Biological Hazards Notes

1. Biological Hazards Notes

2. The Environment’s Role in Disesase • Infectious diseases are caused by pathogens- organismsthat cause disease • Spread person to person through the air • ie: whooping cough & tuberculosis (TB) • Spread by drinking water that contains the pathogen • Transmitted by a secondary host (ie. Mosquito) • Host- organism in which a pathogen lives all/part of its life

3. Waterborne Disease • ¾ of infectious diseases are transmitted through water • In developing countries water is used for: • Drinking • Washing • Sewage disposal

4. Polluted water is a good breeding ground for pathogens • Pathogens breed in water and transfer diseases directly to humans through water • Vectors – organisms that transmit diseases to people • Dangerous, Dangerous Warning ! • No bathing in tropical ponds…snails are vectors for schistosomiasis, an incurable disease that kills thousands of people

5. Bundaa Joseph, 10, Kampala village, Tanzania I have no school. I would like to go but I am the only child at home so if I go to school there will be no one to help my parents. I have to fetch the water. I use the water here for drinking, bathing and washing my clothes. My parents always get sick with diarrhea - I don't know why - but they have to go to hospital. I'm not happy using this water. Some people use it like a toilet.

6. Cholera (and Dysentary) • Deadliest water borne diseases come from drinking water polluted by human feces • Cause the body to lose water by diarrhea and vomiting • Much deadlier to children because of less water in their bodies

7. Christine Mbabazi lives in Bwaise, a slum in the capital city, Kampala, located at the bottom of a gully that often floods, filling her home with contaminated water and human waste. In 2004 her son Stephen died from cholera caused by the poor conditions

8. Malaria – once the world’s leading cause of death • Caused by parasitic protists and is transmitted by a bite from a female mosquito • No effective vaccine exists but preventative measure are used to control mosquitoes.

11. Environmental Change and Disease • Humans alter the environment in ways that make it more suitable for pathogens to live and produce • Ie. –soil (that is polluted with chemicals & pathogens) erodes which causes pollutants to blow and wash away causing contamination thousands of miles away

12. Antibiotic Resistance • Overuse of antibiotics in both humans and organisms used for food has led to a large resistance to antibiotics • Ie. – to salmonella, Escherichia coli and other bacteria • Large amount of resistance causes thousands to get sick every year

13. Malaria on the March • Global warming may increase the area where malaria occurs • At one time it mainly occurred in Europe and US, before mosquito control • Paddies and marshes were drained and sprayed with pesticides • Mosquitoes have since developed a resistance to most pesticides • Newer methods for control include spreading growth regulators to prevent the larva from forming the adult

16. Emerging Viruses – (define) previously unknown viruses (less than 100 years old) • Examples: • AIDS – caused by HIV • Hanta virus – a type of hemorrhagic fever • Ebola Virus – a type of hemorrhagic fever • West Nile Virus – many times found in mosquitoes