A worldwide epidemic of a disease Epidemic = increased number of cases from a disease Pandemics...
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Transcript of A worldwide epidemic of a disease Epidemic = increased number of cases from a disease Pandemics...
A worldwide epidemic of a disease Epidemic = increased number of cases
from a disease Pandemics have occurred from
› Bacteria – cholera, Tuberculosis, Typhus, Bubonic plague
› Viruses – smallpox, influenza
The smallest of the microbes
Contain genetic material (DNA or RNA or both)
Nuclear material contained within a capsid
Parasitic, hijack host cell and replicate
New strains of virus Take advantage when herd immunity is
low Transmissible Limited treatment options
Influenza takes advantage of all of these to cause pandemics
Virus first described by Hippocrates in 412 BC
Influenza pandemics occur every 10-30 years
RNA virus
Disease characterized by fever, headache, malaise, myalgias
Respiratory symptoms include sore throat, cough, nasal congestion
May include GI symptoms Onset 3-6d after exposure Symptoms last 4-7 days
• results from RNA mutations
•changes surface proteins so they are not recognized by existing antibodies
Can occur in 3 ways
A)Genetic mixing in an intermediate hostB)Direct transmission to a new hostC)Direct transmission to an intermediate host and then on to humans
First reported in Russia May1889 Hit North America by December 1889 By February 1890 it had travelled to
South America Later reaching India and Australia High mortality rate Estimated one million deaths
Started in the fall of 1918 and rapidly spread across the globe
Killed 20-40 million people by end of 1919
Mortality approximately 2-3% Most deadly for 20-40 year olds Avian H1N1
Feb. 1957, new influenza identified in the far east, H2N2
Vaccine available Aug. 1957 Milder illness than Spanish flu (0.2-0.5%
mortality) Most disease in children and young adults Most deaths Sept 1957-Mar 1958 Estimated 2 million deaths worldwide
1968/9 pandemic 2 peaks Milder disease, H3N2 Vaccine available in US one month
after first cases identified Estimated one million deaths
worldwide Mortality rate 0.1%
Jan 1976 respiratory outbreak Fort Dix Identified as swine H1N1 influenza Fear that this virus may case pandemic
as H1 and N1 had not circulated in humans in 50 years
In the end 13 ill, 1 dead, 500 others exposed
Did not spread beyond Fort Dix
Began in China in May 1977, identified in Russia in Nov.
Affected those < 23yo Disease mild and mortality low Mortality = seasonal influenza H1N1 virus
Another pandemic was imminent Lots of work done in Pandemic planning Identify a team of “experts” Plan for high absentee rates (10-50%) Protect staff in the workplace Communication and knowledge
management
Identify a team of “experts” Plan for high absentee rates (10-50%) Protect staff in the workplace Communication and knowledge
management
H1N1 virus has previously been identified in humans
New strain with genetic elements from North American and European swine influenza, North American avian influenza and human influenza
Never previously seen in humans
Initial cases identified in Mexico Initial reports showed high mortality WHO began actively tracking cases Once virus identified, track of spread
Phase 1 – no animal influenza known to be circulating in humans
Phase 2 – a circulating animal influenza known to infect human posses a threat
Phase 3 – animal or human-animal virus has caused sporadic disease but no human-human transmission sufficient to cause pandemic
Prepare pandemic plans, surveillance systems, communication systems and plan to scale up as needed
Phase 4 – human-human transmission of animal or animal-human virus able to sustain community level outbreak
Implement containment protocols to prevent spread, increase surveillance, communicate protection plan to population and activate contingency plans
Phase 5 – virus as in phase 4 causes sustained community outbreaks in 2 or more countries in one WHO region
Pandemic – implement pandemic plans, active surveillance and monitoring, update public health and other stakeholders on ways to mitigate risk
WHO declared phase 5 on April 29, 2009
Phase 6 – same criteria as phase 5 with spread to one other WHO region
WHO declared phase 6 in June 2009
April 12, 2009-March 27, 2010 1,843 hospitalizations 319 ICU admissions 128 death March 21-28 8,759 lab confirmed cases
of H1N1
PHAC FluWatch 2009-2010, Ontario Influenza Bulletin
April 12, 2009-March 27, 2010 8,677 hospitalizations 1,473 ICU admissions 428 deaths Hospitalization rate 25:100 000, death
rate 1.3:100 000 (0.0013%)
Only 13 hospitalizations and 2 deaths since 2010
PHAC FluWatch 2009-2010
9 April 2010 -- As of 4 April 2010, worldwide more than 213 countries and overseas territories or communities have reported laboratory confirmed cases of pandemic influenza
H1N1 2009, including over 17700 deaths. WHO Most activity in Southeast Asia, West
Africa Mortality rate 0.01-0.03%
Access to supplies Access to reliable information Communication within organizations
Arepanrix (adjuvanted) Contains split, inactivated influenza virus Single dose of vaccine is effective AE – pain, redness, swelling at inject. Site,
myalgias and fatigue Jan30/10 – 25.143 million doses administered 6,131 AE (24.4/100,000) – 250 “serious”
(0.99/100,000)– of these 131 anaphylaxis(0.52/100,000) – all within acceptable range for vaccines
Vaccine supply chain in Canada› Vaccine comes from supplier to
government› Supply is reviewed› Customer service determines distribution› Vaccine is repackaged› Shipments prepared in warehouse› Vaccine delivered to PH units› Vaccine delivered to public
Health Canada
Federal government purchased 50 .4 million doses if vaccine for distribution to provinces and territories
Excess vaccine estimated at 25-30 million doses
Many reasons for this Initial estimates were that 25% of
population received H1N1 vaccine 37% US HCP received the H1N1 vaccine
4 Canadian studies Monitoring of flu found those who had
seasonal flu vaccine were 68% more likely to get H1N1 infection
Case control studies in Canada and Quebec and transmission study in Quebec showed risk increased by 1.4-5X
PLoS Medicine, April 6, 2010
Antivirals – recommended for age < 1, severe illness, immunocompromised, pregnant
Should be started within 48hr of symptom onset
Oseltamavir (Tamiflu) – oral Zanamivir (Relenza) - inhaled