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Mon 5 Nov, 2007 08:50 am
Scientists Track Time and Place of HIV's Arrival
By Rob Stein
Washington Post Staff Writer
Monday, November 5, 2007; A10
In the decades since young gay men in the United States started dying from a mysterious syndrome in the 1980s, scientists have wondered how and when the AIDS virus arrived. Many scenarios have been proposed, including one early but now-discounted theory that the disease was imported by a promiscuous Canadian flight attendant dubbed "patient zero."
Now, however, scientists reconstructing the genetic evolution of the deadly virus say they have traced its true path -- concluding that the insidious pathogen used Haiti as a steppingstone from Africa to the United States and arrived much earlier than had been thought. It then simmered silently here for more than a decade before it was detected, beginning its global spread along the way.
"This is the first time that we've been able to bring together the geographical picture with the timing picture to show with a pretty high degree of certainty where the virus went from Africa, and when," said Michael Worobey, a professor of ecology and evolutionary biology at the University of Arizona in Tucson, who led the research.
Others praised the detailed genetic analysis of human immunodeficiency virus (HIV) from around the world as an impressive bit of biomedical sleuthing.
"For those of us who have been interested in HIV evolution and the origins of the virus, this is very interesting," said Beatrice H. Hahn, a professor of medicine at the University of Alabama in Birmingham. "It's a very nice piece of work."
In addition to writing a key chapter in the history of the AIDS pandemic, the new insights into the genetic variability of the virus could aid the long-frustrated efforts to develop an effective vaccine.
"What this might tell us is how the virus might evolve molecularly," said Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases. "That might have an impact on the virus that you put in your vaccines. So this not only has historical value but practical implications for vaccine design."
The new work fills in the latest piece of the puzzle of the origins of the AIDS pandemic. Hahn and her colleagues had previously established that HIV originally jumped from chimpanzees to humans, possibly when hunters in Africa butchered animals infected with a version of the virus. In 2000, Bette Korber of Los Alamos National Laboratory and her colleagues found that the virus began to proliferate in Africans around 1930.
But the exact route the virus took as it crept out of Africa before exploding in other parts of the world has been the subject of intense debate and speculation.
"We know that the virus has a deep history in Africa," Worobey said. "I wanted to find out how it emerged from Africa and became the pandemic that we know today."
Worobey started by retrieving six blood samples from cold storage at the federal Centers for Disease Control and Prevention in Atlanta. Arthur E. Pitchenik of the University of Miami had collected them in 1982 and 1983 from Haitian immigrants who had died from a mysterious syndrome, later determined to be AIDS.
"We now know that these are samples from several of the earliest Haitian AIDS patients in the United States," Worobey said.
In the laboratory, his team extracted HIV from five of the samples and analyzed the viral genes. The researchers then compared their findings to molecular sequences stored at Los Alamos of 117 samples of the strain of HIV that is primarily responsible for the global spread of the pandemic outside of Africa. (Other strains, however, account for far more AIDS cases worldwide today.) The researchers used specimens from 19 countries, including the United States, Canada, Haiti and several in Europe, Latin America and parts of Asia, focusing on the diversity of mutations in two key genes.
"Wherever the virus has been circulating the longest, you expect to see the most diversity, because the virus accumulates mutations over time. The longer the virus has been in a place, the more changes you'll see," Worobey said.
Based on the analysis, the researchers reported last week in the Proceedings of the National Academy of Sciences that there is a 99.8 percent certainty that the virus moved first from Africa to Haiti and then leapt to the United States.
Because the mutations accumulate at a predictable rate, the researchers were able to use them as a kind of molecular clock to calculate when the virus arrived in each location. The results indicated that it appeared in Haiti in about 1966 and the United States in about 1969, before traveling to Europe, Canada, Latin America, Australia, Japan and other parts of the world.
"That doesn't mean the virus traveled directly from the U.S. independently to each of those other countries," Worobey said. "It might have gone from the U.S. to Germany and Germany to Estonia and so forth. But once it got into the U.S. population, Americans traveling to other countries and people traveling to America allowed it to flow to other countries. The United States probably served as a worldwide hub for this spread."
The virus may have made its initial jump from Africa to Haiti after the Democratic Republic of Congo won its independence in 1960 and many Haitians sought work there, Worobey speculated.
"There were a lot of Haitian teachers in the Congo. One of those workers may have brought the ancestral subtype B virus back to Haiti. We can't prove that, but it seems plausible. The timing is consistent," he said.
It is unlikely that anyone will be able to identify the individual who first brought the virus to Haiti or the person who took it to the United States, Worobey said.
"Whoever that person was, they had no idea they were carrying the virus, and the person they transmitted it to had no idea," Worobey said. "The chances we'll ever locate a sample from that individual is almost zero."
The findings have raised concern in the U.S. Haitian community that the results could reignite prejudices, but Worobey and others cautioned against assigning blame.
"The idea of blaming groups afflicted by AIDS should be something for the past," Worobey said.
In retrospect, the discovery that HIV arrived in the United States much earlier than anyone knew is not surprising, Worobey and others said. It takes as many as 10 years after infection for most people to get sick, which would have allowed the virus to spread before health authorities became aware of it.
"There likely were individual cases here and there that simply went unnoticed," Fauci said. "You could have had a case in New York and one in Los Angeles or someplace else. Unless you have someone very astute noticing and saying, 'Wow this is unusual' for some reason, no one would realize until they started to see those first clusters."
So we brought Africans over here and enslaved them.
Later, Africa said "Hold on a minute you forgot something the first time you came. We'll send it over now."
There's a symmetry to that.
White mans burden baby, and the wheel of karma never stops turning. :wink:
I'm not following the white man's burden point.
Quote:According to the 2000 census, African Americans make up approximately 13% of the US population. However, in 2005, African Americans accounted for 18,510 (49%) of the estimated 38,096 new HIV/AIDS diagnoses in the United States in the 33 states with long-term, confidential name-based HIV reporting 2.*
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gosh JPB it's pretty simple to follow. White man brings Africans over and enslaves them. A good thing? Not so much.
Years later HIV comes to USA via Africa. A good thing? Not so much.
White man wrings hands and bears burden of HIV, which came from Africa, social unrest, a perceived loss of "his" country and culture to blacks, white man's daughter dating black kid with saggy pants..... white man's suburban Trevor walking around trying to be Dr. Dre...... white man horrified....
Next time an entire culture is in their country minding their own..... perhaps white man should consider picking his own cotton. Karma baby.
That's sort of the point. Justice is always served eventually.
Bi-Polar Bear wrote:gosh JPB it's pretty simple to follow. White man brings Africans over and enslaves them. A good thing? Not so much.
Years later HIV comes to USA via Africa. A good thing? Not so much.
White man wrings hands and bears burden of HIV, which came from Africa, social unrest, a perceived loss of "his" country and culture to blacks, white man's daughter dating black kid with saggy pants..... white man's suburban Trevor walking around trying to be Dr. Dre...... white man horrified....
Next time an entire culture is in their country minding their own..... perhaps white man should consider picking his own cotton. Karma baby.
That's sort of the point. Justice is always served eventually.
So....what are we going to be catching from the indigenous folk in our respective countries?
Hey, bear. "Take up the White Man's Burden" was by Rudyard Kipling and referred to the East Indian. Never in my life have I seen more beautiful skin than that of my East Indian friends. Just went there today to do some shopping. Of course, as a result of that poem, Kipling was banned for a while.
Don't know about HIV and Africa, BBB. But I recall the ebola virus started in Restin, Virginia.
EBOLA VIRUS
Someone once said that the truth is sometimes stranger than fiction. This is not surprising because the author of fiction must maintain some level of credibility with his reader and is thereby limited in what he can say. Reality has no such limitations, as evidenced by the following article, which is a more terrifying and diabolical story than most fiction authors would ever dream of creating.
The following is a news clip taken from the 1996 update to the Funk and Wagnalls encyclopedia.
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Ebola Outbreak Vexes Zaire
August 95
The spread of the deadly Ebola virus infection, an illness with no known vaccine or cure, continued in Zaire into the summer months, after a brief lull in May that had led health officials to mistakenly believe the virus was under control. Since mid-April, when doctors and nurses performed emergency surgeries on a 36-year-old man who had been infected with Ebola, the virus had claimed the lives of more than 200 people in the city of Kikwit and its outlying villages.
The man, a hospital technician whose job was to draw blood samples, died soon after his operations. Not long afterward, the doctors and nuns who had treated him became infected with the virus themselves. Initially, they experienced flulike symptoms: headaches, high fever, and diarrhea. But unlike persons experiencing the flu or a common cold, within a few more days they were vomiting a thick black substance-the highly contagious, virus-infected remains of their internal tissues. Soon they, like the initial victim, began to bleed massively from every orifice of their bodies, and then they died.
In mid-May, a team of international doctors and virologists arrived in Kikwit, a city with an estimated population of about 400,000, located about 400 km (250 mi) from Kinshasa, the capital of Zaire. By then, the virus had already raged throughout the hospital and had killed or infected most of the staff and patients. Those who had not fallen victim to the virus had fled the hospital in terror. Many who fled had unknowingly been infected with the virus, which has an incubation period of anywhere from 2 to 21 days, and they carried the virus with them.
Armed with sterilized needles and other sanitized hospital supplies and medical equipment, the team of health experts moved quickly to try to contain the outbreak and to educate the citizens of Kikwit about the nature and transmission of Ebola. Until this outbreak, the virus had not been seen among humans for 16 years. Like human immunodeficiency virus (HIV), the virus that causes acquired immune deficiency syndrome (AIDS), Ebola can only be transmitted through direct contact with the blood or bodily fluids of an infected individual. Ebola virus does not travel through the air. According to health experts, within days of the initial symptoms, Ebola virus attacks an individual's immune system and can destroy the body's soft tissues, including the liver, heart, and brain. After the first symptoms appear, the virus takes about a week to run its course. The only internal body parts the virus cannot destroy are muscle and bone.
Ebola was first identified in Zaire in 1976 and has resurfaced three times among humans in central Africa. In all four outbreaks, the main victims were doctors, medical staff, and patients exposed to the virus through unsanitary hospital conditions. Many hospitals in the impoverished region of central Africa lack fresh water, rubber gloves, gowns, and other sanitized supplies that can prevent the transmission of disease. Also, it is not uncommon for hospital workers in the region to use the same needle when drawing blood from different patients, further facilitating the spread of Ebola and other blood-borne diseases. Hospitals in central Africa are overcrowded, and often several patients share a single bed, which can consist of a soiled mattress lying on the floor. During the outbreak in Kikwit, where it is common practice to wash the body of a dead relative before burial, many family members of victims unknowingly contracted the virus.
The first reported cases of Ebola surfaced in Zaire and the Sudan. The virus was named after the Ebola River in Zaire, where in 1976 the virus spread to more than 55 villages located along the river's edge after an initial outbreak in the city of Yambuku. Soon after, the virus appeared in the western Sudanese cities of Nzara and Maridi. These early occurrences resulted in more than 500 cases of Ebola and more than 400 deaths. Before the May 1995 epidemic in Kikwit, the last outbreak of Ebola virus among humans occurred in Nzara, Sudan, in 1979. Of the 34 cases reported at that time, 22 resulted in death.
Despite 16 years of scientific research and field investigations, the origin of the Ebola virus remains a mystery. Researchers do know that Ebola is made up of seven proteins that surround a piece of genetically encoded material, but they know little about the inner workings of the virus. From Ebola's structure, scientists suspect it may be an ancient organism. In addition, Ebola and a related virus, called Marburg, are the only known filoviruses in the world. Under a microscope, most viruses are round in appearance, but filoviruses form long, curly, ropelike shapes.
Ebola and Marburg, along with certain other viruses, cause hemorrhagic fevers. All illnesses caused by hemorrhagic fever viruses begin with fever and muscle aches. Some of these viruses eventually cause massive internal bleeding, kidney and liver failure, respiratory problems, shock, and even death. However, not all hemorrhagic fever viruses are deadly, and the illnesses caused by some types never progress beyond mild flulike symptoms. No other known hemorrhagic fever virus causes as much bleeding as Ebola.
Most hemorrhagic fever viruses live in host organisms such as rodents or insects. Some of the viruses can jump to a new species when they come in contact with other populations of animals, such as monkeys or humans. Since the first reported cases of Ebola, investigators have tested the blood of thousands of mammals and insects captured near the sites of the initial African outbreak in an attempt to isolate the virus's host organism. Their attempts have been unsuccessful, and the source of the virus or where it circulates in between outbreaks is unknown.
Scientists have identified four different strains of Ebola virus: Zaire, Sudan, Reston, and Tai. Virus strains are usually named after the place where they were first discovered. Ebola Zaire is the deadliest known strain of the virus. With a fatality rate as high as 90 percent, it attacks every organ and tissue in the human body, except muscle and bone. It creates blood hemorrhages under the skin, dissolves connective tissue, and destroys the brain. According to researchers, the virus in the Kikwit outbreak is Ebola Zaire, virtually identical in structure to the strain seen nearly 20 years ago during the initial outbreak along the Ebola River. This similarity is an unusual phenomenon, since viruses are unstable organisms that usually mutate over time-some become weaker, while others become more virulent. The main difference between the two outbreaks of Ebola Zaire is that the strain responsible for the outbreak in Kikwit has an average incubation period of four days, while 20 years ago the virus had an average incubation period of seven days.
Ebola Sudan, while still extremely lethal, is half as strong as Ebola Zaire. Ebola Reston was named after a 1989 outbreak that occurred among monkeys imported to the United States from the Philippines and housed in a facility in Reston, Virginia, just outside Washington, D.C. All the imported monkeys tested positive for Ebola and either hemorrhaged to death or were sacrificed during a covert operation by federal health officials to control the virus. The Reston strain of Ebola was not lethal to any of the humans exposed to it.
In November 1994 a new strain of Ebola virus, known as Ebola Tai, was discovered. The new strain was named after the Tai Forest in the western African republic of Cote d'Ivoire, where it was found. A Swiss zoologist developed symptoms of hemorrhagic fever after performing an autopsy on an infected chimpanzee. She was flown to a hospital in Switzerland, where she soon recovered. Blood samples and other immunological tests confirmed that she had come down with a new strain of Ebola. The zoologist had been part of a team of scientists sent to the Tai Forest to study a band of chimpanzees that had been dying of hemorrhagic fevers. None of her colleagues from the expedition had been infected with the new strain of Ebola. The case marked the first time that a human Ebola infection was directly linked to wild African monkeys.
Despite the extremely high fatality rate of certain strains of Ebola, health officials maintain that, under sanitary conditions, the virus is actually difficult to contract. Like HIV, Ebola spreads through direct contact with an infected person's blood or bodily fluids. Unlike HIV, which can live inside an individual and be passed along to others for ten years or more before symptoms appear, Ebola has a relatively short incubation period. Once the symptoms of Ebola appear, precautions can be taken to halt its spread to others. Health officials say that because Ebola kills its victims so quickly, the chance of the virus ever becoming widespread among human populations is low.
Like all viruses, Ebola needs a constant supply of host organisms to survive and propagate. Outside of a host organism, viruses survive as inert genetic material encircled by a shell of proteins waiting to be activated. Inside a host organism, however, viruses become active and are able to attach to or inject their genetic material into the host's cells. The virus's genetic material redirects the cell to produce more viruses. The newly created virus cells are then capable of infecting other cells. During the replication process the virus usually destroys the host cell. Scientists hypothesize that apart from occasional human outbreaks, Ebola survives among a population of wild animals and then jumps species when a human comes in contact with the virus's host organism. Scientists do not know specifically where the virus lives between outbreaks.
Ebola is one of several types of deadly viruses detected over the last 25 years. Other lethal African viruses that have emerged among human populations during the late 20th century include Marburg, Lassa, Rift Valley Fever, and HIV. Seven out of 31 people died in 1967 after being infected with Marburg virus by Ugandan green monkeys. Marburg is closely related to Ebola, although it is far less deadly. Lassa, another hemorrhagic fever virus, infects 200,000 to 400,000 annually in West Africa. Approximately 5000 of those infected die from the disease. Rift Valley Fever, a mosquito-borne virus, reached epidemic proportions when it infected more than 10,000 people along Egypt's Nile River Delta in 1977. The virus was first detected in Kenya in the 1950s. HIV is perhaps the most deadly virus, believed by health experts to have originated on the African continent. Since its emergence during the 1970s, HIV has infected more than 13 million people worldwide, and experts expect that number to climb to 40 million by the year 2000.
In addition to Africa, outbreaks of newly reported lethal viruses have appeared in North America, South America, Asia, Australia, and Europe. Scientists note that the emergence of these deadly viruses, in most cases, coincides with the recent encroachment of human beings on tropical rain forests and once-isolated rural villages. Experts believe that the original hosts of these deadly viruses are somewhere in these areas. Health experts hypothesize that newly built roadways connecting urban centers with small villages in western and central Africa, the development over the last few decades in tropical rain forests, the advent of jet travel, large-scale farming, and a massive trend toward urbanization have facilitated the spread of these previously unknown viruses among human populations.
BBB
Does anyone know the origin site of the deadly Neocon virus?
BBB
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