Published by
Stanford Medicine

Category

HIV/AIDS

Global Health, HIV/AIDS, Infectious Disease, Public Health, Research, Rural Health

Drought causes spike in HIV infections in Africa

Drought causes spike in HIV infections in Africa

75148497_50e081cd5b_zHere in California, the drought is plenty serious. Shortages mean short showers, brown lawns, empty reservoirs and fallow fields.

But in sub-Saharan Africa, drought spreads disease, including the still-rampant HIV virus. The phenomenon is more sociological than ecological: Slim harvests slash farmers’ incomes, forcing them to find new ways to earn money. Some turn to sex, according to a new study in The Economic Journal.

As described in a recent article from Stanford’s Center on Food Security and the Environment (FSE):

Analyzing data on more than 200,000 individuals across 19 African countries, the research team finds that by changing sexual behavior, a year of very low rainfall can increase local infection rates by more than 10 percent.

That means condoms and sex education aren’t all that’s needed to thwart the epidemic’s spread, the study’s authors say. Affected farmers also need economic support and alternatives to help them weather the dry period, without sacrificing their health.

“These are the people who really suffer when the rains fail, and who are forced to turn to more desperate measures to make ends meet,” co-author Marshall Burke, PhD, a fellow at the FSE, said in the piece.

Previously: Spread of drug-resistant HIV in Africa and Asia is limited, Stanford research finds, Stanford study: South Africa could save millions of lives through HIV prevention and Changing the prevailing attitude about AIDS, gender and reproductive health in southern Africa 
Photo by Jon Rawlinson

Genetics, HIV/AIDS, Infectious Disease, Research, Stanford News

Study shows toothed whales have persisted millions of years without two common antiviral proteins

Study shows toothed whales have persisted millions of years without two common antiviral proteins

1821221135_4a6cd4e8f8_z

Our ability to fend off the flu, HIV and other viruses is enhanced when proteins are produced by two “immune genes,” called MX1 and MX2. Other mammals also have these genes, but little is known about the role they play in the immune responses of these animals.

Now a study comparing the genomes and Mx genes of 60 mammal species has revealed a surprising finding: Every species in the study has functioning Mx1 and Mx2 genes except for dolphins, whales and orcas — species from a lineage of toothed whales that’s persisted for roughly 33 million years.

Gill Bejerano, PhD, a geneticist and developmental biologist, graduate student Benjamin Braun and their team wanted to know more about the status and function of Mx genes in non-human mammals. To do this, they examined and compared the part of the genome that contains the Mx genes in 60 different species including humans, cows, whales, dolphins and orcas.

I think this will open up very exciting research avenues, either to better protect the compromised whales, or to study their different viral defenses, and someday add them to our own arsenal.

The study, published this week in the Proceedings of National Sciences, showed that the Mx1 and Mx2 genes in the toothed whales (bottlenose dolphin, orca, Yangtze river dolphin and sperm whale) they tested were non-functional, and couldn’t produce the proteins that help fight viral infections. Bejerano explained the significance of this finding in our press release:

Given how important the Mx genes seem to be in fighting off disease in humans and other mammals, it’s striking to see a species lose them both and go about its business for millions of years.

To find out when in evolutionary history these genes became inactive the researchers compared the genomes of toothed whales to that of their closest ancestors, the baleen whales and hoofed mammals (ungulates). They found that the Mx genes function in baleen whales and hoofed mammals, but not in toothed whales. This means that some — perhaps all — toothed whales likely lost use of their Mx genes when this lineage split off from these ancestors about 33 million years ago (see Fig. 1).

Continue Reading »

Evolution, Genetics, HIV/AIDS, Immunology, Infectious Disease, Research, Stanford News

Study: Chimps teach people a thing or two about HIV resistance

Study: Chimps teach people a thing or two about HIV resistance

I, personally, have never had trouble distinguishing a human being from a chimp. I look, and I know.

But I’m not a molecular biologist. Today’s sophisticated DNA-sequencing technologies show that the genetic materials of the two species, which diverged only 5 million or so years ago (an eye-blink in evolutionary time), are about 98 percent identical. Think about that next time you eat a banana.

One major exception to that parallelism: a set of three genes collectively called the major histocompatibility complex, or MHC. These genes code for proteins that sit on the surfaces of each cell in your body, where they serve as jewel cases that display bits of proteins that were once inside that cell but have since been chopped into pieces by molecular garbage disposals, transported to the cell surface and encased in one or another of the MHC proteins. That makes the protein bits highly visible to roving immune cells patrolling our tissues to see if any of the cells within are harboring any funny-looking proteins. If those roving sentry cells spot a foreign-looking protein bit, they flag the cell on whose surface it’s displayed as possibly having been infected by a virus or begun to become cancerous.

Viruses replicate frequently and furiously, so they evolve super-rapidly. If they can evade immune detection, that’s groovy from their perspective. So our MHC has to evolve rapidly, too, and as a result, different species’ MHC genes  diverge relatively quickly.  To the extent they don’t, there’s probably a good reason.

Stanford immunologist and evolutionary theorist Peter Parham, PhD, pays a lot of attention to the MHC genes. In a new study in PLOS Biology, he and his colleagues have made a discovery that may prove relevant to AIDS research, by analyzing genetic material found in chimp feces. Not zoo chimps. Wild Tanzanian chimps. As I noted in a news release about the study:

The wild chimps inhabit Gombe Stream National Park, a 13.5-square-mile preserve where they have been continuously observed from afar since famed primatologist Jane Goodall, PhD, began monitoring them more than 50 years ago.

One thing that sets the Gombe chimps apart from captive chimps, unfortunately, is a high rate of infection by the simian equivalent of HIV, the virus responsible for AIDS.

The study’s lead author, postdoc Emily Wroblewski, PhD, set up shop in a corner of Parham’s lab and extracted DNA from fecal samples legally obtained by other researchers (close contact with the animals is prohibited). Each sample could be tied to a particular Gombe-resident chimp. RNA extracted from the same sample indicated that chimp’s infection status.

Parham, Wroblewski and their colleagues found that one particular MHC gene came in 11 different varieties – astounding diversity for such a small collection of chimps (fewer than 125 of them in the entire Gombe). Surprisingly, one small part of one of those 11 gene variants was nearly identical to a piece of a protective version of its human counterpart gene, a version that seems to protect HIV- infected people slowing HIV progression to full-blown AIDS.

Why is that important? Because any piece of an MHC gene that has maintained its sequence in the face of 5 million years of intense evolutionary pressure must be worth something.

Sure enough, fecal samples from chimps with that MHC gene variant, so strikingly analogous to the protective human variant, had lower counts of virus that those from infected chimps carrying other versions of the gene.

You can believe that scientists will be closely examining the DNA sequence contained in both the human and chimp gene variant, as well as the part of the MHC protein that DNA sequence codes for. Because it must be doing something right.

Previously: Revealed: Epic evolutionary struggle between reproduction and immunity to infectious disease, Our species’ twisted family tree and Humans share history – and a fair amount of genetic material – with Neanderthals
Photo by Emily Wroblewski

Global Health, HIV/AIDS, Infectious Disease, Stanford News

Spread of drug-resistant HIV in Africa and Asia is limited, Stanford research finds

Spread of drug-resistant HIV in Africa and Asia is limited, Stanford research finds

In the last decade, millions more people in the developing world have gained access to anti-viral drugs to treat HIV, with nearly 12 million now on this life-giving treatment. But with more people on medication, there’s concern about the spread of drug-resistant strains of the virus, which can be transmitted from one individual to the next.

A new, multi-center study led by Stanford researchers offers some good news on this front: The transmission of drug-resistant strains thus far has been fairly limited in the hard-hit regions of Africa and Asia. The research involved more than 50,000 patients in 111 countries.

It is inevitable that transmitted drug resistance will increase further, so we need to continue ongoing monitoring to ensure successful, long-term treatment outcomes

“What we are showing is that the rates of transmitted drug-resistant HIV in the low- and middle-income countries most affected by HIV have increased modestly,” Stanford infectious disease expert Robert Shafer, MD, principal investigator on the study, told me. “The rate of increase in sub-Saharan Africa has been low, and an increase has not been detected in south Asia and Southeast Asia.”

Shafer is nonetheless cautious, as drug resistance remains a problem in these regions, where patients are prescribed drug regimens that are not as effective as those used in the West. And adhering to a daily regimen can be challenging for these patients, as transportation, drug supply and other issues may get in the way. Resistance can occur when there is a gap in treatment.

“It is inevitable that transmitted drug resistance will increase further, so we need to continue ongoing monitoring to ensure successful, long-term treatment outcomes for the millions of people on therapy worldwide,” Shafer said.

In the study, he and his colleagues identified four mutations that were linked to resistance to two HIV drugs, nevirapine and efavirenz. That result points to the possibility of creating a simple test that could be used to detect these mutations, he said. Clinicians then could tailor their treatment accordingly.

Another key finding was that the drug-resistant strains that did occur were not from a single line of resistant viruses, but were quite distinct. That means they developed independently, not as a result of a single transmission chain. That differs from some other microbes, such as malaria and tuberculosis, where resistant strains can move very quickly through the population.

“We are finding that the strains being detected in low-income countries are pretty much unrelated to one another,” Shafer said. “So that suggests these have not yet gained a foothold in the population and are less often being transmitted among people who have never received the drugs before.”

The study appears online today in PLoS Medicine.

Events, Global Health, HIV/AIDS, LGBT, Medicine and Society

Changing the prevailing attitude about AIDS, gender and reproductive health in southern Africa

Changing the prevailing attitude about AIDS, gender and reproductive health in southern Africa

5015384107_517a74d0b5_zDuring the 1990s and early 2000s, HIV/AIDS pummeled through southern Africa killing thousands. Although the epidemic has abated somewhat, the disease is still spreading through certain communities, including the lesbian, gay, bisexual, transgender and intersex (LGBTI) population.

In Zimbabwe, where homosexuality is illegal and President Robert Mugabe has actively spoken out against the LGBTI community, health-care provider Caroline Maposphere works behind the scenes, trying to change the prevailing attitudes and laws without sparking a homophobic backlash like that in Uganda. Maposphere, who serves as a nurse, midwife, chaplain and gender advocate, will visit the Stanford campus this evening to discuss her efforts.

“She tells great stories about how you deal with the kind of social and community issues that lie around HIV prevention and gay and lesbian health issues in a very homophobic and resource-poor environment,” said David Katzenstein, MD, a Stanford infectious disease specialist who met Maposphere in 1992 while working on the Zimbabwe AIDS Prevention Project.

Preventing the spread of HIV in Zimbabwe isn’t as simple as handing out condoms or launching an education campaign, although those are key strategies, said Maposphere. The nation is poor, has few health-care facilities of any kind and LGBTI rights are non-existent. The traditional southern Africa culture view of homosexually, which was sometimes attributed to witchcraft, further complicates the issue.

“It’s very difficult to reach out with services to groups that are not coming out in the open,” Maposphere said. “We try to reach out and remove some of the barriers through discussion rather than being outright confrontational.”

Maposphere often encounters LGBTI individuals who feel they have been shunned by God and have been excluded from their churches in the predominantly Christian nation. In an effort to offer spiritual guidance as well as health care, she earned a college degree in theology and hopes to explore the religious aspects of her work while at Stanford.

In addition, Maposphere is planning to connect with gay-rights activists here and learn effective methods for countering homophobia in her native country. “I’m very hopeful that things will change,” she said.

The free discussion begins at 7:30 PM in the Vaden Education Center on the second floor of the health center on campus.

Previously: Remembering Kenyan statesman and Stanford medical school alumnus Njoroge Mungai, In poorest countries, increase in midwives could save lives of mothers and their babiesSex work in Uganda: Risky business and In Uganda, offering support for those born with indeterminate sex
Photo by Remi Kaupp

Global Health, History, HIV/AIDS, Infectious Disease

A doctor’s dilemma: to help or hold back from treating dangerous infections

If, like me, you’ve wondered why a doctor or nurse would decide to volunteer to help patients with often fatal infectious diseases like Ebola, The New York Times Magazine ran an essay today by Stanford physician and author Abraham Verghese, MD, MACP, in which he addresses, among other issues, the tension for clinicians between self-preservation and the impulse to help.

We doctors feel the pull. But each of us has reasons to stay back, reasons that get bigger as we age

He begins with his time treating patients in a hospital in India, detailing his encounters with tuberculosis, malaria, and filariasis among other diseases, but his description of his fear of and his reflections of his encounter with his first rabies patient is poignant:

I felt terribly sorry for this man who was old enough to be my father. Squatting by his mat, I was ashamed of my earlier fear and hesitation. I was glad to spend some time with him. By the next morning he was comatose and convulsing. By nightfall, he’d transcended the mortal world.

He  goes on to discuss his work with HIV patients in the 1980s, and the fear that surrounded the disease at the time. Many physicians donned full protective gear, even though researchers had determined, even in the early days of the epidemic, that the disease wasn’t spread via casual contact. Verghese connects these fears to current fears about Ebola, but doesn’t blame physicians who are cautious. He also documents his own impulses:

I have the urge to sign up, to head to Liberia or Sierra Leone; the call for doctors seems personally addressed to me. When I tell my mother, who is in her 90s, that I am thinking of volunteering in West Africa, she clutches my hand and says: “Oh, no, no, no. Don’t go!” I’m secretly pleased.

….

We doctors feel the pull. But each of us has reasons to stay back, reasons that get bigger as we age: children, partners, parents, grants.

Verghese captures the conundrum facing doctors and nurses who want to help, but who are – for a  variety of reasons – pulled away.

Previously: Ebola: This outbreak is differentStanford physician shares his story of treating Ebola patients in Liberia and Dr. Paul Farmer: We should be saving Ebola patients

Ebola, Events, HIV/AIDS, Infectious Disease, Public Health, Stanford News

Dr. Paul Farmer: We should be saving Ebola patients

Dr. Paul Farmer: We should be saving Ebola patients

The photo says it all: A very slender, ailing man sits on the floor with his head bent, completely alone in the dark in what used to be an Ebola treatment center in West Africa.

Paul Farmer, MD, PhD, the brilliant physician and humanitarian, flashed the photo on a screen to a rapt Stanford audience last Friday to show the emaciated state of health care systems in West Africa, incapable now of treating the most basic ailments.

Every time someone dies, it’s a failure to diagnose and deliver the imperfect tools we have

“The primary determinant of outcomes is the strength of health care systems. And if this is what ETU’s (Ebola Treatment Units) look like, there are going to be a lot of fatalities,” he told the crowd of some 400 people at Stanford’s Graduate School of Business. “We should be saving most of these patients. Every time someone dies, it’s a failure to diagnose and deliver the imperfect tools we have.”

But this vast inequity in care need not exist, said Farmer, MD, PhD, a Harvard professor. He pointed to examples from his own experience, in which he and the group he co-founded, Partners in Health, helped build robust health systems in Haiti and more recently, Rwanda, saving thousands of lives.

Farmer started working in Haiti while he was a student at Harvard Medical School nearly 30 years ago. In 1998, during the peak of the AIDS epidemic there, he established the HIV Equity Initiative, which relied on community health workers to visit the homes of patients daily to check on their status and ensure that they took their antiretroviral and/or tuberculosis medications. The approach proved remarkably successful, as people rose from their deathbeds to return to normal, functioning lives.

More recently, after the 2010 quake in Haiti, his group helped to build a medical center and teaching hospital in rural Haiti; he showed a photo of the modern, expansive new facility to the Stanford audience, which applauded the work.

“This is what I think of for rural Liberia, rural Sierra Leone,” he said. “This is not rocket science. Just think what we could do if we had a lot of help with systems and partners. It just requires sticking with some of these problems for a long time.”

Previously: Ebola panel says 1.4 million cases possible, building trust key to containmentExpert panel discusses challenges of controlling Ebola in West Africa, Should we worry? Stanford’s global health chief weighs in on Ebola and Biosecurity experts discuss Ebola and related public health concerns and policy implications

HIV/AIDS, In the News

Mourning the loss of AIDS researcher Joep Lange

Stanford researchers specializing in HIV/AIDS mourned the loss today of Dutch scientist Joep Lange, MD, PhD, a leading AIDS researcher who died in the Malaysian Airlines crash yesterday in Ukraine. Lange, a virologist, was particularly well-known for his work in helping expand access to antiretroviral therapy in developing countries. He was among dozens of people on the ill-fated flight who were heading to the 20th International AIDS Conference that opens Sunday in Melbourne, Australia.

“We are all in a state of shocked disbelief here in Melbourne at the tragic loss of one of the giants in the global fight against AIDS and HIV,” Andrew Zolopa, MD, professor of medicine at Stanford, told me in an e-mail from the conference site. “I have known Joep Lange for more than 25 years – he was a friend and a colleague.  Joep was one of the early leaders in our field to push for expanded treatment around the globe – and in particular treatment for Africa and Asia… The world has lost a major figure who did so much good in his quiet but determined manner.  I am shocked by this senseless act of violence. What a terrible tragedy.”

David Katzenstein, MD, also an HIV specialist at Stanford, learned of the death while in Zimbabwe, where he has a long-standing project on preventing transmission of HIV from mother to child. He said Lange, a friend and mentor, had been a “tireless advocate for better treatment for people living with HIV in resource-limited settings. He was universally respected and frequently honored as a real pioneer in early AIDS prevention and treatment.” In 2001, Lange founded the PharmAccess Foundation, a nonprofit organization based in Amsterdam, which aims to improve access to HIV therapy in developing countries. He continued to direct the group until his death.

Lange served as president of the International AIDS Society from 2002 to 2004 and had been a consultant to the World Health Organization, the federal Centers for Disease Control and Prevention and the National Institutes of Health. He led several important clinical trials in Europe, Asia and Africa and played a key role in many NIH-sponsored studies, said Katzenstein, a professor of medicine.

“He was a gentle, thoughtful and caring physician-scientist with a keen sense of humor and a quick and gentle wit. He was constantly absorbing, teaching and thinking about the human (and primate) condition and psychology,” Katzenstein told me. “He was much loved and will be sorely missed.”

HIV/AIDS, In the News, Public Health

Free, one-minute HIV testing…while you shop for clothes?

Free, one-minute HIV testing...while you shop for clothes?

outoftheclosetPerhaps you’re familiar with cafe-laundromats or sushi restaurants with tap dancing. But did you ever visit a second-hand clothing and furniture store to take care of your health-care needs? An audio segment and post on the KERA News (Dallas) blog features a local Out of the Closet shop with a free HIV testing site, and soon a community pharmacy, inside their thrift store – making it the 22nd branch of the U.S. chain to have both.

Bret Camp, the Texas regional director of the AIDS Healthcare Foundation, which operates the thrift stores, said in the post, “Our pharmacy will have everything from blood pressure meds to diabetes supplies…How many places can you go and look at jeans while you’re waiting for your medication?”

More from the post:

It’s an innovative idea, says [Douglas Owens, MD,] a professor of medicine at Stanford University who also serves on the U.S. Preventive Services Task Force.

A number of organizations, including the CDC and U.S. Preventive Services Task Force recommended universal HIV testing. Of course testing is only the first step, Owens says.

“When people get an adequate treatment for HIV, the drugs reduce their infectivity and so treatment for HIV not only benefits the person who has HIV; it also provides a very important public health benefit that reduces transmission,” Owens explains in the audio segment.

Previously: Task force recommends HIV screening for all people aged 15 to 65, Using Facebook to prevent HIV among at-risk groupsTask force issues draft recommendation for universal HIV screening and National HIV screening and testing could be very cost-effective
Photo by Marilyn Roxie

Global Health, HIV/AIDS, Research, Stanford News

Foreign aid for health extends life, saves children, Stanford study finds

Foreign aid for health extends life, saves children, Stanford study finds

Kenyan child pic - smallMany people are deeply skeptical of foreign aid, believing that these monies often wind up in the pockets of corrupt leaders or never make it down the chain of bureaucracy to the people who really need it. But a new Stanford analysis of both government and private aid programs shows that health aid has been extremely effective not only in extending the lives of people in developing countries but also saving the lives of children under age 5.

Lead researcher Eran Bendavid, MD, said foreign aid programs had their biggest impact between 2000 and 2010, when investments in health reached their peak. During that time, the U.S. government launched its hugely successful initiative, the President’s Emergency Plan for AIDS Relief (PEPFAR), while other private groups, such as the Gates Foundation, stepped up investments in health as well.

During that time, low-income countries receiving aid saw a dramatic decline – between 26 and 34 percent – in the number of children who died before their 5th birthday. With just a 4 percent increase in aid, or $1 billion, foreign aid could continue to have a major impact on child mortality, Bendavid said.

“If health aid continues to be as effective as it has been, we estimate there will be 364,800 fewer deaths in children under 5,” Bendavid said. “We are talking about $1 billion, which is a relatively small commitment for developed countries.”

He said many people may find the results surprising. “But for me, it fits with other evidence of the incredible success of public health promotion in developing countries,” he said. For instance, he did a study in 2012 which found that more than 740,000 lives were saved between 2004 and 2008 in nine countries as a result of the PEPFAR program. Other technologies, such as diphtheria, tetanus, measles and polio vaccines for children and insecticide-treated bed nets to prevent malaria, all have contributed to better health among adults and children in low-income countries.

He and colleague Jay Bhattacharya, MD, PhD, also found that aid programs had a lasting impact. The signs of aid’s impact on child mortality were measurable for three years after aid was distributed, while the link between aid and longer life expectancy was detectable five years after aid was made available, the researchers reported.

Previously: Stanford study: South Africa could save millions of lives through HIV prevention and PEPFAR has saved lives – and not just from HIV/AIDS, Stanford study finds
Photo by Karen Ande

Stanford Medicine Resources: