Any disease that can be transferred from person to person.
a disease that does not occur in the subject country. Said of infectious diseases that may be introduced, e.g. rabies is exotic to the UK, contagious bovine pleuropneumonia is exotic to the USA. focal disease. a localized disease. 1. a disease subsequent to or a consequence of another disease or condition. 2. a condition due to introduction of incompatible, immunologically competent cells into a host rendered incapable of rejecting them by heavy exposure to ionizing radiation. : an infectious disease communicable by contact with one who has it, with a bodily discharge of such a patient, or with an object touched by such a patient or by bodily discharges—compare communicable disease.  The boundary between contagious and non-contagious infectious diseases is not perfectly drawn, as illustrated classically by tuberculosis, which is clearly transmissible from person to person, but was not classically considered a contagious disease. The non-contagious category of infections usually require a special mode of transmission between persons or hosts. These include need for intermediate vector species (mosquitoes that cause malaria) or by non-casual transfer of bodily fluid (such as transfusions, needle sharing or sexual contact). An infectious disease or communicable disease is caused by a biological agent such as by a virus, bacterium or parasite. The vector does not have to be biological. Many infectious diseases are transmitted by droplets which enter the airway (e.g. common cold and tuberculosis). Infectious diseases are the invasion of a host organism by a foreign replicator, generally microorganisms, often called microbes, that are invisible to the naked eye. Microbes that cause illness are also known as pathogens. The most common pathogens are various bacteria and viruses, though a number of other microorganisms, including some kinds of fungi and protozoa, also cause disease. An infectious disease is termed contagious if it is easily transmitted from one person to another Infectious disease requires an agent and a mode of transmission (or vector). A good example is malaria, which is caused by Plasmodial parasites, chiefly Plasmodium falciparum but does not affect humans unless the vector, the Anopheles mosquito, is around to introduce the parasite into the human bloodstream. Infectious diseases are the invasion of a host organism by a foreign replicator, generally microorganisms, often called microbes, that are invisible to the naked eye. Microbes that cause illness are also known as pathogens. The most common pathogens are various bacteria and viruses, though a number of other microorganisms, including some kinds of fungi and protozoa, also cause disease. An infectious disease is termed contagious if it is easily transmitted from one person to another Contagious Diseases: Any disease that can be transferred from person to person. More detailed information about the symptoms, causes, and treatments of Contagious Diseases is available below. Evidence Based Medicine Research for Contagious Diseases. Medical research articles related to Contagious Diseases include: 1  Sexually Transmitted Disease (STD). 2  Detoxification and substance abuse treatment: an overview of the psychosocial and biomedical issues during detoxification. Hypernyms (contagious disease is a kind of...): communicable disease (a disease that can be communicated from one person to another). Hyponyms (each of the following is a kind of contagious disease): flu; grippe; influenza (an acute febrile highly contagious viral disease). measles; morbilli; rubeola (an acute and highly contagious viral disease marked by distinct red spots followed by a rash; occurs primarily in children). Infection is the invasion of an organism's body tissues by disease-causing agents, their multiplication, and the reaction of host tissues to these organisms and the toxins they produce. Infectious disease, also known as transmissible disease or communicable disease, is illness resulting from an infection. 
http://medical-dictionary.thefreedictionary.com/contagious+disease http://www.merriam-webster.com/medical/contagious%20disease https://en.wikipedia.org/wiki/Contagious_disease http://www.metrohealth.org/what-is-infectious-disease http://www.metrohealth.org/what-is-infectious-disease http://www.rightdiagnosis.com/c/contagious_diseases/intro.htm http://www.audioenglish.org/dictionary/contagious_disease.htm https://en.wikipedia.org/wiki/Infectious_disease
what is contagious disease