Silicosis historical perspective: Difference between revisions
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*In 2000, ''Shigella'' was found to be phylogenically closely related to ''E. coli''. Both species are thought to be derived from similar ancestral virulence plasmids. | *In 2000, ''Shigella'' was found to be phylogenically closely related to ''E. coli''. Both species are thought to be derived from similar ancestral virulence plasmids. | ||
===Silicosis Outbreaks=== | |||
*In certain places in the world, an age-old scenario is being repeated. In the 16th century Agricola wrote of mines in the Carpathian mountains in Europe: "women are found to have married seven husbands, all of whom this terrible consumption (silico-tuberculosis) has carried off to a premature death". Only a few years ago certain villages in Northern Thailand were called "villages of widows" because of the large number of pestle-and-mortar-making workers who died early from silicosis. | |||
*During the period 1991 to 1995, China recorded more than 500 000 cases of silicosis, with around 6 000 new cases and more than 24 000 deaths occurring each year mostly among older workers. | |||
*In VietNam the cumulative number of diagnosed cases has now reached 9 000. They constitute 90% of all cases of occupationally compensated diseases. Some 18% of workers engaged in surface coal mining, quarrying, foundry and metallurgy have been found to have silicosis. | |||
*In India, a prevalence of 55% was found in one group of workers, many of them very young, engaged in the quarrying of shale sedimentary rock and subsequent work in small, poorly ventilated sheds. Studies on silicotic pencil workers in Central India demonstrated high mortality rates; the mean age at death was 35 years and the mean duration of the exposure was 12 years. | |||
*In Brazil, in the state of Minas Gerais alone more than 4 500 workers have been diagnosed with silicosis. In drought-affected regions in the north-east of the country the hand-digging of wells through layers of rock with very high quartz content (97%), an activity that generates great quantities of dust in confined spaces, resulted in a prevalence of 26% of silicosis, with many cases of accelerated forms. The state of Rio de Janeiro banned sandblasting after a quarter of shipyard workers were found to have silicosis. | |||
*In the USA, it is estimated that more than one million workers are occupationally exposed to free crystalline silica dusts (more than 100 000 of these workers are sandblasters), of whom some 59 000 will eventually develop silicosis. It is reported that each year in the USA about 300 people die from it, but the true number is not known. | |||
Abrasive blasting with silica sand, often used to prepare surfaces for painting, has been associated with exposures 200 times greater than the level recommended by the US National Institute for Occupational Safety and Health. This agency recommended that silica sand be prohibited as an abrasive blasting agent. | |||
*In Quebec, Canada, in the years 1988-1994, 40 newly diagnosed workers were compensated (12 were less than 40 years old). | |||
*The Colombian Government estimates that 1.8 million workers in the country are at risk of developing the disease.<ref> {{title:Silicosis url:http://web.archive.org/web/20070510005843/http://www.who.int/mediacentre/factsheets/fs238/en/}}<ref/> | |||
===Silicosis Outbreaks=== | ===Silicosis Outbreaks=== | ||
Several Shigella outbreaks have been reported in USA in the past, including the following outbreaks: | Several Shigella outbreaks have been reported in USA in the past, including the following outbreaks: | ||
Revision as of 12:34, 22 June 2015
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Despite the fact that the term "silicosis" would not be widely used in the United States until after 1915, dust had been long recognized as a problem for hard-rock miners, cutters, potters, buffers, glass workers, sandblasters, and foundry workers [3]. Since antiquity, observers had recognized that workers developed serious breathing problems when they inhaled the dust of certain rocks and minerals. Throughout most of the nineteenth century, doctors and laymen alike had accepted dust as a source of phthisis or, more commonly, consumption, chronic lung conditions that affected broad cross-sections of western European and American society. For the previous two centuries, this condition was the single greatest cause of death in Europe and America. Despite the great attention to epidemics of smallpox, cholera, or typhoid, consumption was "the great white plague" that threatened "the very survival" of European and American society. The symptoms of wasting away, coughing, spitting, and weakening might appear in victims from various classes and social strata.==Overview== Shigella was first discovered by Dr. Kiyoshi Shiga following a bacillary dysentery outbreak in Japan in 1896. Since then, several outbreaks have occurred.
Silicosis Historical Perspective
- Silicosis was first discovered by Dr. Kiyoshi Shiga, a Japanese scientist, following a bacillary dysentery outbreak in Japan in 1896.
- Silicosis was then adopted as a genus with 4 species in 1950s.
- In 2000, Shigella was found to be phylogenically closely related to E. coli. Both species are thought to be derived from similar ancestral virulence plasmids.
Silicosis Outbreaks
- In certain places in the world, an age-old scenario is being repeated. In the 16th century Agricola wrote of mines in the Carpathian mountains in Europe: "women are found to have married seven husbands, all of whom this terrible consumption (silico-tuberculosis) has carried off to a premature death". Only a few years ago certain villages in Northern Thailand were called "villages of widows" because of the large number of pestle-and-mortar-making workers who died early from silicosis.
- During the period 1991 to 1995, China recorded more than 500 000 cases of silicosis, with around 6 000 new cases and more than 24 000 deaths occurring each year mostly among older workers.
- In VietNam the cumulative number of diagnosed cases has now reached 9 000. They constitute 90% of all cases of occupationally compensated diseases. Some 18% of workers engaged in surface coal mining, quarrying, foundry and metallurgy have been found to have silicosis.
- In India, a prevalence of 55% was found in one group of workers, many of them very young, engaged in the quarrying of shale sedimentary rock and subsequent work in small, poorly ventilated sheds. Studies on silicotic pencil workers in Central India demonstrated high mortality rates; the mean age at death was 35 years and the mean duration of the exposure was 12 years.
- In Brazil, in the state of Minas Gerais alone more than 4 500 workers have been diagnosed with silicosis. In drought-affected regions in the north-east of the country the hand-digging of wells through layers of rock with very high quartz content (97%), an activity that generates great quantities of dust in confined spaces, resulted in a prevalence of 26% of silicosis, with many cases of accelerated forms. The state of Rio de Janeiro banned sandblasting after a quarter of shipyard workers were found to have silicosis.
- In the USA, it is estimated that more than one million workers are occupationally exposed to free crystalline silica dusts (more than 100 000 of these workers are sandblasters), of whom some 59 000 will eventually develop silicosis. It is reported that each year in the USA about 300 people die from it, but the true number is not known.
Abrasive blasting with silica sand, often used to prepare surfaces for painting, has been associated with exposures 200 times greater than the level recommended by the US National Institute for Occupational Safety and Health. This agency recommended that silica sand be prohibited as an abrasive blasting agent.
- In Quebec, Canada, in the years 1988-1994, 40 newly diagnosed workers were compensated (12 were less than 40 years old).
- The Colombian Government estimates that 1.8 million workers in the country are at risk of developing the disease.<ref> Template:Title:Silicosis url:http://web.archive.org/web/20070510005843/http://www.who.int/mediacentre/factsheets/fs238/en/
Silicosis Outbreaks
Several Shigella outbreaks have been reported in USA in the past, including the following outbreaks:
- January, 2000: Senor Felix outbreak in Washington, California, Idaho, Arizona, New Mexico, Oregon, and Alaska. A total of 122 cases were reported.
- October, 2000: Viva Mexico outbreak in California, USA. A total of 221 cases were reported.
- January, 2001: Royal Fork outbreak in Washington, USA. A total of 8 cases were reported.
- May, 2001: Tomato outbreak in New York. A total of 118 cases were reported.
- August, 2004: Gate Gourmet outbreak in Hawaii. A total of 22 cases were reported.
- August, 2006: Filiberto's outbreak in San Diego, USA. A total of 73 cases were reported.
- March, 2010: Subway Restaurant outbreak in Illinois, USA. A total of 328 cases were reported.
- March, 2015: Drug-resistant Shigella outbreak in Massachusetts, California, and Pennsylvania, USA.