AQA A Level Biology复习笔记2.6.4 AIDS

Symptoms of AIDS

• Immediately after infection with HIV people often suffer mild flu-like symptoms
• These symptoms pass and for a period of time infected people might not know they are infected
• After several months or years, the viral DNA replicated by the HIV virus particles becomes active
• They gradually destroy and reduce the number of helper T cells present in a host
• This is detrimental as helper T cells play an important role in the specific immune response
  • They stimulate B cells, the production of antibodies and increased rates of phagocytosis

   

• When an individual can no longer produce antibodies they are said to have advanced acquired immunodeficiency syndrome (AIDS)
• As they can no longer produce antibodies against pathogens they are immuno-comprised and unable to fight off infections
• They begin to suffer from diseases that would usually cause very minor issues in healthy individuals
  • These diseases are described as opportunistic
  • Tuberculosis (TB) is a common example

   

• It is these opportunistic diseases that cause an individual with advanced AIDS to die

Treatment of AIDS

• As of yet, there is no cure for AIDS
• There are many drugs that are very effective at slowing the spread of the virus within the body
• When provided with adequate medical care individuals with HIV have the same life expectancy as those without the virus

Antibiotics and viruses

• Antibiotics are commonly used to kill bacteria or limit bacterial growth
• The mechanism by which they work can vary. Some interfere with the metabolism of bacterial cells while others prevent protein synthesis
• Antibiotics are ineffective against viruses as they are non-living
• Viruses are particles and not cells
  • They have no metabolism or cell structure for antibiotics to act on and disrupt

   

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