The state's integrated disease surveillance unit has decided to seek help from the National Institute of Virology in Pune to identify the strain of dengue virus stalking Jamshedpur and its surrounding areas.

The East Singhbhum surveillance office, following instructions from capital Ranchi, has asked the microbiology unit of MGM Medical College and Hospital in Mango to isolate at least 10 blood samples of dengue patients for tests in Pune.

Till date this year, the number of dengue cases in and around the steel city has touched 248, with 22 samples testing positive on Tuesday evening . Since nearly a month left for the virus to lose sting, more patients can be expected. In 2016, the total number of positive cases was 204.

State officer for the Centre's integrated disease surveillance programme (IDSP) Dr Ramesh Prasad said such a large number of cases, despite containment efforts by the district IDSP unit, was a matter of concern.

"The district unit, along with urban local bodies, is actively educating people about the dengue virus and also taking measures to control vector-borne diseases. However, the number of cases continues to alarmingly increase. We want to know the strain of this stubborn virus, which is why samples will be sent to the Pune institute," Dr Prasad said.

The National Institute of Virology is a part of the Indian Council of Medical Research and is known as a reference lab in the whole of South East Asia.

Dr Prasad maintained that there were four major dengue virus strains or serotypes (DENV 1 to 4) prevalent in the country, out of which DENV-3 is less virulent. DENV-1 causes classic dengue fever while DENV-2 leads to haemorrhagic fever and shock. DENV-4 causes fever without shock or profound shock.

"It is possible that the viral strain is DENV-3 this year, which is why there are more cases but few fatalities. We want to get this confirmed," he added.