Now, a 10-min strip test for Ebola, dengue

New Delhi: Researchers at the Massachusetts Institute of Technology have created a simple paper strip device similar to a pregnancy test capable of diagnosing Ebola and viral hemorrhagic fevers such as yellow fever and dengue fever, described in a paper that appears in the journal Lab on a chip. “As we saw with the recent Ebola outbreak, sometimes people have symptoms and it’s not clear what they have,” said Kimberly Hamad-Schifferli, a visiting scientist in MIT’s department of mechanical engineering and a member of the technical staff at MIT’s Lincoln Laboratory.

 “We wanted to come up with a rapid diagnostic that could differentiate between different diseases,” Hamad-Schifferli added in a statement. Ebola diagnostic kits used in West Africa send patient blood samples to a lab that can perform advanced techniques such as polymerase chain reaction (PCR), which can detect genetic material from the Ebola virus. The whole process takes around two hours, while the paper test can diagnose the viral in 10 minutes. 

“For many hemorrhagic fever viruses, like West Nile and dengue and Ebola, and a lot of other ones in developing countries, like Argentine hemorrhagic fever and the Hantavirus diseases, there are just no rapid diagnostics at all,” said Lee Gehrke, a professor at MIT’s Institute for Medical Engineering and Science (IMES), in a press release by MIT. The MIT strips are colour-coded in a way that they can differentiate between several diseases. Researchers used triangular silver nanoparticles that can take on different colours. They used red, orange, and green nanoparticles and linked them to antibodies that recognize Ebola, dengue fever, and yellow fever. 

When the patient’s blood serum is dropped on the strip, any viral proteins that match the antibodies painted on the stripes will get caught, and those nanoparticles will become visible. “When we run a patient sample through the strip, if you see an orange band you know they have yellow fever, if it shows up as a red band you know they have Ebola, and if it shows up green then we know that they have dengue,” Hamad-Schifferli explained. The researchers are expecting to get the approval of Food and Drug Administration to begin using the device in areas where the Ebola outbreak is still ongoing. 

New test uses saliva to detect dengue, no need to go to lab

New test uses saliva to detect dengue, no need to go to lab. This is going to make at least testing less cumbersome 

Dengue is spreading very fast. In India a large number of people lose their lives annually. The worst thing about it is that you don’t have a shot for this vector borne disease.

Dengue was unheard of in India till a few years ago. But now with every passing day we have more and more incidences of dengue in almost every part of the country. From March till October this disease continues to scare people. Things become so tough during rainy season that hospitals have to display ‘no bed available’ sign. This is very common in the Indian capital Delhi too.

Another problem is that the tests are lengthy and time consuming. It also delays the beginning of treatment. But things seem to become less complicated as far as detection is concerned. Researchers have developed a new paper-based disposable device that allows dengue-specific antibodies to be detected easily from saliva within 20 minutes. The device developed by The Institute of Bioengineering and Nanotechnology (IBN) in Singapore is currently undergoing further development for commercialisation.

Researchers are excited with the development. “Our rapid diagnostic kit can detect a key dengue antibody from saliva that is present in early-stage secondary infection,” said IBN Executive Director Professor Jackie Y Ying. “The ability to differentiate between primary and secondary dengue infections makes it a valuable early diagnosis tool that would help to ensure timely treatment and proper care of patients,” said Ying. Patients with secondary infection, who have previously been infected with other serotypes of dengue virus, stand a higher risk of developing dengue hemorrhagic fever or dengue shock syndrome.

So at least detection of the disease will become less cumbersome. According to Singapore’s National Environment Agency, dengue fever and its more severe form, dengue hemorrhagic fever, are the most common mosquito-borne viral diseases in the world. This disease poses a serious health threat, and is a leading cause of illness and death in tropical and subtropical climates. There are four known serotypes of the dengue virus but no vaccine or medicine has been developed to treat the illness. The incubation period before symptoms develop generally ranges from 4 to 10 days after infection. Therefore, early diagnosis would enable the patient to receive prompt medical attention and avoid further complications.

Now going to laboratory for detection will not be needed. Currently, dengue infection is diagnosed in the laboratory by testing the patient’s blood sample for the presence of dengue antigens or antibodies. The device, on the other hand, is capable of detecting IgG, a dengue-specific antibody found at the onset of secondary infections, directly from saliva in one step. Unlike blood samples, saliva can be collected easily and painlessly for rapid point-of-care diagnostics. However, unlike other body fluids, it cannot be applied directly to commercially available test kits as it would cause the sensor nanoparticles to stick haphazardly to the test strip.