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

2 studies offer new insights from the front lines of battle against malaria

In most comprehensive review of a decade of data researchers confirm indoor insecticide treatments, dramatically reduce malaria; study finds world’s best drug still effective in African malaria 'hot zone' while researchers question for how long

2012-07-04
(Press-News.org) Deerfield, Il (July 3, 2012) A pair of provocative studies in the July 2012 issue of The American Journal of Tropical Medicine and Hygiene (AJTMH) provides a window into the intense ground war now underway against malaria. In one review, researchers offer new evidence supporting indoor insecticide spraying as a way to dramatically reduce malaria deaths. In another study, scientists in Mali simultaneously affirm the effectiveness of a critical drug to treat malaria infection in the West African malaria "hot zone" amidst concerns that it may follow the path of its predecessors and succumb to resistant parasites already being detected in other parts of the world.

In the most comprehensive review to date of the malaria-fighting potential of indoor insecticide treatments, researchers at North Carolina Central University (NCCU) and Duke University found that over the last decade on average they have reduced infections in malaria endemic communities by 62 percent—despite rising insecticide resistance among mosquitoes. But the investigators believe the more important contribution of the study is its identification of factors that appear to influence the success of indoor residual spraying (IRS).

A study led by scientists at the University of Bamako in the West African country of Mali found that that the life saving drug artemisinin continues to rapidly cure young children infected with malaria—even as it is showing signs of weakness in Southeast Asia. The researchers raise red flags about gaps in surveillance in Africa as new evidence that drug resistance may be spreading from Thailand to Myanmar renews fears that it could soon cross to Africa and reverse decades of progress against the disease. In an accompanying editorial, experts cite the urgent need for investment in new research and drug development.

"Both of these studies demonstrate the incremental successes and long-term challenges faced by our drive to prevent needless deaths due to malaria. Make no mistake, this is a winnable battle. We can and will ultimately eradicate malaria from its strongholds in Africa and Asia," said James W. Kazura, MD, President of the American Society of Tropical Medicine and Hygiene.

In House-to-House Combat Against Malaria, Insecticides Emerge as Lethal Weapon

Researchers at NCCU and Duke University conducted a "meta-analysis"— a form of research that synthesizes the results from previous studies—of 13 peer-reviewed reports published between 2000 and 2010 that considered the impact of IRS on malaria transmission in various settings, mostly in Africa. IRS involves coating the walls of homes or community buildings with insecticides in an effort to curb infections by killing malaria-carrying mosquitoes.

"Our findings show that during the last decade IRS has remained a powerful tool for fighting malaria, even though mosquitoes, particularly in Africa, are developing the ability to evade widely used insecticides," said Dohyeong Kim, PhD, the study's lead author and a professor in NCCU's Department of Public Administration.

Kim said the fact that IRS can significantly reduce malaria infections is widely accepted. What's less known, he said, are the factors that can influence the magnitude of success.

Kim and his colleagues found that IRS appears to be best at reducing malaria infections in areas experiencing a high rate of disease and where there is a threat from both Plasmodium falciparum parasites—the most deadly form of the disease—and Plasmodium vivax parasites. Also, IRS campaigns were found to be more effective if they involved several rounds of spraying. Another factor that appeared to improve IRS effectiveness was the use of the controversial insecticide DDT.

"Our (study) results show that DDT is more effective at reducing malaria prevalence than pyrethroids or other insecticides," the authors state. Pyrethroids are the most widely-used class of insecticides in IRS programs. But over the last decade mosquito populations in many malaria-endemic areas have developed genetic traits that make them resistant to these compounds.

DDT has been banned in many countries, including the United States, over concerns about its toxicity to humans and animals. Nevertheless, these dangers were primarily linked to its liberal use in agricultural settings. DDT applications for IRS are relatively small by comparison. However, Kim and his colleagues note that recent studies have provided evidence that even at low levels DDT may still be harmful to those exposed.

Kim said the study's findings indicate DDT may be worth considering in locations where malaria transmission is particularly intense, but the potential health dangers of DDT would need to be weighed against its potential to reduce malaria illnesses and deaths.

While providing some guidance for when indoor spraying is most effective, the IRS review also reveals the critical need for more insights—particularly given the relatively high costs of IRS programs and limited budgets for malaria control.

Kim and his colleagues note that the finding of substantial effectiveness (62 percent with considerable variation) for indoor spraying implies that mosquito control methods have "improved substantially during the past decade." They also called for more studies that consider the effectiveness of IRS and insecticide-treated bed nets (ITNs) together to see whether "there is any additional benefit of combining" the two in the same households.

Looking for Signs of Artemisinin Resistance in Africa

Researchers at the University of Bamako in Mali sought a way to quickly detect the emergence in Africa of a malaria parasite resistant to the life-saving drug artemisinin, which several years ago emerged as the most important medicine for treating malaria—in part because parasites have defeated other first-line therapies, such as chloroquine (CQ) and sulfadoxine/pyrimethamine (SP)

Researchers using the synthetic derivative of artemisinin - called artesunate - found that it rapidly purged the deadly malaria parasite Plasmodium falciparum from infected children treated in late 2010 and 2011 in a village in Mali that has "high-intensity" seasonal malaria transmission. The median time to "parasite clearance" was 32 hours, compared to 84 hours in tests conducted in areas of Cambodia where falciparum parasites are developing resistance. Furthermore, the clearance rate in Mali was very close to what had been observed in the same village in a study conducted several years earlier.

"Our study indicates that in this region of Africa there does not appear to be any artemisinin resistance," said Abdoulaye A. Djimde, PhD with the University of Bamako's Malaria Research and Training Center and the senior author of the study.

But what concerns Djimde is the lack of similarly intensive surveillance underway throughout Africa, particularly in light of an April 2012 article in The Lancet that has rattled malaria researchers and clinicians worldwide. Scientists reported finding artemisinin resistance among falciparum parasites in Thailand near its border with Myanmar, just a few years after scientists detected artemisinin-resistant parasites on the other side of country along Thailand's border with Cambodia.

Whether these episodes of resistance are distinct cases that arose in isolation or related events illustrative of resistant parasites on the move has yet to be determined, said Christopher Plowe, MD, MPH, a co-author of the Mali study and a malaria expert at the University of Maryland School of Medicine and the Howard Hughes Medical Institute. Past experiences provide reason to be concerned for Africa, he said.

"Historically, parasite resistance to malaria medicines has started in Southeast Asia and then eventually moved into Africa," he said. "We have to be very proactive if we want to avoid a public health disaster in Africa, which is where most of the world's malaria deaths occur and where artemisinin resistance would have its gravest effect."

Urgent Need For New Research and Drug Development

In an editorial accompanying the Mali study, Caroline L. Ng and David A. Fidock, PhD, of Columbia University Medical Center say one reason there is such alarm over the prospect of artemisinin resistance spreading broadly is that "we are still several years away from any other drugs being licensed and available to replace artemisinin should they fail." They see an urgent need for increased investments in research focused on discovering new drugs.

Plowe and Djimde pointed out that their effort in Mali probing for drug resistance differs from surveillance occurring elsewhere in Africa in an important way: it studies the reaction of parasites to artemisinin (in the form of the drug artesunate) when administered by itself. In African clinics that serve as World Health Organization (WHO) "sentinel" sites for detecting drug-resistance, treatment involves artemisinin combination therapies or ACTs that include other malaria medicines as well.

The combination is intended to make it more difficult for the parasite to develop resistance. Yet, some researchers worry that surveillance focused on ACT efficacy could delay detection of resistance emerging in Africa because other drugs in the compound might mask early signs of the parasite becoming less sensitive to artemisinin.

"We're not recommending clinics use artesunate by itself, but we need to periodically and safely conduct studies in malaria endemic regions of Africa with just artesunate if we want to detect resistance and still have enough time to intervene," Plowe said. "I think everyone agrees that we need more surveillance of this type. The question is where do we get the resources to do more comprehensive and frequent monitoring?"

Plowe said a major boost to the hunt for artemisinin resistance would be the discovery of a tell-tale genetic marker on the malaria parasite, such as the marker that reveals chloroquine resistance. He believes scientists are close to just such a discovery. But in the meantime, they must use a decline in the rate of parasite clearance in clinical studies as the indicator for resistance. Plowe noted that for malaria researchers, one of the key contributions of the Mali study is that it provides a new standard methodology for measuring parasite clearance in areas of intense seasonal transmission that he and his colleagues hope others will adopt.

###

About the American Society of Tropical Medicine and Hygiene

ASTMH, founded in 1903, is a worldwide organization of scientists, clinicians and program professionals whose mission is to promote global health through the prevention and control of infectious and other diseases that disproportionately afflict the global poor.

About the American Journal of Tropical Medicine and Hygiene

Continuously published since 1921, AJTMH is the peer-reviewed journal of the American Society of Tropical Medicine and Hygiene, and the world's leading voice in the fields of tropical medicine and global health. AJTMH disseminates new knowledge in fundamental, translational, clinical and public health sciences focusing on improving global health.

END



ELSE PRESS RELEASES FROM THIS DATE:

Some diabetes drugs may increase risk of bladder cancer

2012-07-04
An increased risk of bladder cancer is linked to the use of pioglitazone, a medication commonly used to treat type 2 diabetes, according to a new study published in CMAJ (Canadian Medical Association Journal) (pre-embargo link only) http://www.cmaj.ca/site/press/cmaj112102.pdf People with type 2 diabetes are at risk of several types of cancer, including a 40% increased risk of bladder cancer, compared to people without diabetes. Previous studies have shown a higher incidence of bladder cancer in people taking pioglitazone, a type of thiazolidinedione. To determine whether ...

The food industry should be regulated

2012-07-04
"The obesity crisis is made worse by the way industry formulates and markets its products and so must be regulated to prevent excesses and to protect the public good," writes a leading food expert in this week's PLoS Medicine. Kelly Brownell from the Rudd Center for Food Policy and Obesity at Yale University argues that like all industries, the food industry plays by certain rules: "It must defend its core practices against all threats, produce short-term earnings, and in do doing, sell more food. If it distorts science, creates front groups to do its bidding, compromises ...

SA government should act on Big Food Corporations and the obesity epidemic: international experts

2012-07-04
"The South African government should develop a plan to make healthy foods such as fruit, vegetables, and whole grain cereals more available, affordable, and acceptable, and non-essential, high-calorie, nutrient-poor products, including soft drinks and some packaged foods and snacks, less available, more costly, and less appealing to the South African population," write international health experts in this week's PLoS Medicine. The authors, led by Ehimario Igumbor from the University of the Western Cape in Bellville argue that in South Africa, ''Big Food'' (large commercial ...

Brazil has laws that protect against “Big Food” and “Big Snack”

2012-07-04
Under pressure from civil society organizations, the Brazilian government has introduced legislation to protect and improve its traditional food system, standing in contrast to the governments of many industrialized countries that have partly surrendered their prime duty to protect public health to transnational food companies, argue nutrition and public health experts writing in this week's PLoS Medicine. Carlos Monteiro and Geoffrey Cannon, from the Center for Epidemiological Studies in Health and Nutrition of the University of São Paulo, explain that, in Brazil, traditional ...

Rate of community-onset MRSA infections appears to be on the decline

2012-07-04
CHICAGO – In analysis that included more than 9 million Department of Defense nonactive and active duty personnel, the rates of both community-onset and hospital-onset methicillin-resistant Staphylococcus aureus (MRSA) bacteremia decreased from 2005 to 2010, while the proportion of community-onset skin and soft tissue infections due to MRSA has more recently declined, according to a study in the July 4 issue of JAMA. "The magnitude of invasive MRSA infections as well as the emergence of community-onset MRSA infections in the United States has been well documented," according ...

Shingles vaccine among patients with psoriasis, RA not linked with increased risk of shingles

2012-07-04
CHICAGO – Although some have suggested that patients receiving medication for immune-mediated diseases such as rheumatoid arthritis or psoriasis may be at increased risk of herpes zoster (HZ; shingles) shortly after receipt of the vaccine, an analysis that included nearly 20,000 vaccinated Medicare beneficiaries finds that the live zoster vaccine is not associated with an increased risk of HZ shortly after vaccination in patients currently treated with biologics, and that it is associated with a significantly reduced longer-term risk of HZ in patients with an immune-mediated ...

Risk factors for death identified for children with diarrhea in rural Kenya

2012-07-04
A hospital-based surveillance study conducted by Ciara O'Reilly of the Centers for Disease Control and Prevention, Atlanta, Georgia, USA and colleagues describes the risk factors for death amongst children who have been hospitalized with diarrhea in rural Kenya. Reporting in this week's PLoS Medicine, the authors found that infections with nontyphoidal Salmonella and with Shigella (but not with rotavirus) were associated with an increased risk of death. The authors state that: "This study can help inform policy makers on priority areas for interventions to reduce childhood ...

Urban groups help women but no effect on perinatal outcomes in Mumbai

2012-07-04
In this week's PLoS Medicine, David Osrin of the UCL Institute of Child Health, UK and colleagues report findings from a cluster-randomized trial conducted in Mumbai slums that aimed to evaluate whether facilitator-supported women's groups could improve perinatal outcomes. Their findings indicate that while it is possible to facilitate the discussion of perinatal health care by urban women's groups in the challenging conditions that exist in the slums of Mumbai, there was no measureable effect of community mobilization through the facilitation of women's groups on perinatal ...

Revisiting the association between saturated fat intake and coronary heart disease

2012-07-04
In this week's PLoS Medicine, Kay-Tee Khaw of the University of Cambridge, UK and colleagues analyze data from a prospective cohort study and show associations between plasma concentrations of saturated phospholipid fatty acids and risk of coronary heart disease, and an inverse association between omega-6 polyunsaturated phospholipid fatty acids and risk of coronary heart disease. The authors comment: "Early guidelines to prevent [coronary heart disease] recommended reductions in saturated fat but little consistency as to what might be substituted: other fats, protein, ...

Cutting calories might help you live longer, but not without increased physical activity

2012-07-04
Dietary restriction can slow age-related diseases and extend the lifespan of all species tested to date. Understanding this phenomenon might help people live longer, preferably without having to drastically limit calories. Now, investigators reporting in the July 3 issue of the Cell Press journal Cell Metabolism have found that in flies, dietary restriction causes enhanced fat metabolism in the muscle and increased physical activity, both of which are critical for extending lifespan. The findings suggest that dietary restriction may cause changes in muscle that can lead ...

LAST 30 PRESS RELEASES:

Sound is a primary issue in the lives of skateboarders, study shows

Watch what you eat: NFL game advertisements promote foods high in fat, sodium

Red Dress Collection Concert hosted by Sharon Stone kicks off American Heart Month

One of the largest studies on preterm birth finds a maternal biomarker test significantly reduces neonatal morbidities and improves neonatal outcomes

One of the largest studies of its kind finds early intervention with iron delivered intravenously during pregnancy is a safe and effective treatment for anemia

New Case Western Reserve University study identifies key protein’s role in psoriasis

First-ever ethics checklist for portable MRI brain researchers

Addressing 3D effects of clouds for significant improvements of climate models

Gut microbes may mediate the link between drinking sugary beverages and diabetes risk

Ribosomes team up in difficult situations, new technology shows

Mortality trends among adults ages 25-44 in the US

Discontinuation and reinitiation of dual-labeled GLP-1 receptor agonists among us adults with overweight or obesity

Ultraprocessed food consumption and obesity development in Canadian children

Experts publish framework for global adoption of digital health in medical education

Canadian preschoolers get nearly half of daily calories from ultra-processed foods: University of Toronto study

City of Hope scientists identify mechanism for self-repair of the thymus, a crucial component of the immune system

New study reveals how reduced rainfall threatens plant diversity

New study reveals optimized in vitro fertilization techniques to boost coral restoration efforts in the Caribbean

No evidence that maternal sickness during pregnancy causes autism

Healthy gut bacteria that feed on sugar analyzed for the first time

240-year-old drug could save UK National Health Service £100 million a year treating common heart rhythm disorder

Detections of poliovirus in sewage samples require enhanced routine and catch-up vaccination and increased surveillance, according to ECDC report

Scientists unlock ice-repelling secrets of polar bear fur for sustainable anti-freezing solutions 

Ear muscle we thought humans didn’t use — except for wiggling our ears — actually activates when people listen hard

COVID-19 pandemic drove significant rise in patients choosing to leave ERs before medically recommended

Burn grasslands to maintain them: What is good for biodiversity?

Ventilation in hospitals could cause viruses to spread further

New study finds high concentrations of plastics in the placentae of infants born prematurely

New robotic surgical systems revolutionizing patient care

New MSK research a step toward off-the-shelf CAR T cell therapy for cancer

[Press-News.org] 2 studies offer new insights from the front lines of battle against malaria
In most comprehensive review of a decade of data researchers confirm indoor insecticide treatments, dramatically reduce malaria; study finds world’s best drug still effective in African malaria 'hot zone' while researchers question for how long