoms improve. The medications used to treat bird flu include:.
But the H7N9 and H5N1 viruses have become resistant to the antiviral drugs Gocovri amantadine and Flumadine rimantadine. There is no widely available vaccine to prevent bird flu in the United States. The best way to prevent bird flu is to avoid the sources of the exposure.
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