BIOLOGICAL CLASSIFICATION
VIRUSES
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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HIV is now starting to cause diseases other than AIDS, such as rare types of cancer and pneumonia
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HIV infected humans long before the 80’s, but it has now mutated to a more deadly form
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HIV mutates rapidly making the virus very different from HIV in the early 80’s
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HIV suddenly became more apparent and widespread in the 80’s
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Detailed explanation-1: -An example of an emerging infectious disease that can be attributed to human practices is HIV. It is thought that humans were first infected with HIV through close contact with chimpanzees, perhaps through bushmeat hunting, in isolated regions of Africa.
Detailed explanation-2: -In a number of persistent infections, notably HIV, mutations emerge at an extremely high rate because of the very high replication rate, for example, 1010 new virions per day, and the high error rate of the virion reverse transcriptase (approximately 1 base error per 104 nucleotides transcribed).
Detailed explanation-3: -Viruses like HIV have some of the highest mutation rates known-and this high mutation rate means that HIV evolves quickly. In fact, HIV evolves so quickly that its surface molecules are a constantly moving target-and our immune systems (and vaccine developers) simply can’t keep up.
Detailed explanation-4: -One of the earliest and most striking observations made about HIV is the extensive genetic variation that the virus has within individual hosts, particularly in the hypervariable regions of the env gene29; this variation makes HIV one of the fastest evolving of all organisms.