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THE GLOBAL RESURGENCE OF INFECTIOUS DISEASES
223
TREND REPORT
The Global Resurgence of Infectious
Diseases
Eric K. Noji*
In an increasingly interdependent world, we face an array of new global challenges that
transcend the traditional definition of national security. One important example is the
resurgence of infectious diseases. In the 1960s and 1970s, powerful antibiotic drugs and
vaccines appeared to have banished the major plagues from the industrialized world, leading
to a mood of complacency and the neglect of programs for disease surveillance and
prevention. Over the past few decades, however, infectious diseases have returned with a
vengeance. Many factors, or combinations of factors, can contribute to disease emergence.
New infectious diseases may emerge from genetic changes in existing organisms; known
diseases may spread to new geographic areas and populations; and previously unknown
infections may appear in humans due to changing ecological conditions that increase their
exposure to insect vectors, animal reservoirs, or environmental sources of novel pathogens.
Reemergence may also occur because of the development of anti-microbial resistance in
existing infections (e.g., malaria) or breakdowns in public health measures for previously
controlled infections due to civil conflict (e.g., cholera, tuberculosis). Not only does the reemergence of infectious diseases threaten health directly, but devastating epidemics such as
AIDS are spawning widespread political instability and civil conflict. This instability, in turn,
will contribute to humanitarian emergencies and economic crises.
Infectious diseases: a threat to the
world's health
Of the estimated 52 million deaths in 1996,
infectious diseases led all categories of death,
killing at least 17 million people (CDC, 1998). Of
the top ten megacities in the next twenty years,
nine of them will be in developing nations with
less capability to provide adequate public health
support (Garrett, 1994). One can therefore expect
a rise in morbidity, which will have two
immediate effects. It can lead to the reduction of
labor productivity and to an increased spending
on health care. The worst case scenario is one
where this occurs in the face of a drop in life
expectancy, since the reduction of the working
age population puts an additional strain on the
economy.
Although the vast majority of these infections
and deaths occur in developing countries, they
are increasingly encroaching into developed
regions due to greater globalization trends and
lesser emphasis on prevention programs. The
highly developed countries in North America,
Europe and Asia will continue to be threatened
by infectious diseases because many poorer
countries will be unable to afford the newer
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350 Main Street, Malden, MA 02148, USA.
treatment and preventative drugs and will
continue to serve as nidi of infection for the
rest of the planet.
Risk factors for the continued, or even
accelerated, incidence of infectious disease are
complex and interrelated. When economies and
governments fail, or are chronically enfeebled,
health systems rapidly falter, leaving populations
more prone to illness. As an example, political
instability and disease have reinforced each other
in Rwanda and the countries of the former Soviet
Union.
Patterns of control and eradication are driven not
only by relative national and regional
development, but also by changing priorities,
domestic policies, and national complacency. The
more advanced a country is economically, socially,
and infrastructurally, the more likely that
governments can benefit from public health
surveillance (or disease monitoring) and
intervention. The continued threat of infectious
disease will therefore place direct burdens on
countries least able to address them. In addition, it
will place indirect burdens on, and requiring
sustained attention from, the developed nations
most capable of successful response. However, the
highly developed countries cannot unilaterally
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* National Center for Infectious
Diseases, Centers for Disease
Control and Prevention (CDC),
Mailstop C-14, 1600 Clifton
Road, Atlanta, GA 30333,
United States. E-mail: exn1@
cdc.gov.
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JOURNAL OF CONTINGENCIES AND CRISIS MANAGEMENT
provide health care to the world. Instead, it can
provide leadership for the international health
community. Unfortunately, political differences
among nations affect the credibility of international
organizations and make firm, consistent leadership
even more crucial.
Current patterns of infectious
diseases
Mankind's optimism regarding the battle against
infectious disease built throughout the 1960s
and 1970s. It reached its peak in 1978 when the
United Nations (UN) member states signed the
`Health for All, 2000' accord, which predicted
that even the poorest nations would undergo a
positive health transition before the millennium.
This optimism, however, was based on two false
assumptions. It was assumed that microbes were
biologically stationary targets and that diseases
would remain geographically sequestered. The
current epidemiological picture shows the fallacy
of those assumptions. Of the estimated 52
million deaths in 1996, infectious diseases led
all categories of death, killing at least 17 million
people. When standardized for age and sex, the
death rates per 100,000 population were 446 for
developed market economies, 800 for economies
in transition, and 1575 for lesser developed
countries (Marwick, 1995).
Nowadays, emerging and re-emerging infectious diseases are universally being recognized as
at least variables, if not outright threats, to
global security. It is estimated that at least 29
previously unknown diseases have appeared
globally since 1973 and twenty well-known
ones have re-emerged, often with new drugresistance or in deadlier forms (Wilson et al,
1994). These include: HIV-AIDS, Tuberculosis
(TB), HIV and TB Co-infections, Malaria,
Diseases of Childhood, Diphtheria and Zoonotic
Diseases (e.g., Hantavirus and West Nile virus).
HIV-AIDS
From 1900 to 1990, dramatic progress in the
fight against infectious diseases raised life
expectancy from 40 to 64 years in developing
countries. AIDS, however, has slowed and, in
some countries, reversed this trend. For example,
life expectancy in Zimbabwe is 22 years shorter
than it would have been in the absence of AIDS.
Approximately 1.5 million people died from
AIDS in 1996 and, each day, about 8,500 people
become newly infected. At the end of 1997, the
World Health Organization (WHO) reported
that roughly 30 million people were infected
with HIV worldwide. The worldwide peak for
HIV deaths is expected to be around 2006, with
perhaps 1.7 million deaths that year.
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Regionally, sub-Saharan Africa accounts for over
two-thirds of the world's HIV-positive population;
about 21 million are HIV-positive. Roughly 6
million people are HIV-positive in Asia. Even with
an infection rate of under 1 percent, India leads the
countries of the world with 3 to 5 million infected.
Although experiencing far fewer cases thus far than
more developed regions, the newly independent
states of the Former Soviet Union (FSU) are
especially vulnerable. The United Nations reports
that 150,000 people have contracted HIV in
Eastern Europe and the FSU. As of the end of
1997, the number of officially reported HIVpositive Russians just surpassed 7,000.
Representatives of the Russian Health Ministry
report that, since the majority of cases are
unrecognized/unreported, the true figure is closer
to 100,000 and will be 800,000 by the year 2005
(Winkler, 1996).
Tuberculosis (TB)
Tuberculosis (TB) currently affects 1.9 billion
people, or one-third of the world's population
and continues to kill more people worldwide, 3
million deaths per year, than any other infectious
disease. The number of new tuberculosis cases
occurring each year is expected to increase from
7.5 million (143 cases/100,000) in 1990 to 10.2
million (163 cases/100,000) in 2005. The number
of annual deaths from TB are expected to reach
3.5 million by 2005 (Raviglione, 1995).
HIV and TB Co-infections
Compounding the impact of the HIV and TB
epidemics are the growing number of coinfections with the two diseases. Although only
about 10% of all people infected with TB
organisms will develop the disease in their
lifetimes, this fraction is drastically increased in
the face of immuno-compromisation. Compromise to the immune system is one of the major
contributors to the resurgence of TB in the
United States and the rest of the world. Patients
co-infected with HIV and TB have a thirty-fold
increased risk of progressing to active disease.
An estimated four million people worldwide are
currently co-infected with HIV and TB (National
Science and Technology Council, 1995).
Malaria
Malaria is another extremely prevalent disease
among humans, infecting up to 500 million
people and killing nearly two million people
each year (WHO, 1996). Drug resistance is a
major problem. There is a justifiable fear that,
particularly in Southeast Asia, we could be facing
a situation where malaria may not be treatable or
curable by any drug available.
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THE GLOBAL RESURGENCE OF INFECTIOUS DISEASES
Diseases of Childhood
In general, infectious diseases are by far the
leading causes of death for children in
developing countries. Overall, about 1.3 billion
diarrheal diseases occur annually in children
under the age of five; over three million of these
cases are fatal (Heymann, 1998). The full
deleterious effects of the fighting in the Chechen
region of Russia, for example, and the
interruption of childhood immunizations for
three years will be felt for years to come.
Diphtheria
In 1980, diphtheria was virtually unknown in
Europe. Nevertheless, the dissolution of the
Soviet Union left the Eastern Europe/Central
Asia region without a functioning health system.
As a result, the region is experiencing widespread disease prevalence and is only now
beginning to reinstitute effective preventive
services. Today, an epidemic accounting for
90% of the world's diphtheria cases has spread
throughout Russia, Ukraine, Eastern Europe, and
Germany (WHO European Office, 1997).
Zoonotic Diseases
Zoonotic diseases, or those transmitted between
humans and animals, comprise the majority of
global diseases. Rabies, perhaps the best-known
zoonosis, causes at least 40,000 deaths among
humans each year and more than ten million
rabies post-exposure treatments are reported
worldwide, mostly in Asian and African
countries (MSF, 1996). The sudden discovery
in March 1996 of a new variant of CreutzfeldtJakob disease (nvCJD) and its possible link to
bovine spongiform encephalopathy (BSE) has
given rise to much concern. Depending upon the
incubation period of this disease, about which
little is known, between 200 and 12,000 cases
are expected in the United Kingdom over the
next two decades.
Regional trends in the growth and
spread of infectious diseases
Infectious diseases will continue to be the
primary global threat to health, because the bulk
of the world's population will remain within
lesser or re-developing regions. This continued
threat will place direct burdens on countries least
able to address them and additional indirect
burdens on, and requiring sustained attention
from, the developed nations most capable of
successful response. Regionally, different
developments are expected for Eastern Europe
and the Former Soviet Union, Asia (India),
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Africa, Latin America, Europe and the United
States.
Eastern Europe and the Former Soviet Union
Life expectancy for men in countries of the
Former Soviet Union, primarily Russia, has
dropped from 64 years in 1990 to 57 in 1996.
Contributing factors are numerous, but include
infectious diseases, alcoholism, injuries, violence,
and suicide. Life expectancy is not expected to
rebound at all until at least 2020. As a result,
men between the ages of 15 and 60 could face a
higher risk of death even than men in subSaharan Africa. From an HIV epidemiological
standpoint, many countries of the FSU are where
the United States was in the early 1980s, on the
brink of a major epidemic. Their actions over the
next few years will determine whether they stem
the tide of new infections or succumb to the
epidemic's natural course. Given the already
strained health care infrastructure in the FSU,
preventive measures will, at best, be weakly and
intermittently applied (Lederberg, 1996).
Asia/India
The health scenario in southeast Asia has altered
significantly in recent years. The decline in crude
birth and fertility rates, together with the
increase in life expectancy, have resulted in the
progressive aging of populations and substantial
rises in chronic diseases, even among the
younger generations. Death rates in India are
expected to peak around 2010, at about 500,000
per year. This will lead to increasing costs for
health care. For example, over the next six years
(1998-2004), Asian countries will spend $38±52
billion on health care for AIDS patients (CDC,
1998).
Africa
In sub-Saharan Africa, infectious diseases account
for 65% of all deaths. AIDS/HIV will continu to
have a significant impact, especially in subSaharan regions. By the year 2005, the
subcontinent will lose an estimated 15 to 20
percent of its GDP as a direct result of the
epidemic. USAID predicts that 11% of children
under 15 years of age in sub-Saharan Africa will
be AIDS orphans by 2005. By the year 2005, the
estimated direct (medical) and indirect (loss of
labor force and family impact) costs of the
disease will exceed $500 billion. In Rwanda, the
cost of treating known AIDS cases potentially
amounts to 60% of the public health budget.
Malaria will also remain an important disease in
the region.
However, one should keep in mind that not all
disease trends are negative. For example, as a
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result of WHO's onchocerciasis or river
blindness control program in West Africa, more
than 1.7 million additional person-years of
productive labor have become available (WHO,
1996).
Latin America
Latin American countries are making
considerable progress in infectious disease
control, including the eradication of polio and
major reductions in the incidence and death rates
of measles, neonatal tetanus, some diarrheal
diseases, and acute respiratory infections. According to the AFMIC typology, Latin America's
health care capacity is substantially more
advanced than that of Sub-Saharan Africa and
somewhat better than mainland Asia's, with 70
to 90 percent of populations having access to
basic health care in Chile, Costa Rica, and Cuba
on the upper end of the scale. Nonetheless,
infectious diseases are still a major cause of
illness and death in the region, and the risk of
new and reemerging diseases remains
substantial.
Cholera reemerged with a vengeance in the
region in 1991 for the first time in a century with
400,000 new cases, and while dropping to
100,000 cases in 1997, it still comprises twothirds of the global cholera burden. TB is a
growing problem region-wide, especially in
Brazil, Peru, Argentina, and the Dominican
Republic where drug-resistant cases also are on
the rise. Haiti does not provide data but
probably also has a high infection rate. HIV/
AIDS also is spreading rapidly, placing Latin
America behind Sub-Saharan Africa and Asia in
HIV prevalence. Prevalence is high in Brazil and
especially in the Caribbean countries (except
Cuba), where 2 percent of the population is
infected. Dengue reemerged in the region in
1976, and outbreaks have taken place in the last
few years in most Caribbean countries and parts
of South America. Yellow fever has made a
comeback over the last decade throughout the
Amazon basin, and there have been several
recent outbreaks of gastrointestinal disease
attributed to E. coli infection in Chile and
Argentina.
Europe and the United States
Europe has suffered more reported animalassociated epidemics than any other region.
Nine of the fifteen epidemic livestock diseases
recorded internationally have occurred in
Europe. The United Nations Food and
Agriculture Organization recently warned that
Europe faces devastating animal disease
epidemics, such as swine fever and foot-andmouth disease, and should alter its strategy for
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containing them. The total loss to agriculture
and commerce in the United Kingdom due to
BSE and nvCJD has been estimated in the
billions of dollars. In addition, the European
countries are not immune to the destabilizing
effects of HIV infections. HIV blood test
scandals in Germany, France, and Switzerland
have resulted in national uproars and triggered
the dismissal or prosecution of government and
other officials.
Total direct and indirect costs from infectious
diseases in the United States in 1998 were more
than $150 billion. Combined federal, state, and
municipal government expenditures that year for
infectious disease control were only $74.2
million (neither figure includes AIDS, other
sexually transmitted diseases, or tuberculosis).
The US Department of Agriculture (USDA)
estimates that medical costs and productivity
losses for only seven specific foodborne
pathogens range between $6.5 billion and
$34.9 billion annually. Total costs for all foodborne illnesses likely are much higher. Influenza
is another disease that, even in the absence of a
catastrophic pandemic, results in significant cost,
both in terms of life and capital expenditures.
The lifetime, discounted, direct medical cost of
treating an adult infected with HIV is estimated
at about $96,000 in the United States, and the
cost of treating an HIV-infected child at between
$161,000 and $408,000 (CDC, 1998).
Global trends affecting the growth
and spread of infectious diseases
The emergence of infectious diseases is, with few
exceptions, due more to changes in human
behavior and the environment than to changes
in pathogen genetics. Therefore, it is more
appropriate to recognize that emerging
pathogens generally are not newly evolved.
Rather, it appears that they already existed in
nature and became newly recognized due to
globalization and changes in national development and policies, technology, environment and
commerce. The most influential factors affecting
the spread and growth of infectious disease are:
population expansion and aging; complex
humanitarian emergencies; international travel
and commerce; foodprocessing and landuse; and
absent or ineffective health systems.1
Population expansion and aging
Population expansion raises the statistical
probability that pathogens will be transmitted
from person to person and region to region. In
1996, the world population increased globally
by more than 80 million, reaching a mid-year
total of 5.8 billion people. In 1800, less than
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THE GLOBAL RESURGENCE OF INFECTIOUS DISEASES
1.7% of people lived in urban communities. By
2010, that fraction is expected to rise to 50% of
the global population and 25 cities are expected
to have populations in excess of 11 million.
Aging also increases the statistical probability of
transmission of pathogens. Between 1990 and
1995, the population aged 65 and above
increased by 14% globally and will increase by
another 82% between 1996 and 2020. If the
current trend of infectious disease incidence in
aged populations continues, it is expected that
by the year 2025, more than 60% of all deaths
will be among those above 65 years (National
Science and Technology Council, 1995).
Complex humanitarian emergencies
Wars of ethnicity and nationalism and the failure
of nation-states are features of the post-Cold
War period that fuel mass migration, refugees,
famine, and disease. These are called complex
humanitarian emergencies. According to the UN
High Commissioner for Refugees (UNHCR) in
1998, at least 110 million people emigrated
worldwide, another 30 million moved from rural
to urban areas, and 23 million more were
displaced by war or social unrest (UNHCR,
2000). This facilitates the spread of infectious
diseases.
Malnutrition adds to this because it causes
immuno-suppression or weakening of the body's
ability to fight off infection. Immuno-suppression can be caused by many factors, including
inherited diseases, aging, prematurity, HIV
infection, radiation treatment, immuno-suppressive therapies, trition, pregnancy, severe trauma
and burns, other concurrent infections, and
malignancy. Globally, however, the leading
cause of increased host susceptibility is malnutrition. Overall, malnutrition appears to result
in a thirty-fold increase in the risk for diarrheaassociated death.
International travel and commerce
Between 1984 and 1994, the annual number of
people traveling outside the United States
doubled from 20 million to 40 million.
Moreover, about half of those people visited
tropical locations where the likelihood of
contracting infectious diseases was much greater.
In 1995, more than 56 million air travelers
entered the United States from foreign
destinations. Including land and sea borders,
the number arriving from other countries is
closer to 200 million per year (Berkelman et al.,
1994). Travelers (e.g., tourists) on commercial
flights from high risk areas in the tropics can
reach most American cities from any part of the
world within 36 hours, which is shorter than the
incubation periods of many infectious diseases.
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With the advent of NAFTA and the WTO,
there is a drive to lower trade barriers. This also
results in the arrival of more animals and animal
products at our docks, airports, and roadside
border crossings. Animals also are illegally
imported, providing a sizable risk of a foreign
animal disease outbreak.
Food processing and landuse
Food processing and land use are also of
influence on the spread of infectious diseases.
Food preparers and handlers at each stage of the
food chain lack the knowledge of risks involved
and the related safe food-handling practices. In
addition, approximately half of the tonnage of
antibiotics produced in the United States is used
in the raising of animals for human consumption,
although the contribution of agricultural
antibiotic use to the emergence of resistance is
unclear. This antibiotic use may, over time,
promote the emergence of pathogens resistant
to those antibiotics.
Landuse can have a major impact on the
spread of diseases as well. The emergence of
Lyme disease in the United States, for example,
is directly linked to changes in land use patterns.
During the 1900s, much of the East Coast
underwent reforestation owing to the decline of
the small farm and the movement of agriculture
to the Midwest. Reforestation was accompanied
by increased residential development. The
resultant proximity of people, mice, deer, and
ticks created nearly perfect conditions for the
transmission of the Lyme disease spirochete to
human hosts. First seen in Wisconsin in 1969,
Lyme disease is now the most common vectorborne disease in the United States. Dambuilding
has a similar impact. The Aswan dam construction in the 1950s resulted in the reemergence of diseases in Egypt such as Rift
Valley fever and schistosomiasis, which had
previously been seen only in sub-Saharan Africa.
Absent or ineffective health and surveillance
systems
Alone, or in combination, economic collapse,
war, and natural disasters cause the breakdown
of public health services, which facilitates the
emergence or re-emergence of a number of
deadly diseases. However, even if countries are
not suffering from conflict or disaster, health
systems might not be dealing effectively with
infectious diseases. For example, a contributor to
the explosive growth of the HIV epidemic in the
United States appeared to be the antipathy of
some federal officials to the behaviors of those
sub-populations initially infected by HIV. In
addition, it is estimated that as many as 50% of
prescriptions for antibiotics in the United States
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are inappropriate and are frequently prescribed
to avoid litigation or satisfy expectant patients.
Inadequate, or inappropriate anti-tuberculosis
therapies also encourage resistance by reducing
the populations of only the susceptible
organisms from a mixed infection.
Furthermore, most policymakers and public
health professionals have no basis for developing
and implementing policies to control the spread
of infectious diseases. At present, even the
United States has no comprehensive system for
detecting outbreaks of infectious disease.
Traditional seats of infectious disease research
such as the US military have been attenuated by
downsizing and restructuring. Funds for
research, treatment, and prevention programs
are more commonly driven by emotional
outrage than by actual disease burden. As an
example, annual WHO programs against TB,
causing nearly 3 million deaths per year,
received $16 million compared to $185 million
for AIDS and other sexually transmitted diseases
with 1.5 million deaths and $74 million for
tropical diseases (excluding malaria) with 0.2
million deaths (WHO, 1996).
The impact of international
organizations in combating infectious
diseases
Global interdependence has moved to center
stage a diverse assortment of issues that once
were relegated to the periphery of foreign policy
agendas. A glaring example of this
interdependence in health care delivery is the
fact that many of the nations with the most
significant health concerns are the least capable
of effectively dealing with them. Significant
responses have been made by the World Health
Organization (WHO), the United Nations
International Children's Fund (UNICEF), and
various
non-governmental
organizations
(NGOs) to deal with these concerns.
The efforts of the World Health Organization
The WHO is a UN specialized agency whose
objective is `the attainment by all peoples of the
highest possible level of health' (Leduc, 1996).
The WHO was founded in 1948 and functions
primarily to coordinate efforts to raise
worldwide health levels and monitor observance
of international health regulations. In the 1960s
and 1970s, the WHO led the worldwide effort to
eradicate smallpox. When the program started in
1967, two million people were dying each year
from smallpox. Within ten years, the disease was
eradicated. Polio has been eliminated from the
Americas and is targeted for worldwide
eradication within the next couple of years.
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Measles, the eighth leading cause of death
worldwide, may become the next global target
for eradication. The WHO has also designed and
implemented a successful treatment regimen for
TB characterized by direct observation of oral
therapy by contracted health workers (DOTS).
This strategy maximizes patient compliance and
cure rates while minimizing the potential for the
development of further anti-microbial resistance.
In areas where the WHO TB control strategy or
`DOTS' was implemented, the treatment success
among new cases was 77% compared with 41%
in those areas where it was not. Unfortunately,
only 23% of the global population is currently
living in areas where the WHO TB control
strategy is available (Raviglione, 1995).
The WHO also has the responsibility to
collect and publish epidemiological data from
around the world and to implement international
health regulations. To combat newly emerging
infectious diseases and the spread of resistant
pathogens, WHO is electronically linking more
than 200 WHO collaborating centers, 190 health
ministries, 142 country offices, and six WHO
regional offices, together with almost 100
national laboratories, for the rapid international
exchange of information on disease outbreaks
(Heymann, 1998). In response to increasing
disease emergence and re-emergence, WHO
established the Division of Emerging and other
Communicable Diseases Surveillance and
Control (EMC) in 1995. EMC's mission is to
strengthen and coordinate international efforts
to respond to community diseases and to
develop strategies to strengthen and coordinate
the international response to emerging and
reemerging infectious diseases.
Other bilateral and multilateral initiatives
Regarding bilateral assistance (country to
country) to developing countries in combating
emerging diseases, the United States is joined
increasingly by other developed nations who
directly provide or fund assistance programs.
The European Community Humanitarian Office
(ECHO) and the Japan International Cooperation
Agency (JICA) are examples of national or bloc
agencies that are emerging as significant players.
Other important organizations with expertise
in communicable disease control include
UNICEF and NGOs. The UN Childrens Fund,
for example, was created in 1946 to help the
world's underprivileged children, focusing on
development and emergency assistance to
young victims of natural disasters and social
upheaval.
UNICEF's
efforts
increased
immunization rates among the world's children
against preventable diseases from 20% in 1980
to 80% today (Winkler, 1996). The contribution
of NGOs and other international aid agencies
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has proven invaluable in building community
awareness and support for response efforts by
organizations such as WHO. For example, an
important role for these NGOs is to provide a
seamless transition from WHO-sponsored
immediate public health assistance to long-term,
domestic health care delivery.2
The need for international leadership:
possibilities and constraints
As noted above, emerging infectious diseases
and the increase in antibiotic resistance are
worldwide problems requiring global leadership
in their solutions. The international community
has various possibilities to act upon this need for
leadership. However, these opportunities are
constrained by factors such as the lack of
capacity of recipient countries to use aid and
expertise appropriately, as well as the lack of
effective global surveillance.
Possibilities for international leadership
The WHO strategy described above uses the
existing international health infrastructure as a
base to improve global surveillance; to enhance
capacity of local and national public health
laboratories; to foster applied research to address
practical problems; and to improve infectious
disease prevention and control.
The WHO is therefore uniquely positioned to
play a leadership role in the global response
effort because it has both the mandate and the
networks to enable countries of the world to
intensify their efforts against emerging diseases
in a coordinated manner. For example, the WHO
could play an important role in serving as a
global policy organization for gathering,
analyzing, and disseminating information, and
also for proposing policy alternatives that could
be taken to address these issues. In addition, the
WHO can advise countries, particularly in the
developing world, on effective ways to intensify
national efforts to detect and control emerging
diseases, since it maintains ongoing relationships
with health ministries throughout the world.
Through several collaborating networks, the
WHO interacts with centers throughout the
world, many of which are on the cutting edge of
research and analysis of specific disease and
health issues. With help of these collaborating
centers, the WHO can mobilize the best
scientific and medical experts to assist in
emergency response activities or to serve on
expert committees and study groups.
Although the highly developed countries
cannot provide health care to the world
unilaterally, they can provide leadership for the
international health community. In the US, for
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example, a recent US Presidential `Decision
Directive' affirms the responsibility of US health
agencies such as the CDC to assure domestic
national security through support of disease
control and eradication efforts globally (National
Science and Technology Council).
Constraints on international leadership
The capacity and willingness of international aid
recipients to use international aid appropriately
will vary by country. Regardless, there will be
complex, expensive and, in some cases,
intractable problems with providing aid and
assistance. For example, proposed aid programs
to prevent and treat HIV and associated diseases
in developing countries depend largely on
indigenous health workers for their success. In
the absence of trained health workers, treatment
and prevention measures cannot be effectively
fielded. In some cases, particularly in the case of
TB treatment, partial treatment is worse than
none at all because of the potential for the
development of multi-drug resistant TB
organisms. Moreover, education programs
aimed at preventing disease exposure frequently
depend on literacy levels and cultural and social
factors that determine appropriate risk
communication. If these are not adequately
considered, the programs likely will fail. Beside
that, the information infrastructure needed to
communicate information is becoming more
expensive in order to take advantage of
increased bandwidth demands, even though
automated disease surveillance and reporting
systems are increasingly relying on cheaper and
faster computer equipment. As a result, those
areas of the world most susceptible to infectious
disease problems are also least able to develop
and maintain the necessary communications
equipment.
Another major obstacle to effective global
surveillance is the potential for inaccurate
national health statistical reporting. Announcing
the existence of an outbreak of a dreaded disease
may severely affect commerce and tourism.
Besides the normal barriers to reporting, such
as inadequate national surveillance and
diagnostic capabilities, there are significant
political motivations to misreport or not report
disease incidence data. For example, nearly every
country initially denied or minimized the extent
of the HIV status within its borders. Even today,
at least ten nations known to have extensive
HIV seroprevalence refuse to cooperate with the
WHO, which can only publish information
submitted by these countries themselves (MSF,
1996). Similarly, Egypt and Sudan routinely
deny the existence of cholera in their national
waters and Saudi Arabia has asked WHO not to
warn travelers of mosquito populations infected
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JOURNAL OF CONTINGENCIES AND CRISIS MANAGEMENT
with dengue viruses. Additionally, Russian epidemiologists recently admitted that most Soviet
scientific publications contained nonfactual data,
and their scientific and practical value was zero
(Walter Reed Army Institute of Research, 2000).
Finally, WHO's influence in international
health has recently diminished, due to uncertainty in the effectiveness and efficiency of
WHO's critical normative functions. Although
the creation of the EMC Division (now the
Department of Communicable Disease Surveillance and Response or [CSR]) has bolstered this
influence over time, WHO's total budget in
1996 was only $0.95 billion compared with
World Bank loans for health of $2.5 billion in the
same year. Political differences among nations
negatively affect the credibility of international
organizations such as the WHO even more, and
this makes firm, consistent leadership very
difficult.
Future opportunities and threats in
the prevention and control of
infectious diseases
Infectious diseases, and their potential for
prevention and control, currently receive more
and more attention. This aspect of public health
(so long ignored) is worthy of top-level policy
attention. It is expected that positive strides will
be taken in the future, in the research domain as
well as in the policy domain. Unfortunately,
there are great psychological impediments to get
people to think about protecting their well-being
while they are still healthy and building this
notion into political and social institutions. In
addition, the actions in the research and policy
domain will always stay behind trends in
microbial change and adaptation.
Positive strides in the research and policy domain
Vaccine research will result in the development
of more effective and less expensive vaccines
that are also safer and more acceptable to human
beneficiaries. Examples will include aerosol
vaccines delivered as sprays through the nose
or skin, edible plants containing geneticallyengineered vaccines, and vaccine `pills'. Vaccines
against animal diseases such as hog cholera, footand-mouth disease, and anthrax will be
stockpiled in the event of natural or intentional
outbreaks. In addition, genes that influence
infectious disease risk likely will be discovered
over the next five years. These discoveries will
have important implications for the prevention
and control of infectious diseases. For example,
prevention strategies may be targeted to
populations at particular risk, as is currently
done to prevent pneumococcal pneumonia
Volume 9 Number 4
December 2001
among those with sickle cell anemia a group
with a special susceptibility to such lung
infections. New drugs will be designed making
them potentially more effective and less toxic
than traditional drugs. Other drugs will be able
to change the very structure of bacteria making
them susceptible to antibiotics they were
previously resistant to.
In the policy domain, childhood and adult
immunization rates will improve. Second, the
irradiation of meat products will slowly become
acceptable internationally and correspondingly
adopted by industry in many countries. Third,
the current relative paucity of infectious disease
epidemiologists and laboratorians will begin to
reverse as the number of training epidemiology
programs increase globally.3 Fourth, simple
diagnostic tests, exhibiting greater sensitivity
and specificity for infectious diseases, will be
fielded to aid surveillance and control programs.
Like food irradiation, however, they will not be
instituted widely enough, nor timely enough, to
significantly prevent diseased individuals from
crossing international borders.
The threat of microbial adaptation and change
Antimicrobial-resistant micro-organisms will
continue to emerge and rates of resistance
among currently resistant organisms will
increase. Although guidelines will be formulated
and adopted by various medical, veterinary, and
agricultural groups, they will not be instituted in
time to stem the tide of resistance during this
period. Among these micro-organisms will be
those causing tuberculosis, HIV/AIDS, malaria,
and common human diseases such as pediatric
ear infections, pneumonia, and food-borne illnesses. This increased resistance may also result
in international trade barriers as some countries
will adopt more conservative national policies
for antimicrobial use (e.g., prohibition of cattle
growth promoters in Sweden). `New' pathogens
that were actually previously prevalent but
newly-recognized likely will continue to emerge
as a result of changes in surveillance strategies
and diagnostic capabilities. Possible examples
include diseases once thought to be environmentally related or due to lifestyle factors, such
as diabetes, cancer, heart disease, and gastric
ulcers. Truly newly emergent diseases will also
continue to be recognized as animal pathogens
will continue to be introduced into the human
food chain; drugs and blood products will
continue to be contaminated to some degree;
and prevention and treatment modalities such as
live vaccine vehicles and xeno-transplantation
will prevail.
The development of new, effective antimicrobials will not keep pace with new and/or
resistant organisms. Those few new or newlyß Blackwell Publishers Ltd 2001
THE GLOBAL RESURGENCE OF INFECTIOUS DISEASES
approved antimicrobials will first become
available to the wealthy and treatment failures
among those who cannot afford the new drugs
will increase. Although recommendations will be
made for an integrated, effective global
surveillance system, it will not be instituted in
the near future in most countries of the world.
The institution of a national system, let alone
that of an international one, integrating both the
medical and veterinary professions will not be
soon realized.
Conclusion
In summary, there is a belief among politicians
that doctors and scientists have been unduly
alarmist about the threat of an imminent plague.
In the euphoria of the 1940s and 1950s, the
architects of national public health policies in the
developed world seriously miscalculated by
ignoring three factors that were to decimate
their ambitions. First, they did not anticipate
how modern travel would open up a reservoir of
microbial infection with even greater potential
than that which they hoped to conquer. Second,
medical science was unaware of the microbe's
potential to adapt and mutate in the face of the
antibiotic assault. Last, and most important, they
failed to anticipate how paradoxically the new
bounty of developed society would lead to a
change in sexual mores and to drug abuse,
thereby facilitating the microbe to launch an
offensive far more devastating than the threat
antibiotics and vaccines had briefly presented to
its existence.
Nowadays, it has become clear that infectious
diseases are a real threat to the world's health.
Political leadership and investment of both
developing and developed countries in the
research and policy domain will therefore be
increasingly required in order to catch up and
keep pace with the ability of microbes to change
and adapt to their context.
Notes
1. In addition, there is a trend of microbial
adaptation and change. For example, it is most
alarming that Plasmodium vivax, responsible for
the majority of malaria morbidity worldwide, has
developed resistance to chloroquine, first reported
in 1989. This resistance, perhaps resulting in
higher prevalence rates, may increase the number
of imported cases into the United States,
improving the chances for malaria to gain another
foothold in the USA. Influenza viruses are unique
in that they also evolve relatively rapidly in
nature. This is due to selective pressures on the
virus from the large population of partially
immune people who have antibodies to the virus
ß Blackwell Publishers Ltd 2001
231
as a result of previous infections. Agricultural
practices in Southeast Asia that put ducks, pigs,
and humans in close proximity also may facilitate
viral genetic shift. HIV displays similar genetic
variability, which will present major problems in
the development of an effective vaccine.
2. Examples of these NGOs and their primary efforts
are: the Rockefeller Foundation (e.g., hookworm
reduction and yellow fever vaccination
development); Rotary International (e.g., polio
eradication); and Medicins Sans Frontieres (MSF)
or Doctors Without Borders (emergency relief in
developing regions).
3. For example, Field Epidemiology Training
Program or FETPs, Training in Epidemiology for
Public
Health
Interventions
Network
[TEPHINET], EPIET, Public Health Schools
Without Walls.
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