Causes and spread of infection
Micro-organisms that cause infections are known as pathogens. They may be classified as follows: Bacteria: minute organisms about one-thousandth to five-thousandths of a millimetre in diameter. They are susceptible to a greater or lesser extent to antibiotics. Viruses: much smaller than bacteria and although they may survive outside the body for a time they can only grow inside cells of the body. Viruses are not susceptible to antibiotics, but there are a few anti-viral drugs available which are active against a limited number of viruses. Pathogenic Fungi: can be either moulds or yeasts. For example, a mould, which causes infections in humans, is Trichophtyon rubrum, which is one cause of ringworm, and which can also infect nails. A common yeast infection is thrush caused by Candida albicans. Protozoa: are microscopic organisms, but larger than bacteria. Free-living and nonpathogenic protozoa include amoebae and paramecium. Examples of medical importance include: Giardia lamblia, which causes enteritis (symptoms of diarrhoea). Worms: are not always microscopic in size but pathogenic worms do cause infection and some can spread from person to person. Examples include: threadworm and tapeworm. Prions: are infectious protein particles. Example: the prion causing New Variant Creutzfeldt-Jacob Disease. Illnesses/infections caused by :
* bacteria: Salmonellosis, tuberculosis, MRSA, coccidiosis, food poisoning, dysentery, bronchitis, ear infections, strep throat/tonsilitis, pneumonia, gonorrhea, syphilis, chlamydia— * Viruses: Influenza, common cold, stomach flu, pneumonia, ear infections, HIV/AIDS, herpes, warts, dengue, West Nile Virus, encephalitis * Fungi: Valley fever, athlete's foot, ringworm, yeast infection * Parasites: Worms, schistosomiasis, malaria, sleeping sickness (trypanosomiasis), leishmaniasis. Infection, in general terms, is the illness caused by the growth of a germ on or in a person. Sometimes the...
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