Human Health and Disease
What is health?
‘The state of complete physical, mental and social well-being’
To sustain a healthy lifestyle person needs:
•A balanced and varied diet
Good hygiene will reduce the likelihood of infection
What is disease?
Disease is a disorder or malfunction of the mind
or body, which leads to a departure from good health.
Can be a disorder of a specific tissue or organ due to a
single cause. E.g. malaria.
May have many causes.
Often referred to as multifactorial. E.g. heart disease.
Disease diagnosed by a doctor analysing
the symptoms (physical and mental signs).
Sudden and rapid onset
Symptoms disappear quickly
Symptoms lasting months or years
Categories of diseases
Results from permanent or temporary damage
to the body
Organisms that cause disease inside the human body are
Bacteria and Viruses are the best known pathogens.
Fungi, protists and parasites can also cause disease
Diseases are said to be infectious or communicable if
pathogens can be passed from one person to another.
Influenza is a virus which causes a severe form of respiratory tract infection with generalised bodily symptoms. It spreads around the world in epidemics and is responsible for much ill health as well as many deaths.
If you start to develop cold symptoms but starting more rapidly and rather more violently, with higher fever and severe aches and pains, often in the back and muscles, then you may well be developing influenza. This may be associated with severe headache, cough, and, as a result of the fever, intermittent sweating and shivering. Sometimes there is a gastrointestinal element, with vomiting and/or diarrhoea. Many people think they have had "flu" when all that they have suffered is a bad cold. When you have influenza you will know the difference. Most people will find it impossible to leave their bed and feel terrible. The worst symptoms usually last for three to five days, and then should begin to improve. It is common to need two to three weeks off work as there is considerable debility left after the feverish illness is over. Do not be surprised to be quite depressed, this is a natural after-effect of the condition. Influenza makes everyone feel terrible, but most people recover. It does however have a small, but significant mortality, especially in the very young, the very old, and those with poor immunity.
Influenza is caused by a virus which attacks our body cells resulting in various manifestations depending on the strain of the virus.
New mutations of the virus arise all the time and unfortunately immunity against one strain (which is conferred by exposure or immunisation) does not protect against other strains. In the era of rapid air transport the world wide spread of a new type of influenza can be extremely fast.
Water or food borne
Salmonellosis is an infection with a bacteria called Salmonella. Most persons infected with Salmonella develop diarrhea, fever, and abdominal cramps 12 to 72 hours after infection. The illness usually lasts 4 to 7 days, and most persons recover without treatment. However, in some persons the diarrhea may be so severe that the patient needs to be hospitalized. In these patients, the Salmonella infection may spread from the intestines to the blood stream, and then to other body sites and can cause death unless the person is treated promptly with antibiotics. The elderly, infants,...
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