Dengue conditions are worsening across Bangladesh, raising public concern over the greater danger of a second infection, according to the source. The dengue virus has four serotypes: DEN-1, DEN-2, DEN-3 and DEN-4. A person infected with one type develops lifelong immunity only to that serotype, while remaining vulnerable to infection from the other three types.

DEN-2 had been the dominant serotype in the country for four years, but DEN-3 has been detected this year in Dhaka and several other areas. A second infection with a different serotype can trigger antibody-dependent enhancement, making severe complications more likely. These include haemorrhagic dengue, dengue shock syndrome, rapidly falling platelet levels and internal bleeding, with a substantially higher risk of death than in a first infection.

Warning signs described in the source include severe fever, intense body or abdominal pain, persistent vomiting, bleeding from the gums or nose, breathing difficulty and extreme fatigue. It advises medical consultation and NS1 and CBC tests within the first 24 to 48 hours of fever. Patients should use paracetamol only for fever and pain, avoid aspirin, ibuprofen and diclofenac, drink sufficient fluids, prevent standing water and use mosquito nets.