CRISPR-based malaria testing on-the-fly
To achieve the goal of eradicating malaria set by the World Health Organization (WHO)’s Global Malaria Control Programme, it is critical that all local transmission of malaria parasites in defined geographic areas is eliminated. One important cornerstone on this path is the development of rapid, sensitive, and species-specific diagnostic capabilities that are useful in the low-resource settings (LRSs) of many areas with endemic malaria.
Currently, the presence of the four major malaria-causing Plasmodium species P. falciparum, P. vivax, P. ovale, and P. malariae is determined by microscopic analysis of blood samples in which parasites can be detected in red blood cells, or with so-called rapid diagnostic tests for specific Plasmodium proteins (antigens).
“Unfortunately, available rapid diagnostic approaches cannot distinguish all four Plasmodium species from one other, which can be important to initiate the definitive course of treatment, and, most importantly, they are ineffective for detecting low numbers of Plasmodium parasites in asymptomatic individuals,” said Nira Pollock, M.D., Ph.D., Associate Medical Director of Boston Children’s Hospital’s Infectious Diseases Diagnostic Laboratory and Associate Professor of Pathology and Medicine at Harvard Medical School. “These ‘asymptomatic carriers’ are silent reservoirs for ongoing transmission by malaria-spreading mosquitoes and extremely important for ongoing global efforts to eradicate malaria,” added Jeffrey Dvorin, M.D., Ph.D., Associate Professor of Pediatrics at Harvard Medical School and Senior Associate Physician in Infectious Diseases at Boston Children’s Hospital.
Now, a multi-disciplinary research collaboration which was led by Wyss Core Faculty member James Collins, Ph.D. at Harvard’s Wyss Institute for Biologically Inspired Engineering and the Massachusetts Institute of Technology (MIT), and assembled by clinical fellow Rose Lee, M.D., M.S.P.H., which also included Pollock and Dvorin, has created a field-applicable, ultrasensitive diagnostic assay that specifically detects DNA sequences from all Plasmodium species in symptomatic and asymptomatic malaria. The new malaria diagnostic method combines an optimized 10-minute rapid sample preparation protocol with the CRISPR-based SHERLOCK system to enable highly specific and sensitive Plasmodium detection in another 60 minutes in simple reporter devices. It is published in PNAS.