New Delhi: As dengue season sets in across large parts of India with the onset of the monsoon, scientists warn that COVID-19 and the mosquito-borne disease have overlapping symptoms and worry whether the country's healthcare infrastructure will be able to cope with this double whammy.

The impact of a 'dengue-COVID-19' season would entail two different diagnostic tests and extract a huge toll on patients too, each disease making the other more complicated to deal with and perhaps more fatal.

While the number of COVID-19 cases have raced past the 8,00,000 mark with 8,20,916 cases on Saturday (July 11) and 22,123 fatalities, the incidence of dengue is also high.

Based on 2016-2019 data, virologist Shahid Jameel estimated that India gets about 100,000 to 200,000 confirmed cases of dengue each year.

According to the National Vector Borne Disease Control Programme (NVBDCP), 1,36,422 dengue cases were diagnosed in 2019 and an estimated 132 people died.

"The virus is endemic and present around the year in southern India, and in monsoon and early winter in northern India," Jameel, CEO at DBT/Wellcome Trust India Alliance, a public charity that invests in building biomedical sciences and health research framework, told PTI.

Both COVID-19 and dengue have symptoms such as high fever, headache and body pain. The dengue season may aggravate the COVID-19 situation as both viruses may supplement each other, warned Dhrubjyoti Chattopadhyay, virologist and vice chancellor of the Amity University in Kolkata.

"This situation is not yet well studied. But the information available from South America is dangerous and found to create a major challenge to their medical infrastructure," he said.

"The effect will be very critical. As major symptoms are overlapping, simultaneous infection will be much more fatal. Weakened immune systems will help the other to be more fatal."

Once the dengue season starts, added virologist Upasana Ray, the infection spreads aggressively due to high prevalence of its mosquito vector, aedes aegypti.

"Each season, we experience heavy loads in the hospital wards due to dengue outbreak and those times it gets almost unmanageable. So, have we thought about what will happen when we have two menaces to handle together. Both of them have overlapping symptoms. Are we geared to distinguish if a person has dengue or COVID 19?" asked the senior scientist, CSIR-IICB, Kolkata.