A female Aedes aegypti mosquito, Dengue
A female Aedes aegypti mosquitoReuters

No more waiting, a new saliva test can detect dengue within 20 minutes.

The paper-based disposable device works by identifying an important dengue antibody present in secondary infections.

Dengue is a viral infection, transmitted through the bite of an infected Aedes mosquito. Symptoms, as listed by Mayo Clinic in US, include high fever (41 C), severe headache, pain in joints, muscles and eyes, rashes, vomiting and nausea.

Dengue virus, which belongs to the Flaviviridae family, genus Flavivirus, has four serotypes- DEN-1, DEN-2, DEN-3, and DEN-4.

In dengue, an infected person's body develops antibody against the particular strain. A secondary infection with a different serotype can cause life-threatening conditions known as dengue haemorrhagic fever (DHF) and dengue shock syndrome (DSS).

A person starts getting symptoms only four to 10 days after an infected mosquito bites him or her.

Delay in diagnosing and treating the condition can pose serious threat to important organs of the body including heart, liver and lungs; and can also lead to a sudden decline in blood pressure, causing shock and death.

Currently, two methods are used to detect dengue. The first one, according to labtestsonline, is an antibody test which analyses two types of antibodies produced by the body called IgG and IgM. It works properly only seven days after the infection.

IgM antibodies disappear after sometime. But IgG antibodies remain in the blood for a longer period.

The second one is a molecular testing based on the genetic material of dengue virus present in the blood. It can be done only five days after the symptoms start.

The new test developed by a team of researchers from the Institute of Bioengineering and Nanotechnology (IBN) in Singapore, on the other hand, can give an early diagnosis by checking for IgG in saliva.

"Our rapid diagnostic kit can detect a key dengue antibody from saliva that is present in early-stage secondary infection. 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," IBN Executive Director Professor Jackie Y Ying, said in a news release.

IBN is now planning to launch their oral dengue test like other over-the-counter kits available for pregnancy and fertility.

Details of the new saliva dengue test can be found in the journal Lab on a Chip.