A pandemic is an epidemic of an infectious disease that has spread across a large region, for instance multiple continents or worldwide, affecting a substantial number of individuals. Widespread endemic diseases with a stable number of infected individuals such as recurrences of seasonal influenza are generally excluded as they occur simultaneously in large regions of the globe rather than being spread worldwide.
An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable disease, is an illness resulting from an infection.
Zymotic disease was a 19th-century medical term for acute infectious diseases, especially "chief fevers and contagious diseases ".
Girolamo Fracastoro was an Italian physician, poet, and scholar in mathematics, geography and astronomy. Fracastoro subscribed to the philosophy of atomism, and rejected appeals to hidden causes in scientific investigation. His studies of the mode of syphilis transmission are an early example of epidemiology.
The germ theory of disease is the currently accepted scientific theory for many diseases. It states that microorganisms known as pathogens or "germs" can affect disease. These small organisms, too small to be seen without magnification, invade humans, other animals, and other living hosts. Their growth and reproduction within their hosts can cause disease. "Germ" refers to not just a bacterium but to any type of microorganism, such as protists or fungi, or even non-living pathogens that can cause disease, such as viruses, prions, or viroids. Diseases caused by pathogens are called infectious diseases. Even when a pathogen is the principal cause of a disease, environmental and hereditary factors often influence the severity of the disease, and whether a potential host individual becomes infected when exposed to the pathogen. Pathogens are disease-carrying agents that can pass from one individual to another, both in humans and animals. Infectious diseases are caused by biological agents such as pathogenic microorganisms as well as parasites.
The miasma theory is an abandoned medical theory that held that diseases—such as cholera, chlamydia, or the Black Death—were caused by a miasma, a noxious form of "bad air", also known as night air. The theory held that epidemics were caused by miasma, emanating from rotting organic matter. Though miasma theory is typically associated with the spread of contagious diseases, some academics in the early nineteenth century suggested that the theory extended to other conditions as well, e.g. one could become obese by inhaling the odor of food.
William Farr CB was a British epidemiologist, regarded as one of the founders of medical statistics.
John Snow was an English physician and a leader in the development of anaesthesia and medical hygiene. He is considered one of the founders of modern epidemiology, in part because of his work in tracing the source of a cholera outbreak in Soho, London, in 1854, which he curtailed by removing the handle of a water pump. Snow's findings inspired the adoption of anaesthesia as well as fundamental changes in the water and waste systems of London, which led to similar changes in other cities, and a significant improvement in general public health around the world.
A contagious disease is an infectious disease that is readily spread by transmission of a pathogen through contact with an infected person.
William Pulteney AlisonFRSE FRCPE FSA was a Scottish physician, social reformer and philanthropist. He was a distinguished professor of medicine at the University of Edinburgh. He served as president of the Medico-Chirurgical Society of Edinburgh (1833), president of the Royal College of Physicians of Edinburgh (1836–38), and vice-president of the British Medical Association, convening its meeting in Edinburgh in 1858.
The Epidemic Intelligence Service (EIS) is a program of the U.S. Centers for Disease Control and Prevention (CDC). The modern EIS is a two-year, hands-on post-doctoral training program in epidemiology, with a focus on field work.
Charles Value Chapin was an American pioneer in public health research and practice during the Progressive Era. He was superintendent of health for Providence, Rhode Island between 1884 and 1932. He established one of the earliest municipal public health laboratories in 1888, and the Providence City Hospital for contagious diseases in 1910. Chapin taught at Brown University and Harvard. In 1927 he served as president of the American Public Health Association and as the first president of the American Epidemiological Society.
The third cholera pandemic (1846–1860) was the third major outbreak of cholera originating in India in the 19th century that reached far beyond its borders, which researchers at University of California, Los Angeles (UCLA) believe may have started as early as 1837 and lasted until 1863. In the Russian Empire, more than one million people died of cholera. In 1853–1854, the epidemic in London claimed over 10,000 lives, and there were 23,000 deaths for all of Great Britain. This pandemic was considered to have the highest fatalities of the 19th-century epidemics.
The fifth cholera pandemic (1881–1896) was the fifth major international outbreak of cholera in the 19th century. It spread throughout Asia and Africa, and reached parts of France, Germany, Russia, and South America. It claimed 200,000 lives in Russia between 1893 and 1894; and 90,000 in Japan between 1887 and 1889. The 1892 outbreak in Hamburg, Germany was the biggest European outbreak; about 8,600 people died in that city. Although many residents held the city government responsible for the virulence of the epidemic, it continued with practices largely unchanged. This was the last serious European cholera outbreak of the century.
The Broad Street cholera outbreak was a severe outbreak of cholera that occurred in 1854 near Broad Street in Soho, London, England, and occurred during the 1846–1860 cholera pandemic happening worldwide. This outbreak, which killed 616 people, is best known for the physician John Snow's study of its causes and his hypothesis that germ-contaminated water was the source of cholera, rather than particles in the air. This discovery came to influence public health and the construction of improved sanitation facilities beginning in the mid-19th century. Later, the term "focus of infection" started to be used to describe sites, such as the Broad Street pump, in which conditions are favourable for transmission of an infection. Snow's endeavour to find the cause of the transmission of cholera caused him to unknowingly create a double-blind experiment.
Germ theory denialism is the pseudoscientific belief that germs do not cause infectious disease, and that the germ theory of disease is wrong. It usually involves arguing that Louis Pasteur's model of infectious disease was wrong, and that Antoine Béchamp's was right. In fact, its origins are rooted in Béchamp's empirically disproven theory of pleomorphism. Another obsolete variation is known as terrain theory and postulates that the state of the internal environment determines if germs cause disease rather than germs being the sole cause of it.
Colin Chisholm M.D. (1755–1825) was a Scottish surgeon, medical writer and Fellow of the Royal Society.
Diseases and epidemics of the 19th century included long-standing epidemic threats such as smallpox, typhus, yellow fever, and scarlet fever. In addition, cholera emerged as an epidemic threat and spread worldwide in six pandemics in the nineteenth century. The third plague pandemic emerged in China in the mid-nineteenth century and spread worldwide in the 1890s.
Marko Anton Plenčič, Marcus von Plenciz or Marcus Antonius von Plenciz was a Slovenian physician in Vienna who was among the early adopters of the germ or contagion theory of infection at a time when infectious disease was attributed to bad air or miasmas. He published his theories in Opera medico-physica 1762. He has been called the Slovene Pasteur.