In medicine, the epidemics of the 19th century were known and studied. [4] We can trace the study of epidemics back to the end of the 18th century, when these medical population studies emerged. [5] It is possible to note some medical knowledge also in Greek literature, including Homer (8th century), but it was Thucydides who first wrote about the Peloponnesian Wars in the time of Hippocrates and used the term epidemic for diseases that spread with time, wind and air to other regions. For some outbreaks from common sources, patients may have been exposed for days, weeks or longer. In the case of a continuous outbreak from common sources, exposure areas and the range of incubation periods tend to flatten and increase peaks in the epidemic curve (Figure 1.22). The epidemic curve of an intermittent outbreak from common sources often shows a pattern that reflects the intermittent nature of exposure. Outbreaks occur when a sufficient agent and susceptible hosts are present and the agent can be efficiently transmitted from one source to susceptible hosts. Specifically, an outbreak can result from: Britannica.com: Encyclopedia article on the epidemic A common epidemic results from person-to-person transmission. Normally, transmission occurs through direct person-to-person contact, as in the case of syphilis.
Transmission may also be vehicle-related (e.g., transmission of hepatitis B or HIV through needle sharing) or vector-borne transmission (e.g., mosquito-borne transmission of yellow fever). In routine outbreaks, cases occur over more than one incubation period. In Figure 1.23, note the peaks that occur about 11 days apart, which is the incubation period for measles. The epidemic usually disappears after a few generations, either because the number of susceptible people falls below a critical level needed to maintain transmission or because response measures take effect. But even the first philosophers of ancient Greece and Rome studied diseases and it was Hippocrates who first noticed that some diseases have an epidemic type (he wrote about the plague). [5] Galen also studied epidemic diseases and their occurrence. [5] For example, there was a terrible flu epidemic, followed by a severe fuel shortage due to a railway strike. If the group is exposed for a relatively short period of time, such that anyone who becomes ill does so during an incubation period, the outbreak from common sources is additionally classified as a point source outbreak. The outbreak of leukemia cases in Hiroshima after the atomic bomb explosion and the hepatitis A epidemic in Pennsylvania restaurants that ate green onions each had a point source of exposure. (38, 44) If the number of cases during an outbreak were recorded over time, the resulting graph, called the epidemic curve, would generally have a steep slope and a more gradual downward slope (a “logarithmic normal distribution”). Conditions that determine the outbreak of epidemics include infected food, such as contaminated drinking water, and the migration of populations of certain animals, such as rats or mosquitoes, which can act as disease vectors.
Rape and sexual assault may be less epidemic than other studies suggest. “Epidemic.” Merriam-Webster.com Dictionary, Merriam-Webster, www.merriam-webster.com/dictionary/epidemic. Retrieved 14 October 2022. After all, some outbreaks are neither common in the usual sense nor transmitted from person to person. Outbreaks of zoonoses or vector-borne diseases may be due to sufficient prevalence of infection in host species, sufficient presence of vectors and sufficient human-vector interaction. Examples (Figures 1.25 and 1.26) include the Lyme disease outbreak in the northeastern United States in the late 1980s (spread from deer to humans by deer ticks) and the West Nile encephalitis outbreak in Queens, New York City in 1999 (spread from birds to humans by mosquitoes). (49, 50) These sample phrases are automatically selected from various online information sources to reflect the current use of the word “epidemic.” The views expressed in the examples do not represent the views of Merriam-Webster or its editors. Send us your feedback. While public interest in Ebola continues to wane, the outbreak itself continues to rise. Nglish: Translation of the outbreak for Spanish speakers The coronavirus outbreak in the United States first hit the blue states particularly hard, especially in the northeast. An outbreak of an infectious disease can occur when the virus, bacteria, or any other cause of illness has recently become stronger, is introduced somewhere it has never been before, or finds new ways to enter the bodies of those it affects. It can also happen when people become more sensitive to the cause of the disease or are more exposed to it.
At his instigation, persecution of unprecedented virulence raged like an epidemic throughout the Reich. An outbreak may be confined to one location in a country or develop other sites within a country, but if it spreads to other countries in the region or even between continents, but only if it affects or threatens a significant number of people, it can be monitored as part of the pandemic. [2] Recording and reporting outbreaks generally requires a good understanding of a baseline incidence rate; Epidemics for certain diseases, such as influenza, are defined as a defined increase in incidence beyond this baseline. [3] Some cases of a very rare disease can be classified as an epidemic, while many cases of a common illness (such as the common cold) do not. An outbreak can cause enormous damage due to financial and economic losses, in addition to health problems and loss of life. A pandemic is a global epidemic. It differs from an outbreak or epidemic in that: infectious disease outbreaks are typically caused by several factors, including a significant change in the ecology of the region`s population (e.g. increased stress, perhaps additional terrain or increased density of a vector species), introduction of an emerging pathogen into a spatial population (due to pathogen or host displacement), or genetic modification in the pathogen reservoir.
For each of the following situations, identify the type of outbreak with which it is most consistent. The 2014 Ebola outbreak was the deadliest outbreak of the disease since 1976, infecting more than 28,000 people and killing more than 11,000. West and Central Africa have been particularly affected by the epidemic. We have high rates of heart disease and diabetes, and these factors make an already dangerous epidemic particularly deadly for people like me and my community. A pandemic transcends international borders, unlike regional epidemics. This broad geographic scope means that pandemics cause major social upheaval, economic losses and general hardship. It is important to note that once an outbreak has been declared, it can transition to pandemic status. Although an epidemic is important, it is also usually contained or expected in its spread, whereas a pandemic is international and out of control. With a mortality rate of 70%, the more cases there are, the more deadly this epidemic becomes. Some epidemics have characteristics of both epidemics originating from common sources and generalized epidemics.
The pattern of a joint outbreak followed by secondary person-to-person spread is not uncommon. These are called mixed epidemics. For example, an outbreak of shigellosis occurred in a group of 3,000 women attending a national music festival (Figure 1.24). Many developed symptoms after returning home. Over the next few weeks, several state health departments discovered subsequent generations of person-to-person cases of Shigella transmitted by festival-goers. (48) In general, epidemics concern the spread of infectious diseases. [1] An outbreak may occur when host immunity to an established or new emerging pathogen is suddenly reduced below that found in endemic equilibrium and the transmission threshold is exceeded. We have not spoken out in favour of eliminating gun violence and the epidemic of gun violence because it has an impact on the perpetuation of racism in this country.