Science and Medicine: Genetic Path of AIDS
Monday, November 5, 2007; 11:00 AM
Washington Post staff writer Rob Stein was online Monday, Nov. 5 at 11 a.m. ET to discuss his Monday Science Page story about the genetic evolution of the AIDS virus.
Scientists have recently found that the pathogen came to the U.S. much earlier than had thought, simmering silently for more than a decade before it was detected and before it spread globally.
Read more: Scientists Track Time and Place of HIV's Arrival.
The transcript follows.
Orlando, Fla.: How can you blame HIV on the Haitians when other nations such as France where heavily involve in traveling to the Congos in the 1960s. In fact, Congo was under the occupation of France until the 1960. When you consider the amount of traffic from Frances and other EU nations to the US isn't it much more probable that someone else would have brought AIDS to the US? Beside the few Haitians that went to the Congo in the 1960s were not allowed to return to Haiti because they were enemies of Francois (Papa Doc) Duvalier. This was his way of sending them into exile. For those who don't know, the Duvaliers ruled Haiti until 1986s which mean the probability of one of those people catching AIDS in Africa and Return to Haiti to infect someone, and for that infected person out of 6 mil Haitians to go to the US to infect a person is absurd. The funny thing is around that time Haitians didn't use to travel to the US as much as today. The author of this article is trying to be politically by saying don't blame the Haitians for AIDS We Haitians are not going to buy it. We know well what his trying to do. He's trying to smear the Haitian people on an unfounded claim.
Rob Stein: The research was based on a genetic analysis of samples of the virus from around the world. The lead researcher made a point of saying that he thought it was important that his findins not be used to assign any kind of blame.
Freising, Germany: I'm confused about the spread of AIDS and its prevalence in Africa over the last 20 years. If HIV has a deep history in Africa, when exactly did it become lethal to humans?
Was it a Haitian mutation that developed into the incurable version known to cause AIDS, or is it now thought that Africans were dying of AIDS back in the 1930?
If as many Africans were mysteriously dying then as they have in the last 10 or 20 years of AIDS related symptoms, then missionaries and doctors in Africa must have recorded their observations.
Rob Stein: The virus was probably killing people in Africa for many years before it was identified. Research indicates that the virus started spreading in people in Africa somewhere around 1930. But it takes up to 10 years for most people who are infected with the virus to get sick. So while there may have been some cases in the intervening years, it wasn'tuntil many cases started showing up in the United States in the 1980s that anyone realized what had been happening.
Washington, D.C.: I thought the article was interesting and I liked the map graphic. I'm wondering though, what is the greater value of this research--i.e. the "so what?" How will this information help prevent/treat/cure HIV/AIDS?
Rob Stein: One practical implication is that the research provides scientists with insights into the genetic variability and evolution of the AIDS virus. That could be helpful in their efforts to develop a vaccine. That work has so far been very frustrating and disappointing. Part of the problem is the genetic variability of the virus.
washingtonpost.com: Graphic: Tracing One Branch of a Pandemic
San Mateo, Calif.: So has the "Patient Zero" narrative as described in Randy Shilts' book "And the Band Played On" been discredited? It seemed very compelling at the time. Shilts followed the chain of transmission carefully. But if I read your story right, AIDS had already been quietly in the background in the U.S. for decades, so Gaetan Dugas was perhaps a major transmitter, but hardly the first?
Rob Stein: That's right. That theory has been essentially discredited. While that patient may have played a role in the epidemic, this research shows the virus had already arrived in this country many years earlier.
Boston, Mass.: The first question really disturbed me. HIV is not the first virus to spread by migration and it won't be the last.
Rob Stein: That's absolutely right. Many other viruses are spread by human migration, and many more will be in the future as the number of people moving around the world continues to increase. That's one of the downsides of the increased ability to travel.
Philadelphia, Pa.: This is a fascinating piece of science that the authors have assembled. Please help me understand better their claim of the disease's trajectory: that it originated in the Congo, then was brought to Haiti, where it mutated into the form which became pandemic, then entered the US, from which it spread around the globe?
Rob Stein: This research isn't saying that the virus somehow changed once it got to Haiti into something more dangerous. What it does it trace the path the virus took as it spread out of Africa and then began spreading elsewhere around the world. It started in Africa, possibly the Congo, then went to Haiti, then the United States, and then elsewhere.
Amherst, N.Y.: As I remember, the most recent WHO paper noted that the rate of infection was increasing most rapidly in that part of the world. I noticed that your graphic does not include any strains in most of the former USSR. Is that because the disease is a relatively recent arrival in that region, and as such has had little opportunity to develop into a separate strain, or because data are lacking in that area, or some other reason?
Rob Stein: This study didn't examine samples of the virus from every country in the world. The researchers looked at 117 samples from various parts of the world to track the spread after its arrival in the United States.
Philadelphia, Pa.: One of the more interesting theories mentioned in the report used in your article is that HIV very gradual spread amongst the Haitian population in the 1960s, and then in the US population from 1969 until 1981, suggests that the disease was spreading primarily in the heterosexual community (and, therefore, quite slowly due to the decreased risk of transmission).
Of course, one of the great historical fallacies involving AIDS was its characterization by social and religious conservatives in this country as a "gay disease", sometimes even alleged to be a divine punishment. These same outlets fed into the scapegoating of Patient Zero and other homosexual victims of the disease.
In your opinion, is the science in this study definitive enough to assert the heterosexual origins of this disease in the United States?
Rob Stein: The researchers didn't look at the sexual orientation of those who were first infected with the virus. But there's no reason to think it necessarily was limited to homosexuals.
Chicago, Ill.: The graphic contains more information than is in the article. For instance, it suggests that the virus was reintroduced into Africa through the United States. It also suggests that the virus spread from Haiti to Trinidad and Tobago from 1993-1996. Can you expand on what the authors found in those two instances?
Rob Stein: That's true. The researchers found two discreet events after the virus went from Africa to Haiti -- one jump to the United States and another to Trinidad and Tobago.
Patient Zero: You said in the story that the Patient Zero hypothesis, which I remember reading about in Randy Shilts's "And the Band Played On," had long ago been disproved. How did that happen?
Also, do they have a sense of how much of the worldwide spread came from the US, and whether it left Africa multiple times and went to other countries from there?
Rob Stein: This research suggests that the United States served as a hub for the dissemination of the virus worldwide.
Boston, Mass.: Isn't the strain of HIV prevalent in the US different from the one elsewhere (I don't know, maybe Thailand)? Don't the different strains have to have taken different paths?
Rob Stein: Yes, the strain that is prevalent in the United States is known as subtype B. That's also the strain that is dominant in most parts of the world. It is not, however, the strain that is responsible for most cases of AIDS in the world. The majority of cases are in developing countries, such as central Africa, and are caused by multiple strains other than subtype B.
Arlington, Va.: I would love to hear the argument that it really did there before 10 years scientists detected its existence. Namnam
Rob Stein: The argument is that it would take a while for the number of people infected to add up, and for most people infected they do no begin to show any symptoms for many years, perhaps a decade. So there might have been some people getting sick, but unless someone knew what they were looking for no one would realize what was happening until clusters of similar cases showed up. That's exactly what eventually occurred.
Chicago, Ill.: Thanks for answering my question on Trinidad and Tobago, but you didn't address the question about Africa. The map shows that the virus entered Gabon through the United States. But how can they tell that given that Gabon is right next to Congo? It would seem more likely that it spread directly. If the graphic is true, its a very interesting finding. But I'm curious about the science; it suggests that the virus the authors studied mutated over time. But in response to an earlier question you said that this paper traced the advance of one particular strain of the virus...
Rob Stein: That's right. This research did find that the virus did end up returning to Africa from the United States. By studying the mutations in the virus, the researchers were able to trace its path and the timing of the arrival of different variations in different places.
Alexandria, Va.: Does the research show that the HIV-1-B strain spread from the Congo exclusively to Haiti first or does the possibility exist that it also spread elsewhere and took a more circuitous route to the US?
Rob Stein: This research indicates that the virus spread exclusively first to Haiti before spreading elsewhere.
Chicago, Ill.: One interesting finding by the researchers is that the Trinidad and Tobago strains seem to be derived from a single transmission. That should give our public health officials pause in determining how best to prevent/combat the spread of emerging diseases and bioterrorism.
Did the authors give you a sense of how much they thought ecological/genetic factors played a role in the epidemic spread of the Haitian virus?
Rob Stein: This study didn't examine those factors, but that certainly is an important line of research, though it could be that it was a chance event.
London, U.K.: Of course, no one would notice a disease that hadn't been seen before. But I do wonder if it took longer to notice that it otherwise would have because of the population that had been infected. I can't imagine that Haitian immigrants were either a highly visible population at the time or had access to quality health care. To me, this just adds to the argument that social inequalities tragically contributed to the spread of this terrible disease.
Rob Stein: The researchers do allude to that idea in their paper, noting that it took so long for the virus to be detected in one of the most technologically advanced places in the world.
Dallas, Tex.: My mother contracted AIDS (possibly from a blood transfusion) early in 1977. She was treated at Wadley Research Center, and St.Paul Hospital in Dallas. She was mentioned in an article in a national medical journal due to being the only female in the U.S. to have this virus. I was told by a nurse shortly before her death, what she had was AIDS.
Rob Stein: That timing certainly fits with the findings in this study.
Boston, Mass.: Obviously Haitians are not taking this "news" well. Did the research address any of the discrimination faced by Haitians in the 80s in reference to AIDS and the more than likely resurgence of discrimination to come?
Rob Stein: This study did not address that issue, but the researcher who led the work made a point of saying that he felt like it was important this work not be used to assign blame to any groups, especially those who have been hit hard by a terrible disease.
Bethesda, Md.: What implications, if any, are there for understanding the disparities in HIV among African Americans and others in the U.S.? A social networks model, paired with the news that the virus may have entered the "black" community earlier, could be significant -- or no?
Rob Stein: The same subtype of the virus dominates across racial groups in the United States.
Bangkok, Thailand: How many strains of HIV are there? Is there any empirical evidence that, once infected, some of these may remain dormant for longer than than generally accepted window of one to six months before antibodies can be detected?
Rob Stein: I don't know of any variation in detectability across strains.
San Diego, Calif.: I think the quote from Dr. Fauci is telling -- we still don't know how to vaccinate against HIV. And the virus is able to mutate relatively quickly, making the idea of a fixed vaccine laughable.
Rob Stein: Developing a vaccine against HIV has certainly turned out to be much harder than anyone had thought. But researchers have not given up trying, by any means. And this research suggests vaccines may need to be tailored against various strains and genetic variations of the virus.
Rob Stein: Thanks very much for all the great questions.
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