With around 1,598 and 441 new cases of chikungunya and dengue last week, the total number of cases has gone up to 5,293 and 2,133 respectively. Civic authority, however, claimed that there is a decline in the number of new patients by around 40 per cent.

According to a municipal report released on Monday, out of the total cases recorded till October 1, over 500 of them have been reported in areas falling under the North Delhi Municipal Corporation (NDMC). Nearly 3,700 cases were reported in Delhi till September 24.

According to the South Delhi Municipal Corporation (SDMC), which compiles the data for vector-borne disease cases in the national capital on behalf of all the civic bodies here, among the three corporations, 515 cases are from areas falling under the jurisdiction of NDMC, 498 cases are from the SDMC areas, and 172 under the East Delhi Municipal Corporation have been reported this season.

At least 15 fatalities due to complications triggered by the disease have been reported at various hospitals in the city though the civic bodies have kept the death tally at zero.

Experts had earlier conjectured that the rising number of cases could have been due to evolution in the chikungunya virus.

Health experts at the AIIMS have identified the genotype of the CHIKV which is the same as the one that caused the 2006 outbreak of the vector-borne disease. “We have identified the genotype of the virus — East Central South African — and sent the report to the National Vector-Borne Disease Control Programme (NVBDCP). It is the same genotype that was in circulation in 2006 outbreak,” said Dr Lalit Dar of the department of microbiology at AIIMS. According to a municipal report, 2,133 dengue cases have been recorded till October 1. Of this, 1,362 were reported last month and 441 last week.