MUMBAI: With the H1N1 influenza virus gaining virulence after the onset of monsoon, doctors are witnessing a sharp increase in the instances of cluster infections in families It has raised serious concerns about whether people are following the rules of self or home-isolation, or if awareness about the mode of disease transmission is missing among the population.An eight-month-old healthy baby from Tata Colony in Chembur, for instance, had to be hospitalized last week, because both her parents tested positive for the H1N1 influenza. Her father Shashikant Badhe, who even needed ICU care at Chembur's Zen Hospital, said they had no option but to hospitalise their child as she was too young to stay away from the mother. The baby, however, remained immune to the disease despite staying close to her mother Alka.In June, about 313 people were admitted to hospitals for swine flu . Paediatrician Dr Rohit Narvekar of Zen Hospital said that the father needed ICU care since he had developed breathing difficulty. “Soon after his wife had developed symptoms. We put the baby as well on oseltamivir and that seems to have protected her,” he said, adding that H1N1 cases are rampant in Ghatkopar, Kurla, Sion, etc. The civic body's reports, however, suggest that cases are being reported from across the city .Infectious disease consultant Dr Om Srivastava recently treated 11 members of a family from Mohammed Ali Road, who were all infected by the influenza virus. Among the affected were two senior citizens, three children, two male members and women from the family. Currently too, he is treating five members from one family .“Even 2-3 years back, we didn't have so many cluster infections in family. Overcrowding is a hindrance in tackling an airborne disease,” he said, adding a person should remain in isolation for at least 5 days.Lilavati Hospital's infectious disease consultant Dr Vasant Nagvekar treated six members of a family who had a travel history to Chhattisgarh. Almost all of them tested positive for the virus, including a nine month-old baby who had to be admitted.At Santacruz's Surya Hospital, the outpatient department is flooded with cases of febrile illnesses. Director Dr Bhupendra Avasthi said that at least 20-25 cases of fever are treated in the OPD daily.At Goregaon's SRV Hospital, six patients are currently undergoing treatment for swine flu, including an eight-month-old pregnant woman. “We have more H1N1 cases than dengue, malaria but all have recovered with timely care,” said intensivist Dr R Tripathi.