Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Genetic Variant Protects People Against Malaria

08.11.2002


An international team of scientists has discovered a novel genetic trait that protects its carriers against the deadliest forms of malaria, while people without the trait are more likely to succumb to its fatal consequences.



This trait -- a mutation or “polymorphism” in the NOS2 gene -- controls the production of nitric oxide, a small chemical that can kill parasites and prevent malaria disease. Results of their study are published in the Nov. 9, 2002, issue of The Lancet.

The genetic variant explains why some people with malaria have only mild symptoms and recover fully, while others develop severe disease that may progress to death, said researchers from the University of Utah, the Durham Veterans Affairs (VA) Medical Center, Duke University Medical Center, the U.S. Centers for Disease Control and Prevention, Tanzania and Kenya.


“Malaria is a worldwide epidemic, affecting twice the population of the United States every year,” said Brice Weinberg, M.D., professor of medicine at the Durham VA and Duke University Medical Centers and principal investigator on the study. “Drug resistance to malaria is rampant, so our ability to artificially duplicate the benefits of this genetic trait would be enormous.”

People with the NOS2 gene variant make higher levels of nitric oxide, and the nitric oxide protects them from the extensive tissue and brain damage normally caused by the malaria parasite, said Dr. Maurine Hobbs, lead author and research assistant professor of internal medicine and human genetics at the University of Utah.

The team’s ultimate goal is to develop a simple treatment that boosts levels of nitric oxide to treat and prevent malaria, a prospect that the researchers say is well within their grasp.

Nitric oxide works by reducing the malaria parasites’ ability to multiply in liver and blood cells, preventing infected red blood cells from adhering to the lining of blood vessels, and decreasing the production of inflammatory chemicals (cytokines) that exacerbate the disease. Thus, it reduces the most deadly effects of malaria, which target the blood and vital organs such as the brain, said Dr. Nick Anstey, associate professor of medicine at the Menzies School for Health Research in Darwin, Australia.

While excessive nitric oxide can be harmful and causes inflammation in diseases such as arthritis, Anstey said that nitric oxide can also be beneficial by protecting against infections and preventing damage to cells and organs.

“Nitric oxide can be extremely useful when it is produced by the right cells, at the right levels, and at the right time,” said Anstey. Interestingly, he noted, the NOS2 gene variant does not prevent malarial infection; it simply renders the malaria parasite less harmful to bodily systems.

In fact, the NOS2 gene variant confers such overwhelming protection that Tanzanian carriers have an 88 percent lower risk of becoming ill with malaria than those without the trait, the study showed. In Kenya, its carriers have a 75 percent lower rate of developing severe malarial anemia. The two groups of patients consisted of 1,291 children who lived in highly mosquito- and malaria-infested areas of the two countries. The researchers analyzed blood and urine samples to demonstrate that people with the NOS2 polymorphism had higher levels of nitric oxide.

Weinberg said they believe that evolution has favored this protective mechanism for individuals who are most often exposed to malaria. Not surprisingly, then, Caucasians do not possess this genetic mutation, so they are at much higher risk for severe malaria. While malaria is seemingly a remote possibility in the heartland of America, the disease was once prevalent in the parts of the U.S. It was virtually eliminated by the 1940s through better mosquito control and improved living conditions, yet the disease periodically emerges in the U.S., even today.

Only about 1,200 malaria cases are reported in the U.S. yearly, and it is unlikely to ever reach epidemic proportions here, but malaria is rampant in much of Africa and Asia, infecting about 500 million people each year. Despite some advances in treatment, malaria continues to be deadly -- a malaria death occurs every 30 seconds worldwide.

Many of those infected with the malaria parasite may have no symptoms or only mild flu-like symptoms. However, others progress to more severe disease with extreme fatigue, fever, and chills. A third of these victims with severe disease -- mostly children and pregnant women -- succumb to more deadly consequences, either cerebral malaria or severe anemia.

In cerebral malaria, red blood cells containing the malaria parasite stick to the lining of blood vessels, causing blockages and decreasing blood supply to parts of the brain. Up to one-third of children with cerebral malaria die despite treatment. In severe anemia, parasites gobble up hemoglobin, destroy red blood cells and block blood formation until the patient is beyond rescue. Even with the best of current treatments, more than 1 million people die each year of severe malaria. The newly identified NOS2 gene polymorphism -- called C-1173T NOS2 -- protects against both kinds of malaria.

In addition to investigators from Duke, Utah, Australia and the CDC, researchers from the Hubert Kairuki Memorial University in Tanzania, and the World Health Organization in Switzerland contributed to the work. The research was supported by the National Institutes of Health, the U.S. Veterans Affairs, the U.S. Agency for International Development and the U.S. Centers for Disease Control and Prevention.

Rebecca Levine | EurekAlert!
Further information:
http://dukemednews.org/news/article.php?id=6008
http://www.mc.duke.edu/

More articles from Health and Medicine:

nachricht Satellites, airport visibility readings shed light on troops' exposure to air pollution
09.12.2016 | Veterans Affairs Research Communications

nachricht Oxygen can wake up dormant bacteria for antibiotic attacks
08.12.2016 | Penn State

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>