New Delhi: Swine flu has claimed 42 more lives taking the toll across the country to above 1,800 on Wednesday while those affected by the H1N1 virus inched towards 31,000 mark even as doctors said the number of such cases is expected to dip with the rise in mercury.

According to the health ministry data, 1,809 persons have perished due to the disease while the number of those affected across various states was 30,766.

Dr Randeep Guleria, head of Pulmonary Medicine Department at AIIMS, said that swine flu cases will subside in the next 2-3 weeks because of soaring mercury. “Over the last few days, though the temperature has been fluctuating due to unseasonal rains, but on an average it has shown an upward trend, because of which cases are on decline. Even in OPD we are seeing less patients.

“If we see the government of India figures of the last few weeks, then we will see that there is already a decline in number of H1N1 cases and mortality. It is quite likely that they will subside more in the next 2-3 weeks," Guleria said.

He said swine flu cases tend to rise during winter and monsoon months and also when humidity levels are high. Other doctors pointed out that although there has not been any “dramatic" decrease, they hoped that the cases will decrease with the rise in temperature.

“Even in OPDs these days most cases are of seasonal flu, which will hopefully decrease with the rise in temperature," said Dr Sidharth Ramji, medical superintendent, Lok Nayak Hospital.

Meanwhile, senior CPI(M) leader Gautam Deb’s condition today remained critical but stable after he was tested positive for swine flu. Doctors attending him at AMRI Hospital, Salt Lake, said he was kept in ICU isolation and has been extubated while the 61-year-old leader is however said to be alert,responsive and communicating.