Infectious Diseases

Infectious diseases, also known as contagious diseases or transmissible diseases, and include communicable diseases, comprise clinically evident illness (i.e., characteristic medical signs and/or symptoms of disease) resulting from the infection, presence and growth of pathogenic biological agents in an individual host organism. In certain cases, infectious diseases may be asymptomatic for much or all of their course. Infectious pathogens include some viruses, bacteria, fungi, protozoa, multicellular parasites, and aberrant proteins known as prions. These pathogens are the cause of disease epidemics, in the sense that without the pathogen, no infectious epidemic occurs.

Transmission of pathogen can occur in various ways including physical contact, contaminated food, body fluids, objects, airborne inhalation, or through vector organisms. Infectious diseases that are especially infective are sometimes called contagious and can be easily transmitted by contact with an ill person or their secretions. Infectious diseases with more specialized routes of infection, such as vector transmission or sexual transmission, are usually regarded as contagious but do not require medical quarantine of victims.

The term infectivity describes the ability of an organism to enter, survive and multiply in the host, while the infectiousness of a disease indicates the comparative ease with which the disease is transmitted to other hosts. An infection is not synonymous with an infectious disease, as some infections do not cause illness in a host.

This text uses material from Wikipedia licensed under CC BY-SA

Latest Spotlight News

New study shows how gut immune cells are kept in control

Every day, the human gut works on a fine-tuned balance that ensures the retention of essential nutrients while preventing infection by potential armful microbes. Contributing to this surveillance system is a specialised group ...

Health insurance plans may be fueling opioid epidemic

Health care insurers including Medicare, Medicaid and major private insurers have not done enough to combat the opioid epidemic, suggests a study led by researchers at Johns Hopkins Bloomberg School of Public Health.

New technique helps uncover changes in ALS neurons

Northwestern Medicine scientists have discovered that some neurons affected by amyotrophic lateral sclerosis (ALS) display hypo-excitability, using a new method to measure electrical activity in cells, according to a study ...