The sudden emergence of seven Zika virus cases in Pune, Maharastra has set off concerns among leading virologists, who fear "critical gaps" in the country's ability to detect and track the mosquito-borne disease.

Experts warned that the virus might be "silently spreading" across the country, with only a handful of laboratories equipped to confirm infections.

"India's limited testing capacity for Zika is a major concern," said Dr Vinod Scaria, the virologist who had detected the Delta variant of Covid-19.

"The lack of widespread testing as well as surveillance is particularly worrying given the risks Zika poses to pregnant women," he said.