viruses
VIRUSES
Viruses are not classified in any kingdom yet because they are not really alive. They only show signs of life after they infect a host cell.
Virus: lifeless particle that does not carry out any METABOLIC functions on its own and
CANNOT REPRODUCE on its own until it invades a living HOST cell
Viral history:
Viral history is relatively short. It begins with the isolation of the human influenza virus in the 1930s and crystallization of the tobacco mosaic virus in 1933, and moves through the identification of HIV as the cause of AIDS in 1983 and the mapping of the structure of the comm on cold virus in1985. It continues today with the discovery of the corona virus as the causative agent in severe acute respiratory syndrome (SARS) in 2003.
None of the emerging and re-emerging infectious diseases of the past 25 years, from
HIV /AID S and hep atitis C to Sin N om bre (H antavirus) and W est Nile, is close to eradication or control. Experts predict that the diseases will spread and grow more virulent.
Viruses constantly m utate and ch ange, and for this reason, infectious disease experts worry about a new flu pandemic. The worst pandemic in history, the Spanish Flu of
1918–1919, killed at least 20 million people, including about 30 000 Canadians. The Asian
Flu of 1957, and the milder Hong Kong Flu in 1968, killed hundreds of thousands worldwide. Pandem ic influenza viruses are more infectious than the regular variety because peop le have no im munity to them . These viruses seem to arise where people h andle domestic ducks, chickens, and pigs. These interconnections provide an ideal environment for viruses to mix, mutate, and spread. When an animal flu virus infects a person who already has the flu, genetic material from the two viruses may mix or rearrange to create a new virus. This m ixing is exactly what scientists think happened w ith the normally benign corona virus. The source of the common cold in humans, this virus causes major
Viruses are not classified in any kingdom yet because they are not really alive. They only show signs of life after they infect a host cell.
Virus: lifeless particle that does not carry out any METABOLIC functions on its own and
CANNOT REPRODUCE on its own until it invades a living HOST cell
Viral history:
Viral history is relatively short. It begins with the isolation of the human influenza virus in the 1930s and crystallization of the tobacco mosaic virus in 1933, and moves through the identification of HIV as the cause of AIDS in 1983 and the mapping of the structure of the comm on cold virus in1985. It continues today with the discovery of the corona virus as the causative agent in severe acute respiratory syndrome (SARS) in 2003.
None of the emerging and re-emerging infectious diseases of the past 25 years, from
HIV /AID S and hep atitis C to Sin N om bre (H antavirus) and W est Nile, is close to eradication or control. Experts predict that the diseases will spread and grow more virulent.
Viruses constantly m utate and ch ange, and for this reason, infectious disease experts worry about a new flu pandemic. The worst pandemic in history, the Spanish Flu of
1918–1919, killed at least 20 million people, including about 30 000 Canadians. The Asian
Flu of 1957, and the milder Hong Kong Flu in 1968, killed hundreds of thousands worldwide. Pandem ic influenza viruses are more infectious than the regular variety because peop le have no im munity to them . These viruses seem to arise where people h andle domestic ducks, chickens, and pigs. These interconnections provide an ideal environment for viruses to mix, mutate, and spread. When an animal flu virus infects a person who already has the flu, genetic material from the two viruses may mix or rearrange to create a new virus. This m ixing is exactly what scientists think happened w ith the normally benign corona virus. The source of the common cold in humans, this virus causes major