Hi After going through your baby s history it mostly look like viral fever. You have already given him supportive medicine like cetrizine which is decongestatnt and will help in blocked nose. Dose of 2.5 ml twice a day is sufficient for your baby considering his age. Meftal P is for fever. dose of it 5 ml can be repeated every six hourly if required. If your baby has not high grade fever then you can give it as and when required. Chericof is combination formula which is for cough, congestion,blocked nose and anti allergic. Dose will be 2.5 ml three times a day. I will suggest that if your baby has moderate symptoms then use only chericof and omit cetrizine. If baby has persistent high grade fever with rash, body ache, poor appetite , low platelet count then only test for dengue. For swine flu testing baby should have high grade fever, very bad throat,loose motions, vomiting,breathing difficulties etc. i will advise you to consult pediatrician before doing any investigations for more focused investigations. Hope this helps you.