News / Africa

HIV Transmitted During Sex May Hold Clues to Infection

Multimedia

Audio
Joe DeCapua

HIV / GENITAL TRACT -- A new study finds the AIDS virus circulating in the blood may be very different from the virus that’s transmitted during sex.  And this could have implications in the search for an effective vaccine or microbicide.

University of North Carolina School of Medicine researchers at Chapel Hill say HIV may undergo changes in the genital tract of men.  As a result, the virus contained in semen could hold clues about how to block infection.  More research is needed, however.

Why important

“Most of what we know about HIV is based on analysis of virus that’s in the blood.  And much of the transmission that goes on goes from men to women or men to men.  But the male genital tract, male seminal tract, is involved in those transmissions,” says Ron Swanstrom, professor of biochemistry at UNC and the senior author of the study.

“Anything that makes the virus different in semen, which is the site of the transmitted virus, becomes important to understand just to find out if it’s relevant to the transmission event,” he adds.

Do researchers know why HIV can change in the seminal tract?  “That’s the big question for us,” he says, “and no.”

It could be one of two reasons.

Swanstrom says, “There’s a phenomenon known called the founder’s effect where…by chance it’s one thing that gets started and it grows from that….  So it could be just by luck that one or a few viruses get established in the seminal tract and grow out .  In which case presumably there won’t be any differences in terms of the biology of the virus compared to what’s in the blood.”

On the other hand, there’s another, more important possibility.

“There could be some selective pressure.  That the virus that grows in the seminal tract has some other different set of circumstances that it deals with and has to adapt to that environment.  And therefore, it’s a little bit different than what’s in the blood,” he says.

What’s the difference?

Much of the time HIV in the semen and HIV in the blood may not differ at all.  But other times there may be two different scenarios.

Professor Ron Swanstrom
Professor Ron Swanstrom

“One virus or a couple of viruses seem to take off over a very short period of time and represent a significant fraction of the virus in the semen.  We don’t know why that happens, but it’ll be a much less complex population.  The population of the blood is very complex genetically.  The viruses are all kind of different from each other.  Suddenly the semen looks much more homogeneous,” he says.

Those particular viruses, however, disappear fairly quickly.  Another possibility, he says, is that the virus gets established in the seminal tract and eventually becomes separated from the HIV population in the blood.

“That’s when we see this strong compartmentalization where the virus is very different.  But again, we don’t know what that difference is at this time,” he says.

Vaccines, microbicides

At this stage, it’s unclear whether the finding will affect vaccine and microbicide research.  But Swanstrom says, “If this is the pool of viruses that are being transmitted, then it’s really the virus that we want to understand the most about.”

He cautions that while the differences can be seen at the genome level, they may not have any biological difference from the HIV in the blood and therefore won’t behave any differently.

“But if they do confer some special property, then we certainly need to know about that. If we were really lucky, it might help inform us on either a vaccine or a more efficacious microbicide,” he says.

It’s just a different kind of virus

“I think that’s fair to say.  I’ve been a virologist for a long time and probably what’s different about HIV is that it grows constantly in the host.  And this is also true for HCV (Hepatitis C Virus).”

The biochemistry professor says these are special viruses in that “they know how to survive in the face of our immune system.  For HIV it’s always evolving.  The virus is growing every day.”

The HIV lifecycle is only about a day long.  “So 365 times a year it divides.  It grows.  If you think about that in terms of generations and how long it would be to have 365 generations of a person, that gets compressed into every year for HIV.  And whatever the host is able to throw at it, it evolves away from it.  And so there’s this titanic battle that goes on constantly between the virus and the host,” he says.

The next step is to clone the HIV found in the semen and study it further to learn whether its difference will make a difference in the search for better treatment or a cure.

You May Like

Multimedia US Nurse ‘Cured of Ebola,’ NIH Says

Nina Pham, Texas nurse who treated first Ebola patient in US, received no experimental drugs; WHO expects vaccine surge in 2015 More

Video Islamic State Militants Encroach on Baghdad

Iraqi capital not under ‘imminent threat,’ US military says, amid worries about foothold More

Video Hong Kong Protesters Focus on Holding Volatile Mong Kok

Activists say holding Mong Kok is key to their movement's success, despite confrontations with angry residents and police More

This forum has been closed.
Comments
     
There are no comments in this forum. Be first and add one

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
After Decades of Pressure, Luxembourg Drops Bank Secrecy Rulesi
X
October 21, 2014 12:20 AM
European Union finance ministers have reached a breakthrough agreement that will make it more difficult for tax cheats to hide their money. The new legislation, which had been blocked for years by countries with a reputation as tax havens, was approved last week after Luxembourg and Austria agreed to lift their vetoes. But as Mil Arcega reports, it doesn’t mean tax cheats have run out of places to keep their money hidden.
Video

Video After Decades of Pressure, Luxembourg Drops Bank Secrecy Rules

European Union finance ministers have reached a breakthrough agreement that will make it more difficult for tax cheats to hide their money. The new legislation, which had been blocked for years by countries with a reputation as tax havens, was approved last week after Luxembourg and Austria agreed to lift their vetoes. But as Mil Arcega reports, it doesn’t mean tax cheats have run out of places to keep their money hidden.
Video

Video Kobani Refugees Welcome, Turkey Criticizes, US Airdrop

Residents of Kobani in northern Syria have welcomed the airdrop of weapons, ammunition and medicine to Kurdish militia who are resisting the seizure of their city by Islamic State militants. The Turkish government, however, has criticized the operation. VOA’s Scott Bobb reports from southeastern Turkey, across the border from Kobani.
Video

Video China Political Meeting Seeks to Improve Rule of Law

China’s communist leaders will host a top level political meeting this week, called the Fourth Plenum, and for the first time in the party’s history, rule of law will be a key item on the agenda. Analysts and Chinese media reports say the meetings could see the approval of long-awaited measures aimed at giving courts more independence and include steps to enhance an already aggressive and high-reaching anti-corruption drive. VOA’s Bill Ide has more from Beijing.
Video

Video US ‘Death Cafes’ Put Focus on the Finale

In contemporary America, death usually is a topic to be avoided. But the growing “death café” movement encourages people to discuss their fears and desires about their final moments. VOA’s Jerome Socolovsky reports.
Video

Video Ebola Orphanage Opens in Sierra Leone

Sierra Leone's first Ebola orphanage has opened in the Kailahun district. Hundreds of children orphaned since the beginning of the Ebola outbreak face stigma and rejection with nobody to care for them. Adam Bailes reports for VOA about a new interim care center that's aimed at helping the growing number of children affected by Ebola.
Video

Video Young Nairobi Tech Innovator on 'Track' in Security Business

A 24-year-old technology innovator in Nairobi has invented a tracking device that monitors and secures cars. He has also come up with what he claims is the most robust audio-visual surveillance system yet. As Lenny Ruvaga reports from the Kenyan capital, his innovations are offering alternative security solutions.
Video

Video Latinas Converting to Islam for Identity, Structure

Latinos are one of the fastest growing groups in the Muslim religion. According to the Pew Research Center, about 6 percent of American Muslims are Latino. And a little more than half of new converts are female. VOA’s Carolyn Presutti travelled to Miami, Florida -- where two out of every three residents is Hispanic -- to learn more.
Video

Video Exclusive: American Joins Kurds' Anti-IS Fight

The United States and other Western nations have expressed alarm about their citizens joining Islamic State forces in Syria and Iraq. In a rare counterpoint to the phenomenon, an American has taken up arms with the militants' Syrian Kurdish opponents. Elizabeth Arrott has more in this exclusive profile by VOA Kurdish reporter Zana Omer in Ras al Ayn, Syria.
Video

Video South Korea Confronts Violence Within Military Ranks

Every able-bodied South Korean male between 18 and 35 must serve for 21 to 36 months in the country’s armed forces, depending upon the specific branch. For many, service is a rite of passage to manhood. But there are growing concerns that bullying and violence come along with the tradition. Reporter Jason Strother has more from Seoul.
Video

Video North Carolina Emerges as Key Election Battleground

U.S. congressional midterm elections will be held on November 4th and most political analysts give Republicans an excellent chance to win a majority in the U.S. Senate, which Democrats now control. So what are the issues driving voters in this congressional election year? VOA National Correspondent Jim Malone traveled to North Carolina, one of the most politically competitive states in the country, to find out.
Video

Video Comanche People Maintain Pride in Their Heritage

The Comanche (Indian nation) once were called the “Lords of the Plains,” with an empire that included half the land area of current day Texas, large parts of Oklahoma, New Mexico, Kansas and Colorado.The fierceness and battle prowess of these warriors on horseback delayed the settlement of most of West Texas for four decades. VOA’s Greg Flakus reports from Lawton, Oklahoma, that while their warrior days are over, the 15,000 members of the Comanche Nation remain a proud people.
Video

Video Turkey Campus Attacks Raise Islamic Radicalization Fears

Concerns are growing in Turkey of Islamic radicalization at some universities, after clashes between supporters of the jihadist group Islamic State (IS) or ISIS, and those opposed to the extremists. Pro-jihadist literature is on sale openly on the streets of Istanbul. Critics accuse the government of turning a blind eye to radicalism at home, while Kurds accuse the president of supporting IS - a charge strongly denied. Henry Ridgwell reports from London.

All About America

AppleAndroid