BIOLOGY

One of the good example of water borne disease is cholera.In the part of Asia this cholera is endemic, especially in India.From th time to time the endemic used to occurs in some other countries.As in 1992 in Peru which was one of the first out break is South America of twentieth century.More the sixteen thousand of people died over all the world wide from the half million case of cholera in 1991.But the improved and advanced treatment has decrease the death rate dramatically but this is still one of the serious disease counted.Before discovering the cholera the death rate due to it was enormous.For e.g. nearly half a million of people were killed in New York in one epidemic in 1832 A.D.

The transmissions, sign and the symptomss of cholera:-
The name of the organism that cause the cholera is comma-shaped motile bacterium which is called Vibrio cholera.The main sources to generate this disease is due to the contaminated water by faeces from sufferer of disease or the carrier.The carrier is the individual who is infected by the Vibrios & does not develop the typical symptom of cholera.Therefore it is found that only one infected person in so develop the disease , rest being the carriers.The faeces containing the Vibrios are considerable threat when carrier are free moving in the society of it is due to drinking the contaminated water or washing utensils or food in it.The direct contaminations of eating food with the faeces result the poor hygiene.

The Vibrio cholera use to multiple in intentine by releasing the one of the powerful toxin which is use to results in the violent inflammation of intestine & the production of watery diarrhoea.Especially they used to multiple in the intestine of the human but even they can survice outside of the body too.Main sign of disease is servere diarrhoea due to irritation of the bowel by toxins from Vibrios.Liquid of faeces is so cloudy & profuse that which is called the Rice water.In a single day up to 15dm3(cube) of fluid can be lost.The other common sign is paining the abdominal and vomitting.The fever use to be absent, but the skin feel deathy cold & often damp.The dehydration is very fast & quick which result the death until the rehydration treatment is done.In fact the faeces are not collected or disposed of hygienically then one patient can infect a wide area of the community up to thousands millions of vibrios are contained in each cubic centimeter of diarrhoea.Therefore the mild case of cholera or a carrier may use to creat the greatest hazard as they move arounds.

Treatment and prevention of cholera
Many people use to die due to the disease cholera due to the loss of water with the minerals salts, which is dehydration.Therefore the main work is to replacement of these thing.When there is epidemic then the immediate therapy is by the oral rehydration, which means the administering the pack of water which contains the sugar and balanced mineral salt.This process of replacement of water must be done from the 1.5 volume to the volume of stool losts.Fluid also can be administered by the drip feed into the veins.

Different types of antibiotics can be used for destroying the vibrios & decreasing diarrhoea such as tetracycline & chloramphenicol.The chloramphenicol is one of the most effective against the tetracycline resistants vibrios.

While devasting the epidemic is London in 1849A.D a physican called the John Snow had demonstrate the cholera is transmitted by the way of water by removing handle of Broad Streed pump which is nowBroadwick Street.This was only one water supply for the poor slum community who were very badly affected by the cholera.Local epidemic was cease.The Authorities were not convinced & in the second epidemic in 1854A.D.Snow had shown the cholera ridden communities were drawing or getting water from the lower Thames.The population drawing the water from upper, purer reach of Thames were a nearly the cholera free.For the proper sewage treatment & water purification the Public Health Act was introduced in 1875A.D.After that in 1893A.D newe cases in the Britain have come in only from the abroads.

All the world wide improvement of the human hygiene together with the proper disposal of the garbages & disposals, increasing the cleanliness in the house toilets to prevent from the cholera.Therefore by 1900AD the life expectancy in Britain was markeldy improved & closely all of the infectious disease were in the decline, not only the cholera.

Cholera comes under one of the 5 epidemic disease that must be notified to WHO(World Health Organization) in the Geneva.Therefore the reporting means to prevent from spreading this disease world wide.The restrictions of travelling in and out where cholera is influence.
Followings are the measurement that help in controlling cholera:-

• Drinking only clean water
• Proper treatment of sanitation & sewage
• Providing the knowledge about the personal hygiene.
• Providing people health education
• Vaccination-:recomending the people where the cholera is endemic.The vaccine of cholera used to contain heat killed bacteria which is only 40 to 80% effective & give protection only for 3 to 6 months.The rapid or fast response is brought by the booster dose & give the protection immediately during the epidemic.For the genetic engineering vaccine the work is in progress.The identifications & the cloning of genes coding for toxin & ot's production in an important steps.One of the promising approaches is developing the line attenuated strains of bacterium which has had one of two toxins gene removed.
• By controlling the files which is one of the vectors for transferring the faecal material to food.
• Proper disposal of the vomits and the faeces from the patient.
  

Those disease which are caused by other living organisms which used dto invade the body & live parasitically called the infectious diseases.Such types of organisms are called pathogenes.Following are the disease which are caused by the pathogens.They are Cholera, malaria, tuberculosis, Aids, paratyphoid, typhoid and salmonella food poisoining.Following are the techinical terms we use while discussing the infectious diseases.

• Aetiology-study of cause of disease
• Epidemiology-study of all factors which contribute to the appearance of particular disease.
• Causative agents-organisms that cause disease
• Vector-organism which carry disease from one person to another or we can say one infected animals to human
• Incubation periods-the time period between the original infections & appearance of sign & symptoms
• Carrier-those persons who is infected by disease but no sign & symptoms are visuallised, they can transfer disease to another person.
• Notifiable disease-the disease that are to be reported by the doctors to the health authority because of it's seriousness
• Endemic-disease which are present in the low level in the given population or regions
• Epidemic-the condition in which the disease sperads rapidly through the large number of people and disappears again at last
• Pandemic-epidemic spreads across the whole continents
• Signs-visible expression of disease & which can be found by check up
• Symptoms-the indications of the disease which can not be found by the examination the patients but can reported only by the patients
• Prevention-security from affected by any kinds of disease for example vaccination, sewage treatment, hygiene
• Treatment-curing the disease useing antibiotics etc
  

Regarding the effectiveness of vaccines there are something controvesy in public with in 1986, 160 millions of doses of the measles vaccine were administered in the UK, with the excellent and very good protection record of the children given vaccination, 5 to 15% of developed fever on the fifth day lasting several days.One vaccinated person of vaccine in one million generate the disorder of central nervous system called encephalitis.Which cause extreme concern in parent when this fact published in Newspaper just when the vaccination campaigns started. The chance of these complications from the measle vaccination is in fact, less than incidence of encephalitis from the unknown origins.Per tussis(whooping cough) vaccines contain the dead bacteria, sometimes has rare neurological adverse reaction resulting in conclusions and brain damage.This occurs once in 1000000 doses & possibility of permanent damage once in 3000000 doses.Both diphtheria & measles vaccines can have local reaction of laryngitis & inflammation.The death from these disease were still occuring among unvaccinated children and parents must weigh up information & take responsibility of deciding whether or not to have theirs children vaccinated.

There are different types of vaccine.There has been lots of debates about relative merits of live and killed vaccine.Live vaccines are much more effective though they were more risky in the past.Other factor like safety, costs, politcs and social acceptance can determines whether there is high or more more uptake of a particular vaccine and whether it's successful.
There are many purpose for using and making vaccines.For example in UK three vaccines have licensed for the typhoid vaccination

The above second was the recently introduced in 1992.It needs leat number of doses and is most preferred.The safety of vaccine is one of the most important issued in the developed countries but for the developing countries the cost of vaccines and the way of delivering of it is most important.

In recent days the development and the productions of the vaccines are using techniques of genetic engineering.Different pathogens could not be cultured outsides their natural hosts.Therefore, the conventional approach to vaccinations could not be used.For e.g. bacterium causing leprosy or mycobacterium leprae and microbe causing human syphills or treponema pallidum have never grown outside of the body(victro).Therefore it's diffucult to generate inactivated vaccines or live attenuated with the help of culturing techniques.In this example the recombinate DNA technology offer alternative approaches, which allows genes antigens for transferring from this organisms to much more useful host like as E-coil, yeasts or mammalian cells, which is used to produce huge quantity of antigenes for vaccine.For e.g. it is easy to identify express and clone the surgace antigen gene of hepatitis.But all the protective antigens are difficult t develop.

The best example of the successful task of the vaccination is the elimination of smallpox.In 1960 lately there were 15 million cases of small pox with in 33 different countries occured annually.In 1956 and by 1977 the last report of smallpox was recorded in Somalia according to the programmes started by the World Health Organization(WHO) in that years.After 1977 the disease was effictively extint.The virus is still kept in secure lab in Russia and USA, although there have been calls for last samples to be destroyed.
Following are the successful factors for the eradication of smallpox:

Surveillance:

Containment:

10 million people in this world are dying due to the infectious disease.Therefore vaccination is one of the greatest success of human medicines to fight the terrible loss of the life in this world.Vaccination is the giving of antigenes from disease causing organisms, either by orally or injection, with the objectives of casuing body's immune system to learn to make antibodies against the disease.The body should then will be able to fast respond enough to infections by that disease to eliminate to eliminate it before developing symptoms.

Inorder to make for the vaccination to be one of successful as strategy this must administered to ever number of people as possible and must because continueously untill the disease is eradicated.In Britain the vaccination is not compulsory because goverenment backed education of public is uptaking high enough.Providing the certain more high level of percentage of population are protected , epidemics can be prevented.Isolated cases quickly be ring vaccinated in essential, whereby contacts and everyone in a given area around an outbreak of the disease can be vaccinated.However, it is essential not to become complacent.Whooping cough began to increase in Britain again because many people stopped having their children vaccinated after scares about the safety of the vaccines.

Another factor which must be taken into account is that disease can spread across to mational policies, a world-wide co-ordinated approach.This is one of the roles of the W.H.O(World Health Organization).

The health i s defined as the total mental,physical and the social well being and do not merly the absence of infirmity or diseases.There are three main features or dimensions to define this definition,that are mental,physical and social.The diseases is defined as the disorder state of organisms or organs or disorders of thebody.Actually it is difficult to define the meaning of disease.For example it is easy to define that a victims of Tuberculosis(TB) that their liver is affected by the alcohol or a tumour on lung,but what to say about broken legs,arms etc?We can say about broken legs is in disordered state.It do not describe arguable term which sometime preferred as disease or as in case of disease or genetic disorders.The better way to define the diseases is better way how disease are classified.
Classification of different diseases:-
The diseases can be classified into six different main groups,They are given below:
1.Disease that are caused by other organisms:
There are different organisms that are causing the diseases.They are viruses, fungi, bacteria, protozoans, round worms.These organisms are called parasite which live inside the human body as the parasite.The commuicable diseases or infectious diseases that are mainly caused by the viruses, bacteria, and fungi, for example cholera is caused by the bacterium and the measles are caused by virus.Diseases that are parasitic diseases for example malaria by protozoan.

2.Self inflicted or human induced diseases:
These are the diseases that are brought by human being themselves either as individually or collectively as the society.This disease are also can be said as social disease.Many disease like heart disease, drug abuse, alcoholism, lung cancer, are generated with modern industrialised socities.Asbestosis, pollution disorders are caused by the human from industries.There are also disease like brain damage, asthma and some cancers generated in human by living near the nuclear power stations.These are also caused by human themselves.

3.Disease due to deficiency:
These are the disease caused by the absense of certains nutirents.This types of disease may caused due to the lack of the proteing in the food as the result generate marasmus and kwashiorkar.The lack of vitamins caused different types of disease like pellagara due to the lack of vitamin B1 scurvy due to lack of vitamins C or rickets due to lack of vitamin D.Due to the lack of minerals also may cause varietu of diseases such as rickets due to the lack of phosphate and calcium, thyroid goitre due to the lack of iodine etc.


4.Disease due to congential and genetic disorders:
Disease are also generate due to the disorders of genetic.For examples Down's syndrome,Huntington's and cystic fibrosis are generated due to the genetic disorders.Our today's advanced medical science has said in past many childrens have died due to such disorders and still are suffering from their infancy to adulthood.Therefore we must provide the people of the society the proper solutions.But in otherhand the genetic screening can increasingly provide the information before birth whereby babies with genetic disorders can be aborted.This types of activities are raising different social and ethical issues which provke controversy in society.

5.Disease due to Aging and degenerative:
This disease are also caused by the degeneration of the tissues.For examples longsightedness is caused by the weakining of eye muscles,disease in circulatory system.Such as arteriosclerosis are caused due to the hardening of dthe arteries.Arthritis are caused due to the aging of the joints.

6.Disease due to the mental illness:
Mental disorder is one of the greatest disease.Some mental disorders examples are depression,schizophrenia and senile dementia.There are few drugs made to control these disease or illness.Dramatically change of these illness was from the twentieth century from life long comfinement in lunatic asylums to care in the community.

The above six categories also can be grouped in the following categories:

• Communicable or infectious disease:

There are different disease that transfer from one organism to another.Such disease are said to be communicable or transmissible, contagious, infectious disease.Many disease in group 1 mention above are transmitted by the way of the air, food or water, liquid, by sexual contact or even by touch.Many disease are transmitted by the intermediate organism called vector, like malaria by the mosquitos, bubonic plague by the rat flea.

• Non infectious or non communicable disease:

The above 2 to 6 groups are said to be non infectious or non transmissible disease.But the group 4 is on of the special case of communicable disease because genetic disorders are transferred from the parents to offspring due to the presense or absence of one or more inherited genes.

So, according to the above discussion of disease it is clear that there are not any rigid boundries between the diesease categories.Different kinds of the disease involve the genetic predisposition and therefore overlap between group four above and other categories like heart disease in group 2 and some other mental disease in group 6.Therefore similar to health,the disease have mental, physical and social dimensions.Some disease are generated with the help of poverty , such as Tuberculosis(TB) and different therefore be described as having an important social dimensions.