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Lecture 10

ANT C68 Lecture 10- March 21.doc

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University of Toronto St. George
Bianca Dahl

ANT C68 Lecture 10: March 21, 2013 Emerging Infectious Diseases II Ebola, SARS, Kuru/CJD Emerging Infectious Disease • disease after the discovery of effective medications • But since then, there have been dozens of new and “re- emerging” diseases Heliobacter pylori, AIDS, Ebola, Lyme disease, MDR-TB, MRSA, SARS, vCJD, Legionnaires, hantavirus, hepatitis C, …. • In 1995 the CDC created the journal “Emerging Infectious Disease” to promote recognition of new diseases and dissemination of information to the scientific community Re-emerging: critique this word, because some things have been with us the whole time; just not visible. Surveillance • How do we keep track of what’s happening in the world? • Notifiable diseases are those that must legally be reported to the government (started with the plague in … you guessed it … England) • In Canada, PHAC (Public Health Agency of Canada) maintains a list of over 50 notifiable diseases • Canada produces a weekly communicable disease report (CCDR) as well as FluWatch • Exam: Know notifiable disease-> legally required to inform the government. • Don’t need to know short forms for things other than diseases (ex. PHAC) Surveillance: WHO • The World Health Organization used to have a list of specific notifiable diseases • Starting in 2005, the WHO changed their notification requirements • No longer about specific diseases, may include non-disease emergencies • Now, each member state defines “an event that may constitute a public health emergency of international concern” (PHEIC), plus …. • Group 1: smallpox, polio, human influenza from new subtype, SARS • Group 2: any other PHEIC that could become a pandemic • Because some things are so new, they didn’t want to create a list, because they always have to update it. • WHO wants to monitor this very closley Surveillance: USA • The Centre for Disease Control (CDC) in the USA publishes the “Morbidity and Mortality Weekly Report” (MMWR) • The US started an Epidemic Intelligence Service (EIS) in 1950, fear of malaria from troops • Turned out malaria was already gone in USA • Next surveillance programs: polio (1955), influenza (1957) • Focus of EIS is fieldwork – large role in smallpox eradication • These days, NIAID (National Institute of Allergy and Infectious Disease) monitors infectious disease in the US > Concern that troops were going to come back and bring malaria, but they found out that they didn’t malaria- it’s already gone Important to have specific measures • Foege (2000) argues 4 steps are necessary to monitoring diseases, and that it requires USA leadership: 1. Combine marketplace and disease-control needs (ex: cheaper vaccines/drugs, business compensation) 2. Thinking about a global plan (human and animal surveillance, rapid diagnostic techniques, modelling) 3. Global equivalent of EIS 4. Exert pressure on US political system for leadership in international health (Exert pressure on the US to invest more (in vaccines, etc) à blaance between profits vs. social justice “health for all” Ebola: First Case • August 1976: Mabalo Lokela, a schoolteacher, showed up at a mission hospital in Zaire with a fever • They thought he had malaria, gave him chloroquinine • A week later, he returned, critically ill: • Fever; uncontrolled vomiting; diarrhea; bleeding from nose, gums and eyes; severe headache • Nurses tried to treat him, but failed. He died on Sept 8, 1976. • His body was prepared in the traditional way for his funeral • Shortly after, friends and family and hospital staff succumbed to same symptoms Zaire (democratic Republic of Congo) Nun/nurses thought it was malaria, and sent him home When he went back home, his symptoms got worse Ebola wasn’t known to the world until 1976. Ebola: Background • This was the beginning of the first Ebola outbreak, ultimately spread to 50 villages. 318 cases, 280 deaths. (Another outbreak in the Sudan at the same time, 284 cases, 151 deaths.) • Ebola is a member of the family of filoviruses (looks like spindly filaments) • Filoviruses are very old, although Ebola is quite recent • Slower rate of mutation compared to influenza • Four types cause disease in humans: Ebola Zaire, Ebola Sudan, Ebola Bundibugyo, Ebola Ivory Coast • A 5 type, Ebola Reston, has not been known to cause symptoms in humans • Another one in Sudan at the same time. • Compared to influenza it is a virus. • Named after places it broke out • Ebola is a hemorrhagic fever, which means it causes extensive bleeding from orifices • Compared to media portrayals, most bleeding is internal • Other symptoms include rashes, headache, vomiting, diarrhea • Case fatality rate of Ebola Zaire = over 90%. Other forms: 50- 90% • Spread through personal contact with blood, body fluids, bedding • Treatment: palliative (care for patient but no cure) • possible respiratory transmission in lab monkeys (a frightening prospect) • Hemorrhagic: uncontrolled bleeding and fever • 90% of the people who get it, die . Ebola: Hospitals and Funerals • The practice of re-using needles contributed to the initial (and subsequent) outbreaks • The mission hospital had 5 needles each day, 500-600 patients • Funerals were also instrumental in the early spread of the outbreak • “Barrier nursing” effectively prevents spread: wearing disposable gowns, masks, gloves. Sterilized equipment, removing contaminated bedding. • Because of poverty, because of core sanitation praoctice (don’t have enough needles so re-using them). • Wearing protective clothing • Creating a barrier between you and the disease Ebola: Epidemics • Since 1976, there have been almost 2400 cases of Ebola, with almost 1600 deaths • Epidemics occur in African countries: Zaire (Democratic Republic of the Congo), Sudan, Uganda • Isolated outbreaks in other countries, usually as a result of lab accidents (either from Ebola virus or monkeys) • Most recently, epidemics in Uganda (24 cases, 17 deaths) and DRC (72 cases, 32 deaths) in July 2012 • Two vaccines in development Ebola Reston • In 1989, lab monkeys (crab-eating macaque) imported to Reston, Virginia from the Philippines • Researchers were investigating simian hemorrhagic virus • The monkeys were found to have a filovirus similar to Ebola … turned out to be a new strain, Ebola Reston • Despite its status as Level-4 biosafety hazard (requires hazmat suits, protective gear), workers were infected • Luckily, this strain turned out not to cause symptoms in humans, although they developed antibodies • Shipment of monkeys, but half of them die • They had a similar strain of ebola virus, but it wasn’t the exact one. Ebola: Sensationalism in Media • The Reston incident caused quite a media sensation due to the proximity of Reston, Virginia to major US cities (including Washington, DC) • Ebola-like diseases captured the public’s imagination: movies, books • Ebola captured public’s interest: exotic locales, terrifying symptoms, images of high-tech protective gear (this is why you’ve heard of it) • Ebola was seen as the most frightening of the “new” viruses (until AIDS) Ebola: Where did it come from? • Ebola can be found in chimpanzees and gorillas; other primates have similar hemorrhagic fevers • Most likely that human epidemics are caused by bushmeat (note: relationship with economics, population increase) • But Ebola has such a high CFR in primates that it’s probably new to them too • There must be another animal reservoir. 100’s of species tested. • Most likely candidate for natural reservoir: bats • Big problem in gorillas and chimps -> destroying their population. • It kills them really quickly. • Ebola is named after the river. • It comes from a cave (in the book). SARS: Why such a big deal? Recall: experts are worried about the next BIG pandemic, and the most likely source is (avian) influenza. It will be like 1918 influenza, but worse. SARS, as an influenza-like illness came close to being that big pandemic. Scary stuff. SARS: Discovery of Epidemic • In Feb 2003, the WHO’s Weekly Epidemiological Record mentioned a mysterious “atypical pneumonia” in Guangdong province, China • Symptoms were similar to the flu: muscle aches, chills, cough. But also caused damage to lungs in severe cases. • At the time it had caused the deaths of 5 people • Within a few weeks, reports started coming in from Hong Kong, Singapore, Vietnam, and Toronto • On March 17, 2003 the new illness was labelled SARS: Severe Acute Respiratory Syndrome  Know what SARS stands for SARS: Super-Spreaders • The sequence of events was pieced together by the WHO retrospectively • First case: Guangdong province, China. November 16 , 2002 th • human-to-human transmission was limited, but some people were “super-spreaders” able to infect a disproportionately large number of people. • The first super-spreader infected three hospitals and a nephrology professor who then went on to a conference in Hong Kong • Several people at the Hong Kong hotel were infected, and travelled back to Vietnam, Singapore and Toronto > Chain of infection of SARS died out pretty quickly. SARS and Air Travel • SARS brought to light the issue of air travel in spreading epidemics • Travel is now quicker than the incubation period of disease • On March 15, 2003, the WHO issued an alert about SARS as well as a travel advisory against non-essential travel to Toronto (SARS became provincial emergency) > With planes, you can get anywehre in the world in 24 hours, and you spread it to other regions of the world . . Heat-sensing technology SARS Pandemic • Media response to SARS was one of fear, terrorism (occurred soon after 9/11) • SARS officially declared over on July 5, 2003 • In the end, 8,273 cases worldwide, 775 deaths in 26 countries > Portrayal of SARS in media is fear. There was government control where people in Asian countries weren’t allowed to talk about it -> they didn’t’ want people getting the word out For reading on SARS: don’t need to know anything other than lecture material Other readings: should read them ! SARS Clinical Info • SARS is caused by a coronavirus (SARS-CoV) • Same family of viruses that cause the common cold • Not influenza • Clinical symptoms: fever, muscle aches, chills, cough • Respiratory transmission • 20% of cases were in health care workers • CFR = 9.4% highest in elderly (65+) SARS Response • WHO set up worldwide collaborative initiative online for researchers, daily teleconferences • SARS provoked an unprecedented amount of research • Because it was new, no vaccine or effective drug • Controlling the outbreak required traditional epidemiological methods • Contact tracing • Patient isolation • Quarantine • Travel restrictions • Screening at borders • Infection-prevention measures in hospitals • Appropriate response: set up a website, conference with each other daily • Dissemination of research -> tried to reduce any barriers • Contact tracing: who have you talked to; where have you been • Patiennt isolation • quaranteen • In Singapore, patients were given home-quarantine orders. Webcams set up to make sure they followed. Severe penalties • Beijing: closed schools, internet cafes, discos, cinemas, theatres. Spitting prohibited. Marriages suspended. • Beijing: construction of a brand-new 1000-bed isolation hospital in 8 days(!?!). • Taiwan: issued special stamps to raise money for SARS SARS in Toronto • SARS was declared a provincial emergency for
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