Someone asked me to go over a chapter he wrote, about the impact of certain customs on human health. One of them was the health advantages of quick burial: the problem is, usually there aren’t any. People seem to think that the organisms causing decomposition are pathogenic, but they’re not. People killed by trauma (earthquakes, floods, bullets) are dead enough, but not a threat. Sometimes, the body of someone that died of an infectious disease is contagious – smallpox scabs have been known to remain infectious for a long, long time – but most causative agents are unable to survive for long after the host’s death. Now if you’re dissecting someone, especially if they’re fresh, you probably don’t want to nick yourself with the scalpel – but if you just walk past the corpse and refrain from playing with it, you’re usually OK.
In the past, it may have been a good idea to bury people quickly, so as not to encourage a taste for human flesh in local predators, but that’s a somewhat indirect risk
Someone asked Lewis Thomas about the health risks of unburied bodies, with the intent of using a public-health threat as a legitimate reason to break the undertaker’s strike in New York – but the threat just wasn’t there. He said so, being an imperfectly political person.