All the sweat, saliva, dandruff, and dead skins cells people leave behind after a night’s sleep is just the tip of the iceberg when it comes to a less-than-cleanly bed. All these things create the perfect environment for bacteria, fungi, viruses, and even microscopic bugs to grow. The author adds that people shed about 500 million skin cells each night while sleeping. This provides microscopic dust mites with a smorgasbord to feed on. FULL STORY