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Sunday, October 4, 2009

Penyakit Demam Kepialu


Virus kepialu atau Salmonella typhi

Demam kepialu atau Demam paratifoid (Typhoid Fever dalam bahasa Inggeris) merupakan penyakit yang disebabkan oleh bakteria yang dikenali sebagai Salmonella typhi. Demam kepialu biasa terdapat di seluruh dunia, dan hanya boleh dibawa dalam saluran usus dan darah manusia.

Demam kepialu merebak melalui makanan atau air yang tercemar dengan bakteria dari orang yang dijangkiti, atau dari sisi kumbahan yang mengandungi bakteria. Oleh itu kebersihan tempat penyediaan makanan perlu dikekalkan setiap waktu. Mereka yang mengendalikan makanan jualan perlu menjalani pemeriksaan perubatan seperti yang disyaratkan dalam lesan perniagaan makanan. Elakkan daripada membeli makanan daripada peniaga tidak berlesen terutamanya apabila terdapat wabak demam kepialu di sesuatu kawasan.

Selepas membiak di dalam badan pesakit, antara gejala termasuklah demam tinggi 103° ke 104°F (39° ke 40°C), lemah, sakit kepala, hilang selera makan, dan sakit perut. Gejala lain pula termasuklah radang leper, tompok bewarna merah bunga ros. Demam kepialu mampu membawa maut. Gejala akut kebocoran usus kecil (intestinal perforation), berkhayal (delusions), dan menjadi keliru juga boleh berlaku. Antibiotik, seperti ampicillin, trimethoprim-sulfamethoxazole, dan ciprofloxacin biasa digunakan bagi merawat demam kepialu.

Seseorang itu mampu menjadi pembawa penyakit demam kepialu, tanpa menunjukkan sebarang gejala, tetapi mampu menjangkiti orang lain. Pada tahun 1907, Mary Mallon ("Typhoid Mary") menjadi pembawa Amerika Syarikat yang pertama dijejak dan dikenal pasti. Menurut Pusat Kawalan Penyakit (Centers for Disease Control) dianggarkan 1 sehingga 20 orang yang dijangkiti demam kepialu masih membawa penyakit demam kepialu selepas sembuh.

Demam kepialu mungkin berlarutan selama tiga minggu sehingga satu bulan sekiranya tidak dirawat. Kematian berlaku antara setiap 1 dalam 9 ke 1 dalam 3 kes. Suntikan vaksin berserta pemilihan makanan merupakan cara utama mengelakkan terkenanya demam ini.

Demam kepialu telah meragut nyawa beberapa orang terkenal, termasuk Rudyard Kipling, Franz Schubert, Wilbur Wright, dan Putera Pengiring British Albert of Saxe-Coburg-Gotha.


Penyakit Taun

Penerangan mengenai penyakit taun atau nama lainnya kolera

Penyakit taun atau kolera merupakan penyakit akibat daripada jangkitan virus (kuman), vibrio cholera.

Salah satu punca bagaimana kuman taun boleh tersebar ialah melalui pengambilan makanan dari persekitaran yang kotor dan tidak terurus seperti pengambilan makanan yang dicemari kuman taun atau tidak dimasak .

Penyakit taun merupakan penyakit saluran penghadaman (intestinal tract) yang disebabkan oleh bakteria Vibrio cholerae. Virus ini biasanya ditelan melalui air minuman yang tercemar kerana pengendalian yang tidak bersih atau melalui ikan yang tidak dimasak dengan betul terutamanya kerang. Simptom termasuk cirit-birit ( diarrhea ), perut tegang (abdominal cramps), mual, muntah, dan kekeringan. Penyakit Taun dirawat dengan rehidrasi dan antibiotik, tetapi dalam kes teruk, taun boleh menyebabkan kematian.

Statistik Kementerian Kesihatan Malaysia menunjukkan penyakit taun atau kolera telah menurun dari 1,304 kes (19 kematian) pada tahun 1998 kepada 365 kes (7 kematian) pada tahun 2002. Penurunan ini adalah petanda baik bahawa pendidikan dan penguatkuasaan yang dijalankan oleh Kementerian Kesihatan berkesan, namun pengguna harus sentiasa berwaspada terhadap tahap kebersihan dan keselamatan makanan mereka.

  • Sekitar sejuta virus Vibrio cholerae harus dihadamkan sebelum taun menjangkiti seseorang dewasa yang sihat, walaupun peningkatan jangkitan boleh diperhati pada mereka dengan sistem pertahanan diri yang lemah, mereka yang asid gastrik kurang (akibat penggunaan antasid), atau mereka yang kekurangan makanan.
  • Wabak taun terakhir di Amerika Syarikat adalah pada tahun 1911..
  • 1,099,882 kes dan 10,453 kematian dilapurkan di Hemisphere Barat antara Januari 1991 dan Julai 1995.
  • Secara purata, satu kes taun dilapurkan di Amerika Syarikat setiap minggu.

Vibrio cholerae menyebabkan penyakit dengan membebaskan toksin yang melumpuhkan fungsi GTPase pada protin G yang merupakan sebahagian pasangan penerima-protin G ( G protein-coupled receptor ) di dalam sel usus. Ini mengakibatkan protin G terkunci dalam "kedudukan terpasang" mengikat GTP (biasanya, protin G kembali "tertutup" dengan pantas dengan hydrolizing GTP kepada GDP). Protin G mengakibatkan adenylate cyclase menghasilkan sejumlah besar cyclic AMP (cAMP) yang mengakibatkan kehilangan cecair dan garam yang banyak pada lapisan perut.

Cirit-birit yang berlaku membenarkan virus tersebar kepada orang lain akibat keadaan yang tidak bersih. Pembawa gen penyakit Sistik Fibrosis (cystic fibrosis) dilindungi dari kesan taun teruk akibat mereka tidak kehilangan air dengan cepat. Ini menjelaskan jumlah tinggi cystic fibrosis dikalangan penduduk yang pernah terdedah kepada taun.

Kajian genetik terkini menunjukkan kecenderungan seseorang kepada taun (dan cirit-birit lain) bergantung kepada jenis darah mereka. Mereka dengan darah jenis O paling mudah dijangkiti. Mereka dengan darah jenis AB paling tahan, hampir kebal. Antara kedua melampau terdapat jenis darah A dan B, dengan jenis A lebih tahan berbanding jenis B

Penyakit Hepatitis A



Virus demam kepialu berasal dari lalat




Kuman Hepatitis A menyerang organ dalaman manusia

Hepatitis A merupakan sejenis penyakit kelamin. Virus hepatitis A (HAV) mengakibatkan penyakit berjangkit yang teruk serta keradangan hati. Keadaan klinikal penyakit ini berbeza, iaitu daripada sakit ringan yang berlanjutan selama satu hingga dua minggu kepada sakit teruk yang menyebabkan hilang keupayaan selama beberapa bulan. Sebahagian besarnya langsung tidak menunjukkan kesan, hanya sakit ringan lazimnya di kalangan kanak-kanak.

Hepatitis A jarang menyebabkan kematian dan mempunyai kadar kematian amat rendah. Kematian hanya berlaku kepada pesakit tua yang mendapat penyakit ini dengan mendadak. Virus hepatitis A tersebar melalui saluran najis, mulut serta saluran penghadaman. Keram, tiram dan kima (siput besar) boleh menjadi punca utama wabak hepatitis A jika tidak dimasak dengan betul.

Hepatitis A adalah penyakit berjangkit yang paling mudah dijangkiti. Kadar jangkitannya lebih 1,000 kali lebih tinggi daripada taun dan 10 hingga 100 kali lebih tinggi daripada demam kepialu. Kematian akibat hepatitis A dilaporkan lebih dua orang setiap 100 mangsa yang berusia lebih 40 tahun dan meningkat hingga seorang dalam setiap 30 mangsa yang berumur lebih 49 tahun. Kajian yang dijalankan di negara kita menunjukkan bahawa 50 peratus daripada penduduk Malaysia di bawah usia 30 tahun tidak mempunyai pelalian kepada hepatitis A.


Kuman Hepatitis A

Kesan Penyakit

PENYAKIT BAWAAN AIR

Contoh penyakit bawaan air :

  1. Hepatitis A
  2. Taun
  3. Demam kepialu ( paratifoid )

Causes

Many causes of pollution including sewage and fertilizers contain nutrients such as nitrates and phosphates. In excess levels, nutrients over stimulate the growth of aquatic plants and algae. Excessive growth of these types of organisms consequently clogs our waterways, use up dissolved oxygen as they decompose, and block light to deeper waters. This, in turn, proves very harmful to aquatic organisms as it affects the respiration ability or fish and other invertebrates that reside in water.

Pollution is also caused when silt and other suspended solids, such as soil, washoff plowed fields, construction and logging sites, urban areas, and eroded river banks when it rains. Under natural conditions, lakes, rivers, and other water bodies undergo Eutrophication, an aging process that slowly fills in the water body with sediment and organic matter. When these sediments enter various bodies of water, fish respirationbecomes impaired, plant productivity and water depth become reduced, and aquatic organisms and their environments become suffocated.

Pollution in the form of organic material enters waterways in many different forms as sewage, as leaves and grass clippings, or as runoff from livestock feedlots and pastures. When natural bacteria and protozoan in the water break down this organic material, they begin to use up the oxygen dissolved in the water. Many types of fish and bottom-dwelling animals cannot survive when levels of dissolved oxygen drop below two to five parts per million. When this occurs, it kills aquatic organisms in large numbers which leads to disruptions in the food chain


The pollution of rivers and streams with chemical contaminants has become one of the most crutial environmental problems within the 20th century. Waterborne chemical pollution entering rivers and streams cause tramendous amounts of destruction.

Pathogens are another type of pollution that prove very harmful. They can cause many illnesses that range from typhoid and dysentery to minor respiratory and skin diseases. Pathogens include such organisms as bacteria, viruses, and protozoan. These pollutants enter waterways through untreated sewage, storm drains, septic tanks, runoff from farms, and particularly boats that dump sewage. Though microscopic, these pollutants have a tremendous effect evidenced by their ability to cause sickness.

The pathway of contamination

Sewer systems



Paris sewer system

Japanese sewer system

A Word About Sewers: Besides having a set of sewer pipes-- called, strangely enough, sanitary sewers-- which carry wastewater to a treatment plant, cities and towns also need pipes to collect stormwater. These are needed to prevent street flooding and usually lead directly to a waterway without any treatment. The runoff of pollutants from streets and yards into these storm sewers contain oil and other automotive wastes, which may contain toxic metals and organic compounds-- as well as pesticides and nutrient-containing fertilizers from lawns and gardens, and pathogenic microorganisms from animal wastes. The problem of pollution from storm sewers is currently being addressed by the USEPA. Further complicating the situation is the fact that while some cities and towns have completely separate sanitary and storm sewer systems, many others have combined systems. During rainy periods, combined sewers cause two problems: overloading of the treatment plant with extra water and contaminating waterways with untreated sewage from overflows. Even in cities with separate sewer systems, the flows to the treatment plants often increase greatly when it rains because of cracks or separations in the pipes, which allow groundwater or stormwater from broken storm sewer pipes to infiltrate into the sanitary sewer-- or from direct inflow of stormwater into manholes and from illegal connections of roof drains and sump pumps in buildings.



How sewer system is work

Prevention

To keep our used water from spoiling our water resources, we have to remove the pollutants before the water gets back into the environment. In urban areas in most developed countries, the wastewater from homes, businesses and factories is collected by a system of underground pipes-- sewers-- which carry it to one or more central treatment facilites. Most of these are located near bodies of water into which the treated wastewater is discharged.

In the U.S., all such facilites must have a permit issued by the federal and/or state government, describing limits on the amounts of various pollutants which may be discharged. The U.S. EPA (Environmental Protection Agency) refers to these as NPDES (National Pollutant Discharge Elimination System) permits. Industries located in areas where they are not connected to a sewer can discharge directly into a waterway, but will need a permit, and will probably have to have their own treatment plants. Even industries which are connected to sewers may have to pretreat their wastewaters before discharging them into the sewers, because they may contain materials which will harm the sewers or the treatment plants-- or may be a danger to the people who work in maintaining the sewer system.

Homes in non-urban areas that are not connected to a sewer are usually required by their town to have on-site treatment systems. Most common for single homes are septic systems, which consist of a buried tank connected to a set of perforated pipes, embedded in gravel, which distribute the water into the soil. (The "Links" page has several references on this subject.) Larger housing complexes may have treatment systems based on the principles used in full-scale sewage treatment plants.

Sejarah pencemaran air


Alam sekitar kita ini saling terikat antara satu sama lain. Perkara yang sama juga berlaku dengan pencemaran air. Pencemaran ini berlaku akibat daripada perbuatan manusia memusnah alam yang semakin lama semakin menjadi. Pengendalian dan penggunaan tanah yang salah akhirnya mengakibatkan tanah terhakis dan tanah ini akan memasuki ke dalam sungai dan akan mengakibatkan sungai menjadi berlumpur. Ada juga tanah yang dihanyut ke sungai dan kemudian memasuki ke dalam laut. Pembuangan sampah sarap di merata-rata juga akan terus dihanyut ke dalam sungai oleh air hujan. Fenomena tersebut dikenali sebagai air larian.

Pencemaran air ini sudah mula mengancam menusia dari dulu lagi, iaitu pada Zaman Neolitik. Kematian secara besar-besaran yang disebabkan oleh air yang tercemar telah berlaku pada Zaman Keagungan Rom. Ini merupakan kes kematian yang disebabkan oleh pencemaran air yang terawal pernah direkodkan. Orang Rom pada zaman itu telah membina sistem bekalan air yang canggih. Pada masa itu sebanyak lapan aqueduct (saliran air) telah dibina untuk menyalurkan air ke bandar itu. Sistem bekalan air ini bukan sahaja dibina di sekitar Rom malah di koloni-koloni mereka juga iaitu di Gaul, Sepanyol dan Ingggeris.

Kedua-dua aqueduct dan juga pembetung mula menghadapi kekurangan perhatian dan jagaan rapi pada kurun pertama A.D. Pada kurun ke-4, Zaman Orang Gasar, sistem pembentungan menjadi lebih teruk apabila ia tersumbat dengan lumpur dan juga sampah-sarap. Tanah pertanian yang dahulunya disaliri oleh Cloaca Maxima telah bertukar menjadi sebuah paya pembawa kuman penyakit yang kini dikenali sebagai Pontine Marshes, dan menyebabkan penyakit-penykit epidemik dan juga Malaria. Kesan-kesan ini mungkin sekali menyumbang kepada keruntuhan Tamadun Rom.

Dengan kejatuhan Tamadun Rom, langkah-langkah untuk mengekalkan kesihatan mulai dilupakan. Bandaraya pada Zaman Pertengahan Eropah mempunyai sistem pembetungan terbuka dengan sistem perparitan yang tidak sistematik dengan sedikit kawasan takungan dan tandas yang selalunya berdekatan dengan parit air. Pada akhir Zaman Pertengahan Eropah, keadaan yang tidak bersistematik ini telah membawa kepada "Black Death" di mana ia mungkin telah mengorbankan setengah hingga tiga perempat daripada populasi penduduk Eropah yang berlaku dari tahun 1348 hingga 1349. Keadaan ini sering kali berlaku di bandar-bandar Eropah sehingga ia pulih pada abad ke-19. Sungai digunakan sebagai pusat untuk pembuangan sampah sejak kewujudan manusia di dunia ini. Dengan ada penciptaan alat dan pembersihan sungai, sungai tidak diancam pencemaran yang lebih teruk sehingga tahun 1825.

Pada hari ini juga, sampah sarap yang tidak diproses dilonggokkan ke dalam sungai walaupun manusia tahu perbuatan ini boleh membahayakan dirinya sendiri. Pada masa itu juga, iaitu pada zaman pemerintahan Raja Richard II, Raja Inggeris dari tahun 1377 hingga 1399, baginda telah membina sebuah patung yang melarang supaya tidak mengalirkan air kumbahan ke dalam sungai yang berdekatan dengan bandar. Raja Henry VIII yang memerintah Inggeris pada awal kurun ke-16, juga menubuhkan ordinan yang berhubung dengan pencemaran air. Ramai rakyat tidak sedar bahawa air yang tercemar mungkin boleh jadi punca kepada penyakit yang menyerang pada masa itu. Di London, sebagai contoh, diserang oleh taun yang datang secara berkala. Dalam satu kejadian, ia telah meragut 50,000 nyawa manusia pada tahun 1831. Diikuti pula dengannya adalah disentri dan deman kepialu yang sering kali berlaku di kalangan masyarakat luar bandar.

Taun yang disebabkan oleh air yang tercemar telah juga membunuh 20,000 orang di London pada tahun 1849 dan 1953. Deman Kepialu yang menyebabkan individu itu lumpuh juga menyerang Utara Boston, New York pada tahun 1843. Di Plymouth, Pa., pada tahun 1885 dan di Hamburg, Jerman pada tahun 1892. Menurut Donald E. Carr dalam bukunya iaitu Death of the Sweet Waters menyatakan bahawa air yang dicemari oleh air kumbahan merupakan punca kepada tersebarnya deman kepialu dan taun yang mewakili 20% dalam kes-kes yang dilaporkan di hospital di India dan China. Penyakit lain yang merebak secara meluas adalah hepatitis yang berpunca daripada meminum air yang tercemar ataupun memakan kerang yang hidup di kawasan yang tercemar. India pernah diserang oleh hepatitis pada tahun 1956 tetapi tidak begitu banyak tersebar di Mississippi, New York, New Jersey dan Connecticut pada tahun 1961 di mana ia berpunca daripada kerang.

Kaitan di antara mikroorganisma, pembunuh yang terdapat di dalam air dan penyakit yang dibawanya telah membuka jalan kepada penciptaan penawar penyakit tersebut. Sebagai contoh Eberth menemui bacillus taun pada tahun 1880, Koch telah menjumpai kuman Kholera pada tahun 1883 dan Pasteur telah berjaya menjumpai penawar untuk manusia menentang penyakit anjing gila pada tahun 1885. Pada tahun yang sama juga Franklund telah memulakan rutin analisis biologi terhadap air yang disalirkan oleh syarikat air di London dan berupaya menunjukkan bahawa penurasan air melalui pasir boleh mengurangkan kandungan bakteria sehingga 98%.

Wikipedia Definition


Water pollution is the contamination of water bodies such as lakes, rivers, oceans, and groundwater. All water pollution affects organisms and plants that live in these water bodies and in almost all cases the effect is damaging either to individual species and populations but also to the natural biological communities. It occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful constituents.

Water....




It covers 71% of the earth's surface and makes up 65 % of our bodies. Everyone wants clean water-- to drink, for recreation, and just to enjoy looking at. If water becomes polluted, its loses its value to us economically and aesthetically, and can become a threat to our health and to the survival of the fish living in it and the wildlife that depends on it.



Dictionary Means


WATER!!!!

According to the American College Dictionary, pollution is defined as: to make foul or unclean; dirty.Water pollution occurs when a body of water is adversely affected due to the addition of large amounts of materials to the water. When it is unfit for its intended use, water is considered polluted. Two types of water pollutants exist; point source and nonpoint source. Point sources of pollution occur when harmful substances are emitted directly into a body of water. The Exxon Valdez oil spill best illustrates a point source water pollution. A nonpoint source delivers pollutants indirectly through environmental changes. An example of this type of water pollution is when fertilizer from a field is carried into a stream by rain, in the form of run-off
which in turn effects aquatic life. The technology exists for point sources of pollution to be monitored and regulated, although political factors may complicate matters. Nonpoint sources are much more difficult to control. Pollution arising from nonpoint sources accounts for a majority of the contaminants in streams and lakes.

Homes


Waste channeled to the main river

Sewage generated by houses or runoff from septic tanks into nearby waterways, introduce organic pollutants that can cause eutrophication.

Fertilizers, herbicides and pesticides used for lawn care can runoff and contaminate the waterway. As with agriculteral fertilizers, home fertilizers can lead to the eutrophication of lakes and rivers.

Improper disposal of hazardous chemicals down the drain itroduce toxic materials into to the ecosystem, contaminating the water supplies in a way that can harm aquatic organisms.

Leaks of oil and antifreeze from a car on a driveway can be washed off by the rain into nearby waterways, polluting it.

Business



Smoke from the industries



Toxic and mineral oil pollution from the industries

Clearing of land can lead to erosion of soil into the river.

Waste and sewage generated by industry can get into the water supply, introducing large organic pollutants into the ecosystem.

Many industrial and power plants use rivers, streams and lakes to despose of waste heat. The resulting hot water can cause thermal pollution. Thermal pollution can have a disasterous effect on life in an aquatic ecosystem as temperature increaces decreace the amount of oxygen in the water, thereby reducing the number of animals that can survive there.

Water can become contaminated with toxic or radioactive materials from industry, mine sites and abandoned hazardous waste sites.

Acid precipitation is caused when the burning of fossil fuels emits sulfur dioxide into the atmosphere. The sulfur dioxide reacts with the water in the atmosphere, creating rainfall which contains sulfuric acid. As acid precipitation falls into lakes, streams and ponds it can lower the overall pH of the waterway, killing vital plant life, thereby affecting the whole food chain. It can also leach heavy metals from the soil into the water, killing fish and other aquatic organisms. Because of this, air pollution is potentially one of the most threatening forms of pollution to aquatic ecosystems.

Chemical waste from the industries

Farming



pesticides process

herbicides process

Farms often use large amounts of herbicides and pesticides, both of which are toxic pollutants. These substances are particularly dangerous to life in rivers, streams and lakes, where toxic substances can build up over a period of time.

Farms also frequently use large amounts of chemical fertilizers that are washed into the waterways and damage the water supply and the life within it. Fertilizers can increase the amounts of nitrates and phosphates in the water, which can lead to the process of eutrophication.

Allowing livestock to graze near water sources often results in organic waste products being washed into the waterways. This sudden introduction of organic material increaces the amount of nitrogen in the water, and can also lead to eutrophication.

Four hundred million tons of soil are carried by the Mississippi River to the Gulf of Mexico each year. A great deal of this siltation is due to runoff from the exposed soil of agricultural fields. Excessive amounts of sediment in waterways can block sunlight, preventing aquatic plants from photosynthesizing, and can suffocate fish by clogging their gills.



Process of absorbing pesticides and herbicides by the ground

Saturday, October 3, 2009

Thermal pollution




Smoke pollution



How thermal pollution occur

Thermal pollution is the degradation of water quality by any process that changes ambient watertemperature. A common cause of thermal pollution is the use of water as a coolant by power plants and industrial manufacturers. When water used as a coolant is returned to the natural environment at a higher temperature, the change in temperature impacts organisms by

(a) decreasing oxygen supply, and

(b) affecting ecosystem composition. Urban runoff--stormwater discharged to surface waters from roads andparking lots--can also be a source of elevated water temperatures.


When a power plant first opens or shuts down for repair or other causes, fish and other organisms adapted to particular temperature range can be killed by the abrupt rise in water temperature known as 'thermal shock'.


Thermal pollution can also be caused by the release of very cold water from the base of reservoirs into warmer rivers. This affects fish (particularly their eggs and larvae), macroinvertebrates and river productivity.


Thermal Pollution -- Thermal pollution can occur when water is used as a coolant near a power or industrial plant and then is returned to the aquatic environment at a higher temperature than it was originally. Thermal pollution can lead to a decrease in the dissolved oxygen level in the water while also increasing the biological demand of aquatic organisms for oxygen.


Industrial Effluents

Waste water from manufacturing or chemical processes in industries contributes to water pollution. Industrial waste water usually contains specific and readily identifiable chemical compounds. During the last fifty years, the number of industries in India has grown rapidly. But water pollution is concentrated within a few subsectors, mainly in the form of toxic wastes and organic pollutants. Out of this a large portion can be traced to the processing of industrial chemicals and to the food products industry. In fact, a number of large- and medium-sized industries in the region covered by the Ganga Action Plan do not have adequate effluent treatment facilities. Most of these defaulting industries are sugar mills, distilleries, leather processing industries, and thermal power stations. Most major industries have treatment facilities for industrial effluents. But this is not the case with small-scale industries, which cannot afford enormous investments in pollution control equipment as their profit margin is very slender.

Industrial seewage