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Chapter 17 New Infectious threats A. Definitions infection, pathogen, epidemic, pandemic

Chapter 17 New Infectious threats A. Definitions infection, pathogen, epidemic, pandemic B. Diseases Factors affecting how diseases spread: Host susceptibility/pathogen virulence Herd Immunity Weather Route of transmission Direct contact, Food, Water, others… C. Specific problems

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Chapter 17 New Infectious threats A. Definitions infection, pathogen, epidemic, pandemic

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  1. Chapter 17 • New Infectious threats • A. Definitions • infection, pathogen, epidemic, pandemic • B. Diseases • Factors affecting how diseases spread: • Host susceptibility/pathogen virulence • Herd Immunity • Weather • Route of transmission • Direct contact, Food, Water, others… • C. Specific problems • Bioterrorism • Anthrax, Small pox, ? • STD’s • bacterial, viral • Antibiotic resistance

  2. Niche role, position and function in the community Community organisms living with and interacting with each other

  3. Niche normal bacteria living with (in) us • prevent cavities • help digestive system • prevent “bad guys” • from growing

  4. 0 New Infectious Threats Infection: organism finds a place to grow within another species, causing it harm

  5. 0 New Infectious Threats Pathogen: organism infects and causes a disease (parasite)

  6. Measles Chicken pox Disease is there, but at a low,constant rate Endemic

  7. SARS Disease is becoming more frequent and spreading Epidemic

  8. AIDS Disease is becoming more frequent and spreading worldwide Pandemic

  9. bacteria bacteria 0 Name some pathogens: HIV (AIDS; 16) TB (tuberculosis; 17) Plasmodium (malaria; 7) E. coli (food poisoning) Candida (yeast infection) Worms (tapeworms, etc.) virus protist fungus animal

  10. fig. 17-1

  11. 0 Pathogens - characteristics enter host species specific adhere and replicate binding molecules escape immune system change proteins (antigenic drift) exit the host transmission methods

  12. 0 Pathogens - how they spread Host / pathogen Herd immunity Weather Routes of transmission

  13. 0 Pathogens - how they spread Host / pathogen Susceptible host Virulent pathogen (can cause disease)

  14. 0 Pathogens - how they spread Herd immunity Proportion of non-susceptible people in a population Increase herd immunity via vaccination programs Polio and measles

  15. Pathogens - how they spread Weather Flooding Draught Climate change

  16. 0 Pathogens - how they spread Routes of transmission Physical contact Vectors Food / water Used needles

  17. 0 Size of the epidemic (pandemic) Increase in population size Increase in travel int. departures 1950 - 5,000,000 2000 - 200,000,000

  18. 0 Bioterrorism Intentional transmission of disease 13th century Europe Bubonic plague October 2001 Anthrax in mail 23 deaths, $$$$

  19. 0 Kill bacteria drying freezing heating fig. 17-2 (endo)spores resist killing

  20. 3/10 die Smallpox India and China 1000 BC Europe 700 AD Central America 1520 Aztec Indians

  21. Smallpox

  22. Smallpox People who lived through infections were protected from future infections Expose people to dried crusts most were protected, some died Dairy workers exposed to cowpox were protected

  23. Smallpox Edward Jenner (MD) exposed an boy (James Phipps, 8 years old) to cowpox Later he was exposed to smallpox He did not get smallpox vacca(L. cow) vaccination,vaccine

  24. Smallpox Vaccine developed to give life-long immunity Spread by close contact No other host Eradication - proposed in 1958 began in 1967

  25. Last case Ali Maalin Somolia 1977 Smallpox eradicated (gone since 1979) (WHO declared world free of smallpox) Cultures kept in US, Russia • Vaccinations discontinued- • losing herd immunity Should we vaccinate people for it?

  26. 0 STD’s sexually transmitted diseases Transferred via body fluids Viral Bacterial Protists AIDS, genital herpes, HPV syphylis, gonorrhea, Chlamydia trichomoniasis

  27. Figure 17.3

  28. 0 Prognosis (forecast) AIDS Syphilis (untreated) death Sterility, paralysis, chronic pain, severe disease in newborns, arthritis… Others:

  29. 0 Chlamydia 3,000,000 cases/year (US) 1984 3.2/100,000 1997 207/100,000 Most carriers are asymptomatic PID pelvic inflammatory disease

  30. Figure 17.4

  31. 0 Gonorrhea • 62,000,000 cases/year (world) • If untreated (asymptomatic): • Scar tissue (infertility) • Spread to brain, heart • Passed to baby (blindness)

  32. 0 Syphilis 12,000,000 cases/year (world) Often mis-diagnosed Passed to newborn

  33. 0 Viral STD’s HPV Genital warts Also causes cervical cancer

  34. 0 Viral STD’s HPV Genital warts Herpes HSV herpes simplex virus cold sores type 1 type 2 genital herpes 20% of US adolescents/adults

  35. 0 Viral STD’s HPV Genital warts Herpes HSV herpes simplex virus cold sores type 1 type 2 genital herpes More susceptible to HIV infection

  36. 0 CDC “Genital herpes is a sexually transmitted disease (STD) caused by the herpes simplex viruses type 1 (HSV-1) and type 2 (HSV-2). Most genital herpes is caused by HSV-2” “Nationwide [USA], at least 45 million people ages 12 and older, or oneoutoffive adolescents and adults, have had genital HSV infection.”

  37. HSV-1 and HSV-2 can be found in and released from the sores that the viruses cause, but they also are released between outbreaks from skin that does not appear to be broken or to have a sore. Generally, a person can only get HSV-2 infection during sexual contact with someone who has a genital HSV-2 infection. Transmission can occur from an infected partner who does not have a visible sore and may not know that he or she is infected.

  38. HSV-1 can cause genital herpes, but it more commonly causes infections of the mouth and lips, so-called “fever blisters.” HSV-1 infection of the genitals can be caused by oral-genital or genital-genital contact with a person who has HSV-1 infection. Genital HSV-1 outbreaks recur less regularly than genital HSV-2 outbreaks.

  39. 0 Viral STD’s HPV HSV Genital warts Herpes AIDS HIV

  40. 0 Good news/Bad news “Abstinence or lifelong monogamy with an uninfected partner will prevent STD’s” BT3, pg. 625

  41. 0 Chlamydia Gonorrhea Syphilis All caused by bacteria All treatable with antibiotics There aren’t any drugs to eradicate viral STD’s

  42. Chapter 17 • New Infectious threats • A. Definitions • infection, pathogen, epidemic, pandemic • B. Diseases • Factors affecting how diseases spread: • Host susceptibility/pathogen virulence • Herd Immunity • Weather • Route of transmission • Direct contact, Food, Water, others… • C. Specific problems • Bioterrorism • Anthrax, Small pox, ? • STD’s • bacterial, viral • Antibiotic resistance

  43. 0 protozoan STD Trichomonasvaginalis Only one antibiotic works Drug has bad side effects

  44. 0 Use of antibiotics • Kill or stop growth of bacteria • Put selective pressure • on populations • (natural selection)

  45. Figure 17.6

  46. Figure 17.5

  47. 0 Diseases can be transmitted via: Sexual contact (body fluids) Aerosol (coughing)

  48. Tuberculosis (TB) 0 • Mycobacterium tuberculosis • Resurgence in 1980’s and 1990’s • Infection in lungs, coughing will put bacteria into the air

  49. Tuberculosis (TB) 0 • In Nigeria: • 300,000 cases/year • 30,000 deaths/year • Leading killer of people with HIV/AIDS • Fairly economical to treat ($10)

  50. 0 Diseases can be transmitted via: Sexual contact (body fluids) Aerosol (coughing) Foods Food preparation/storage Weak immunity - at risk

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