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Year 9 - Risky Earth - Human Risks

Not all hazards are created by nature.  There are many hazards which are manmade, and many risks owe their origins to Human beings.  Civil war is one hazard, as are chemical weapons and crime.  HIV/AIDS is a human hazard and is the most devastating disease humankind has ever faced. Since its discovery in the 1980s 65 million people have been infected with HIV and AIDS has killed more than 25 million people.

AIDs cartoon
HIV stands for Human Immunodeficiency Virus, and is the virus that causes AIDS. HIV destroys certain blood cells that are crucial to the normal function of the immune system, which defends the body against illness.
AIDS stands for Acquired Immunodeficiency Syndrome. It occurs when the immune system is weakened by HIV to the point where a person develops any number of diseases or cancers
The patterns of infection and mortality (deaths) from HIV have a very clear GEOGRAPHIC PATTERN.  The map below reveals this pattern.
Map of Global AIDS prevalence

Map of AIDs prevalence

Southern and Sub Saharan Africa have by far the greatest rates of prevalence (the % of the population living with the disease). Other poor countries and regions have similarly high rates, such as India, Thailand and Laos.  Wealthier nations tend to have lower prevalence rates.  This is due to many factors, including cultural factors which might limit protection, a lack of available protection, low education levels about the disease and an inability to afford the drugs which can slow the progression of HIV.  The impact on these countries is devastating, the life expectancy is falling and many children are born with the disease, and are destined to become AIDS orphans.

HIV Detection

HIV infection is most commonly detected through the test of a sample of blood or oral fluid. If the blood or oral fluid sample contains HIV antibodies – proteins the body produces to fight off the infection – the person is HIV-positive. All rapid tests provide results in less than 30 minutes; however, positive results require confirmatory tests.

How HIV is spread

HIV does not survive well outside the body. Therefore, it cannot be transmitted through casual, everyday contact. Mosquitoes and other insects do not transmit HIV. HIV can be spread through certain sexual behaviours with an infected person, by sharing needles, syringes and/or other injecting equipment and, less commonly (and now very rarely in countries where blood is screened for HIV antibodies), through transfusions of infected blood or blood clotting factors. Babies born to HIV-infected women may become infected before or during birth or through breast-feeding after birth.


Condom use is one of the least expensive, most cost-effective methods for preventing HIV spreading. Consistent, correct use of condoms significantly reduces the risk of spreading of HIV and other STDs. Vaccines to prevent HIV infection or improve the ability of the immune system to defend itself are being tested by researchers. The world pumped $19billion into HIV and AIDs research in 2013, but it is likely that a successful vaccine is still a number of years away.

Mother-to-child transmission (MTCT) of HIV can be reduced through the use of anti-retrovirals by HIV-positive women during pregnancy and delivery, and by their infants following birth.
Educational programs designed to encourage individuals to change their behaviour to reduce their exposure to HIV and risk for infection.


There are 4 different types of treatment available but they all work in much the same way.  ARV stands for antiretroviral and refers to a type of drug that works by stopping/slowing the replication of HIV.  These are mainly available in richer nations.
Combination Therapy is a course of antiretroviral treatment that involves two or more ARVs in combination.

Find out more
Think about the questions below whilst watching the video.

    How has AIDS affected Africa?
    What can be done to help?
    How many Africans have access to the drugs they need to combat AIDS?
    What impact does AIDS have on children?

Visit Gapminder World and complete either this hard task sheet or this easier one.





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