Pandemic Understand what the term “pandemic means. Discuss different types of pandemics throughout history
Pandemic • Definition: An epidemic of infectious disease that is spreading through human populations across a large region • Examples: • Smallpox • HIV • H1N1 Flu • Pandemic can start when 3 conditions are met: • Emergence of a disease to a new population • Agents infect humans, causing serious illness • Agents spread easily among humans
Cholera • What is Cholera? • Infection the small intestines caused by a bacterium. • Transmission is usually through contaminated drinking water or food • What are the symptoms of Cholera? • Watery diarrhea • Vomiting • Abdominal pain • Symptoms usually began 1-5 days after infection, and are the result of a toxin produced by the bacterium. • People usually died due to severe dehydration and electrolyte imbalance
http://upload.wikimedia.org/wikipedia/commons/9/9d/Cholera_bacteria_SEM.jpghttp://upload.wikimedia.org/wikipedia/commons/9/9d/Cholera_bacteria_SEM.jpg Cholera • 1854 Broad Street Cholera Outbreak- London, England • Poor sanitation allowed for this outbreak • Human waste was dumped into the River Thames • Water became contaminated http://en.wikipedia.org/wiki/Cholera
Cholera Outbreak • John Snow- Physician in the city • Over the course of 3 days, 127 people on or near Broad Street died • Snow began talking to residents and created a map of which people were infected. • All of the people infected had drank from the same Broad Street water pump
Cholera in today’s world • http://www.cbsnews.com/video/watch/?id=6983160n • The Haiti cholera outbreak is an ongoing cholera outbreak that began in late October 2010 in the rural Artibonite Department of Haiti, about 100 kilometers (62 mi) north of the capital, Port-au-Prince, killing 4672 people by March 2011and hospitalizing thousands more.The outbreak followed a powerful earthquake which devastated the country on 12 January 2010. • By March 2011, some 4,672 people have died and 252,640 cases had been reported.By the first 10 weeks of the epidemic, cholera spread to all of Haiti's 10 departments or provinces.In November 2010, the first cases of cholera were reported in the Dominican Republic and a single case in Florida, United States; in January 2011 a few cases were reported in Venezuela. As of late September, 2011, some 6,435 deaths have been reported and is expected to continue rising. Neighboring Dominican Republic has reported 135 cholera deaths as well.
1918 Spanish Influenza Outbreak • Spread widely across the world from 1918 to 1920 • Victims- healthy, young adults, in contrast to most influenza outbreaks which usually affect very young, very old, or weakened patients. • Why? • The virus kills by cytokine storm- overreaction of the body’s immune system • Approximately 50 million people died of the disease (500 million were infected).
1918 Spanish Influenza Outbreak • 2 Waves of the disease • 1st wave- typical flu epidemics- those at risk were the sick and elderly. Younger, healthier people recovered easily • 2nd wave- the virus mutated to a more deadly form. • Mostly killed young adults, with 99% of the deaths occurring in people under the age of 65. • More than ½ of these fatalities were in young adults ages 20-40 years old.
1918 Spanish Influenza • World War I going on. Flu first struck many U.S. troops overseas. • Then… it hit the U.S. • Most people developed a secondary infection- • Pneumonia • In 1 week, 4,597 Philadelphians died of the flu and related respiratory diseases • By the end of the month, 11,000 Philadelphians had died; 195,000 died nationwide
Swine Flu- 2009 H1N1 • Primarily targets: • Ages 6 months to 24 years of age • And higher risk people ages 24-65 • People over the age of 65 are not at a high risk
Immune Response • Definition- specific defenses the body uses against pathogens. • A healthy immune system recognizes all cell and proteins that belong in the body. • It also recognizes foreign organisms and molecules that do not belong there. • When the immune system recognizes invaders (viruses, bacteria, parasites, etc.) it uses cellular and chemical weapons to attack them. • After encountering a specific invader, the immune system “remembers it so if the pathogen attacks again it can recognize it and respond immediately.
How does the Immune System recognize pathogens that don’t belong there? • Antigens- Foreign substance that can stimulate an immune response. These are usually located on the outer surfaces of bacteria, viruses, or parasites. • Antibodies- Antibodies- Proteins that recognize and bind to antigens (pathogens). • Attack the pathogen • Once the body has been exposed to a pathogen, millions of memory B cells are created and reduce the chance an infection could happen a second time. • The body makes up to 10 billion different antibodies.
Immune System • Immune Response: B and T cells continually search the body for antigens or signs of antigens. • B Cells- White blood cells that are produced and mature in red bone marrow. These cells have embedded antibodies that search for antigens in body fluids like blood. • T Cells- Also produced in the bone marrow, but mature in the thymus. These cells look for antigens on infected body cells or immune cells.
Immune System • Active Immunity- Body makes its own antibodies • Appears after exposure to an antigen • Natural- fighting an infection, you develop active immunity • Deliberate Exposure- vaccine • Passive Immunity- Antibodies produced by another animal/human and are injected into bloodstream • Mother to child • Vaccines against tropical diseases like Malaria
Vaccines • Smallpox- widespread disease that killed many people. • Edward Jenner- English physician that noticed milkmaids who contracted a mild disease called cowpox didn’t develop smallpox. • Developed a question: Could people be protected from smallpox by deliberately infecting them with cowpox? • Experiment: • Put fluid from a cowpox patient’s sore into a small cut he made on a young boy • Boy developed cowpox • 2 months later- Jenner injected boy with smallpox • Results: • Boy did not develop smallpox. The cowpox infection protected the boy from smallpox. • This led to the development and use of vaccines!
Vaccines and Your Immune System • Help the body prepare in advance to fight illnesses and potentially deadly diseases. • Give the body a preview of a bacterium, virus, or toxin • This allows the body to learn how to defend itself in advance • If the body is ever invaded by that particular pathogen, the body’s immune system is ready for it and can attack it.
Vaccines • Most vaccines contain viruses or bacteria that have been weakened or killed. • T and B cells (white blood cells) work to recognize and destroy the pathogen • Once a person receives a vaccine and develops immunity to the pathogen, they are usually protected for life, but not always • Tetanus- boosters shots are needed • Certain viruses, like the flu vaccine, must be given every year because there are many strains of the flu.