There are tons of microscopic bacteria and organisms living in the pile that are breaking down organic material into good humus. Generally speaking, bacteria are pretty harmful to humans. The wrong ones can definitely hurt you, and if in some cases could even be pretty serious. So what about the bacteria in your compost pile?
Here are a few illnesses that can be common among gardeners, farmers, and sometimes composters.
First is Farmer’s Lung. Symptoms are similar to those of pneumonia. It’s caused by bacteria and fungal spores that live in rotted hay (for the most part). If you ever have to deal with hay that has white or gray dusty patches, make sure to grab a dust mask. Change into clean clothes and wash the clothes you worked in when you’re done. If you are unfortunate enough to breathe in any of the spores, antibiotics can be prescibed by your doctor.
Next up is paronychia. It’s an extremely painful infection around the edges of fingernails. This happens when there are any cuts or abrasions around the edges of your fingernails (for example, from biting your nails) that bacteria can enter. Moisture compounds the issue. To prevent this, make sure your gloves do not have any holes in the fingertips and that they are always dry when you use them. If a glove becomes wet and dirty, it would be a good idea to put on fresh dry ones. Again, cases of paronychia can be cleared by antibiotics (minor cases often clear up on their own).
Histoplasmosis is caused by fungus that grows in bird and bat droppings. This fungus attacks the respiratory system and causes a respiratory infection. For most people, this is not a common problem because the immune system can ward off infection before it ever occurs. However, care should still be taken when dealing with large amounts of bird or bat droppings. If you think you’ve been infected with histoplasmosis, please see your doctor.
Finally there’s tetanus. It attacks the central nervous system and causes muscles spasms (starting in the jaw, hence the term lockjaw). Tetanus is caused by bacteria that are widely spread through almost all soil. In this case, prevention is more effective than treatment. That means make sure your tetanus shots are up to date.
All this information and much more can be found in The Complete Compost Gardening Guide by Barbara Pleasant and Deborah Martin (2008).