Infectious diseases and antibiotics

B1

 Infectious disease are caused by parasitic microogranisms that infect you

Thease disease causing microoranisms are called pathogens 

Invading pathogens may damage cells and also release toxins 

---------------------------------------------------------------------------------------------------------------------------------Different types of pathogen 

Type                                                   Example of disease caused 

fungi athleates foot 

bacteria cholera

viruses flu

protozoa  malaria 

Infectious diseases spread 

Spread by VECTORS 

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Malaria+ caused by a parasite spread by female mosquitoes 

when they bite they can spread disease 

humans and mosquities are both hosts for the malaria parisite 

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Incidence of disease 

The rate in which new cases occur each year-

This can depend on climate and socio-economic factors 

Climate 

Hot/ warm places= vectors may multiply rapidly 

e.g 

malaria mosquitoes need water to breed- high rainfall= increases incidence of maleria

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Socio-economic factors 

Incidence of diseases e.g cholera= high in countries where there is not clean drinking water or proper sewage system 

Antibiotics and antivirals 

Antibiotics = Chemically produced by some fungi and bacteria, to kill or prevent the growth of other bacteria or fungi. 

Used to kill pathogens in our bodies when we have an infectious disease .

Penicilin= First- Accident- 1920s- 1940s- Today 

ANTIBIOTICS DO NOT TREAT VIRUSES as viruses have no metabolic rate and do not grow

Antiviral= Inhibit the replication of viruses inside the host 

e.g Tamiflu and Relenza 

USE ANTIBIOTICS CAREFULLY 

- Finish whole course- even when  feeling better 

If not used carefully- resistant strains of bacteria develop 

e.g MRSA- harmless, lives on our skin BUT if gets into a wound after sugery causes bad infection.

MRSA= resistant to many antibiotics, so difficult to deal with- may be killed by antiseptics.

So cleaning skin before operation prevents infection- Iodine solution= good antiseptic for this.