Japanese researchers develop 30-minute Ebola test
JUNYA IWAI, Nikkei staff writer
TOKYO -- Researchers at Japan's Nagasaki University, in collaboration with Eiken Chemical, have developed a method that can detect the presence of the Ebola virus in just 30 minutes. The new method is simpler than the current one and can be used in places where expensive dedicated testing equipment is unavailable, said professor Jiro Yasuda.
He and his team of researchers hope to tie up with companies to make the method available in countries hit by the virus. Ebola hemorrhagic fever has a high fatality rate and is now seriously affecting West Africa, where more than 1,500 people have died in the current outbreak.
Yasuda's team developed a substance called a primer that amplifies, or increases, only those genes specific to the Ebola virus. There are five types of the virus, which differ in the base sequences of their genes. The team selected the six sections of these genes with the fewest differences in sequence among the virus types and made primers that combine with them. "The method can probably be used on new types of the Ebola virus," Yasuda said.
To determine if Ebola is present in a blood sample, it is first detoxified to prevent infection. RNA is extracted from any viruses present in the sample and used to synthesize DNA. This DNA is then mixed with the primers and other substances and placed in a transparent plastic tube. Next, the liquid is heated to 60-65 C. If Ebola is present, DNA specific to the virus is amplified in about 30 minutes due to the action of the primers. The by-products from this process cause the liquid to become cloudy, providing visual confirmation of detection.
The RT-LAMP (reverse transcription-loop-mediated isothermal amplification) technique developed by Eiken Chemical was used to synthesize and amplify the DNA. The team tested their new method at a research facility in Canada. It succeeded in detecting the Ebola virus, as well as the viruses of Marburg hemorrhagic fever and Lassa fever, Yasuda said.
Currently, the polymerase chain reaction, or PCR, method is used to detect the Ebola virus. To amplify the DNA of the virus using this method, it must be heated and cooled repeatedly. The procedure takes one to two hours and requires dedicated equipment and a stable supply of electricity, making it difficult to use in regions with poor power infrastructure.
The new method can use a small, battery-powered warmer, and the researchers believe it can be used in Ebola-affected regions in developing countries.