The soaring Celsius and humidity have triggered a viral outbreak with residents from across the city complaining of high fever, sore throat and aching bones and muscles.
Microbiologists and doctors said on Thursday the symptoms were caused by a group of viruses that thrives in hot and humid conditions.
Certain viruses that cause upper respiratory tract infections such as Rhinovirus and some types of Adenovirus are responsible for the outbreak of fever. These viruses multiply in hot and humid conditions, such as the one prevailing in the city, said a scientist at the Indian Council of Medical Research in Calcutta.
Hospitals and clinics across the city are flooded with patients suffering from high fever, accompanied by cough and sore throat, running nose, joint and muscle pain and gastroenteric disorder.
Those suffering from viral infections are also vulnerable to secondary bacterial infections as bacteria, too, prefer hot and humid weather for survival and multiplication, said city-based microbiologist Bhaskar Narayan Chaudhuri.
Thursdays maximum temperature was 36.5 degrees Celsius, while relative humidity peaked at 89 per cent. The discomfort index stood at 65.2 degrees Celsius, more than 10 degrees above the comfort level.
Critical care expert Subrata Maitra warned that drinking chilled water and entering or leaving air-conditioned rooms frequently would aggravate the infection.
Those suffering from diabetes, chronic renal failure and other ailments that reduce immunity are vulnerable to lung infections during this time of the year.
We are having a number of patients suffering from pneumonia, bronco-pneumonia, chronic obstructive pulmonary disease and asthma, said pulmonologist Ashok Sengupta.
Apurba Ghosh, the director of the Institute of Child Health, said around 70 per cent of the children at his clinic were suffering from viral infections.