There are over 2.5 billion of us at risk of dengue and infection with one strain will only provide lifetime protection against that particular strain. Those who catch virus a second time are at a higher risk of death.

The World Health Organization (WHO) explains on its website that a second infection is more likely to lead to acute dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS): “The presence of antibodies to one serotype of the dengue virus is believed to facilitate the occurrence of DHF/DSS in certain individuals through immune-enhancement when infected by a second serotype.” These severe forms of dengue cause plasma leakage, severe bleeding, and severe organ impairment. Any delay in a dengue diagnosis for a second infection could be fatal.

Timely dengue diagnosis could save lives

In preventing dengue from getting serious, speed is of the essence and so is proper care. The Institute of Bioengineering and Nanotechnology (IBN) in Singapore has demonstrated a prototype saliva test that can detect dengue from spiked saliva samples within 20 minutes. It has the potential to rapidly reveal whether someone has previously been exposed to the dengue virus.

The simple test detects IgG, a dengue-specific antibody found at the onset of secondary infections in one step, directly from saliva. Currently, earlier dengue infections are diagnosed from a blood sample. The testing process is lengthy: the blood sample has to be sent away to a laboratory for analysis, delaying potentially lifesaving treatment.

The IBN research team that developed this device (from left to right): Executive Director Professor Jackie Y. Ying, Postdoctoral Fellow Dr. Yi Zhang, and Research Scientist Dr. Jianhao Bai. Image courtesy of Institute of Bioengineering and Nanotechnology.

“The device’s 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,” adds Professor Ying, IBN’s Executive Director.

Commercializing the diagnosis technology

To develop the disposable paper-based dengue diagnosis device, the IBN researchers had to overcome two key challenges; both precluded current commercially available kits from being used for the test.

“Unlike other body fluids, saliva cannot be applied directly to commercially available test kits as it would cause the sensor nanoparticles to stick haphazardly to the test strip,” notes Professor Ying. “And conventional paper-based tests are not designed to handle the larger volumes of saliva the test requires.”

3D model of IBN’s rapid test kit that detects dengue-specific antibodies from saliva. Image courtesy of Institute of Bioengineering and Nanotechnology.

IBN is collaborating with ARKRAY Inc., a pioneer in the field of automated analysis systems, to commercialize its technology. The company set up its first Asian research center outside Japan in 2013, in IBN. The center is focused on developing novel detection kits for infectious diseases based on IBN’s innovative diagnostic platforms.

Working towards a more definitive diagnosis

Dengue is a very complicated disease and detecting the IgG antibody alone will not provide a definitive diagnosis. So, IBN is exploring ways of detecting other dengue antibodies in saliva. “This may prove challenging,” reveals Profession Ying. “Once we’ve demonstrated successful detection of dengue-specific IgM or IgA antibodies using our device, we will plan clinical trials as a first step towards commercialization.”

IBN also hopes to adapt the oral test kit to detect other diseases and is also investigating the use of other common fluid samples – such as blood, urine, and serum – for rapid, high-sensitivity test kits. It hopes its devices will be as easy to use as over-the-counter pregnancy or fertility test kits.

Rapid dengue diagnosis is a must in the fight against the disease. The sooner we get technology like this in the hands of the people, the better we can break dengue.

—