|
The history of malaria stretches from its prehistoric origin as a zoonotic disease in the primates of Africa through to the 21st century. A widespread and potentially lethal human infectious disease, at its peak malaria infested every continent, except Antarctica. Various scientists and scientific journals, including ''Nature'' and ''National Geographic'', have theorized that malaria may have killed around or above half of all humans who have ever lived.〔(Portrait of a killer ), ''Nature News'', "Malaria may have killed half of all the people that ever lived." 〕〔(Malaria ), ''National Geographic Magazine'', "Some scientists believe that one out of every two people who have ever lived have died of malaria."〕〔(The Tenacious Buzz of Malaria ), ''The Wall Street Journal'', "The malaria parasite has been responsible for half of all human deaths since the Stone Age,"〕〔(How scientists will win the war against malarial mosquitoes ), ''IO9 (peer-reviewed blog)'', George Dvorsky, "() Mosquitoes have killed more than half of all humans who have ever lived"〕〔''Brain Fuel'', Joe Schwarcz, "...malaria, the terrible disease that has killed about half the humans who have ever lived," p.184〕〔''Bio-inspired Innovation and National Security'', Center for Technology and National Security Policy (National Defense University), "Malaria is the biological agent, which some believe is responsible for killing half of all the humans who have ever lived," p.157〕 Its prevention and treatment have been targeted in science and medicine for hundreds of years. Since the discovery of the parasites which cause it, research attention has focused on their biology, as well as that of the mosquitoes which transmit the parasites. The most critical factors in the spread or eradication of disease have been human behavior (shifting population centers, changing farming methods and the like) and living standards. Precise statistics do not exist because many cases occur in rural areas where people do not have access to hospitals or other health care. As a consequence, the majority of cases are undocumented. Poverty has been and remains associated with the disease. References to its unique, periodic fevers are found throughout recorded history beginning in 2700 BC in China. For thousands of years, traditional herbal remedies have been used to treat malaria. The first effective treatment for malaria came from the bark of cinchona tree, which contains quinine. After the link to mosquitos and their parasites were identified in the early twentieth century, mosquito control measures such as widespread use of DDT, swamp drainage, covering or oiling the surface of open water sources, indoor residual spraying and use of insecticide treated nets was initiated. Prophylactic quinine was prescribed in malaria endemic areas, and new therapeutic drugs, including chloroquine and artemisinins, were used to resist the scourge. Malaria researchers have won multiple Nobel Prizes for their achievements, although the disease continues to afflict some 200 million patients each year, killing more than 600,000. Malaria was the most important health hazard encountered by U.S. troops in the South Pacific during World War II, where about 500,000 men were infected. According to Joseph Patrick Byrne, "Sixty thousand American soldiers died of malaria during the African and South Pacific campaigns." At the close of the 20th century, malaria remained endemic in more than 100 countries throughout the tropical and subtropical zones, including large areas of Central and South America, Hispaniola (Haiti and the Dominican Republic), Africa, the Middle East, the Indian subcontinent, Southeast Asia, and Oceania. Resistance of Plasmodium to anti-malaria drugs, as well as resistance of mosquitos to insecticides and the discovery of zoonotic species of the parasite have complicated control measures. == Origin and prehistoric period == The first evidence of malaria parasites was found in mosquitoes preserved in amber from the Palaeogene period that are approximately 30 million years old. Human malaria likely originated in Africa and coevolved with its hosts, mosquitoes and non-human primates. Malaria protozoa are diversified into primate, rodent, bird, and reptile host lineages. Humans may have originally caught ''Plasmodium falciparum'' from gorillas. ''P. vivax'', another malarial ''Plasmodium'' species among the six that infect humans, also likely originated in African gorillas and chimpanzees. Another malarial species recently discovered to be transmissible to humans, ''P. knowlesi'', originated in Asian macaque monkeys. While ''P. malariae'' is highly host specific to humans, there is spotty evidence that low level non-symptomatic infection persists among wild chimpanzees. About 10,000 years ago, malaria started having a major impact on human survival, coinciding with the start of agriculture in the Neolithic revolution. Consequences included natural selection for sickle-cell disease, thalassaemias, glucose-6-phosphate dehydrogenase deficiency, Southeast Asian ovalocytosis, elliptocytosis and loss of the Gerbich antigen (glycophorin C) and the Duffy antigen on the erythrocytes, because such blood disorders confer a selective advantage against malaria infection (balancing selection). The three major types of inherited genetic resistance (sickle-cell disease, thalassaemias, and glucose-6-phosphate dehydrogenase deficiency) were present in the Mediterranean world by the time of the Roman Empire, about 2000 years ago. Molecular methods have confirmed the high prevalence of ''P. falciparum'' malaria in ancient Egypt.〔 〕 The Ancient Greek historian Herodotus wrote that the builders of the Egyptian pyramids (circa 2700 - 1700 BCE) were given large amounts of garlic, probably to protect them against malaria. The Pharaoh Sneferu, the founder of the Fourth dynasty of Egypt, who reigned from around 2613 – 2589 BCE, used bed-nets as protection against mosquitoes. Cleopatra VII, the last Pharaoh of Ancient Egypt, similarly slept under a mosquito net. The presence of malaria in Egypt from circa 800 BCE onwards has been confirmed using DNA-based methods. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「History of malaria」の詳細全文を読む スポンサード リンク
|