1. Infectious Diseases Chapter 20, section 2

2. Disease is a major focus of environmental health Two categories: transmissable (or infectious) disease – can spread from one person to another; ex. malaria, flu, TB nontransmissable disease – cannot be transmitted from one person to another; ex. cancer, heart disease, respiratory disorders Despite our technology, disease kills most of us Disease has a genetic and environmental basis – Poverty and poor hygiene can foster illnesses Q1. What is the difference between a transmissible and nontransmissable disease? Q2. Give two examples of each. Q3. What are the top three leading causes of death worldwide, according to the pie graph at right?

3. Infectious diseases kill millions Infectious diseases kill 15 million people per year – Half of all deaths in developing countries – Developed countries have better hygiene, access to medicine, and money Vector = an organism that transfers pathogens to a host (Ex: mosquito, snail, fly) Pathogen – something that causes disease (bacteria, fungus, virus) Q4. Refer to the figure above. What are the six deadliest infectious diseases for people in order of the number of deaths they cause each year? Q5. Define and give an example of a pathogen. Q6. Define and give an example of a vector.

4. Viruses HIV (AIDS) Hepatitis B Smallpox Ebola On this scale, a human hair would be 6 meters (20 feet) wide 1 micrometer Bacteria Vibrio cholerae (cholera) Myobacterium tuberculosis (tuberculosis) Treponema pallidum (syphilis) 6 micrometers Protozoa Plasmodium (malaria) 10 micrometers Q7. List four pathogens that are viruses. Q8. List three pathogens that are bacteria. Pathogens that cause disease:

5. Ways infectious diseases spread Pathogens can infect people through different routes: Through the air Through contaminated water Through contaminated food By a vector Through the skin From mother to fetus/newborn By contact with an infected person’s bodily fluids Q9. List a disease caused by each of the above transmission routes. You may use your disease flashcards.

6. How do the cause of deaths for rich and poor countries compare? Lung cancer

7. Q10. List the top three causes of death for high income countries. Are any of these infectious diseases? If so, which ones? Q11. List the top three causes of death for low income countries. Are any of these infectious diseases? If so, which ones?

8. What factors have reduced infectious disease in high income countries? Vaccinations Better sanitation – clean water Antibiotics and other medicines Q12. Can you list four infectious diseases that YOU have been vaccinated against? Q13. What type of pathogen is affected by antibiotics?

9. Anopheles mosquito (vector) in aquatic breeding area 1. Female mosquito bites infected human, ingesting blood that contains Plasmodium gametocytes 4. Parasite invades blood cells, causing malaria and making infected person a new reservoir 3. Mosquito injects Plasmodium sporozoites into human host 2. Plasmodium develops in mosquito eggs larva pupa adult “Malaria is a mosquito-borne disease caused by a parasite. People with malaria often experience fever, chills, and flu- like illness. Left untreated, they may develop severe complications and die. In 2010 an estimated 219 million cases of malaria occurred worldwide and 660,000 people died, most (91%) in the African Region.” (CDC website) Q14. What vector carries malaria? Q15. What organism infects the blood and actually causes malaria Q16. What are the symptoms of malaria?

10. How to reduce malaria – Eliminate breeding grounds for mosquitos (reduce standing water) Kill mosquitos with insecticides Avoid getting bitten – use insect repellent and mosquito nets for sleeping Take anti-malarial drugs if traveling to areas affected by malaria Q17. How could an individual protect themselves from getting malaria? Q18. How could a community reduce the number of cases of malaria?

11. Many diseases are increasing Tuberculosis, acquired immunodeficiency syndrome (AIDS), and the West Nile virus have increased in recent years Our mobility spreads diseases – the more globalization occurs, the more people travel and contact other people Q19. List three infectious diseases that are increasing worldwide. Q20. When did the highest number of cases of West Nile virus occur in the U.S.? What part of the U.S. had the disease first? Q21. How does globalization affect the spread of disease?

12. Some diseases cross from animals to humans Avian flu – people in Asia who work with live birds (ducks, geese) can get the virus Swine flu – also called H1N1 Q22. Name two animals from which people can contract a type of flu virus.

13. Current issues with infectious diseases Drug-resistant strains of bacteria have developed in response to the increased use of antibiotics Q23. Using the diagram above, explain how the final population became more resistant after the use of an antibiotic. Q24. MRSA, a drug-resistant form of staph bacteria, was ___% resistant to antibiotics by 2001. Original pop treated with antibiotic:

14. Current issues with infectious diseases Climate change will expand the range of diseases Q25. How could warmer global temperatures affect the spread of diseases such as dengue fever and malaria, which are spread by mosquitos?

15. Solutions Infectious Diseases Increase research on tropical diseases and vaccines Reduce poverty Decrease malnutrition Improve drinking water quality Reduce unnecessary use of antibiotics Educate people to take all of an antibiotic prescription Reduce antibiotic use to promote livestock growth Careful hand washing by all medical personnel Immunize children against major viral diseases Oral rehydration for diarrhea victims Global campain to reduce HIV/AIDS Q27. One textbook says that this is the best weapon to fight the spread of viruses. Write down the solution that the arrow indicates. Q26. List five ways to prevent or reduce the incidence of infectious diseases throughout the world.

16. Bioterrorism From the CDC website: “A bioterrorism attack is the deliberate release of viruses, bacteria, or other germs (agents) used to cause illness or death in people, animals, or plants. These agents are typically found in nature, but it is possible that they could be changed to increase their ability to cause disease, make them resistant to current medicines, or to increase their ability to be spread into the environment. Biological agents can be spread through the air, through water, or in food. Terrorists may use biological agents because they can be extremely difficult to detect and do not cause illness for several hours to several days. Some bioterrorism agents, like the smallpox virus, can be spread from person to person and some, like anthrax, can not. ”

17. Bioterrorism using pathogens Q28. What are six agents that could be used by bioterrorists? Q29. What are two ways to reduce threats from bioterrorists? CategoryABC Definition Pose the highest risk to national security because they Can be easily disseminated or transmitted from person to person Result in high mortality rates Have potential to cause public panic and social disruption Require special preparedness actions Pose the second highest risk because they Are moderately easy to disseminate Result in low mortality rates Require enhancement of diagnostic and surveillance capability Emerging pathogens that could be engineered for mass dissemination because they: Are available Are easily produced and disseminated Have potential for high mortality rates Examples Anthrax Botulism Plague Smallpox Tularemia Viral hemorrhagic fevers (e.g. Ebola, Marburg)Ebola West Nile Virus Caliciviruses Hepatitis A Ricin toxin Salmonella Diarrheagenic E. coli Influenza SARS Rabies Multi-drug resistant tuberculosis Multi-drug resistant tuberculosis Yellow fever Tickborne hemorrhagic fever