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

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

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

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

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

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

Epidemic Disease is becoming more frequent and spreading SARS

Pandemic Disease is becoming more frequent and spreading worldwide AIDS

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

fig. 17-1

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

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

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

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

Pathogens - how they spread Weather Flooding Draught Climate change

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

Size of the epidemic (pandemic) Increase in population size Increase in travel ,000, ,000,000 int. departures

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

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

Smallpox India and China1000 BC Europe700 AD Central America1520 Aztec Indians 3/10 die

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

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

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

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

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

Figure 17.3

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

Chlamydia 3,000,000 cases/year (US) /100, /100,000 Most carriers are asymptomatic PID pelvic inflammatory disease

Figure 17.4

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

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

Viral STD’s Genital warts HPV Also causes cervical cancer

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

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

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 one out of five adolescents and adults, have had genital HSV infection.”

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.

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.

Viral STD’s Genital warts Herpes AIDS HPV HSV HIV

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

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

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

protozoan STD Trichomonas vaginalis Only one antibiotic works Drug has bad side effects

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

Figure 17.6

Figure 17.5

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

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

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

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

table 17-2

Figure 17.7

Diseases can be transmitted via: Sexual contact (body fluids) Aerosol (coughing) Foods Water Cholera Giardiasis Legionaires…

Cholera 5 pandemics, before identified Spread by “bad water” Described by Koch (1886) Specific to humans Cause diarrhea dehydration death (25%) clean water >1%

Figure 17.8 Giardiasis

Diseases can be transmitted via: Sexual contact (body fluids) Aerosol (coughing) Foods Water Vectors Carry from host to host Malaria, Leishmaniasis West Nile virus

Figure 17.9

Year(s)cases deaths , , , , /28/06

Factors to control disease biological social economic population size population health vector distribution complicated

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