Search results
Results from the WOW.Com Content Network
Primary pathogens cause disease as a result of their presence or activity within the normal, healthy host, and their intrinsic virulence (the severity of the disease they cause) is, in part, a necessary consequence of their need to reproduce and spread. Many of the most common primary pathogens of humans only infect humans, however, many ...
An infectious disease agent can be transmitted in two ways: as horizontal disease agent transmission from one individual to another in the same generation (peers in the same age group) [3] by either direct contact (licking, touching, biting), or indirect contact through air – cough or sneeze (vectors or fomites that allow the transmission of the agent causing the disease without physical ...
A contagious disease is an infectious disease that can be spread rapidly in several ways, including direct contact, indirect contact, and Droplet contact. [1] [2] These diseases are caused by organisms such as parasites, bacteria, fungi, and viruses. While many types of organisms live on the human body and are usually harmless, these organisms ...
Relevant microbes may be viruses, bacteria, or fungi, and they may be spread through breathing, talking, coughing, sneezing, spraying of liquids, toilet flushing or any activities which generate aerosol particles or droplets or generate fomites, such as raising of dust. [13] [14]
Widespread non-communicable diseases such as cardiovascular disease and cancer are not included. An epidemic is the rapid spread of disease to a large number of people in a given population within a short period of time; in meningococcal infections , an attack rate in excess of 15 cases per 100,000 people for two consecutive weeks is considered ...
Asymptomatic carriers have furthered the spread of many infectious diseases. A common principle in epidemiology, the 80–20 rule, speculates that 80% of the disease transmission is conducted by only 20% of people in a population. [15]
The Plague of Athens (c. 1652 –1654) by Michiel Sweerts, illustrating the devastating epidemic that struck Athens in 430 BC, as described by the historian Thucydides. The United States Centers for Disease Control and Prevention defines epidemic broadly: "Epidemic refers to an increase, often sudden, in the number of cases of a disease above what is normally expected in that population in ...
Bacteremia can travel through the blood stream to distant sites in the body and cause infection (hematogenous spread). Hematogenous spread of bacteria is part of the pathophysiology of certain infections of the heart ( endocarditis ), structures around the brain ( meningitis ), and tuberculosis of the spine ( Pott's disease ).