They are small growth that are transmitted, in the case of fungi, usually thought spores released in the air, and bacteria, if inside a person will be transmitted by caughing and the liquid can survive in the air, but on our hands for quite some time. That is why you should avoid shaking hands if they are coughing. Most likely a cold virus. Bacteria is all around un and in us, some are good some are bad, same goes for fungi
