You would think folks in Bangladesh would have bullet-proof immune systems with everything they have to deal with over there.
They probably do. Many years ago I rented a room in a house full of people from Indonesia. They would leave fish loosely covered with plastic wrap, and half consumed bottles of orange juice on a table without bothering to refrigerate it. The roaches streamed under the gaps in the saran wrap and over the fish like stop motion animation. The next day they would resume eating, without cooking and finish the orange juice. As far as I know this regular unsanitary practice never made them ill.