KEGS Biology Blog

Thursday 13th December Section 3
December 13, 2012, 7:12 pm
Filed under: Uncategorized

Pathogens, health, disease and HIV


3 Comments so far
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Health: A state of physical, mental and social well-being, which includes the absence of disease and infirmity.

Disease: A condition that impairs the normal functioning of an organism.

Disease is caused by one of two different types of agents: Pathogens or Parasites

Pathogen: Not simply an infective agentm it is something that is deleterious to the organism.

Parasite: An organism that lives ON OR IN (not off) another organism.


-Non living things
-Made of RNA
-Cannot reproduce on their own, have to ‘hijack’ a cells machinery



Human Imuno defficiency Virus

-This virus affects white blood cells due to the presence of CD4 within their cells

Symptoms of HIV
-Possible weight loss
-Possible cough/cold for +3 weeks
-Sometimes a rash

HIV is a retro virus
1) Inserts its own genetic material into the DNA of the WBC
2)As the WBC replicates it also replicates the virus’s genetic material
3)After the virus has reproduced the cell lyses (bursts) leaving the new virus particles free to infect other cells

4 ways to aquire HIV
-unprotected sexual intercourse
-infected blood products
-infected bodily fluids
-Mother to foetus (horizontal transmition)

Demographic most at Risk: Gay Male Africans


Aquired Immune Defficiency Syndrome

Syndrome: A variety of diseases that together indicate the presence of an additional disease


Process called Seroconvertion

Can be cured (reverted from AIDS to HIV by curing the infection)

When an opportunistic infection associated with HIV is contracted
-Karposi’s sarcoma
-Polycystic Pneumonia
-Candidiasis: Yeast infection (NOT THE BREAD TYPE)

Comment by bensubhani

Also, vaccines are used so the immune system can identify viruses and produce the relevant anti bodies.

These can prevent the viruses from inserting their RNA into cells however if this has already happened the immune system can no longer stop the viruses as it would involve damaging indigenous cells.

Comment by bensubhani

Government intervention on preventing spread of HIV:
– Needle exchange programme, whereby infected needles are swapped for clean ones to prevent HIV spreading through blood.
– Free contraception to prevent spread through bodily fluids.
– Sex education to prevent underage sex and to raise awareness of STI’s including HIV.
– Blood screening programmes before blood transfusions.

Comment by candicetam

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