PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Malaria from monkeys now dominant cause of human malaria hospitalizations in Malaysia

New study released at ASTMH annual meeting targets deforestation as a possible problem for increasing human encounters with macaques

2014-11-03
(Press-News.org) NEW ORLEANS (November 3, 2014)—The majority of malaria hospitalizations in Malaysia are now caused by a dangerous and potentially deadly monkey-borne parasite once rarely seen in humans, and deforestation is the potential culprit in a growing number of infections that could allow this virulent malaria strain to jump from macaque monkeys to human hosts, according to research presented today at the American Society of Tropical Medicine and Hygiene (ASTMH) Annual Meeting.

An analysis of malaria patients hospitalized in Malaysian Borneo in 2013 showed that 68 percent had been sickened by Plasmodium knowlesi, said Balbir Singh, PhD, director of the Malaria Research Center at the University of Malaysia in Sarawak. The parasite is increasingly associated with malaria deaths and is three times more frequent as a cause of severe malaria in Borneo than the more common P. falciparum parasite that is currently considered the world's most deadly form of the disease.

The main host of knowlesi malaria has been the long-tailed and pig-tailed macaques found in the tropical forests of Malaysia and elsewhere in Southeast Asia. The infections are concentrated in areas of Malaysia where over the last decade massive loss of native forest to timber and palm oil production has led to substantially increased human interactions with macaques. That puts knowlesi malaria in the company of a growing list of dangerous emerging and re-emerging diseases—including Ebola and AIDS—that are being passed from animals to humans as development peels back more and more layers of tropical forest previously uninhabited by humans.

"This is a form of malaria that was once rarely seen in people, but today, in some remote areas of the country, all of the indigenous malaria cases we are seeing are caused by the P. knowlesi parasite," Singh said. "If the number of cases continue to increase, human-to-human transmission by mosquitoes becomes possible. In fact, this may already have happened, which would allow P. knowlesi malaria to spread more easily throughout Southeast Asia."

Evidence to date has strongly suggested that victims of P. knowlesi malaria have been bitten by mosquitoes that had first bitten an infected macaque, making humans a dead-end host for the parasite. Of concern, however, is recent research that the parasite could change so that it can jump from person to person via mosquito bites, without requiring a monkey as part of its life cycle. Laboratory tests in the 1960s indicated that a mosquito variety in Malaysian Borneo that carries the two most common human malaria parasites—P. falciparum and P. vivax—also can spread the knowlesi parasite. Moreover, P. knowlesi was recently found in Vietnam in mosquitoes that transmit falciparum and vivax malaria, raising the possibility that human-to-human transmission is already occurring.

P. knowlesi is the fifth species of malaria known to infect humans in nature. The parasite causes only mild malaria in macaques, Singh said, but in people it is the fastest replicating malaria parasite, multiplying every 24 hours in the blood.

The majority of the macaques carrying the parasite once lived in remote forested regions that saw little human activity or settlements. This has changed over the last ten years as a result of significant deforestation in Malaysia. According to a 2013 study in the journal Science, Malaysia lost about 47,000 square kilometers of forest between 2000 and 2012, or about 14 percent of its total land area, which environmentalists blame on logging and conversion of native forests to palm oil plantations.

At the ASTMH meeting, a team from the London School Hygiene and Tropical Medicine is presenting preliminary findings from an ongoing study that is outfitting people in the Sabah region of Malaysia with GPS tracking devices to explore the role of human movements into different macaque and mosquito habitats on the spread of P. knowlesi infections.

Researchers have been warning for decades that more frequent human incursions into undeveloped tropical forests will significantly increase the threat from diseases that could spread far beyond the forest canopy. The current Ebola outbreak is linked to a growing number of people living and hunting in forested areas and consuming "bush meat" from infected animals, chiefly chimpanzees. Meanwhile, illegal mining operations in tropical forests have been linked to the recent resurgence of malaria in Venezuela and may have intensified the rise of drug resistant malaria in Thailand.

These interactions are prompting a growing interest in research that probes the threat of disease from multiple vantage points—including economical, biological, and anthropological—an approach known as One Health.

Singh said that P. knowlesi malaria is currently a major public health problem in Malaysia, as it is causing illness serious enough to require medical treatment in about two thousand people a year. "But the P. knowlesi strain of malaria should stay within Southeast Asia as there are no mosquitoes outside the region capable of carrying these parasites," he said.

Singh also pointed out that, in terms of overall burden of disease, knowlesi malaria still ranks far behind dengue fever. Infections and deaths with that mosquito-borne disease have more than tripled in Malaysia in just the last year. The rising threat of the P. knowlesi parasite, however, which is carried by mosquitoes that prey on humans when they are outdoors, presents a new challenge for the broader effort to control and eliminate malaria in Southeast Asia—a fight that has been focused on using bed nets and indoor spraying to prevent malaria infections caused mainly by mosquitoes that attack indoors and at night. Malaria control campaigns also have not faced a malaria strain that is entrenched in a large animal population.

"Controlling a zoonotic—meaning an animal-to-human infection—carried by outdoor feeding mosquitoes is almost impossible with currently used methods," Singh said.

"These intriguing results are yet another example of the complexity and diversity of the interaction between man, his activities, parasites, and mosquitoes. P. knowlesi is now a significant cause of human malaria in Malaysian Borneo that must be addressed across multiple levels: research, development, implementation, funding and evidence-based policies," said Alan J. Magill, MD, FASTMH, president of the American Society of Tropical Medicine and Hygiene.

INFORMATION:



ELSE PRESS RELEASES FROM THIS DATE:

Report: Performance measures should include patient actions

2014-11-03
WASHINGTON (Nov. 3, 2014) — The actions — or inaction — of patients should be considered in programs designed to improve care and patient outcomes, according to a report released today by the American College of Cardiology, American Heart Association, American Association of Cardiovascular and Pulmonary Rehabilitation, American Academy of Family Physicians and the American Nurses Association in collaboration with other professional organizations. The work of doctors and other clinicians is often evaluated based on "performance measures," specific measurable ...

New test shows promise in identifying new drugs to treat Lyme disease

2014-11-03
Researchers from the Johns Hopkins Bloomberg School of Public Health have developed a test they say will allow them to test thousands of FDA-approved drugs to see if they will work against the bacteria that causes tick-borne Lyme disease. The researchers, reporting Nov. 3 in the journal PLOS ONE, say doctors and patients are desperate for new treatments for Lyme disease, which in many people is cleared up with a few weeks of antibiotics but, in some, lingers long after completion of the standard drug regimen. Until now, it has been very difficult to determine on a large ...

PNAS: From HIV to cancer, IL-37 regulates immune system

PNAS: From HIV to cancer, IL-37 regulates immune system
2014-11-03
A University of Colorado Cancer Center study published in this month's Proceedings of the National Academy of Sciences describes the activity of a recently discovered communication molecule of the body's immune system, Interleukin 37 or IL-37. It has been known to limit inflammation and the current study reports its activity in the adaptive immune system: IL-37 inhibits the ability of the immune system to recognize and target new antigens. "Knowing this mechanism that underlies IL-37's effect on the immune system now allows us to study IL-37 function and perhaps dysfunction ...

NASA sees Super Typhoon Nuri's eye open in 2 days

NASA sees Super Typhoon Nuris eye open in 2 days
2014-11-03
Over the course of two days, from Nov. 1 to Nov. 3, NASA's Aqua satellite watched from space as Tropical cyclone Nuri strengthened into a Super Typhoon and "opened" or developed an eye. On Nov. 1, when the Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard NASA's Aqua satellite captured a visible image of Super Typhoon Nuri at 04:30 UTC (12:30 a.m. EDT) and it had not yet developed an eye. On Nov. 3 at 04:20 UTC (12:20 a.m. EDT) MODIS on Aqua passed over Super Typhoon Nuri again after it developed an eye. By Nov. 3 the bands of thunderstorms spiraling ...

String field theory could be the foundation of quantum mechanics

2014-11-03
Two USC researchers have proposed a link between string field theory and quantum mechanics that could open the door to using string field theory — or a broader version of it, called M-theory — as the basis of all physics. "This could solve the mystery of where quantum mechanics comes from," said Itzhak Bars, USC Dornsife College of Letters, Arts and Sciences professor and lead author of the paper. Bars collaborated with Dmitry Rychkov, his Ph.D. student at USC. The paper was published online on Oct. 27 by the journal Physics Letters. Rather than use quantum ...

'Mild' control of systolic blood pressure in older adults is adequate: 150 is good enough

Mild control of systolic blood pressure in older adults is adequate: 150 is good enough
2014-11-03
CORVALLIS, Ore. – A broad review of the use of medications to reduce blood pressure has confirmed that "mild" control of systolic pressure is adequate for adults age 65 or older - in the elderly, there's no clear benefit to more aggressive use of medications to achieve a lower pressure. Historically, most medical practitioners tried to achieve control of systolic pressure – the higher of the two blood pressure readings – to 140 or less. Recently changed guidelines now suggest that for adults over 60, keeping the systolic pressure at 150 or less is adequate, ...

Inhaled Ebola vaccine may offer long-term protection from virus

2014-11-03
AUSTIN, Texas—A potentially breathable, respiratory vaccine in development has been shown to provide long-term protection for non-human primates against the deadly Ebola virus, as reported this week in the online edition of the journal Molecular Pharmaceutics. Results from a recent pre-clinical study represent the only proof to date that a single dose of a non-injectable vaccine platform for Ebola is long lasting, which could have significant global implications in controlling future outbreaks. A breathable vaccine could surmount the logistical obstacles of storing, ...

New research reveals what to discuss near life's end

2014-11-03
Hamilton, ON (Nov. 3, 2014) – A study led by a McMaster University researcher has identified the top five things health care teams should discuss with hospitalized patients and their families at the end of life, but the research also found gaps between what patients would like and the care they receive. In the study published today in CMAJ (Canadian Medical Association Journal), seriously ill hospitalized patients and their families say the most important aspects to discuss are: Preferences for care in the event of life-threatening illness ...

End-of-life discussions: The top 5 things to talk about with patients and their families

2014-11-03
What are the most important things for health care teams to talk about in end-of-life discussions with patients in hospital and their families? A new study published in CMAJ (Canadian Medical Association Journal) asked older patients and their families for their top priorities and found gaps between what patients would like and the care they actually receive. "Our findings could be used to identify important opportunities to improve end-of-life communication and decision-making in the hospital setting," states Dr. John You, lead author of the study and associate professor ...

Most mental health disorders not increasing in children and youth: Large Canadian study

2014-11-03
Symptoms of mental illness in children and adolescents do not appear to be increasing, according to a large study of Canadian youth published in CMAJ (Canadian Medical Association Journal) "Popular media tends to perpetuate the idea that the prevalence of mental disorders is increasing," writes Dr. Ian Colman, Canada Research Chair in Mental Health Epidemiology and associate professor at the University of Ottawa, Ottawa, Ontario, with coauthors. "However, research supporting this position has been inconsistent." Dr. Colman and colleagues sought to better understand ...

LAST 30 PRESS RELEASES:

New research boosts future whooping cough vaccines

Mechanistic understanding could enable better fast-charging batteries

No bones about it: new details about skeletal cell aging revealed

UNM scientists discover how nanoparticles of toxic metal used in MRI scans infiltrate human tissue

UMaine research examines best methods for growing Atlantic sea scallops

Medical cannabis could speed recovery, especially at community recovery homes

Study assesses U.S. image amid weakening of democracy

Two scientific researchers to receive 2025 Ralph L. Sacco Scholarships for Brain Health

Researchers improve chemical reaction that underpins products from foods to fuels

Texas Tech to develop semiconductor power devices through $6 million grant

Novel genomic screening tool enables precision reverse-engineering of genetic programming in cells

Hot Schrödinger cat states created

How cells repair their power plants

Oxygen is running low in inland waters—and humans are to blame

ACP’s Best Practice Advice addresses use of cannabis, cannabinoids for chronic noncancer pain

Beyond photorespiration: A systematic approach to unlocking enhanced plant productivity

How a small number of mutations can fuel outbreaks of western equine encephalitis virus

Exposure to wildfire smoke linked with worsening mental health conditions

Research uncovers hidden spread of one of the most common hospital-associated infections

Many older adults send their doctors portal messages, but who pays?

Fine particulate matter from 2020 California wildfires and mental health–related emergency department visits

Gender inequity in institutional leadership roles in US academic medical centers

Pancreatic cells ‘remember’ epigenetic precancerous marks without genetic sequence mutations

Rare combination of ovarian tumors found in one patient

AI-driven clinical recommendations may aid physician decision making to improve quality of care

Artificial intelligence has potential to aid physician decisions during virtual urgent care

ACP and Annals of Internal Medicine present breaking scientific news at ACP’s Internal Medicine Meeting 2025

New study reveals polymers with flawed fillers boost heat transfer in plastics

Signs identified that precede sudden arrhythmic death syndrome in young people

Discovery of bacteria's defence against viruses becomes a piece of the puzzle against resistance

[Press-News.org] Malaria from monkeys now dominant cause of human malaria hospitalizations in Malaysia
New study released at ASTMH annual meeting targets deforestation as a possible problem for increasing human encounters with macaques