The Most Deadly Viruses Before COVID-19
Plague (or plague disease) is an infectious disease caused by the bacterium of the plague bacillus (Latin Yersinia Pestis; discovered in 1894), found on small animals (rodents) and the parasites living on them – fleas. It is transmitted to humans through the bite of an infected flea, through direct contact with infected materials, or by airborne droplets from a sick person. The incubation period is 3-7 days, then symptoms typical of influenza develop along with the sudden rise in temperature, chills, headache, body aches, weakness, nausea, and vomiting.
There are three forms of plague. In bubonic, the most common form, the plague bacillus attacks the lymphatic system. As a result, the lymph node becomes hard, a bubo body appears. In the late stage, the inflamed lymph nodes turn into festering wounds. A septic infection penetrates through cracks in the skin and enters the bloodstream immediately. Pneumonic plague, the most severe and least common form of plague, is associated with respiratory damage. If untreated, the disease can lead to serious complications and death (mortality – 30% -60%). In the fight against plague, antibiotic treatment is effective, as well as supportive therapy. If untreated, the disease can be fatal in a short time.
The first information about the disease with similar symptoms of the disease to the time of Ancient Rome. However, it was widespread and considered in an earlier period in the territory of modern Libya, Syria, and Egypt. Plague has caused widespread pandemics in the past. In the XIV century, one of the forms of plague, better known as the “black death,” according to some sources, claimed the lives of 50 million people. According to the World Health Organization (WHO), in 2010-2015, 3,248 cases of the plague of various forms were registered, 584 people died from the disease.
Smallpox is caused by the Variola virus (Latin Variola). It is transmitted by airborne droplets, as well as through objects, with the help of an infected person. The incubation period is 7-17 days. The disease begins with a sharp increase in temperature, headache, often nausea and vomiting. After 2-3 days, the temperature drops, a nodular-bubble rash appears on the skin and mucous membranes, leaving behind scars (pockmarks). In 30% of cases, a lethal outcome is observed; in rare forms (confluent, hemorrhagic, purple), mortality reaches 70% or more.
Until recently, it was believed that smallpox appeared in Africa or Asia in the 4th millennium BC. e. Suppose that the human virus is close to the camelpox virus. The smallpox epidemic first swept across China in the IV century, Korea in the VI and VIII century. It entered Europe in the 17th-18th centuries, 1.5 million people died of epidemics every year; By the beginning of the 16th century, these are the first mentions of smallpox in America, where the Spanish conquerors could have brought it. At the end of the 18th century, smallpox came to Australia.
It was possible to cope with the disease thanks to the WHO global vaccination program, implemented in the second half of the 1960s. The last human case of smallpox was recorded on October 26, 1977, in Somalia. The victory over the disease was officially announced in 1980. The right to store the virus and conduct research in two laboratories – the Russian State Scientific Center for Virology and Biotechnology “Vector” (settlement Koltsovo, Novosibirsk region) and the American Center for Disease Control and Prevention (Atlanta, USA).
Cholera is an acute intestinal infection caused by bacteria of the Vibrio cholera species, characterized by damage to the gastrointestinal tract, impaired water-salt metabolism, and dehydration. Spreads through poor water and food. Cholera has been known since ancient times until the middle of the 20th century and remained one of the most dangerous epidemic diseases. In the XIX century. Cholera has spread from its original reservoir in the Ganges delta in India throughout the world. Six consecutive pandemics have claimed the lives of several million people around the world. The seventh epidemic began in 1961 in South Asia and spread to Africa in 1971 and America in 1991. Currently, cases and outbreaks of the disease occur in medicine and poor countries, especially during massive isolated natural disasters. So, after the devastating earthquake in Haiti in January 2010, the number of cholera outbreaks exceeded 7.5 thousand. In January 2011, cholera from Haiti was transferred to Venezuela, the Dominican Republic, Spain, the United States, and Mexico in 2012 – to Cuba.
According to the WHO, between 3 million and 5 million cases occur annually in cholera diseases, of which over 100 thousand were fatal. Two types of vaccines are used to prevent this disease. They provide sustained protection of over 50% for two years.
“Swine Influenza” is a shorthand name for a viral infectious disease in humans that originally spread among domestic pigs (in 2009 in Mexico and the United States). The virus is transmitted by household and airborne droplets and causes symptoms typical of influenza and SARS – cough, headache, fever, vomiting, diarrhea, runny nose. The most dangerous complications are pneumonia. “Swine flu” is one of the most common influenza type A and includes the subtypes H1N1 (most common), H1N2, H3N1, H3N2, and H2N3. The most reliable way to avoid getting swine flu is to get the seasonal vaccine.
In 1957-1958, the H2N2 virus led to a pandemic, then from 20% to 50% of the world’s population fell ill, and from 1 million to 4 million people died, while most often the flu affected children. Another pathogen, the H3N2 virus, caused an epidemic of 1968-1969, the first cases of which were recorded in Hong Kong. The disease spread throughout the world has claimed the lives of up to 4 million people. A significant outbreak of the H1N1 virus occurred in 2009-2010. According to WHO, then the pandemic covered 30% of the world’s population in 214 countries, more than 18 thousand people died.
It is believed that one of the types of “swine flu” was the so-called. Spanish flu – an epidemic of 1918-1919 that spread around the world from Spain. Then more than 500 million people fell ill, from 20 million to 50 million died. This is the most massive pandemic in terms of the number of deaths in the history of humankind.
Ebola virus disease (EVD) affects humans and some species of animals. The virus was first recorded in 1976 in Zaire (now the Democratic Republic of the Congo, DR Congo), in a village on the banks of the Ebola River, which is why it got its name. It is believed that bats were originally carriers of the virus. It is transmitted to humans from wild animals and spreads from person to person through close contact through mucous membranes or skin lesions. The disease manifests itself with fever, jaundice, hemorrhagic syndrome, and renal failure. The incubation period ranges from 2 to 21 days. During outbreaks of the disease, the mortality rate reaches 90%. Experts identify five types of the virus: Bundibugio (BDBV), Zaire (EBOV), Sudan (SUDV), Tai Forest (TAFV), Reston (RESTV; affects only animals).
Outbreaks of fever were reported in DR Congo in 1976, 1995, and 2007, in Sudan in 1976, in Uganda in 2000, and in the Republic of the Congo in 2003. The epidemic claimed the greatest number of lives in 2013-2016, which covered Guinea, Sierra Leone, and Liberia. Cases have also been reported in Mali, Nigeria, Senegal, Spain, Great Britain, Italy, and the United States. According to the WHO, since the beginning of this epidemic, about 30 thousand people have been infected, 11.3 thousand people have died. In 2018-2019, outbreaks of the epidemic took place intermittently in DR Congo (3.4 thousand cases, 2.3 thousand deaths).
Acquired immunodeficiency syndrome (AIDS) is a disease that develops when infected with the human immunodeficiency virus (HIV). The virus attacks the immune system and weakens the body’s defenses against infection and disease. HIV can be transmitted through sexual contact, contaminated blood transfusions, the use of contaminated needles or sharp instruments, and from mother to child during pregnancy, childbirth, and breastfeeding. AIDS can develop 2-15 years after infection. There is no cure for HIV infection. However, treatment with antiretroviral drugs can control the virus, prevent transmission, and reduce the damaging effects on the body.
Some scientists believe that HIV was passed from monkeys to humans as early as the 1920s. The first victim of this disease, presumably, was a man who died in Congo in 1959 (the doctors came to this conclusion after analyzing his medical history later). For the first time, the symptoms of the disease characteristic of HIV infection were described in June 1981 in the United States. In 1983, researchers from the United States and France described a virus that can cause HIV / AIDS.
According to the Joint United Nations Program on HIV / AIDS, in 2018, about 37.9 million people were living with HIV in the world, of which 1.7 million were children under the age of 15. The most unfavorable region is the countries of Eastern and Southern Africa, where about 20.6 million people are infected. The number of new HIV infections decreased by 40% compared to 1997, when this indicator peaked, from 2.9 million to 1.7 million.