Microbiology

Microbiology Study Guide

The virus is known as a retrovirus and it combines the spike glycoproteins with the CD4 receptor sites of T-lymphocytes of the infected person, reversing the transcriptase and synthesizing the DNA molecules with the help of RNA. Later on, DNA molecules enter the state of lysogeny, encoding the new particles of HIV. This exerts pressure on the defense system of the human body, and finally the counts of the T-lymphocyte cells reduce drastically from 800 to about few hundred, or even tens. The duration of this dropping ranges between six months to 12 years after the spread of infection in the human body. Early symptoms of this disease are swollen lymph nodes, prolonged fever, malaise, and diarrhea. The initial stages of this disease are known as an HIV infection, while the last stage is known as AIDS, wherein the affected person suffers from opportunistic infections like candidiasis, very low count of T-lymphocyte cells, wasting syndrome, and even destruction of mental senses. Major opportunistic injections at the later stages of AIDS can take any of the forms of Pneumocystis carinii pneumonia, Cryptosp ridium diarrhea, encephalitis due to Toxoplasma gondii , severe eye infection and blindness due to cytomegalovirus, candidiasis of the mucous membranes and esophagus due to Candida albicans , meningitis due to Cryptococcus neoformans , or herpes simplex, tuberculosis, or cancer of the skin known as Kaposi’s sarcoma. These infections are curable using prescribed drugs, but the season of these infections never end and the AIDS patient constantly fights from one or the other infections until the will power of the patient breaks. Scientists, researchers, and doctors have successfully been able to develop a few drugs to reduce the multiplication of the HIV cells like azidothymidine (AZT), dideoxycytidine (ddC), and dideoxyinosine (ddI). These are known as chain terminators and the role played by these drugs is that they use the viral RNA, interfere with the DNA molecules, and combat the reversal transcriptase caused by the HIV virus. Another category of drugs is protease inhibitors, like saquinivir and indivir. These drugs interfere with the protein preparation and prevent the synthesis of the viral capsid.

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