The expert took to Instagram to share the important tests on dengue and the symptoms to watch out for.
Apart from NS1, the expert says in a video shared on the social media platform, one should also test IgG and IgM levels for dengue.
On the importance of these tests, the expert explains: While NS1 is a common dengue test which reveals whether the individual is infected with a virus or not, the levels of IgG and IgM actually decode the severity of the disease.
NS1 test detects the non-structural protein NS1 of the dengue virus. During the infection, this protein is secreted into the bloodstream of the individual. This protein is detectable during the first 7 days of the infection, post which it is not recommended.
IgM or immunoglobulin M is released into the blood during the infection. “As the immune system fights the infection, IgM antibodies against dengue virus are detectable starting 4-5 days after onset of symptoms and are reliably detectable for approximately 12 weeks,” says the US CDC>
IgG test, which has been cited by Dr Parekh as the most important part of the dengue test and diagnosis, is the test of the antibodies which are released after the 14th day of infection and persist in the body for a longer duration.
Why is the IgG test important?
A positive IgG test means the person was infected with dengue virus earlier and has been infected again. “After you’ve recovered from dengue fever, you have long-term immunity to the type of virus that infected you — but not to the other three dengue fever virus types. This means you can be infected again in the future by one of the other three virus types. Your risk of developing severe dengue fever increases if you get dengue fever a second, third or fourth time,” say experts at MayoClinic.
Dengue is caused by Aedes aegypti mosquitoes through the transmission of dengue virus or DENV. The four different types of dengue viruses are: (DENV-1, DENV-2, DENV-3 and DENV-4. These belong to the Flaviviridae family.
Recovery from infection can provide immunity to only that type of virus. Cross immunity is not seen in dengue cases. “Cross-immunity to the other serotypes after recovery is only partial, and temporary. Subsequent infections (secondary infection) by other serotypes increase the risk of developing severe dengue,” says the World Health Organisation (WHO).
The IgG tests will determine whether this is the second, third or fourth episode of dengue, even though the previous ones were mild and were undiagnosed, says Dr Parekh highlighting the importance of the test.
Common symptoms of dengue
The common symptoms of dengue are fever for 3-5 days, bone breaking fever, headache, body ache, itchy rash all over the body though it comes a bit late, pain behind the eyes.
The symptoms of dengue persist for about a week. Most people recover after a week of the infection.
In a special message to parents, Dr Parekh advises them to not panic if the blood test report comes positive for dengue. “A positive report for dengue does not mean that your kid needs admission in hospital, do not panic,” the expert says.
Status of dengue
“The global incidence of dengue has grown dramatically with about half of the world’s population now at risk. Although an estimated 100-400 million infections occur each year, over 80% are generally mild and asymptomatic,” says the WHO.
Until July 2022, national capital Delhi had reported over 150 dengue cases. Till August 31, a total of 30627 dengue cases were reported in the country along with 12 deaths. In 2011, the total number of cases were 193245 and the number of deaths was 346.