The 2014 Ebola epidemic – surprisingly – already
ranks 10th on the list of deadliest infectious disease outbreaks of the last 100 years. It’s
officially killed nearly 5,000 people in five countries, including the United States, although
the unofficial death toll may be closer to 15,000. It started in the African country
of Guinea, where experts believe patient zero was a two year old boy who contracted the
virus from a bat. Now, you might be thinking: how can an outbreak
that has killed 15,000 people at most, make it on this list when things like typhoid or
malaria can kill 100,000 or more a year in developing countries? Well, it comes down
to the definition of outbreak: which we’re defining as a well-documented incidence of
an infectious disease breaking out somewhere it’s not expected to, or it infects an unusually
large number of people, relative to other occurrences of that disease. For instance, number nine on the list occurred
when, ten months after a powerful earthquake devastated Haiti’s capital, Port-au-Prince
and it’s surrounding towns – killing 160,000 people – Cholera broke out, rapidly killing
more than 4,600 people and hospitalizing tens of thousands more in the first five months
of the epidemic. It eventually spread to its neighbor, the Dominican Republic, and to Cuba
and Mexico, and killed nearly 9,000 people. Smallpox was eradicated from the world in
1980, but just six years before, it hit India hard, killing at least 15,000 people, mainly
in the states of Bihar, Orissa and West Bengal. Thousands more who survived were permanently
disfigured or blinded. There was a silver lining to the tragedy in that it raised awareness
that the disease needed to be – and could be – aggressively stamped out, because Indians
up to that point had just considered smallpox a routine fact of everyday life. In 1996, Africa experienced the largest recorded
outbreak of epidemic meningitis in history with more than a quarter of a million cases.
The disease traditionally occurs in the sub-Saharan region known as the “Meningitis Belt”,
stretching from Senegal in the west to Ethiopia in the east, with an estimated total population
of 300 million people. The climate of the dry season and social habits such as overcrowded
housing make the area extra-susceptible. The sixth deadliest epidemic of the last 100
years is the 2009 H1N1 outbreak, also known as the swine flu. It resulted from a bird,
swine and human flu viruses further combining with a Eurasian pig flu virus, leading to
the term “swine flu”. Unlike most strains of influenza, H1N1 does not mostly infect
the old or the very young, making the 2009 flu unusually deadly, because the entire human
population was susceptible. The deadliest cholera epidemic in the last
100 years lasted for 24 years and started in India, before spreading to the Middle East,
North Africa, Eastern Europe and Russia. Upwards of 300,000 people died in the last nine years
of the disease from 1914-1923, but only 11 of them were in the United States, thanks
to health authorities who successfully quarantined a steamship full of infected people on Swinburne
Island before the ship had a chance to dock and unload its passengers in New York City,
likely saving tens of thousands of American lives. The 1968 flu pandemic was caused by an H3N2
strain of the influenza virus that originated in Hong Kong in July of that year. By the
end of the month, extensive outbreaks were reported in Vietnam and Singapore. By September
the flu reached India, the Philippines, northern Australia, Europe, and California, thanks
to troops coming home from the Vietnam War. Even though 33,800 Americans and over 1,000,000
people worldwide would die, the case-to-fatality ratio was only 0.5%, meaning more than 200
million people worldwide caught this strain of the flu. Part of the reason why the death
toll wasn’t even higher was because many had retained immunity after the same strain
was spread throughout the world a decade earlier. That outbreak, called the Asian Flu, is third
on this list, killing 2,000,000 people worldwide. It originated in China and spread to Singapore
in February 1957, reaching the US by June, where it eventually killed about 70,000 people.
A vaccine was introduced within the first year of the pandemic, which slowed it down,
but a second wave that hit the following year was still very deadly. HIV/AIDS has killed more than 36,000,000 people
worldwide and roughly the same number are estimated to be currently living with HIV.
The earliest well documented case of HIV dates back to 1959 in the Congo. Sub-saharan Africa
has been hit hardest by the disease, which takes years to interfere with the immune system
to the point that a person becomes much less able to fight off infections and tumors. There
is no cure or vaccine, but antiretroviral treatment has progressed to the point where
some who are HIV positive may have near-normal life expectancy. 2005 saw the peak death toll
from the pandemic as 2.2 million people worldwide lost their battles with AIDS. The deadliest infectious pandemic of the last
century is the Spanish Influenza, which infected 500 million people, killing 15% of them, or
4% of the total world population at the time. Unlike other versions of the flu, it predominantly
killed healthy young adults by causing an overreaction of the body’s immune system.
Many countries – already facing low morale among their people because of WWI – minimized
reports of illness and death from the disease, but papers in neutral Spain were free to report
the true figures. This created the false impression that Spain was especially hard hit, which
is why the pandemic’s nickname is the “Spanish Flu.” Well, now you know how Ebola stacks up against
the worst viruses of the past 100 years. It’s amazing to think that some of these incredibly
healthy people setting records for being the world’s oldest ever to live have seen – and
may be able to remember – all of these diseases coming and going. Thanks for watching, make sure to subscribe
for our next, daily video. For TDC, I’m Bryce Plank.