The global fight against malaria may face serious threat as scientists have discovered that the parasite that causes the most common form of malaria share the same genetic variations even when the organisms are separated across continents.
The latest discovery also raised concerns that mutations to resist existing medications could spread worldwide, making the global eradication efforts even more difficult.
The scientists from the Case Western Reserve University and the Cleveland Clinic Lerner Research Institute are the first to sequence the genome of the parasite Plasmodium vivax to verify genome-wide DNA sequence variation.
According to the findings published in the September 6th issue of the online journal PLoS Neglected Tropical Diseases, the ability to sequence is crucial to understanding the hard-to-study parasite, which annually causes up to 250 million cases of malaria and places an economic burden, mostly on the poor, in excess of $1.4 billion by some estimates.
It is no longer news that Nigeria is one of the countries worst hit by malaria and contributes almost a quarter of the global malaria burden. According to the Minister of Health, Prof. Onyebuchi Chukwu, the country occupies the unenviable position as one of the leading five countries with the highest malaria burden in the world. The other four countries are Democratic Republic of Congo, Ethiopia, Tanzania and Kenya. Nigeria lose about N132 billion to malaria in the form of treatment, prevention and loss of man-hours annually.
Further, the researchers noted that the parasites transmitted by mosquitoes share genome-wide variations on three continents, Madagascar and Cambodia and South America.
The scientists who were at first surprised added that "The parasite's life cycle enables P. vivax to be a microbial globe-trotter."
Commenting on the findings, Professor of International Health, Genetics and Biology in the Center for Global Health and Diseases at Case Western Reserve University School of Medicine, Mr. Peter Zimmerman, explained that "In parts of the world where Plasmodium vivax malaria is endemic, the primary infection gets into the red blood cells and makes people sick When they feel better, people resume their normal activities and travel."
"But a portion of the infectious form can remain in their liver, where it may lay dormant for months or a year, then re-emerges into the blood when that person is in a different place.
"In that new place, local mosquitoes bite, become infected, and start spreading the P. vivax parasite and its genome in locations that can be a long distance away from where the original human infection occurred," Zimmerman, added. This ability for worldwide travel raises concerns among the researchers. There is no vaccine and there is only one drug that kills the parasite in the liver.
"If drug resistance arises, with modern travel, how long would it be before the resistance is spread over the world?" Zimmerman said. "This data suggests it could quickly become a big problem."
They further explained that the finding also provided the malaria research community with more than 80,000 genetic markers that can now be used for trait mapping or population monitoring, describing it as a critical step to understand the biology of the parasite that cannot be studied in the laboratory yet affects millions of people each year.
The 80,000 genetic markers identified can now be used to search for links to drug-resistant malaria, a growing problem in some part of the world including Nigeria.
The researchers, includes; Cleveland-based David Serre and Peter Zimmerman, Didier Menard, Institute Pasteur-Cambodia, and Arsene Ratsimbasoa, Madagascar National Malaria Control Program.