Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!elroy.jpl.nasa.gov!ucla-cs!usenet From: bwoodman@magnus.acs.ohio-state.edu (Robert H Woodman) Newsgroups: sci.med.aids Subject: Re: life cycle, methods of infection Message-ID: <1991May23.011445.10031@cs.ucla.edu> Date: 22 May 91 21:12:11 GMT References: <1991May22.110023.27019@cs.ucla.edu> Sender: news@magnus.acs.ohio-state.edu Distribution: sci Organization: The Ohio State University Lines: 84 Approved: phil@wubios.wustl.edu Note: non-commercial reproduction. Nntp-Posting-Host: squid.cs.ucla.edu Archive-Number: 3173 In article <1991May22.110023.27019@cs.ucla.edu> decwrl!well.sf.ca.us!well!gregs@uunet.UU.NET (Greg Strockbine) writes: >I have a couple of questions: > * can someone tell me the life cycle of a virus in general, > does it also apply to the aids virus? The AIDS virus (HIV) is a retrovirus. Its genetic information is stored by RNA rather than (the normal) DNA. DNA viruses have the following, generalized life cycle: (1) Attachment to the cell. (2) Injection of the viral DNA into the cell. (3a) Takeover of cellular functions by the virus to begin producing massive numbers of viral particles. Cell death quite often results from this. (3b) Integration of the viral DNA into the genome of the cell. The virus enters a quiescent phase, and may stay this way for a long time, but shock to the cell can trigger (3a). An example of this is the herpes virus, such as causes fever blisters. (4) Release of virus particles into the environment around the cell, where new rounds of infection may then occur. With HIV, steps (1) and (2) are the same, except that "DNA" is changed to "RNA" for HIV. With infected T4 cells, the attachment point is the CD4 antigen on the T4 surface. Between steps (2) and [(3a) or (3b)], a step must be introduced in which transcription and translation of the HIV genome occurs. The reverse transcriptase of HIV then converts the HIV RNA to DNA, thus allowing either integration of the DNA into the genome or production of many new viral particles. Recent research has shown that, with HIV, step (3a) occurs for awhile, until many cells are affected, and then the virus enters a quiescent phase for a period of time. It re-emerges later with devastating effect. Please note that, though I am a molecular biologist, I am not a virologist, so I am presenting only a generalized picture, and not the specialized view held by people who work with this all of the time. > * regarding methods of infection, is it safe to perform fellatio > up to the point of ejaculation? No. > In particular, there is a > clear, sticky fluid that comes out of the penis before ejaculation, > could this also carry the aids virus? Yes. > * does stomach acid kill the aids virus? This might sound > silly but I have a friend who is an occasional prostitute > and makes this claim. Yes, stomach acid can kill HIV, but the efficacy varies, and relying on this is damn stupid. > * regarding my friend, her clients are exclusively well to do > men she is referred to thru friends, she sees them about > once or twice a week. Obviously she is not in the same risk > category as a woman who works the street, but can we say > anything about her risks? She is high risk. Period. > * is it easier for a man or a woman to contact aids? Male-to-male transmission and male-to-female transmission has been shown to occur quite readily, while female-to-male transmission *does* occur, as has been convincingly shown, but is much less easy than m-m or m-f transmission. >I appreciate any feed back anyone can give me on these questions. > thanks, greg s. You're welcome. Bob Woodman -- ********************************************************************* *Robert H. "Bob" Woodman, PhD * "A job not worth doing well is not * *INTERNET: woodman.1@osu.edu * worth doing."--Salvador Luria * *********************************************************************