BIO 101
B I O LO G Y O F T H E H U M A N
CONDITION
OUR MODERN SOCIETY IS FUNDAMENTALLY DEPENDENT ON
SCIENTIFIC RESEARCH AND DEVELOPMENT.
YOUR FUTURE WILL DEPEND ON SOCIETAL DECISIONS IN THE
GENERAL AREA OF BIOLOGY.
THIS CLASS WILL USE BIOLOGICAL DATA TO ADDRESS
MODERN MEDICAL AND SOCIAL ISSUES.
200 COUNTRIES, 200 YEARS, 4
MINUTES…
http://www.flixxy.com/200-countries-200-years-4-minutes.htm
Data are from Gapminder.org
SURVIVORSHIP THROUGHOUT HISTORY
McMichael, 2001
PUBLIC HEALTH IN 20TH CENTURY
1918 Flu
pandemic
Flu over the last few years
From CDC website
INFLUENZA
•Eight genomic segments
•Three groups A,B,C with
many subgroups of A
• Hemagglutinin (H)
• Neuraminidase(N)
• E.g., H1N1
•Antigenic drift and shift.
• Mutation
• Reassortment
•Seasonal vs. Pandemic flu.
HA AND
TROPISM
Avian flu (H5N1) is deadly
in humans but it doesn’t
transmit effectively
Sialic acid
Avian flu tropism can be
modified to binding 2,6 or
both 2,6 and 2,3 by one or
two mutations
Microbe 2: 489 (2007)
REASSORTMENT
FLU VIRUSES
TRIG, ~1998.
TRIG: Triple
Reassortment,
Internal Genes
Jon Cohen, Science
325: 140-1 (2009).
Evolved.
European.
Flu PB1-F2 expression
The 1918 strain
produces this
protein.
It goes to the
mitochondrion
and causes cell
death.
Swine origin
H1N1 does not
make it.
Lamb and Takeda (2001) Nature Medicine 7:1286.
FLU STRATEGY
UNDER REVIEW
Science 306:1123 (Nov. 12, 2004)
Visit http://flucliniclocator.org/
TRANSMISSIBILITY WITHIN A POPULATION
New Cases
Ro > 1
Ro = 1
Ro < 1
Time
•Ro = “Reproductive rate” =
Number of new cases per current
patient.
•Ro depends on many factors
including the organisms, social
practices that affect transmission
(sharing food, handwashing,
etc.), and the level of acquired
immunity in the population.
Millions of people
OPTIMAL STRATEGY FOR MINIMIZING
DEATHS IN A PANDEMIC
Age groups
•Computer simulations based on parameters from the 1957 pandemic to determine
optimal strategy for achieving Ro < 1.
•Average pre-vaccination Ro = 1.4.
•Solid line is current US population profile.
•Gray bars are numbers vaccinated in specific age groups.
•Can be done with only 61 million doses. We currently administer ~135M doses/yr.
•Medlock et al. (2009), Science 325:1705.
MINIMIZING
VARIOUS
COSTS
YLL = Years of Life
Lost.
CV = Contingent
Valuation (based on
surveys).
“Cost” includes
costs of vaccination
and of disease.
OPTIMAL
STRATEGY-3
If vaccine supply limited
to only 40 million doses:
•Former CDC = kids 19 months to 5 yrs and adults > 49 yrs.
•Seasonal (2009 CDC), includes kids through age 18, adults >49.
•Uniform treats all ages > 6 months equally (CDC recommendation since 2013-2014).
•2009 Pandemic = kids 6 month to adults 25 yrs (close to 5-19, above)
•Optimal is kids 5 yrs to 19, some adults to 24 yrs, and some adults 30 to 39 yrs.
•Optimal strategy would do better than all other strategies, although 5 to 19 yrs is close.
•Medlock et al. (2009), Science 325:1705.
THE EBOLA EPIDEMIC
EBOLA
EBOLA EPIDEMIOLOGY
EBOLA
GEOGRAPHY
Outbreaks have been observed
since the 1970’s
Previous epidemics in Central
Africa died out quickly due to
low population densities
Higher densities and travel have
contributed to the current
epidemic
EBOLA CONTROL
Put out the fire in Africa
 Stopping sparks that land in US and Europe is relatively easy
In Africa
 Isolate those infected and use great precautions
 Educate the public
 Funerals are major avenues for transmission
Be vigilant for future outbreaks
 Monitor for Ebola and for more virulent mutants
 Vigilance for other emergent pathogens
The Viral Storm, Nathan Wolfe