Dr Jonathan Darby
About Dr Jonathan Darby
Dr Jonathan Darby, Fitzroy, VIC, Australia.
An infectious disease is one caused by a microorganism or other agent, such as a bacterium, virus, fungus, protozoa, or multicellular parasite, which enters the human body. The diseases are usually transmitted by a specific kind of contact, and so are also known as communicable diseases, or transmissible diseases. They are sometimes the cause of disease epidemics. Transmission (passing on) of disease-causing agents (pathogens) can occur in a variety of ways including physical contact between people, contaminated food, body fluids, objects, airborne inhalation, or through organisms (e.g. mosquitoes) which carry the disease. There are numerous common and less common infectious diseases, including measles and influenza, rheumatic fever, tuberculosis, enteric (intestinal) infections, meningococcal disease, hepatitis C, chlamydia and gonorrhoea.