The question about yellow fever brought up a question I have. Why did they fumigate the plane just before we landed in Buenos Aires? There was an announcement that according to Argentine law they would be spraying for bugs. Then a steward went up and down the aisles spraying insecticide. Since I have a lot of allergies and am ultra sensitive to perfumes, smoke, etc. I wondered why they would take the risk that someone might have an allergic reaction or asthma attack. Why not wait until everyone is OFF the plane instead of just before we land. Were they worried that the passengers themselves were carrying bugs and were fumigating us? I have never had such an experience on a plane before. I was on LAN if that makes any difference.