Diseases that can be carried from one person to another are called infections．How do such diseases go round？Some diseases go round in one way, some in another．For example, the germs（病菌）that make you catch cold can travel from one person to another with a cough.They are breathed in with the air．That is why it is important to stay away from people when you have a cold. It is a good idea to stay away from people who have a cold, too. What seems to be a coldmay be the beginning of some more serious diseases．Germs travel from one person to another in many ways. For example, some diseases are carried by insects（昆虫）,such as flies and mosquitoes．Larger animals can also carry diseases．People can get diseases from rabbits or even dogs． At one time many people got tuberculosis（肺结核）by drinking milk from cows that had the diseases．It is vital to drink milk from cows that has a mad disease.
