The number of dengue tests has increased around four times in Bengal this year compared to last year and experts said extensive testing was one of the important tools to fight the mosquito-borne disease that has taken several lives already this season.
The number of dengue tests reported this year across Bengal is 9,28,538 till September 13, said a health department official.
The number during the same period last year was 2,47,489, the official said. About 65 per cent of the tests have been performed in the government sector, he added.
“Tests for dengue have increased manifold this year because of an increase in the number of testing facilities and emphasis on tests in the early phase of the disease," said the health official.
He said dengue testing laboratories in the government sector are functional in 203 healthcare units, including government hospitals and urban primary health centres. The figure does not include private facilities.
“We are focusing on early and extensive testing for dengue so that the infection in a person can be detected early which would ensure early interventions," said another official of the state health department.
Advisories issued both by the Union health ministry and the state health department suggest that dengue tests should be done on the second day from the onset of fever.
Experts said testing was important in case of dengue for treating an individual.
“In the case of Covid, testing was beneficial for individuals and was a also huge benefit for the community because the virus transmitted from one person to another. So testing and isolation helped control the spread of the disease,” said Chandramouli Bhattacharya, infectious diseases specialist at Peerless Hospital.
"However, in the case of dengue, testing has no relation in controlling the spread of disease unless there is a cluster map prepared and vector control measures taken in that area. But it helps an individual in getting appropriate treatment at the appropriate time," he said.
According to Bhattacharya, dengue tests should ideally be done between days two and three.
“Theoretically, dengue NS1 antigen remains positive from day one to five of the fever. But a negative test on day one does not eliminate the possibility of dengue completely,” he said.
“Ideally testing should be done on day two or three and if negative still then in most cases it excludes the disease,” said Bhattacharya.
Public health experts pointed out that along with extensive testing, vector control was equally important.
“To prevent the spread of dengue, there is a need to control the population of mosquitoes causing the diseases as these are the source of transmission,” said a senior official of the National Vector Born Disease Control Programme in Delhi.
“There may be asymptomatic patients who carry infections and if a mosquito bites them then it gets infected and spreads the diseases," the official pointed out.
An official of the state government said the panchayat and rural development department has been asked to intensify vector control programmes along with the urban local bodies.
“This time, maximum dengue cases are happening in rural areas. Because of the panchayat polls, the rural bodies were formed recently and so the vector control programme could have been affected,” said the official. "We have asked them to step up the drives,” he said.
However, several hospitals in Kolkata said they were getting most patients from in and around the city.