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Edexcel GCSE Biology · 1BI0
Edexcel 1BI0 · 5.5 Common Infections Check the specification (PDF) (opens in a new tab)
White blood cells help defend the body against pathogens. Some white blood cells, called lymphocytes, are involved in producing antibodies that help the body fight infection. HIV is a virus that infects certain lymphocytes and uses the cells to make more virus. As HIV destroys these cells, the body has fewer lymphocytes and its defences against other infections become weaker.
A person with HIV may initially have flu-like symptoms. HIV infection and AIDS are not the same thing: HIV is the virus, while AIDS is the condition that can develop later if the immune system becomes severely weakened. Without treatment, the loss of white blood cells can lead to the onset of AIDS, leaving the person vulnerable to serious illnesses that the immune system would normally help control.
Ebola is also a virus, but its characteristic illness is different from that caused by HIV. Early symptoms can include a high temperature, headache and muscle or joint pain. Serious cases may progress to haemorrhagic fever: fever accompanied by bleeding, which may be internal. Bleeding is a possible feature of severe Ebola illness, not a symptom that every infected person must have.
HIV is a virus that infects and destroys certain white blood cells. Fewer lymphocytes weaken the immune response; if the infection is untreated, AIDS can develop. HIV names the virus, not the later condition.
Ebola is a virus that can cause haemorrhagic fever. Early flu-like symptoms may be followed, in serious cases, by fever and bleeding.
Distinguish HIV, the virus, from AIDS, the condition that can develop when the immune system is severely weakened.
For Ebola, link haemorrhagic fever to fever and bleeding; do not imply that every infected person develops bleeding.
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Last updated
Virus
An infectious agent that can reproduce only inside a host cell.
HIV
A virus that infects and destroys certain white blood cells, weakening the immune system.
AIDS
Acquired immune deficiency syndrome: a condition that can develop when HIV has severely weakened the immune system.
Haemorrhagic fever
A serious illness involving fever and bleeding.
Put your knowledge into practice — try past paper questions for Biology
Virus
An infectious agent that can reproduce only inside a host cell.
HIV
A virus that infects and destroys certain white blood cells, weakening the immune system.
AIDS
Acquired immune deficiency syndrome: a condition that can develop when HIV has severely weakened the immune system.
Haemorrhagic fever
A serious illness involving fever and bleeding.