Cholera is a disease of the human digestive system and it is passed from person to person through the drinking if infected water or eating food infected with the cholera bacteria. Cholera is caused by the bacterium Vibrio Cholerae which is a comma shaped gram negative bacteria.
Cholera is usually contracted when the feces of an infected person or persons comes into contact with food or a water supply but cholera has been know to exist in non feces infected brackish water. However cholera has also been know to be contracted by eating raw shellfish which can be infected with cholera. Some coastal areas including the Gulf of Mexico, the west African Coast, The east African Coastline, parts of the Brazilian coastline and parts of the South China Sea coastlines are renowned for having cholera infected shellfish. It is suspected that the pumping of raw sewage into the sea is responsible for this phenomenon.
Cholera is very common in areas which have poor treatment of sewage and drinking water. Many cases of cholera infection are very mild but other instances may be very severe. The disease is caused when the bacteria produce cholera toxin which inserts itself into the cell walls of the cells which line the small intestine. It acts as a very efficient chemical water pump which draws vast amounts of water into the lumen of the small intestine.
The bacterial infection which causes cholera is not very dangerous in itself on condition that the symptoms of the disease are well managed. It is the symptoms which present the danger. Persons infected with cholera have been know to be seriously dehydrated within one hour from the onset of diarrhoea, can go into shock within three hours and can die from severe dehydration in the space of twelve hour if they do not receive proper medical attention.
If properly managed the body can wash the disease out in the space of a few days. the main problem with cholera is re infection. If there is no clean water or uncontaminated food to be had the cycle continues. The main impact of cholera is on the elderly, the very young and people who may already be weakened by malnutrition or another disease. The main treatment which is now used to combat this disease is oral re hydration therapy. Re hydration should be started as soon as possible. In very severe cases a drip may be needed in addition to oral re hydration therapy. Medical staff who are used to treating this disease and in using this technique have saved many millions of lives especially in the developing world.
E. Coli or escherichia coli are gram negative, rod shaped, motile or non motile, non spore producing facultative anaerobic bacteria which live in the lower intestine of all warm blooded animals. E. Coli species that are capable of propulsion do so by means of a ‘flagella’ which is a whip like tail.
Most types of e. coli are absolutely harmless and are part of the normal and necessary flora of warm blooded species. In fact they are very necessary because they produce vitamin K as a bi product of their metabolic activity and by existing in great numbers help by preventing other pathogenic bacteria from colonizing the gut.
Some species of e.coli are pathogenic which means that they can cause desease. The strains that are pathogenic are 0157:H7 and 0111:B4. This particularly virulent capacity was transferred to these e.coli bacteria from shigella bacteria which passed shiga toxin to e.coli by means of bacteriofages which are a type of viral species. Both these strains of e.coli have the capability of transferring their virulent qualities to other bacteria around them by means of their sex pilus which is a needle like protrusion from the side of their body wall by which they insert the DNA codes necessary for the production of virulent qualities into bacteria next to them. One such virulent quality is the ability to resist certain anti biotics.
The very virulent strains of coli such as 0157:H7 and 0111:B4 are capable of causing serious intestinal illness particularly in the very young, old and the immunologically compromised. However it must be stressed that the majority of common e.coli outbreaks are mild and cause only diarrhea and mild temperature increase. More serious virulent cases can cause complications such as hemolytic-uremic syndrome.
E. coli toxins can be heat tolerant or heat labile. This quality makes the boiling of water to kill e. coli unsure and in such a case water should be boiled in a pressure cooker, if available, for at least twenty minutes. Another alternative would be to only drink safe bottled water if possible. E. coli bacteria which escape from the intestine into the abdominal cavity through means of a perforated ulcer, intestinal lesion or a ruptured appendix will cause peritonitis and be life threatening if not treated promptly with antibiotics such as streptomycin and gentamycin to which e.coli are very sensitive. E. Coli which are associated with the intestinal mucosa lawyer can be found in greater numbers in conditions such as Crohns disease, iritable bowel disorder and ulcerative colitis.
E.coli is contracted through contact with contaminated food or water sources in which the content of the gut as come into direct or ‘indirect’ contact with food or water. Severe cases of e. Coli infection can resemble cholera.
New strains of E.coli are continually being produced by the process of mutation. Some strains may develop traits that are harmful to the host animal. E.coli prefers to reproduce at the temperature of 37 degrees Celsius but some strains have shown the capacity to reproduce at temperatures of up to 49 degrees Celsius.
E. coli has been found in agricultural produce such as spinach. In 2006 there was a famous outbreak of contaminated spinachin the US due to the fact that bovine feces polluted a spinach field which was at the bottom of the hill on which a herd of cattle were kept. In this case all the spinach was recalled and destroyed.
E. coli contamination can be prevented for the most part by maintaining a correct food hygiene policy in the kitchen and by using reputable food suppliers.