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Epidemics of the 19th century were faced without the medical advances that made 20th-century epidemics much rarer and less lethal. Micro-organisms (viruses and bacteria) had been discovered in the 18th century, but it was not until the late 19th century that the experiments of Lazzaro Spallanzani and Louis Pasteur disproved spontaneous generation conclusively, allowing germ theory and Robert ...
The germ theory of disease proposes that invisible microorganisms (bacteria and viruses) are the cause of particular illnesses in both humans and animals. [2] Prior to medicine becoming hard science, there were many philosophical theories about how disease originated and was transmitted.
The cause of malaria was unknown until August 20, 1897. Colonial physicians attributed it to "miasma" or bad air. [25] In reality this disease is a parasite that is found in certain species of mosquitoes, which bred more rapidly as virgin soil was broken in the Carolina lowlands for rice cultivation. [26]
The American era of limited infectious disease ended with the arrival of Europeans in the Americas and the Columbian exchange of microorganisms, including those that cause human diseases. European infections and epidemics had major effects on Native American life in the colonial period and nineteenth century, especially.
The Columbian exchange of crop plants, livestock, and diseases in both directions between the Old World and the New World. In 1972, Alfred W. Crosby, an American historian at the University of Texas at Austin, published the book The Columbian Exchange, [2] thus coining the term. [1]
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 ...
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 ...
Epidemiology has its limits at the point where an inference is made that the relationship between an agent and a disease is causal (general causation) and where the magnitude of excess risk attributed to the agent has been determined; that is, epidemiology addresses whether an agent can cause disease, not whether an agent did cause a specific ...