Chipping Away at Malaria (web article)

In the past three decades, when more than a thousand new drugs were registered for human use, only a handful were antimalarials. Yet malaria may be the world’s most devastating infectious disease, annually causing more than 300 million acute illnesses and more than 1.5 million deaths—90 percent of which occur among children in sub-Saharan Africa.

Speeding the search for new antimalarials: Alan Scott helps invent the malaria GeneChip.

Finding new drugs to fight the disease and developing a suitable vaccine have become increasingly urgent priorities as new strains of drug-resistant malaria have emerged.

Recently, researchers at the Bloomberg School in partnership with Affymetrix, a genomic instrument manufacturer, have developed a new tool that promises to speed the identification of potential antimalarial drug and vaccine interventions.

The Affymetrix GeneChip Plasmodium/Anopheles Genome Array is the first integrated platform that allows scientists to study the genetic make-up of the malaria parasite and its mosquito host at the same time. The chip has more than 200,000 tiny compartments containing short DNA strands unique to Plasmodium falciparum (the parasite that causes the most severe form of malaria) and Anopheles gambiae (a mosquito host that transmits the disease).

A major advance in the search for new insights into how to attack the parasite, the GeneChip enables researchers to quickly and easily measure how potential new drugs affect gene expressions of the parasite and its insect host.

One of the challenges in fighting malaria has always been that the Plasmodium parasite has such a complex life cycle, says Molecular Microbiology and Immunology Professor Alan Scott, PhD, who conceived the idea of a two-genome chip and then helped develop it and select the genes that were included.

“Our goal was to design a chip that would enable us to look at patterns of gene expression in the parasite in all stages of its life cycle, in both the mosquito and human hosts,” he says. Scott directs the Johns Hopkins Gene Array Core Facility, part of the Johns Hopkins Malaria Research Institute.

Although the Plasmodium genome was first published in 2002, Scott hopes the ability to study it in relationship to its insect host will reveal new means of fighting malaria by generating new targets and approaches for potential vaccines and antimalarial drugs, including, possibly, making the mosquito itself incapable of carrying the disease.—Mike Field

"Chipping Away at Malaria" appears in the Fall 2004 edition of the Johns Hopkins Public Health Magazine.

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