'Benign' malaria key driver of human evolution in Asia-PacificSeptember 05, 2012
Professor Ivo Mueller from the Walter and Eliza Hall Institute and Barcelona Centre for International Health Research (CRESIB) led the study, with colleagues from the Papua New Guinea Institute of Medical Research, Centre of Global Health and Diseases, US, and the University of Western Australia.
Malaria is a devastating parasitic disease that kills up to one million people a year. It is a major cause of poverty and a barrier to economic development. Approximately half of the world's population is at risk of malaria infection.
"Humans and malaria parasites have been co-evolving for thousands of years," Professor Mueller said. "Malaria has been a major force in the evolution of the human genome, with gene mutations that provide humans with some protection against the disease being preserved through natural selection because they aid in survival."
Professor Mueller said the study has challenged the perception that P. falciparum malaria is the only malaria species that affects human genome evolution. "It has long been assumed that Plasmodium falciparum, the species that causes the most severe disease and most deaths from malaria, is the most important driver of this gene selection in humans," Professor Mueller said. "Our results suggest that P. vivax malaria, though until recently widely considered to be a 'benign' form of malaria, actually causes severe enough disease to provide evolutionary selection pressures in the Asia-Pacific."
Professor Mueller said that the research team was interested in whether P. vivax malaria might be the cause of the unusually high rates of Southeast Asian ovalocytosis (SAO), a hereditary red blood cell disorder, in the Asia-Pacific region. "SAO occurs in approximately 10 to 15 per cent of the population in parts of the South West Pacific and is caused by a hereditary mutation in a single copy of a gene that makes a red blood cell membrane protein. This is almost an absurdly high frequency when you consider that inheriting two copies of the mutation is invariably fatal, so we figured it must confer a strong advantage to the carriers," he said.
The research team looked at the incidence of P. vivax and P. falciparum infections in three studies that included a total of 1975 children in Papua New Guinea aged 0-14 years. "We found that SAO-positive children were significantly protected against P. vivax infection, with 46 per cent reduction of clinical disease in infants with little or no immunity, and 52-55 per cent reduction in the risk of infection in older children. We also saw a significant decrease in parasite numbers in infants and older children, which is linked to a decrease in risk of clinical disease," Professor Mueller said.
The finding could have dramatic implications for future malaria vaccine design and development, Professor Mueller said. "Studying the mechanisms that cause SAO-positive people to be protected against P. vivax malaria could help us to better understand the mechanics of infection and help us to identify better targets for a malaria vaccine," he said.
Walter and Eliza Hall Institute
Related Malaria Current Events and Malaria News Articles
Hidden infection shortens life
Recent research shows that mild infections without symptoms of illness can still lead to serious consequences by reducing the lifespan of the infected individuals.
New computation method helps identify functional DNA
Striving to unravel and comprehend DNA's biological significance, Cornell University scientists have created a new computational method that can identify positions in the human genome that play a role in the proper functioning of cells, according to a report published Jan. 19 in the journal Nature Genetics.
Scientists identify important mechanism involved in production of mosquito eggs
Diseases transmitted by mosquitoes have contributed to the death and suffering of millions throughout human history, earning the mosquito the title as the world's most dangerous animal.
Bed nets and vaccines: Some combinations may worsen malaria
Combining insecticide-treated bed nets with vaccines and other control measures may provide the best chance at eliminating malaria, which killed nearly 600,000 people worldwide in 2013, most of them African children.
Genetics underpinning antimalarial drug resistance revealed
The largest genome-wide association study to date of the malaria parasite Plasmodium falciparum unveils a complex genetic architecture that enables the parasite to develop resistance to our most effective antimalarial drug, artemisinin.
World leaders gathering at Davos face calls for bold action to turn the tide on cancer
World leaders will face calls for bold action to respond to the rising human and economic toll of cancer when they meet in Davos at this year's World Economic Forum (WEF).
Hybrid 'super mosquito' resistant to insecticide-treated bed nets
Interbreeding of two malaria mosquito species in the West African country of Mali has resulted in a "super mosquito" hybrid that's resistant to insecticide-treated bed nets.
Vitamin B may counter negative effect of pesticide on fertility
Women who have adequate levels of B vitamins in their bodies are more likely to get and stay pregnant even when they also have high levels of a common pesticide known to have detrimental reproductive effects, according to new Johns Hopkins Bloomberg School of Public Health research.
Malaria combination drug therapy for children
A drug combination of artemisinin-naphthoquine should be considered for the treatment of children with uncomplicated malaria in settings where multiple parasite species cause malaria.
Latest research by NTU discovers reasons for malaria's drug resistance
Scientists from Nanyang Technological University (NTU) have discovered exactly how the malaria parasite is developing resistance towards the most important front-line drugs used to treat the disease.
More Malaria Current Events and Malaria News Articles