P ANDEMICS T HROUGHOUT H ISTORY

A pandemic is defined as an unusually high outbreak of a new infectious disease that is spreading through the human population across a large region “pan” – all, “demos” – people

According to the World Health Organization (WHO), a pandemic can start when three conditions have been met:World Health Organization emergence of a disease new to a population; agents infect humans, causing serious illness; and agents spread easily and sustainably among humans.

Throughout human history there have been numerous pandemics, including the bubonic plague, smallpox, cholera, the Spanish influenza, and more recently HIV In 2009, we were faced with another pandemic - with the novel strain of influenza A, H1N1 – otherwise known as swine flu

T HE B UBONIC P LAGUE ( ) Also known as the “Black Death” Caused by a bacteria (Yersinia pestis) carried by rats and spread by fleas Infectious agent: Yersinia pestis Reservoir: rats Vector: fleas Kills within 3-7 days if untreated Killed tens of millions across Europe (between ¼ and ½ of the total population)

C HOLERA P ANDEMIC ( ) A water-borne bacteria, Vibrio cholerae causes severe diarrhea leading to dehydration and death The first pandemic was characterized by the unprecedented spread of the bacteria throughout Asia, starting at the Lower Ganges River in India Total estimated deaths:

S MALL P OX (18 TH C ENTURY ONWARDS …) In total, smallpox killed more than million people around the world in the 20th century A very contagious disease caused by viruses, Variola major (killed 30 to 30 percent of its victims) and Variola minor (killed about 1 percent) Smallpox localizes in the small blood vessels in the skin, mouth and throat – causes a rash and then, fluid- filled blisters Can leaves scars, blindness, limb deformities in survivors

S MALLPOX …. CONTINUED Smallpox has been around since 10,000 BC Killed an estimated 400,000 Europeans in the 18th century Smallpox devastated Aboriginal populations in North and South America (90 to 95 percent died) As recently as 1967, around 15 million people contracted the disease and 2 million of those died The disease is the only human infectious disease that has been eradicated (1979 – due to vaccination campaigns)

S PANISH I NFLUENZA ( ) A very virulent influenza A subtype H1N1 strain Approximately 1/3 of the world’s population became infected, and anywhere from 50 to 100 million people died worldwide (10-20% of those infected)

WW I killed 15 mill., WWII 12 mill., Spanish flu 50 mill.

HIV (human immunodeficiency virus) is a retrovirus (RNA virus that produces DNA,which is incorporated into the host DNA) o HIV can cause AIDS (acquired immunodeficiency syndrome) It is thought to have originated in sub-Saharan Africa HIV is passed through sexual relations, blood or blood products, and mother-to-child transmission

HIV AND AIDS 2.6 million new people were infected with HIV in million people died in 2009 The number of new infections and AIDS-related deaths are declining steadily due to antiretroviral therapy

P EOPLE LIVING WITH HIV (2008) In 1990, 8 million people were living with HIV, in 2009 it was 33 million (the population of Canada)

T HE “ SWINE FLU ”: H1N1 (2009) Caused by a strain of influenza A, H1N1 Originated as a mixture of swine, avian, and human influenzas The genetic change that allows a virus to “jump species” is called antigenic shift

Influenza is mainly a disease of water fowl H1-16\N1-9

S EASONAL INFLUENZA COMPARED TO PANDEMIC — PROPORTIONS OF TYPES OF CASES 22 Asymptomatic Clinical symptoms Deaths Requiring hospitalisation Seasonal influenza Pandemic Asymptomatic Clinical symptoms Deaths Requiring hospitalisation

EVERYONE IS WORRYING ABOUT INFLUENZA (KIDS, PARENTS, TEACHERS...)