Human Diseases

Human Diseases
Human Diseases The disease causing organisms Bacteria, Viruses and Fungi enter the body through natural openings and wounds/breaks in the skin. Natural openings such as the nose, mouth, urethra, anus and vagina are lined with mucous membranes which are moist providing the perfect environment for microbial growth, and consequently micro-organisms then infect other organs. Wounds and breaks in the skin (which can be caused by a multitude of things including scratches and cuts) enable bacteria to enter and can cause wounds to become septic, alternatively fungi or ringworm could enter and cause their own problems (athlete?s foot being one). Deep wounds can allow pathogens to cause more serious problems, as they can infect muscles and joints. Muscles and joints are normally completely sterile and once infected can quickly succumb to disease. Hair follicles can also be an entry point for pathogens; staphylococci can invade here and cause localised infections. Insect bites are another way a person can be infected in some cases they are a minor irritation but in others they can be very serious, for example the mosquito can inject malarial parasites directly into the bloodstream whilst they are feeding on your blood. A bite from a rabid animal can pass on the disease to the victim through the infected animals? saliva.
There are a variety of ways that these things can be spread. Water is very effective when spreading diseases a contaminated water supply can spread things such as cholera, typhoid fever and many others, this is particularly the cases when the water is not cleaned and has come into contact with faeces of an infected individual as it will contain pathogens. A clean and sanitary water supply is vital in the fight against these diseases. Food is another way these diseases can spread. As in the natural openings of a human, food is often warm and moist and if not handled in the correct manner pathogens can reproduce at an incredible speed entering each person who eats the food in question. Some bacteria can cause serious food poisoning and can be fatal, for example botulism and clostridium. These bacteria are particularly virulent in foods that are a by-product of animals i.e. eggs meat & milk. Before food is handled the handler must wash their hands and ensure all surfaces and tools are thoroughly cleaned, once food is prepared it needs to be covered (as flies can be carriers of disease) and refrigerated if necessary. Droplet infection such as sneezing, coughing, breathing and talking is another way disease can be transferred from one person to another. If there are any of the disease causing bacteria in the water droplet it can easily be inhaled and cause respiratory infections. Direct contact is the way some diseases make it from one person to another. Sexually transmitted diseases such as aids and Gonorrhoea are transferred during direct physical contact. Some fungal diseases can also be transferred in this way although they may only need superficial contact, such as using the same towel or flannel as an infected person. Infection by insects is also a good way for diseases to travel from one place to another, they may be carried internally or externally. Houseflies are attracted to faeces and after landing on it can then land on food this can cause various intestinal diseases. Cockroaches are another carrier of intestinal diseases. Mosquitoes and other blood-sucking insects can carry more serious diseases such as malaria. Finally other animals, (mainly vermin) can carry diseases that can be fatal to humans rats brought Bubonic plague to Europe in the middle ages, the great plague of London (1665) and many other outbreaks killing untold numbers. A species called plasmodium is the cause of malaria it has a various strains and is carried by the female Anopheles mosquito. Below is a diagram showing the life cycle of Plasmodium vivax as can be seen it starts when the mosquito feeds on the blood of an infected person. The mosquito doesn?t digest the parasite and the plasmodium actually sexually r4eproduces inside the mosquito. In turn the mosquito passes the disease on (through its saliva) to the humans when it feeds on their blood. Malaria needs a certain temperature to enable it to sexually reproduce inside the mosquito and as a result it is not found north of latitude 60Â? N or south of 30Â? S. The most proficient carrier of Malaria is the Anopheles gambiae which is found in tropical Africa where most adult humans have Malaria in one form or another. In other places the mosquito?s carrying the disease have sorter life-spans and do not feed exclusively on humans the effect of this is a more seasonal outbreaks. In dry season the mosquito?s are not breeding to the extent they are in the wet season, obviously the more mosquito?s the more malaria. Life Cycle of Plasmodium Vivax [image] Eradicating this disease is approached from two angles. Firstly if the mosquito can be killed the disease has no way of reproducing and spreading. There are several ways this can be done but unfortunately none that are 100 % successful. One thing that can be attempted is the draining of all breeding grounds, this is costly and it is not possible to drain every place that mosquito?s could use. Another idea is to cover the grounds with a film of oil this suffocates the larvae, but again it is impossible to cover every pond, ditch etcâ?? also this method is not selective and it kills a lot of other wildlife and is too pollutant. Biological control (fish that eat the larvae and mosquito), can only be partially effective as once again it?s not possible to cover all areas. Finally insecticides can be used but as with the oil it is pollutant and also the disease becomes resistant. The other approach is to kill the parasite directly. No single drug to date has been found that can kill all forms. The drugs that are used prevent the disease from spreading into the general circulation of the victim. The oldest drug to be used is Quinine and whilst it has been effective it is expensive to make and is gradually being replaced by stronger and cheaper synthetic drugs. One of the main problems with drugs is the disease?s ability to build up resistance to them, some have been used as a precaution to prevent the disease, this over use enables the parasite to build up a tolerance more quickly. Vaccinations are being developed but are as yet not widely avaliable. The parasite has so many variations and different stages that it is difficult to produce an effective vaccine. Bovine Spongiform Encephalopathy (bse) The possibility that Creutzfeldt-Jacobs disease might be linked to B.S.E is very serious. The department of health believe there is sufficient evidence that humans cannot contract B.S.E. As a precaution all infected cattle are destroyed and some animal parts are banned from use in products that humans eat. However there are a number of scientists that are not so sure as the dept of health base their conclusions on the assumption that B.S.E. is a form of scrapie. These scientists argue that B.S.E. could be a mutant organism, and given it?s long incubation period there could be animals showing no sign of the disease being slaughtered and then consumed by humans. They also believe that it could be passed on in any form of nervous tissue, implying that it is possible for humans to contract Creutzfeldt-Jacobs disease in this way. 4 Summary chart of some human diseases Disease Rabies Influenza aids Typhoid Salmonellosis Listeriosis Thrush Malaria Organism Virus Myxovirus virus Bacteria bacteria bacteria Fungus Parasites Host/s Mammals Human beings Human beings Human beings Human beings Human Beings Human beings Humans, apes, monkeys, birds, & reptiles How transmitted Bites from infected animals Droplet infection & personal contact Direct contact Water Food Food PH imbalance. Mosquito?s Incubation period average of 40 days 24-48hrs Unknown 12-24 hrs 12-24 hrs 12-24 hrs 10-14 days Symptoms/clinical features Headaches restlessness high fever convulsions, delirium and hydrophobia Sneezing, coughing, fever, muscular aches & pains Depression of immune response. Diarrhoea, 2nd infections septicaemia, fever & rashes. Diarrhoea, pain, vomiting & fever Sneezing, coughing, fever, muscular aches & pains. Fluffy white patches & inflammation. Shivering, fever & sweating Importance Is widespread in Europe. Most important respirator y disease Extreme importance as always fatal & epidemic. Can be fatal, rare in western countries. Rarely fatal. Widespread. Can lead to miscarriage. Easily treated, not fatal Extremely, most important fatal disease in tropics. Treatment Antiserum followed by vaccination Bed rest & pain relief only Drugs- azidothymindine. Antibiotic drugs ? chloramphenicol. Bed rest. Bed rest. Magenta paint, Anti-biotics & live yoghurt. Quinnine, synthetic drugs & vaccination. Prevention Quarantine, education, vaccination Immunisation Education, free condoms counselling & needle exchange. Purification of drinking water, good hygiene & pasteurise milk. Good food hygiene &practice & education in such. Pasteurisation of dairy products Eradicate vector. Insecticides, biological control etcâ?? Control Elimination of infected &wild animals in area Predicting outbreaks & issuing vaccine Education Isolation of patients, carriers not handle food. As above Education, good food practices. Drugs vaccines to eradicate parasite. 5 2. Two diseases caused by organisms that enter via the respiratory tract are; Influenza and listeriosis. Two organisms that are contracted by sexual contact are; hiv and Gonorrhoea. Two diseases where the organism is ingested are; Salmonellosis and Typhoid. 3. Thrush is a Fungus that causes disease, Malaria is a Protozoan that causes disease, Rabies is a virus that causes disease and finally Typhoid is a bacterium that causes disease. 4. (a) the tests I would carry out are; check the remaining food in the canteen for the salmonella bacteria, see how the food is stored/ chilled. Ask questions relating to the freezing/defrosting and treatment of food that had already been cooked once. See if the raw and cooked food has come into contact with each other. (b) I would advice the canteen staff to ensure that they wash their hands thoroughly before handling any food and to ensure they do this between food preparations also. They must ensure that all food is thoroughly cooked and is hot in the middle before serving. Preferably have two refrigerators one for raw and another for cooked food if this is not possible then have separate shelves and make sure they are thoroughly cleaned on a regular basis. It is also important to keep the whole kitchen clean, tidy and hygienic as rodents will be attracted to it and they can transmit the disease.

Human Diseases 8.1 of 10 on the basis of 4022 Review.