After a four-year-old boy from the city lost his life to swine flu at a Delhi hospital a few days ago, three more cases of swine flu have been detected in the city which have put the health authorities on alert. Arnav (4), a resident of Model Town, had recently tested positive of swine flu, following which he was admitted to a hospital in Delhi where he died last Thursday. The Health Department immediately swung into action and took samples of all his family members living in the city. As the report of the samples came, it was confirmed that Arnav