Glossary of Terms
An outbreak of disease that spreads within a specific region and/or country
A state of being protected against infectious diseases by either specific or non-specific mechanisms (i.e., immunization, previous natural infection, inoculation, or transfer of protective antibodies)
The period of time after exposure to a disease that it takes for the host to display symptoms of that disease
The growth of a parasitic organism within the body. (A parasitic organism is one that lives on or in another organism and draws its nourishment therefrom.) A person with an infection has another organism (a "germ") growing within him, drawing its nourishment from the person.
An infection of the deep, spongy parts of the lungs which can also be caused by viruses. Viral pneumonia causes cough with fever, chills and rapid breathing
The upper respiratory tract includes the nose, sinuses, pharynx (throat), and larynx (voice box). The lower respiratory tract includes the trachea (windpipe), bronchial tubes (two branches from the windpipe), bronchioles (smaller bronchial tubes), and alveoli (tiny sacs in the lungs where the exchange of oxygen and carbon dioxide occurs).
An acute, potentially fatal metabolic disease seen primarily in children and characterized clinically by vomiting, hypoglycemia (low blood sugar), and confusion, which may progress to coma. Effects of the disease include cerebral edema (an accumulation of fluid between cells, causing swelling of the involved area) and fatty infiltration of the liver and other organs. (From Adams et al., Principles of Neurology, 6th ed, p1120) 
A specific biologic version of a microorganism (i.e. bacterium or virus). The identity of a strain is defined by its genetic makeup, or code; changing just one piece of the code produces a new strain
The Centers for Disease Control and Prevention (CDC) (US) www.cdc.gov/ (external link)
The Health on the Net Foundation. www.hon.ch/Dossier/MotherChild/glossary/index.html (external link)
The United Nations CyberSchoolBus. www.un.org/Pubs/CyberSchoolBus/special/health/glossary/ (external link)
MedicineNet. www.medterms.com/script/main/art.asp?articlekey=12923 (external link)