communicable diseases Flashcards
what is a communicable disease?
disease caused by a pathogen which can be passed between animals
what is a pathogen
a disease-causing micro-organism (e.g bacteria)
how do bacteria cause disease?
once inside the body, they divide rapidly by binary fission. they kill cells and produce harmful toxins
how do viruses cause disease?
they invade and reproduce inside living body cells, leading to cell damage
give three ways in which pathogens can spread
- by air : flu, tuberculosis and the common cold and spread by droplet infection
- by water : fungal spores in water spread plant diseases
- by direct contact : common in plant diseases and sexually transmitted infections
give four ways in which the spread of pathogens can be reduced
- hygiene : hand washing, disinfectants, tissues
- reducing contact with infected individuals - quarantine
- removing vectors : use of pesticides and insecticides, remove of habitats
- vaccination
why is it especially important to prevent the spread of viral diseases?
scientists have not yet developed cures for many viral diseases
what is measles?
a serious viral disease that can cause blindness and brain damage. the main symptoms are a fever and red skin rash
how is measles spread?
by air - through the inhalation of droplets from coughs and sneezes
what is HIV/AIDS
HIV is a virus which attacks and damages the immune system until it can no longer function properly. AIDS is the condition resulting from a long-term HIV infection. there is no cure/vaccination for HIV/AIDS.
how is HIV spread?
direct sexual contact and the exchange of bodily fluids e.g blood, breastmilk
how can the spread of HIV/AIDS be prevented?
- use of condoms
- screening of blood for transfusions
- not sharing needles
- bottle-feeding by HIV-positive mothers
- use of antiretroviral drugs to prevent the development of AIDS
what is tobacco mosaic virus?
a plant pathogen which causes leaf discolouration when cells are damaged. affected areas cannot photosynthesise, reducing the crop yield. as there is no treatment, farmers grow TMV-resistant crop strains to avoid infection
how is tobacco mosaic virus spread?
contact between infected and healthy plants. insects may act as vectors which transfer the virus between different plants
what is salmonella
a type of bacteria found in raw meat, poultry and eggs. if they enter the body via food poisoning, they can affect natural gut bacteria.
what are the symptoms of salmonella food poisoning?
- fever
- abdominal cramping
- vomiting
- diarrhoea
- may be fatal in very young or elderly populations due the risk of dehydration
how can the spread of salmonella be limited
- vaccinating animals intended for consumption
- keep raw meat away from cooked meat
- disinfect hands and surfaces after contact with raw meat
- thoroughly cook meat
what is gonorrhoea?
a sexually transmitted bacterial infection caused by unprotected sex with an infected individual. early symptoms include yellow/green discharge from genitals and painful urination, although it may be symptomless. its spread can be controlled through the use of antibiotics ( no longer penicillin as many strains are resistant) and using condoms
what is rose black spot?
a fungal disease which causes purple or black spots to develop on rose leaves. it reduces the area of the leaf which is available for photosynthesis and caused leaves to turn yellow and drop prematurely.
how is the rose black spot fungus spread?
fungal spores are spread by the wind and in water
how can the rose black spot fungus be treated?
- using fungicides
- destroying infected leaves
what is malaria?
malaria is a disease caused by protist pathogens. the disease is carried from host to host by mosquitoes, and the protists enter the human bloodstream when they feed. symptoms include fever and shaking, and it may also be fatal in some cases.
how can the spread of malaria be reduced?
- using insecticides
- using insect nets to avoid bites
- prevent mosquito breeding by removing stagnant water
- antimalarial drugs
how does the skin prevent pathogens from entering the body?
- acts as a physical barrier
- scab formation after skin is cut/ wounded
- antimicrobial secretions which can kill pathogens
- healthy skin flora compete with pathogens and act as an additional barrier
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