B5 Communicable Diseases Flashcards
Pathogen Def-4 types
Microorganism that causes disease : viruses, Bacteria, Fungi, Protists
Ways of transmition
Direct contact, Water, Air, Unhygienic food preparation, vectors
Direct Contact
This can be sexual contact during intercourse or non-sexual contact, like shaking hands.
How can water spread disease
Dirty water can transmit many diseases, such as the cholera bacterium.
Spreading disease through Air
Coughing and sneezing spread pathogen particles to others
what does Unhygienic food preparation cause
Undercooked or reheated food can cause bacterial diseases like Escherichia coli which is a cause of food poisoning.
Vector
Any organism that can spread a disease is called a vector.
Viruses GK
Not alive, ‘strains’ not species due to short DNA length surronded by protein coat. Not affected by antibiotics
Viruses Life Cycle
- find suitable host
- inject host with DNA
- replicate DNA and protein coats inside
- burst cell to infect more
Tobacco mosaic virus
infects tobacco and close species. Trasmitted by contact between plants. Infects chloroplasts, changes colour and reduces its ability to photosynthesis
HIV/AIDS
HIV, Spread through body fluids, mild fever. AIDS months - years after infection of HIV. Attacks patient’s immune system
Bacterial diseases GK
Not all bad. Do not have a nucleus. much larger than viruses. Treated using antibiotics
Gonorrhoea
STD. burning pain when urinating. Thick yellow/green discharge from infected penis/vagina.
Salmonella
Causes food poisoning, found in undercooked food. all poultry in UK vaccinated against it to reduce vectors
Protist Diseases GK
Mix of plant animal and fungi. eukaroyotic
Malaria
Spread by vector (mosquitos). gives fever sweats and chills
Fungal diseases GK
not all bad, Not all single celled, eukaroyotic. Can be treated using antifungal medication and fungicides
Athlete’s foot
rash caused by fungus. Red dry or white wet skin. Spread in communal areas.
Rose black spot
Infects roses, black purple spots on leaves, stop photosynthesis, spreads through air and water
How to prevent the spread (6)
Sterilising water-Cholera-Chemicals or UV light kill pathogens in unclean water.
Suitable food hygiene - Salmonella- Cooking foods thoroughly and preparing them in hygienic conditions kills pathogens.
Suitable personal hygiene - Athlete’s foot - Washing surfaces with disinfectants kills pathogens. Treating existing cases of infection kills pathogens.
Vaccination - Measles - Vaccinations introduce a small or weakened version of a pathogen into your body, and the immune system learns how to defend itself.
Contraception - HIV/AIDs - Using barrier contraception, like condoms, stops the transfer of bodily fluids and sexually transmitted diseases.
Phagocytes
surround pathogens and engulf them by binding to them. Membrane surrounds them and breaks down from the inside. They are non-specific as they destroy all pathogens
Lymphocytes
Recognise proteins on surface of pathogen called antigens. They produce antibodies from them which takes time. These antibodies stick to pathogen and makes it easy for phagocytes to engulf them. They can also produce antitoxins.
Skin
Physical barrier. Produce antimicrobial secretions. Microorganisms living on skin prevent growth of pathogens
nose
cilia and mucus trap particles in the air, preventing them from entering the lungs. Trachea and bronchi produce mucus which is moved from the lungs to the back of the throat
stomach
produces strong acid (hydrochloric pH 2) that destroys pathogens
