Tuesday, August 31, 2010

A new treatment

A new anti-malarial drug may soon progress to clinical trials. This new treatment "is made from simple organic molecules and will be cheaper to mass produce compared to existing therapies."

Malaria is widespread and deadly. Many of the nearly 250 million people who contract the malaria parasite each year do not have access or cannot afford adequate treatment. Drugs that are easy and cheap to produce and distribute may save many of the nearly one million lives that are lost each year due to malaria infection.

With the goal of easing the cost of malaria eradication on poor countries and individuals, the research "team at Liverpool" has "created a synthetic drug based on the chemical structure of artemisinin, an extract of a Chinese herb commonly used in malaria treatment. The new drug, which can be taken orally, is more potent than naturally derived artemisinin."

"Malaria affects the world's poorest countries and hospitals are unable to afford expensive treatments. The problem with current artemisinin-based therapies is their limited availability, poor oral absorption and high cost. We have created a new drug that is easily absorbed by the body, chemically stable and highly potent. It is made from very simple organic materials and therefore will be more cost-effective to mass produce than current therapies," says Professor Paul O'Neill.

Artemisinin is known to interact with a substance inside parasite-infected red blood cells, causing a chain of events that destroys malaria. The treatment, however, is difficult to mass produce and can be chemically unstable in the body. Scientists have now found a way of creating the most reactive part of artemisinin synthetically and fusing it with a cage-like structure made of organic molecules to make the drug more chemically stable. The stability of the chemical structure in the body makes the drug last longer, reducing the chance of the parasite reappearing.

University of Liverpool (2010, August 16). New drug treatment for malaria?. ScienceDaily. Retrieved August 31, 2010, from http://www.sciencedaily.com­ /releases/2010/08/100816095715.htm

Sunday, August 22, 2010

Biological warfare

Scientists from Johns Hopkins University are waging biological warfare against mosquitoes by using a "naturally occurring virus" that "may serve as a "late-life-acting" insecticide. The virus only affects adult mosquitoes, which "are responsible for the bulk of malaria transmission."

Malaria is a widespread and deadly disease that is transmitted by mosquitoes and kills approximately one million people each year. "Insecticides are one of the main strategies currently used to control malaria transmission[;] however, evolving resistance to such therapies continues to impact such efforts." Scientists now look to late-life-acting insecticides (LLAIs), which "selectively kill older mosquitoes that spread the disease, while younger mosquitoes survive just long enough to reproduce." In this way, LLAIs kill malaria transmitting mosquitoes without affecting the gene pool in a way that will stimulate the propagation of insecticide-resistant mosquitoes.

"Reproduction allows for relaxation of evolutionary pressures that select for resistance to the agent," say the researchers. "If resistance alleles exert fitness costs, there are theoretical scenarios under which resistance is not expected to evolve, leading some to provocatively term LLAIs as 'evolution-proof'."

American Society for Microbiology (2010, August 21). Virus may act as 'evolution-proof' biopesticide against malaria. ScienceDaily. Retrieved August 22, 2010, from http://www.sciencedaily.com­ /releases/2010/08/100820133238.htm

Ren et al. Potential for the Anopheles gambiae Densonucleosis Virus To Act as an "Evolution-Proof" Biopesticide. Journal of Virology, 2010; 84 (15): 7726 DOI: 10.1128/JVI.00631-10

Tuesday, August 10, 2010

Population at risk

Nearly 3 billion people live at risk of infection with Plasmodium vivax, one of the most common varieties of the blood-borne malaria parasite. A global distribution map, "published August 3 in the open-access journal PLoS Neglected Tropical Diseases," estimates that 2.85 billion people live in areas and conditions that put them at risk for contracting deadly malaria.

Malaria is a parasite that infects humans and is transmitted through the bite of an anopheles mosquito. Every year 250-500 million cases of malaria are reported, many malaria cases end in death. In recent years, scientists, doctors, and health-care workers have made progress against malaria. Still, more information is needed to truly understand how effective treatments and preventative techniques are against malaria and where these techniques still need to be applied.

"The map, created as part of the Malaria Atlas Project (MAP), a multinational research collaboration funded mainly by the Wellcome Trust, reviews a host of information that challenges the dogma that P. vivax transmission is absent through large swathes of Africa and uses novel methods...to estimate global populations at risk."

Of the nearly "3 billion people exposed to some risk of P. vivax" malaria transmission in 2009, 91% live in Central and South East Asia. It is important to note that "more than half of those exposed to this risk live in areas where P. vivax malaria transmission is extremely low or unstable". In these areas, prospects of sustained malaria control and "elimination are relatively good".

The authors of this study used the most recently available P. vivax data from reported cases for all malaria-endemic countries and classified risk into three classes: malaria free, unstable, and stable. Risk areas were further refined, and some regions were eliminated based on temperature, aridity, and isolation. Some urban regions known to be malaria-free were also excluded from the at-risk population estimate.

"This study represents the first step in our efforts to provide the malaria control and research community with an evidence-based cartography of P. vivax malaria," says co-author Dr. Simon Hay of the University of Oxford. "We can now focus on trying to model the endemicity of the disease to provide more detailed global burden estimates, although this is complicated by the unusual biology of P. vivax."

Co-author Dr Carlos Guerra adds: "New evidence shows that P. vivax malaria is not as benign as was thought, and yet, as our study shows, remains the most widespread form of human malaria. Understanding where transmission of this parasite occurs at the global scale is fundamental in planning strategies for the control of this debilitating, and often lethal, disease."

Further information about the Malaria Atlas Project can be found at www.map.ox.ac.uk.

Guerra CA, Howes RE, Patil AP, Gething PW, Van Boeckel TP, et al. The International Limits and Population at Risk of Plasmodium vivax Transmission in 2009. PLoS Neglected Tropical Diseases, 2010; 4 (8): e774 DOI: 10.1371/journal.pntd.0000774

Malaria Atlas Project [MAP]. www.map.ox.ac.uk. Retrieved August 10, 2010.

Public Library of Science (2010, August 4). New estimates of the global population at risk of Plasmodium vivax malaria. ScienceDaily. Retrieved August 10, 2010, from http://www.sciencedaily.com­ /releases/2010/08/100803174854.htm