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8. Infectious Disease
Apart from the scenarios already considered, there are
other potential causes of excess mortality and sickness.
Illnesses that infected large numbers of people in the past
have now largely been mitigated by modern medicine
and public hygiene. However, there remain occasional
modern diseases that defy our medical defenses.
The assumption that infectious diseases have been
completely conquered by antibiotics and vaccines has
been criticized by healthcare professionals, and virus
experts have warned that the growth of world population,
rapid international travel, and the development of
drug-resistant microbes and pesticide-resistant insects
make a worldwide spread of infectious disease more likely.
8.1 Novel Diseases
8.1.1 AIDS
In the 1980s, a new disease became recognized after sudden
increases in a rare cancer were discovered in otherwise
healthy men. Acquired immunodeficiency syndrome
(AIDS) soon became recognized as a killer, and
was traced to the human immunodeficiency virus (HIV).
Transmission of the virus through sex, communal drug
use, and blood transfusion led to rapid increases of AIDS
cases.The quick spread of the disease in many communities
caught people by surprise, and nobody could have
known how extensive it was to become.The 1985 public
health campaign recognized that there was a huge hidden
case load, but predicted that 150,000 Americans were
infected with AIDS, a considerable underestimate. The
development of new drugs and lifestyle changes finally
brought the disease and related deaths under a more
manageable proportion. New AIDS cases began to decline
in 1994 and deaths began declining two years later.
Figure 8.1 The rapid increase of AIDS cases showed how a new disease could
spread through modern populations (1)
8.1.2 SARS
In 2003, an outbreak of another previously unknown disease
spread around the world with alarming speed. SARS
is a respiratory illness caused by a new type of coronavirus,
for which there is no consistently effective medical
treatment. It first appeared in China in 2002 and in
an outbreak the following year over 8,000 people worldwide
became sick with SARS, of which nearly 800 died.
Its effects on the U.S. were limited---there were 156
reported cases. However, the speed at which the cases
appeared in across Asia, and surfaced in other parts of the
world, caused a global crisis. The ease of transmission
(droplets spread through coughs and sneezes) and the
mobility of the carriers, many of whom flew internationally
and caused new outbreaks in the cities they visited,
raised alarms about international disease spread.
Treatments for SARS are in development, such as an
antiviral drug treatment for hepatitis C which may
reduce infectiousness, and studies are improving the
understanding of the origin of this rare virus and its
interaction with other conditions.
8.1.3 Virus Mutation
Virus mutation is a major cause of potential new diseases
or strains of disease that are immune to standard treatments.
Viruses with high mutation rates include HIV,
influenza, hepatitis C, and polio. Mutation processes and
rates of mutation are the subject of extensive medical
research. By looking at mutagens that boost the mutation
rates, scientists can find ways of combating the disease.
The process of virus mutation may include jumping animal
species, causing a greater threat to humans due to
the increased degree of contagion and lethality.
The chances of a major outbreak or a resistant strain
of a disease of a disease may be of concern to the life and
health insurance industry. The quantification of this risk
is in its infancy, but studies are progressing to understand
the scale of this threat. Stochastic models of branching
processes can simulate outbreaks such as the experience
of SARS in 2003, and model hypothetical epidemics arising
from a more contagious mutation of the coronavirus.
This chapter examines the threat to the insurance
industry from new strains of disease by looking at an
influenza scenario.
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(1) Centers for Disease Control and Prevention, Department of Health and Human Services. United States HIV and AIDS Statistics by Year.
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