Delaying Evolution Of Drug Resistance In Malaria Parasite Possible - Study
There's no magic bullet for wiping out malaria, but a new study offers strong support for a method that effectively delays the evolution of drug resistance in malaria parasites, a University of Florida researcher says.
David Smith, associate director of disease ecology at UF's Emerging Pathogens Institute, said the study will guide scientists and policy makers in extending the longevity of current artemisinin-based malaria drugs combined with partner drugs. Smith is a co-author of a report on the study, online in the... Proceedings of the National Academy of Sciences and in print on Sept. 16.
Smith collaborated with lead author Maciej Boni of Resources for the Future and Princeton University, and Ramanan Laxminarayan, also with RFF, to create mathematical models assessing the strategic effectiveness and clinical outcomes of using one, two and three first-line drug therapies to treat malaria within a population over a 20-year period. Their results show that using two or three drugs simultaneously reduced the total clinical cases and number of failed treatments , and slowed the rate at which drug-resistant genes spread within the parasites that cause malaria: Plasmodium falciparum, P. vivax, P. malariae and P. ovale.
"The models indicate that we can slow the evolution of resistance to current artemisinin-based therapies if nations use them in combination with two or more partner drugs," Smith said. "Currently, most nations don't do this. They use one therapy at a time, wait for it to fail, and then switch to a different therapy."
Artemisinin-combined therapies, or ACTs, are currently not widely implemented due to operational challenges and expense, Smith said. But he said the study offers compelling evidence for global leaders to collaborate and overcome these issues.
"This is not to say that implementing multiple first-line therapies solves all of our malaria problems," Boni said. "Anti-malarial drug development needs to continue so that we have novel and highly effective anti-malarials that can be plugged into the recommended strategy of deploying multiple therapies."
In the past century, chloroquine and sulfadoxine-pyrimethamine were widely used to combat malaria, but the parasites eventually evolved resistance leading to the drugs' failure. Artemesinin drugs, derived from the herb Artemisia annua, are relatively new and the malaria parasite does not yet appear to have a resistance to it. They work by triggering chemical reactions which damage the Plasmodium parasite.
"We don't have anything in the pipeline after ACTs, and it's basically just a matter of time until drug resistance evolves and artemisinin also fails," Smith said. "So the question becomes how do we keep ACTs in our arsenal for as long as effectively possible?"
The researchers' models also show that cycling through single drugs accelerated the rate at which malaria parasites evolved drug resistance. Smith said this occurred because cycling a single drug degraded the parasite's average fitness, which made it easier for drug-resistant genes to spread throughout the parasite population.
The cycling models predicted a declining therapeutic value of a single drug within 3.54 years, versus a longer effective therapeutic value of 9.95 years when three drugs were used in equal proportions within a population. The research was funded in part by grants from the Bill and Melinda Gates Foundation, and the National Institutes of Health.
"Using multiple first-line drugs reduces the selection pressure for resistance to a single drug," Smith said. "This is one way to make the ACTs last longer and benefit more people."
Co-author Laxminarayan, a senior research fellow at RFF, said ACTs are the best treatment option for malaria, now as well as in the foreseeable future.
"Novel treatment strategies improve our ability to delay the emergence of drug resistance without the need to deny treatment," Laxminarayan said.
Wil Milhous, associate dean for research at the University of South Florida's College of Public Health, said the research is "clearly a superb breakthrough in mathematical modeling applied to malaria drug deployment." Milhous has worked to develop new drugs for malaria for more than 25 years and is unaffiliated with the study.
"We have done the math in drug development, but only in terms of the cost of goods for drug combinations to include advanced preclinical and clinical testing. These are extremely time-consuming and costly but critical to regulatory approval," Milhous said. "Now we have a highly quantitative reality check that poor implementation strategies doom drugs to failure."
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Article adapted by Medical News Today from original press release.
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David Smith, associate director of disease ecology at UF's Emerging Pathogens Institute, said the study will guide scientists and policy makers in extending the longevity of current artemisinin-based malaria drugs combined with partner drugs. Smith is a co-author of a report on the study, online in the... Proceedings of the National Academy of Sciences and in print on Sept. 16.
Smith collaborated with lead author Maciej Boni of Resources for the Future and Princeton University, and Ramanan Laxminarayan, also with RFF, to create mathematical models assessing the strategic effectiveness and clinical outcomes of using one, two and three first-line drug therapies to treat malaria within a population over a 20-year period. Their results show that using two or three drugs simultaneously reduced the total clinical cases and number of failed treatments , and slowed the rate at which drug-resistant genes spread within the parasites that cause malaria: Plasmodium falciparum, P. vivax, P. malariae and P. ovale.
"The models indicate that we can slow the evolution of resistance to current artemisinin-based therapies if nations use them in combination with two or more partner drugs," Smith said. "Currently, most nations don't do this. They use one therapy at a time, wait for it to fail, and then switch to a different therapy."
Artemisinin-combined therapies, or ACTs, are currently not widely implemented due to operational challenges and expense, Smith said. But he said the study offers compelling evidence for global leaders to collaborate and overcome these issues.
"This is not to say that implementing multiple first-line therapies solves all of our malaria problems," Boni said. "Anti-malarial drug development needs to continue so that we have novel and highly effective anti-malarials that can be plugged into the recommended strategy of deploying multiple therapies."
In the past century, chloroquine and sulfadoxine-pyrimethamine were widely used to combat malaria, but the parasites eventually evolved resistance leading to the drugs' failure. Artemesinin drugs, derived from the herb Artemisia annua, are relatively new and the malaria parasite does not yet appear to have a resistance to it. They work by triggering chemical reactions which damage the Plasmodium parasite.
"We don't have anything in the pipeline after ACTs, and it's basically just a matter of time until drug resistance evolves and artemisinin also fails," Smith said. "So the question becomes how do we keep ACTs in our arsenal for as long as effectively possible?"
The researchers' models also show that cycling through single drugs accelerated the rate at which malaria parasites evolved drug resistance. Smith said this occurred because cycling a single drug degraded the parasite's average fitness, which made it easier for drug-resistant genes to spread throughout the parasite population.
The cycling models predicted a declining therapeutic value of a single drug within 3.54 years, versus a longer effective therapeutic value of 9.95 years when three drugs were used in equal proportions within a population. The research was funded in part by grants from the Bill and Melinda Gates Foundation, and the National Institutes of Health.
"Using multiple first-line drugs reduces the selection pressure for resistance to a single drug," Smith said. "This is one way to make the ACTs last longer and benefit more people."
Co-author Laxminarayan, a senior research fellow at RFF, said ACTs are the best treatment option for malaria, now as well as in the foreseeable future.
"Novel treatment strategies improve our ability to delay the emergence of drug resistance without the need to deny treatment," Laxminarayan said.
Wil Milhous, associate dean for research at the University of South Florida's College of Public Health, said the research is "clearly a superb breakthrough in mathematical modeling applied to malaria drug deployment." Milhous has worked to develop new drugs for malaria for more than 25 years and is unaffiliated with the study.
"We have done the math in drug development, but only in terms of the cost of goods for drug combinations to include advanced preclinical and clinical testing. These are extremely time-consuming and costly but critical to regulatory approval," Milhous said. "Now we have a highly quantitative reality check that poor implementation strategies doom drugs to failure."
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Article adapted by Medical News Today from original press release.
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New Research Suggests That Action As A Goal May Be Too Broad
A series of experiments conducted by researchers at the University of Illinois suggest that society's emphasis on action over inaction may lead to unforeseen consequences.
"Our research highlights how the pressures of society to be active may produce fairly unregulated behavior," said Dolores Albarracín, a professor of psychology who led the work.
The new analysis appears this month in the Journal of Personality and... Social Psychology. According to Albarracín, the findings could help understand how common words used in everyday life may influence conditions such as attention deficit hyperactivity disorder and bipolar disorder. While such conditions have genetic roots, Albarracín said, the social and cultural factors that exacerbate them are not well understood.
In a series of experiments, researchers primed participants with a set of words suggesting action or inaction and then observed their behavior. The primes list consisted of words such as "go" and "motivation" that represented an active thought, or words like "rest" and "stop" that indicated inaction.
In previous studies, Albarracín said, behavior and stimulus were always tightly linked. For example, participants primed to be hungry would eat more. In this research, however, Albarracín noted that the association between the word primes and outcomes was very weak.
In the new analysis, Albarracín and colleagues subjected participants to different sets of word primes and then asked them to perform a task. The tasks ranged from doodling to eating, and in some cases, learning new information. The intensity of the behavior was measured, and in two of the studies participants could choose to do none of the tasks and instead rest.
The studies demonstrated that participants primed with an action word were more likely to choose active tasks. But what was most compelling to Albarracín was that the same stimulus triggered a diverse array of tasks that are normally not seen together, such as eating, learning and doodling. The researchers successfully reproduced this paradigm in the laboratory. In one setting, the active word prime enhanced learning, but in a different context the same stimulus encouraged participants to doodle or eat.
"What you actually end up promoting is a very general message to be active," Albarracín said. "You can be active by exercising or learning, but you can also be active by driving fast or taking drugs. That is the danger of a global message to be active."
The studies suggest that it is important to provide more specific cues about how to be active. It also rings a note of caution about how children are educated, Albarracín said.
"If you think about the number of activities that kids are engaged in these days - going to school, playing the piano, etc. - to what extent is this pattern desirable?" Albarracín said. "Are you conveying that specific activities are valuable or that being busy and active all the time is what you are supposed to be doing?"
Source: Kaushik Ragunathan
University of Illinois at Urbana-Champaign
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"Our research highlights how the pressures of society to be active may produce fairly unregulated behavior," said Dolores Albarracín, a professor of psychology who led the work.
The new analysis appears this month in the Journal of Personality and... Social Psychology. According to Albarracín, the findings could help understand how common words used in everyday life may influence conditions such as attention deficit hyperactivity disorder and bipolar disorder. While such conditions have genetic roots, Albarracín said, the social and cultural factors that exacerbate them are not well understood.
In a series of experiments, researchers primed participants with a set of words suggesting action or inaction and then observed their behavior. The primes list consisted of words such as "go" and "motivation" that represented an active thought, or words like "rest" and "stop" that indicated inaction.
In previous studies, Albarracín said, behavior and stimulus were always tightly linked. For example, participants primed to be hungry would eat more. In this research, however, Albarracín noted that the association between the word primes and outcomes was very weak.
In the new analysis, Albarracín and colleagues subjected participants to different sets of word primes and then asked them to perform a task. The tasks ranged from doodling to eating, and in some cases, learning new information. The intensity of the behavior was measured, and in two of the studies participants could choose to do none of the tasks and instead rest.
The studies demonstrated that participants primed with an action word were more likely to choose active tasks. But what was most compelling to Albarracín was that the same stimulus triggered a diverse array of tasks that are normally not seen together, such as eating, learning and doodling. The researchers successfully reproduced this paradigm in the laboratory. In one setting, the active word prime enhanced learning, but in a different context the same stimulus encouraged participants to doodle or eat.
"What you actually end up promoting is a very general message to be active," Albarracín said. "You can be active by exercising or learning, but you can also be active by driving fast or taking drugs. That is the danger of a global message to be active."
The studies suggest that it is important to provide more specific cues about how to be active. It also rings a note of caution about how children are educated, Albarracín said.
"If you think about the number of activities that kids are engaged in these days - going to school, playing the piano, etc. - to what extent is this pattern desirable?" Albarracín said. "Are you conveying that specific activities are valuable or that being busy and active all the time is what you are supposed to be doing?"
Source: Kaushik Ragunathan
University of Illinois at Urbana-Champaign
Study Finds Neutral HIV Presentations More Likely To Be Considered Inviting
A recent study by University of Illinois professor of psychology Dolores Albarracín and her colleagues at the University of Florida and the Alachua County Health Department in Florida found a method to increase enrollment among high-risk individuals in HIV prevention programs.
The study, which appeared this month in the journal Health Psychology, found that by offering an experimental introduction to a counseling session, public health institutions could increase enrollment by a significant amount.
Previous research by Albarracín found that those most likely to... engage in behavior that puts them at a high risk for HIV are also the least likely to enroll and stay in HIV intervention programs.
Therefore the researchers studied the effects of delivering different messages to participants screened for high-risk behavior as an invitation to a counseling program delivered at the Alachua County Health Department in Gainesville, Fla. They found one message that increased enrollment among participants.
All the messages informed participants who had signed up for a generic health study that they could speak to a HIV-prevention counselor. In the experimental condition, they were also told that the counseling session was not intended to change their behavior, only to provide them with the most current information. Compared with a message that indicated that the counseling increased condom use, recipients of the experimental message enrolled at a rate higher by 15 percent. This effect was particularly strong when participants had no intention of using condoms at the beginning of the study.
"This kind of research has tremendous public health implications," Albarracín said.
"Public health experts around the world are regularly in search of the most effective methods for curbing preventable health problems," she said. "HIV is a disease caused by a number of risky behaviors like unsafe sex and unsafe needle sharing, but health information is often disseminated without complete knowledge of how it will be received by audiences," she said.
"The research indicates that people will be more receptive to information when they don't believe they are trying to be influenced," Albarracín said. "This approach will be helpful in giving public health professionals effective ways to introduce the public to information without repulsing those they are trying to help most."
----------------------------
Article adapted by Medical News Today from original press release.
----------------------------
Read More..
The study, which appeared this month in the journal Health Psychology, found that by offering an experimental introduction to a counseling session, public health institutions could increase enrollment by a significant amount.
Previous research by Albarracín found that those most likely to... engage in behavior that puts them at a high risk for HIV are also the least likely to enroll and stay in HIV intervention programs.
Therefore the researchers studied the effects of delivering different messages to participants screened for high-risk behavior as an invitation to a counseling program delivered at the Alachua County Health Department in Gainesville, Fla. They found one message that increased enrollment among participants.
All the messages informed participants who had signed up for a generic health study that they could speak to a HIV-prevention counselor. In the experimental condition, they were also told that the counseling session was not intended to change their behavior, only to provide them with the most current information. Compared with a message that indicated that the counseling increased condom use, recipients of the experimental message enrolled at a rate higher by 15 percent. This effect was particularly strong when participants had no intention of using condoms at the beginning of the study.
"This kind of research has tremendous public health implications," Albarracín said.
"Public health experts around the world are regularly in search of the most effective methods for curbing preventable health problems," she said. "HIV is a disease caused by a number of risky behaviors like unsafe sex and unsafe needle sharing, but health information is often disseminated without complete knowledge of how it will be received by audiences," she said.
"The research indicates that people will be more receptive to information when they don't believe they are trying to be influenced," Albarracín said. "This approach will be helpful in giving public health professionals effective ways to introduce the public to information without repulsing those they are trying to help most."
----------------------------
Article adapted by Medical News Today from original press release.
----------------------------
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