Human pathogens are those organisms which cause disease in humans. Certain viruses, bacteria, protozoa, round worms, flatworms, and insects can live inside humans. Most bacter
…ia that live on the skin or in the gut of humans are harmless or beneficial. Some are usually harmless, but can cause disease under certain conditions. Some species of bacteria are known as pathogens but affect small numbers of humans. Some species are highly pathogenic and are lethal for a high percentage of the humans they infect. Some are highly contagious, but rarely cause death. Some bacteria that caused terrible epidemics in the past are today much less dangerous. Some that cause problems today were relatively harmless in the past. If children want to study pathogens, for example to study Kochs Postulates, then work with plant pathogens as they seldom cause any problem in humans. For example you might start with a rotten apple or other fruit, but avoid dusky molds and dry moldy piles of leaves and grass. The main concern about working with microbiology at home is the possibility that you will accidentally isolate a pathogen (disease causing) organism. There are many bacteria found in nature that can cause human disease. Therefore, you need to use much greater caution than you used in isolating bacteria from foods. The main concern about working with microbiology at home is the possibility that you will accidentally isolate a pathogen (disease causing) organism. There are many bacteria found in nature that can cause human disease. Therefore, you need to use much greater caution than you used in isolating bacteria from foods. The best insurance against a human pathogen is to avoid isolating bacteria from habitats known to carry pathogens. Secondly, do not isolate bacteria from the Genera known to contain human pathogens. Thirdly, do not isolate using medium and isolating conditions used for isolating human pathogens. Fourthly, learn all you can about human pathogens. You can search the web for +bacteria +pathogenic +human for further information. and select the majority organism, not a strange unusual colony. Therefore, you need to read about bacteria before you isolate them so that you are armed with much knowledge. For that reason, this website will have pages describing many safe common bacteria and lists and info about those that cause disease. It will take months or years to complete those pages. Meanwhile, read any bacteriology books you can find. (MORE) 
