World Malaria Day

“In a rural hospital in Ethiopia that cares for the poor, a fragile young girl called Zakhiya has recovered recently from severe malaria. In the six short years of her life, Zakhiya has battled a number of infectious diseases. Her struggle will probably continue throughout her childhood. But Zakhiya is fortunate: she has fought off malaria -- this time.”

25 April 2011 is World Malaria Day. Malaria kills over 800,000 people each year, but malaria prevention efforts are helping cut down this number. “An expansion of malaria control programs between 2008 and 2010 has resulted in the distribution of enough [ insecticide-treated mosquito nets (ITNs) ] to protect more than 578 million people in sub-Saharan Africa, according to the World Malaria Report 2010, and indoor spraying has protected 75 million people, or 10% of the population at risk in 2009.”

During the past 10 years, malaria prevention and treatment efforts have saved an estimated 750,000 children in 34 African countries. Distribution of nets, indoor pesticide spraying, and use of effective medications are the best adversaries to the malaria parasite and the mosquitoes that carry it.

A decade ago, Zanzibar recorded over 18,000 cases of malaria. Today, it is virtually absent from the archipelago. “In 2009, Morocco and Turkmenistan were certified by the World Health Organization (WHO) as having eliminated malaria and the WHO European Region reported no cases of Plasmodium falciparum malaria for the first time.”

“These successes have been a collaborative effort of government, multilateral and non-government organizations and the private sector. But much of the leadership and funding has come from the U.S. government, through the President's Malaria Initiative, the Global Fund to Fight AIDS, Tuberculosis and Malaria and the Bill& Melinda Gates Foundation. These donors have helped drive an 18-fold increase in malaria funding between 2003 and 2010.”

We can celebrate this World Malaria Day, because efforts to stop malaria are proving themselves successful. “But malaria remains a deadly killer, threatening half the world's population and taking nearly 800,000 lives a year. Malaria strikes society's most vulnerable, especially children under the age of five -- 85 percent of malaria deaths fall into this group -- and pregnant women.”

Malaria also strikes at the economy. This “disease costs Africa US$12 billion in lost GDP every year and consumes 40 percent of all public health spending in malaria endemic countries in Africa, where lost productivity is estimated to reduce GDP by 1.3 percent per year. And malaria consumes up to one-quarter of household income in some countries.”

“One of the most difficult challenges” malaria presents “is to make novel health interventions affordable, accessible and available to those who need” them the most. “In this long war to eradicate malaria we are at a tipping point. Malaria has been eliminated or is close to elimination in several countries.” We cannot stop fighting.

“To stop efforts before the last parasite has been defeated is to lose the enormous gains already made.” Malaria spreads quickly. We must be faster. Every 45 seconds a child dies from malaria. Malaria eradication is within reach. With global effort we can make this deadly disease a thing of the past.

Source:
Sturchio, Jeffrey L.; David Reddy. "Malaria: Solid Success but No Time for Complacence". Huffpost Health. 23 April 2011.

Troublesome genes

Artemisinin, a plant-based remedy, is one of the most effective drugs used to combat malaria. "In many countries where the [malaria] parasite has developed resistance to previously effective common treatments such as chloroquine, artemisinin remains the only effective treatment against the infection. However, malarial resistance to artemisinin appears to be developing, potentially creating problems in controlling malaria."

A recent study conducted "by scientists from the University of Edinburgh and the Universidade Nova de Lisboa, used emerging technology to scan the genetic fingerprint of drug resistant parasites that infect rodents. This technology allows rapid identification of genes that enable the parasite to withstand existing drug treatments", particularly the "gene that enables the parasite" to resist treatment with artemisinin.

Dr Paul Hunt, from the University of Edinburgh's School of Biological Sciences, said: "This knowledge from rodent malaria parasites opens up new directions that will allow this gene to be investigated in human malaria. This may help track the evolution of drug resistance and may eventually enable the design of alternative, effective drugs."


Sources:
Paul Hunt, Axel Martinelli, Katarzyna Modrzynska, Sofia Borges, Alison Creasey, Louise Rodrigues, Dario Beraldi, Laurence Loewe, Richard Fawcett, Sujai Kumar, Marian Thomson, Urmi Trivedi, Thomas D Otto, Arnab Pain, Mark Blaxter, Pedro Cravo. Experimental evolution, genetic analysis and genome re-sequencing reveal the mutation conferring artemisinin resistance in an isogenic lineage of malaria parasites. BMC Genomics, 2010; 11 (1): 499 DOI: 10.1186/1471-2164-11-499

University of Edinburgh (2010, October 12). Gene linked to drug resistance in malaria pinpointed. ScienceDaily. Retrieved October 16, 2010, from http://www.sciencedaily.com­ /releases/2010/10/101012101629.htm

Sweet incentives

Incentives to develop treatments for "neglected diseases including malaria, tuberculosis and leishmanaisis" may encourage drug companies to focus more on potentially life-saving research and development, declares a U.S. business professor. The suggested incentive comes in the form of a "priority review voucher", which "would give a company accelerated regulatory review of one of its other drugs as a reward for developing a treatment for neglected disease".

Although these diseases affect more than 1 billion people, they occur most frequently in developing nations, providing little financial incentive for pharmaceutical companies to create and test new treatments.

Writing in the Sept. 11 issue of The Lancet, professor David Ridley of Duke University's Fuqua School of Business and Alfonso Calles-Sánchez, a patent expert with the Spanish Patent Office and former pharmaceutical policy maker at the European Commission, propose a European Union version of the priority review voucher system instituted in the United States in 2007.

Bill Gates explained an example of such incentives at the 2008 World Economic Forum in Davos. "If you develop a new drug for malaria, your profitable cholesterol-lowering drug could go on the market a year earlier...This priority review could be worth hundreds of millions of dollars [to the company]," Gates said.


In the U.S., the vouchers and other incentives are working. Firms and drug companies are motivated to begin clinical testing; although, these drugs may take several years to reach patients in need. Still, any forward movement in these fields is improvement. With continued encouragement, drug companies may enact the demise of malaria and other currently neglected diseases.

Do you have ideas or suggestions for other incentives that may encourage the eradication of malaria?


Sources:
David B Ridley, Alfonso Calles Sánchez. Introduction of European priority review vouchers to encourage development of new medicines for neglected diseases. The Lancet, 2010; 376 (9744): 922-927 DOI: 10.1016/S0140-6736(10)60669-1

Duke University (2010, September 9). European Union could create incentive for new drug treatments, experts propose. ScienceDaily. Retrieved September 19, 2010, from http://www.sciencedaily.com­ /releases/2010/09/100909193359.htm

Image by Petar Marjanovic

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.

Source:
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

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'."


Source:
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

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.

Sources:
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

Antibiotics prevent malaria

Preventative malaria "treatment with affordable and safe antibiotics...has the potential to act as a 'needle-free' natural vaccine against malaria", according to a study published in the journal, Science Translation Medicine. This type of treatment "may likely provide an additional valuable tool for controlling and/or eliminating malaria in resource-poor settings."

During research, the multinational team "found that infection with malaria parasites during administration of preventative antibiotics developed a vaccine-like immunity against re-infection."

Approximately one million people die from malaria each year and nearly half of the world's population is at risk of contracting malaria, a mosquito-transmitted parasite. "Only an estimated 10 to 100 parasites per mosquito bite invade the liver where they replicate. About a week after infection, tens of thousands of parasites are released into the bloodstream where they are responsible for malaria's recurring fevers and cause life-threatening complications."

The proposed treatment attacks parasites "during their passage into the liver of the infected host. The "researchers showed that the antibiotics caused a cellular defect in malaria parasites...This action did not prevent parasite replication in the liver but blocked the malaria parasite's fatal conversion to the disease causing blood stage. The very late arrest of parasites in the liver allowed the immune system to mount a robust defense against subsequent infections." In this way, the body produces results that are comparable to vaccines that use weakened varieties of the parasite.

Further reading:
London School of Hygiene & Tropical Medicine (LSHTM) (2010, July 23). 'Needle-free' intervention as natural vaccine against malaria. ScienceDaily. Retrieved July 23, 2010, from http://www.sciencedaily.com­ /releases/2010/07/100723112711.htm