As a result, the CDC establishes the Polio Surveillance Program CDC gains worldwide recognition for the quality and quantity of its contributions to the taxonomy of the Enterobacteriaceae, a family of germs that is difficult to treat because of its resistance to antibiotics The Senate subcommittee on Public Works approves construction of the new CDC Clifton Road Facility in Atlanta, Georgia.
Public Health Service becomes part of the newly created Cabinet-level Department of Health, Education and Welfare after the Federal Security Agency is dissolved First EIS investigations on environmental exposure to trichloroethylene and occupational exposure.
Practicing physicians who have hard-to-identify specimens submit through their health departments CDC becomes a division of the Bureau of State Services of the U. Public Health Service, primarily concerned with assisting state health authorities The United States is declared free of malaria as a significant public health problem Last case of naturally-occurring smallpox is reported in the United States.
Subsequently, CDC is designated as the official response agency for future epidemics and disasters CDC begins a five-year study on what role flies have in the spread and transmission of poliomyelitis CDC is transferred from the State Relations Division and established as a field station under the immediate direction of the Chief of the Bureau of State Services of the U.
Related Links. Other Resources. Sencer CDC Museum. Get Email Updates. All Rights Reserved. Privacy Policy. Cookie Policy. Linking and Reprinting Policy. Many infectious diseases leading to pandemics are caused by zoonotic pathogens that were transmitted to humans due to increased contacts with animals through breeding, hunting and global trade activities. The understanding of the mechanisms of transmission of pathogens to humans allowed the establishment of methods to prevent and control infections.
During centuries, implementation of public health measures such as isolation, quarantine and border control helped to contain the spread of infectious diseases and maintain the structure of the society. In the absence of pharmaceutical interventions, these containment methods have still been used nowadays to control COVID pandemic. Global surveillance programs of water-borne pathogens, vector-borne diseases and zoonotic spillovers at the animal-human interface are of prime importance to rapidly detect the emergence of infectious threats.
Novel technologies for rapid diagnostic testing, contact tracing, drug repurposing, biomarkers of disease severity as well as new platforms for the development and production of vaccines are needed for an effective response in case of pandemics. The shift from hunter-gatherers to agrarian societies has favored the spread of infectious diseases in the human population Dobson and Carper, Expanded trades between communities have increased interactions between humans and animals and facilitated the transmission of zoonotic pathogens.
Thereafter, expanded cities, extended trade territories, increased travels as well as effects on ecosystems due to increased human population raised the emergence and spread of infectious diseases leading to higher risks for outbreaks, epidemics and even pandemics Lindahl and Grace, The terms endemic, outbreak, epidemic and pandemic relate to the occurrence of a health condition compared to its predicted rate as well as to its spread in geographic areas Grennan, An endemic condition occurs at a predictable rate among a population.
An outbreak corresponds to an unpredicted increase in the number of people presenting a health condition or in the occurrence of cases in a new area. An epidemic is an outbreak that spreads to larger geographic areas. A pandemic is an epidemic that spreads globally. An emerging infection newly appears in a population or is spread in a new geographic area Morens et al.
The zoonotic transmission of pathogens from animals to humans is a pivotal mechanism by which emerging infections have afflicted humans throughout history Wolfe et al. The probability of cross-species transmission of pathogens was dramatically enhanced with increased interactions with animals through hunting, animal farming, trade of animal-based foods, wet markets or exotic pet trade Bengis et al.
The process of cross-species transmission of pathogens involves 5 different stages Wolfe et al. The animal species that harbor the pathogen, the nature of human interaction with that animal and the frequency of these interactions likely modulate the risk of zoonotic transmission. Furthermore, land use and climate changes are suggested to play important roles in the transmission of pathogens from wildlife to humans El-Sayed and Kamel, ; White and Razgour, There is thus a need to implement surveillance programs to rapidly detect the emergence of pathogens with a potential for zoonotic transmission at the animal-human interface.
Climate changes also influence the transmission of pathogens e. The emergence of vector-borne pathogens in non-endemic regions often results in explosive epidemics. Land use due to increasing human population also affects the distribution of disease-carrying vectors Kilpatrick and Randolph, Control of vector-borne zoonotic pathogens usually requires vector control to reverse the drivers of transmission.
Furthermore, the spread of several infectious diseases e. These diseases show a wider spread as a result of the acquisition of drug resistance, tolerance of mosquito vector to insecticides, poor sanitation, land use and climate changes as well as increased in human mobility and travels Cutler et al. Furthermore, outbreaks of cholera in regions where natural disasters occurred such as earthquakes and floods were also reported.
Surveillance programs should be also implemented to control the spread of these pathogens from endemic to non-endemic regions. Finally, infectious agents e. These weapons are based on natural microorganisms or microorganisms that are engineered to be more virulent, highly transmissible or resistant to therapy Narayanan et al.
The release of these biological weapons is intended to induce diseases in humans or even death. Therefore, governments should establish biowarfare, bioterrorism and biocrime preparedness plans to protect the population. In this paper, we review major pandemics that have afflicted humankind throughout history such as plague, cholera, influenza and coronavirus diseases, the way they were controlled in the past and how these diseases are managed today. Infectious diseases still represent threats for human health as pathogens can spread rapidly through global trade and travels.
Global surveillance programs are thus needed to detect and identify pathogens spillover from animals to humans as well as to control water-borne pathogens and vector-borne diseases. Furthermore, effective non-pharmaceutical and pharmaceutical measures for the prevention and control of these infections are required to limit their dissemination in the human population.
Plague is caused by the flea-borne bacteria Yersinia pestis that is responsible of at least three human plague pandemics, the plague of Justinian, the Black Death and the third plague Table 1 Zietz and Dunkelberg, Fleas acquire the bacteria by sucking blood from an infected rodent. Bacteria quickly multiply and block the alimentary canal in the gut of the fleas Bacot and Martin, The fleas transmit the bacteria to new rodent hosts by regurgitating the clotted blood.
Plague manifests in three forms, i. The bubonic form is the most common and results from the bite of an infected flea. Clinical manifestations include flu-like symptoms such as fever, chills, headache, body pains, weakness, vomiting and nausea followed by painful swollen lymph nodes.
The mortality rate is higher in patients with septicemic plague than in those with the bubonic form. Pneumonic plague occurs when the bacteria infects the lungs, either primarily by infectious respiratory droplets or secondarily as a complication of bubonic plague. This form is characterized by a fulminating onset and is rapidly fatal when left untreated. Between and , the plague killed an estimated million people in the Roman Empire and especially in its capital, Constantinople.
The highly developed structure of the Roman Empire facilitated the spread of the Justinian plague along its trade and military routes. The high mortality caused by the disease might have contributed to the weakening and eventually to the decline of the Byzantine Empire. After this initial pandemic, intermittent plague outbreaks occurred every 8 to 12 years for two centuries and then disappeared for unknown reasons.
The identification of the causative pathogen involved in the death of victims of past pandemics usually relies on ancient DNA techniques aimed to directly extract DNA from skeletal remains. A great advance in paleomicrobiology techniques was the isolation of microbial DNA in dental pulp specimens Drancourt et al.
Indeed, bacteria are trapped in the dental pulp early in the course of a bacteremia and can be isolated from preserved teeth of victims. Therefore, analysis of the dental pulp is more efficient than bones to accurately identify microbial DNA from rapidly fatal infections that occurred in the past. Corpses of victims of the Justinian plague could be recovered in burial sites.
Ancient DNA techniques from dental pulp samples identified Y. The second plague pandemic, the Black Death, originated in East Asia and swept across Central Asia into Europe through the land and sea trade routes of the medieval Silk Road Zietz and Dunkelberg, The second plague pandemic lasted in Europe until the early of the 19th century and killed million people. The lineages of Y. It is suggested that the bacteria may have persisted in rodent reservoirs in Europe and periodically re-emerged in the human population Seifert et al.
Another hypothesis could be that climate-driven outbreaks of Y. The bacteria suddenly disappeared from Europe and this could be possibly related to the extinction of local rodent reservoirs Spyrou et al. At that time, there was no effective treatment against plague. Initial institutional responses to disease control began during the Black Death Tognotti, A sanitary cordon was imposed by armed guards along transit routes and at access points to cities.
A separation between healthy and infected persons was accomplished in camps and then in permanent plague hospitals called lazarettos. Port cities were closed to ships arriving from plague-infected areas.
Ships with suspicion of plague were put in quarantine, passengers and crew were isolated in lazarettos and vessels were thoroughly fumigated and retained for 40 days. The Black Death decimated Medieval Europe and had major impacts on its socio-economic development, culture, art, religion and politics Bramanti et al. Based on genomic analysis of ancient and recent genomes, it was suggested that a wave of plague may have traveled from Europe to Asia after the Black Death, eventually setting in China and giving rise to the third plague pandemic Spyrou et al.
The latter plague pandemic originated in the middle of the 19th century in the Yunnan region China , reached Canton and spread to Hong Kong Zietz and Dunkelberg, In , Alexandre Yersin discovered the bacteria, Y. The pandemic then reached Japan, Singapore, Taiwan and India via ships. Over the following years, plague became endemic in many countries around the world Stenseth et al. Between and , the number of plague cases was estimated at 3, with fatalities worldwide, most of them occurring in Democratic Republic of the Congo, Madagascar and Peru Glatter and Finkelman, The basic reproduction number R o was estimated at 1.
The case fatality rate was as high as 8. Plague is seasonal in most endemic countries with a well-defined geographic distribution which corresponds to those of the vectors and rodent reservoirs Prentice and Rahalison, Nowadays, plague should be considered as a neglected human threat due to its rapid spread, its high fatality rate without early treatment and its capacity to disrupt social and healthcare systems Valles et al.
The genetic plasticity of Y. Surveillance and control programs of fleas and animals involved in the life cycle of Y. Individuals should protect themselves against flea bites in regions where plague is present. It is also recommended to avoid contact with infected body fluids and tissues as well as animal carcasses. Public health interventions that can be put in place to prevent or limit plague outbreaks include the killing of fleas with insecticides and, if required, the control of infected rodents; the early isolation of patients, the rapid diagnostic and treatment of infected individuals with antibiotics; the detection and isolation of contacts and the administration of chemoprophylaxis to exposed individuals Prentice and Rahalison, Standard treatments against plague include streptomycin and doxycycline.
Alternative drugs consist of gentamicin and fluoroquinolones Butler, ; Yang, The WHO does not recommend vaccination except for health care workers and laboratory personnel who are highly exposed to the pathogen.
Fifty years ago, a plague vaccine based on whole Y. This vaccine was effective against bubonic plague but not against the pneumonic form of the disease. Furthermore, this vaccine was associated with a high reactogenicity. As highlighted in the Madagascar outbreak, Y. Furthermore, Y. Therefore, the development of a plague vaccine against the most deadly form of the disease is needed. Cholera is an acute often fatal disease of the gastrointestinal tract caused by Vibrio cholerae Faruque et al.
The bacteria colonizes the small intestine and produces the cholera toxin which is responsible for a rapid and massive loss of body fluids leading to dehydration, hypovolemic shock and death. Humans are infected through contaminated water used for drinking or preparing foods. The infection is often mild or asymptomatic and bacteria are eliminated with feces in 1 or 2 weeks. Cholera was endemic in Asia until , when a first pandemic spread from India to several other regions of the world Table 1 Faruque et al.
This pandemic emerged during a period of increasing globalization resulting from technological progress in transportation. Indeed, the advent of steamships and railways allowed a dramatic decrease in travel time and a rise in trade.
At that time, health prevention strategies were essentially the same than those implemented during the Black Death Tognotti, Infected persons were isolated in lazarettos. Port entry was forbidden for ships arriving from regions where cholera was present. Travelers who had contacts with infected persons or who came from a place where cholera was circulating were quarantined.
Thereafter, five additional major pandemics of cholera that originated from India and spread to other continents occurred during the 19th and 20th centuries Table 1 Faruque et al. The second and sixth pandemics, and presumably the other ones, were caused by the O1 classical biotype of V.
The second pandemic of cholera reached the British islands. During the cholera outbreak in Soho London , in , the physician John Snow used for the first time epidemiological methods to trace the source of the outbreak. He described the time course of the outbreak and its geographical spread in the city. He identified the public pumps used for water supply in these areas and understood that water was the source of the contamination.
He then proposed effective measures to prevent the transmission through the removal of pump handle in the city areas where the outbreak occurred Smith, The bacillus of cholera was isolated during the fifth pandemic that extensively affected South America by Robert Koch who also understood the importance of clean water in preventing its transmission.
The toxin responsible for the disease was only discovered in De, The seventh cholera pandemic is the most extensive in terms of geographic spread and duration Mutreja et al. It began in Indonesia in and became endemic in many regions of the world. Cholera epidemics usually ended because of a lack of favorable environmental conditions for the survival of vibrios. The seventh cholera pandemic was caused by El Tor biotype strain of V. In late , the O serogroup caused a large cholera outbreak in Bangladesh and neighboring countries and raised the fear of a 8th cholera pandemic Albert et al.
Cholera cannot be eradicated as it is a natural inhabitant of aquatic ecosystems. However, it is estimated that the global burden of cholera is higher due to underreporting.
Between and , the number of cases was shown to range between 1. Environmental and climate changes may increase the geographical distribution of cholera Chowdhury et al. The persistence of cholera is related to poor living conditions including shortage of safe drinking water, insufficient sanitation, crowded housing and the lack of efficient sewage systems.
Re-emergence of the disease can also occur following natural disasters such as earthquakes that disrupt access to safe water supply. Cholera outbreaks could be predicted based on real-time monitoring of oceanic regions, climate fluctuations and epidemiological surveillance program Chowdhury et al.
The disease could be prevented by implementation of public health measures to ensure adequate sanitation and safe water supply Somboonwit et al.
The access to safe drinking water and sanitation are among the primary priorities of the Millenium Development Goals and the sustainable Development Goals Igere and Ekundayo, These vaccines should be used in areas with endemic cholera, cholera outbreaks and humanitarian crisis with high-risk of cholera in combination with other cholera prevention and control measures World Health Organization [WHO], Cholera is first identified based on clinical symptoms of severe acute watery diarrhea.
The disease is then confirmed by the detection of V. The majority of infected individuals can be treated by the administration of prompt oral rehydration solution. Severely dehydrated patients who are at risk of shock require rapid administration of intravenous fluids as well as antibiotics. First-line drug consists of doxycycline whereas alternative treatments include tetracycline, ciprofloxacin and azithromycin Hsueh and Waters, Influenza viruses belong to the Orthomyxoviridae family.
Influenza viruses are enveloped, negative-sense, single-stranded RNA viruses Wright and Webster, Their genome consists of 7 or 8 RNA segments encoding at least 10 structural and non-structural proteins. Structural proteins include a hemagglutinin HA , a neuraminidase NA , two matrix proteins and a nucleoprotein. Influenza viruses can be distinguished in types A, B, C, and D.
Influenza A and B are responsible for outbreaks in tropical regions and seasonal epidemics in temperate regions whereas influenza A viruses are the only ones with a pandemic potential Lofgren et al. Indeed, influenza A virus is endemic in a number of species including humans, birds and pigs Webster et al. Gene reassortments can thus occur between human and animal influenza A viruses and lead to a new virus subtype which can be pathogenic to humans Webster et al.
In a typical seasonal epidemics, influenza virus causes 3 to 5 million cases of severe illness and approximately , deaths worldwide Iuliano et al. Most typical seasonal influenza infections are asymptomatic or cause only mild or classical influenza illness characterized by 4 or 5 days of fever, cough, chills, headache, muscle pain, weakness and sometimes upper respiratory tract symptoms Zambon, Among the most severe complications is pneumonia which can be associated with secondary bacterial infection.
Annual influenza epidemics are sustained in the human population through mutations occurring especially in the HA and NA viral surface glycoproteins, the major targets for neutralizing antibodies. Seasonal influenza virus results from frequent antigenic drifts every 2—5 years in response to selection pressure to evade human immunity Kim et al. Its genome contains segmented genes which may undergo reassortments in cells co-infected with two or more influenza viruses.
Each influenza A virus has a gene encoding for 1 of 16 possible HAs and another gene encoding for 1 of 9 possible NAs that are involved in viral attachment and release, respectively Dugan et al. Rarely, antigenic shift which results from reassortment between human and animal viruses leads to the emergence of a new virus subtype Webster et al.
This antigenically distinct virus may have the ability to infect humans and achieve sustained human-to-human transmission and may cause a pandemic if the immunity in the human population is partial or lacking Webster et al.
The time in which influenza virus began to infect humans or cause a pandemic cannot be determined with accuracy but many historians agree that the first influenza pandemic could have likely occurred in Morens et al. The Russian flu that occurred between and was the first well-described pandemic Taubenberger et al. The virus spread rapidly as it took only 4 months to circumvent the planet Valleron et al. The pandemic virus reappeared every year for 3 years and caused an estimated 1 million deaths worldwide Table 1.
The median R o was estimated at 2. The case fatality rates ranged from 0. Attack rates were highest in individuals aged 1—60 years and lower in infants and seniors Valtat et al. In contrast, mortality rate showed a J-shape curve with highest rates in infants and people over 20 years of age Valtat et al.
Before its identification, the virus spread silently around the world and its region of origin could not be determined. The — pandemic spread in at least 3 distinct waves within a 9 month interval. The first wave occurred during spring-summer and caused high morbidity and low mortality. Both the second and third waves in summer-fall and winter — caused high mortality. The — influenza pandemic resulted in approximately million infections and 50 million deaths worldwide Johnson and Mueller, However, the — pandemic showed a W-shaped mortality curve with high case fatality rates in the very young and the elderly as well as in healthy young adults aged 20—40 years Morens and Taubenberger, This uncommon age distribution suggests that the severity of the — influenza pandemic was not primarily due to a hyper-virulent strain but was more likely related to host factors that prevent individuals to control the infection.
It is suggested that the influenza virus had an enhanced capacity to spread to and damage bronchial and bronchiolar epithelial cells that could allow bacteria to breach the mucociliary barrier leading to fatal bacterial pneumonia Morens and Fauci, The H1 hemagglutinin of the — pandemic virus was identified as a key virulence factor for mammalian and was associated with increased respiratory epithelial pathogenicity and elicitation of a strong pro-inflammatory response Qi et al.
Most deaths occurred from several days to weeks median 7—10 days after the onset of symptoms Shanks and Brundage, Antibiotics are described as chemicals produced by one micro- organism which harms another micro- organism. Large-scale production of penicillin and proof of its effectiveness treating bacterial infections was accomplished by scientists at Oxford University, led by Howard Florey Penicillin was first used on a relatively widespread basis during World War II.
After the war, pharmaceutical companies soon identified many new antibiotics. Madigan et al editors. Post- WWII, people were confident that antibiotics and vaccinations had conquered infectious diseases. Given the state of knowledge in the public health world of that day, it may have seemed appropriate to view infectious diseases in simple cause-and-effect terms. Seen in such a reductionist manner, problems and solutions appeared obvious and readily conquerable, bravado warranted. Understanding, protecting Earth's Biosphere.
Why are they important? Describe 3 reasons the development of agriculture caused an increase in human infectious diseases. Microbiology history: Why were the following folks important? Historically why was it important to prove the Germ Theory of Disease? Karen Carberry-Goh, D. Sacramento City College. Phagocytosis and early predator-prey interactions Predator-prey relationships probably developed soon after the first unicellular cells evolved.
Diamond; see table 2 below Agriculture and increased food production attracted rodents to human settlements. Contamination of animal food products by pathogens E. Contamination of drinking water with pathogens from animal feces Cryptosporidium, Giardia, Cyclospora… 3. Michael A Palladino, ed. Benjamin Cummings Special topics in Biology Series. Emergence caused by human behavior -Dengue Fever, Dengue Hemorrhagic Fever -West Nile Fever -cholera, dysentery, polio -Bacterial meningitis -increased population growth, urbanization, mass migration, war, shanty towns, crowding, nonexistent sanitation, mosquito breeding grounds, rapid transportation -overcrowding in cities, mosquito habitats around human dwellings -large, transient populations, refugee camps, poor sanitation --crowding in college dormitories, exchange of body fluids 3.
Emergence associated with technical failings and public health breakdowns, government deregulations -E. Brief history of microbiology and discovery of agents of infectious diseases Age-old wisdom: if we do not study history, we are destined to repeat the mistakes of the past.
Edward Jenner and the smallpox vaccine People for centuries were unaware of the immune system which protects us against pathogens. The modern smallpox vaccine virus is called vaccinia virus from root vacca - cattle As Professor Meyer says: Remember Semmelweiss!!! The same microbe must be reisolated fro the diseases experimental host. Understanding, protecting Earth's Biosphere E. What are zoonoses? Describe 4 zoonotic diseases. Edward Jenner b. Ignaz Semmelweiss c.
Joseph Lister d. Louis Pasteur e. Robert Koch f. Paul Ehrlich g.
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