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Influenza or Flu is contagious. How flu spreads? What is avian flu? What is H1N1 or swine flu?
How flu spreads?The main form of transmission is from person to person through droplets and small particles produced when infected people cough or sneeze. In rare cases, it can spread from other animals such as the case with avian flu. Infection can also spread if one touches materials infected with the flu virus and then touch their mouth or nose. According to CDC “healthy adults may be able to infect others beginning one day before symptoms develop and up to 5-7 days after becoming sick. That means that you may be able to pass on the flu to someone else before you know you are sick, as well as while you are sick.” Flu may also spread from animals to humans, such as the recent outbreaks of avian and swine flu.
What is avian flu?
Avian refers to bird. Avian influenza or avian flu is caused by avian influenza viruses. Usually transmission from the bird to human is very rare as avian flu viruses do not infect humans. But several cases have been reported where the flu viruses have been transmitted from birds to humans. This is very important during flu outbreaks among poultry. Under normal circumstances, wild birds carry the virus in their intestines without themselves getting sick. However avian flu is very contagious and can make poultry sick and kill. Mortality rate among poultry can reach up to 100% in 48 hours demonstrating how potent and harmful these viral strains can be. Infected birds shed influenza virus in their saliva, nasal secretions, and feces.
Avian flu viruses are referred to as Influenza A viruses. There are different subtypes of this virus, depending on the form of two different proteins they carry, hemaglutinin (HA) and neuraminidase (NA). There are 16 known HA subtypes and 9 known NA subtypes of influenza A viruses. Many different combinations of HA and NA proteins are possible. Each combination represents a different subtype. All known subtypes of influenza A viruses can be found in birds. H5N1 is an influenza A virus that is highly contagious among birds with reported outbreaks in the humans. This is one of the very few flu viruses that crossed species barrier and infected humans. More than half of those people reported to be infected with H5N1 virus have died. CDC states: “While there has been some human-to-human spread of H5N1, it has been limited, inefficient and unsustained. For example, in 2004 in Thailand, probable human-to-human spread in a family resulting from prolonged and very close contact between an ill child and her mother was reported. In June 2006, WHO reported evidence of human-to-human spread in Indonesia. In this situation, 8 people in one family were infected. The first family member is thought to have become ill through contact with infected poultry. This person then infected six family members. One of those six people (a child) then infected another family member (his father). No further spread outside of the exposed family was documented or suspected. “ It is feared that H5N1 virus may one day mutate, like other flu viruses, and gain human-to-human transmissibility. Considering the deadly virulence of this virus, this is a scary scenario. The H5N1 virus that threatened Asia is resistant to antiviral drugs such as amantadine and rimantadine.
What is H1N1, or swine flu?
Originally called swine flu, H1N1, is a new influenza virus causing illness in the people and have scared the public in the year 2009. This virus was first detected in the United States and is spreading world-wide. Scientists call this virus a "quadruple reassortant" virus because it has two genes from the flu that infects pigs, avian flu gene and human genes. It was initially called swine flu as some genes in this virus were closely matching influenza virus that normally occur in pigs. This is contagious like other flu viruses and spreads like any seasonal flu. Apart the usual flu symptoms described above, a significant number of people who have been infected with this virus also have reported diarrhea and vomiting.
 Adapted from cdc.gov |
1. Those who have flu may stay home for at least 24 hours after the fever is gone.
2. Wash hands with soap frequently.
3. If a family member is sick with H1N1 and you develop symptoms of flu, consult a physician and stay home till the symptoms disappear.
| More Flu Information: What is Flu, Flu Symptoms, Treatment and Prevention Flu symptoms and need for annual vaccination Influenza viruses, viral replication and nomenclature (swine flu) Swine flu, drugs, vaccination and pandemic Disclaimer: The above material is only for information purpose and some information may change with advancement of knowledge. Do not use this information to treat any medical condition. If you suspect a medical condition, consult a registered medical practitioner. |