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The newspaper of The Johns Hopkins University December 11, 2006 | Vol. 36 No. 14
Safer Method for Large-Scale Malaria Screening Developed

By Tim Parsons
School of Public Health

Researchers at the Johns Hopkins Bloomberg School of Public Health's Malaria Research Institute have developed a new test for detecting the malaria parasite in human urine and saliva.

Although not a diagnostic test for determining treatment, the method could potentially reduce the need for blood sampling in epidemiological studies where large-scale malaria screening is required. Drawing blood increases the risk of spreading HIV and other diseases, particularly in those developing countries where both HIV and malaria are prevalent. Also, blood drawing must be performed by trained personnel, whereas urine and saliva sampling do not. The study was published online in the Nov. 8 edition of Malaria Journal.

"Testing urine or saliva could be an easier and safer way to collect the information needed for studying malaria in communities," said David J. Sullivan, senior author of the study and a professor in the Malaria Research Institute. "For instance, it could be used in studies to determine if a population is growing resistant to malaria drugs, which is a very serious problem."

The test uses polymerase chain reaction, a technique for duplicating and then examining unique bits of DNA from a sample, thereby allowing DNA to be multiplied in the laboratory. The same PCR technique is used for examining malaria in blood but has never been applied to urine and saliva samples.

The study was conducted in collaboration with colleagues at the institute's research hospital in Macha, Zambia. Urine and saliva samples were obtained from 47 volunteers with malaria and four without, and were then examined with the PCR method. DNA from the Plasmodium falciparum, the parasite that causes malaria, was replicated at higher levels from the saliva compared to the urine samples. However, neither method was as sensitive as that using blood samples.

Lead author Sungano Mharakurwa, a researcher with the Malaria Research Institute in Macha, said, "Programs for monitoring antimalarial drug and vaccine efficacy could therefore adopt such a bloodless method, while maintaining high sensitivity for clinically significant infections."


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