Air Quality Alerts are available for most geographic areas in New England. Note that those areas in New England not covered by Air Quality Alerts do not generally experience unhealthy air quality.
Definition of disease. 1  1 obsolete : trouble. 2  2 : a condition of the living animal or plant body or of one of its parts that impairs normal functioning and is typically manifested by distinguishing signs and symptoms : sickness, malady infectious diseases a rare genetic disease heart disease.
An infectious disease is a disease that is caused by the invasion of a host by agents whose activities harm the host's tissues (that is, they cause disease) and can be transmitted to other individuals (that is, they are infectious).ature of Infectious Diseases. Microorganisms that are capable of causing disease are called pathogens. Although microorganisms that cause disease often receive the most attention, it is important to note that most microorganisms do not cause disease.