My reasoning was thus........................u have a lot of dead bodies...................and/or animals.......u bury them.............in an area that is hot and wet.........like the highlands of Central America.............Southern Mexico....................they will decay slowly......................a dead body left in a place like Northern Mexico............the Sahara desert in Africa............Death Valley in Cali.........in hot and dry conditions......................would dry up very quickly...................just like mosquitoes spawn in humid conditions...........in the summers here in DC..........................dead bodies would accumulate bad stuff..................esp. over time...............the ancient Maya might not have known such things.........and just dumped dead bodies in pits.....................causing them to rot and spawn all kinds of diseases..................and they just up and left.........and went to South America........

Trench foot - Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Trench_foot

Wikipedia

Trench foot is a medical condition caused by prolonged exposure of the feet ... and feet may begin to have a decaying odor due to the possibility of the early ... which lead to fungal infections; this is sometimes called tropical ulcer (jungle rot). ... The causes were the cold, wet conditions and insufficiently waterproof DMS boots  ...

Tropical rainforest - Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Tropical_rainforest

Wikipedia

Tropical rainforests can be characterized in two words: hot and wet. .... which disappears quickly, because the warm, humid conditions promote rapid decay.

Rainforest - Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Rainforest

Wikipedia

Tropical rainforests are characterized by a warm and wet climate with no substantial ...They need to be able to withstand the hot temperatures and strong winds that occur ...quickly, because the warm, humid conditions promote rapid decay.