Memorandum by the World Health Organization
(WHO)
DEPARTMENT OF COMMUNICABLE DISEASE SURVEILLANCE
AND RESPONSE
INTRODUCTION
1. Following the recognition of the threat
of new and emerging infectious diseases, and serious global crises
associated with epidemics such as plague in India (1994) and Ebola
haemorrhagic fever in former Zaire (1995), the World Health Organization
(WHO) created a specific department (now known as the Department
of Communicable Disease Surveillance and Response, CSR) and new
activities dedicated to surveillance, alert and response to epidemic-prone
and emerging infectious diseases. The UK has been a strong supporter
of this department from its initiation.
2. The work of CSR and the vital part played
by the United Kingdom (UK) in this work is outlined below.
BACKGROUND: THE
EMERGING THREATS
TO NATIONAL
AND GLOBAL
HEALTH SECURITY
3. Throughout history, human populations
have experienced major epidemics, often resulting in panic, political
instability, disruption of trade and large numbers of deaths.
While all communicable diseases have the potential to spread,
it is the rapidity of spread of epidemic-prone diseases, the emergence
of previously unknown pathogens and the high mortality rates in
newly affected populations which have marked the human psyche
and determined many of our social and political responses.
4. Global health security is threatened
by the emergence of new or newly recognised pathogens, the resurgence
of known infectious threats, and the possible intentional use
of either of these in acts of terrorism. There is weak and patchy
capacity to respond to these threats in a timely manner. The epidemiology
and geographical distribution of infectious diseases, once thought
to be relatively stable, have become subject to rapid, significant,
and often unexpected changes. No country is safe. An outbreak
anywhere in the world poses a threat to health security everywhere.
This new reality has global implications which go well beyond
matters of health and disease and underscores the vital need for
nations to be more alert to the emergence of new diseases, and
to be more proactive in containing them at an early stage, before
a local epidemic becomes a global pandemic.
5. Over two-thirds of the emerging infections
identified during the 1990s are thought to have originated in
animals, both domestic and wild species. Some are believed to
have emerged from animals living in tropical rainforests or elsewhere
in close proximity to humans. Though intensive research has failed
to disclose the origins of Marburg and Ebola haemorrhagic fever
outbreaks, both are thought to have animal sources somewhere in
the transmission cycle. Increased human mobility has also resulted
in incursions into new or unfamiliar ecological zones, for economic
reasons, research, or adventure. These activities contribute to
the frequency with which diseases, previously confined to animals,
can "jump the species barrier" to man. Man-made changes,
such as deforestation, disrupt natural habitats and can force
animals searching for food into closer contact with humans. For
example, in 2000, the EcoChallenge sports event in the jungles
and rivers of Malaysia, which drew over 300 athletes from 27 countries,
resulted in the importation of leptospirosis to cities in three
continents. Less exotic but more alarming are cases where diseases
of domestic animals have entered human populations, with major
implications for the food supply and huge costs for agriculture
and trade.
6. One of the obvious consequences of globalisation
of travel and trade is the creation of opportunities for the rapid
international spread of epidemics. Transmission from continent
to continent is no longer limited to ships, and the insects, animals,
birds, and humans that travel on them. The number of international
airline passengers has risen from two million in 1950 to over
1.4 billion a year today. This increase in mobility means that
infectious agents can now travel during their incubation period
in unsuspecting travellers and spread from continent to continent
in a matter of hours.
LACK OF
EFFECTIVE SYSTEMS
FOR PUBLIC
HEALTH SURVEILLANCE,
ALERT AND
RESPONSE
7. Today, there is insufficient capacity
in many countries to recognise disease events in a timely manner
and to contain them. Even in developed countries, funding for
the maintenance of systems of surveillance, alert and response
is often challenged. Furthermore, there is the fear of costly
repercussions for countries (such as trade or travel restrictions)
if disease events are notified. WHO data show that new diseases
emerge most frequently, and outbreaks occur most often, in poor
nations or belts of poverty in industrialised nations, where prompt
reporting is often impeded by lack of communications capacity.
In some of these countries, expertise is weak, laboratories are
poorly equipped for epidemiological studies and clinical diagnoses,
and systems for the collection and analysis of epidemiological
data are insufficient. Moreover, some epidemic-prone infectious
agents are extremely difficult to handle; for example, of the
haemorrhagic fever viruses currently identified, virtually all
are classified as biosafety level four pathogens.
WHO'S RESPONSE
8. A strategic framework to address the
threats posed by epidemics and emerging infections and to improve
global health security was approved by the World Health Assembly
in May 2001. The framework comprises three key objectives:
— containing known risks (eg influenza,
meningitis, haemorrhagic fevers, smallpox, cholera);
— responding to the unexpected (eg
outbreaks of natural or intentional origin, emerging infections);
and
— improving both global and national
preparedness (eg laboratory capacity strengthening, epidemiology
training, improved communications systems).
9. The strategy builds on WHO's global public
health mandate, under the umbrella of the International Health
Regulations (currently under revision), exploiting WHO's political
neutrality, public health focus and privileged access to Member
States. It is supported by global partnerships. For example. over
the past five years, WHO has worked with many partners including
the UK and other countries in the G7 and the European Union, taking
advantage of the technical excellence and unique experience of
their institutions, to implement a series of essential activities
aimed at ensuring global health security against epidemics and
emerging diseases. A brief review of the WHO activities in the
domain of global health security, and the critical role played
by the UK follows.
Containing known risks
10. Epidemics and emerging infections are
caused by a wide range of bacterial, viral and parasitic agents
but, despite the emergence of newly recognised pathogens, the
majority of epidemics are caused by known pathogens which, after
detection, verification and immediate response, require disease-specific
control strategies. Detailed and constantly updated understanding
of specific disease trends through surveillance and research,
and the implementation and evaluation of the control and prevention
tools, are critical to detect epidemic "bursts" and
build optimum containment strategies. The UK contributes to the
work of WHO in containing known risks through specialist advice
and facilities provided by the WHO Collaborating Centres based
in and supported by the UK, through the participation of individual
experts in WHO consultations and through the financial support
provided by the UK Department for International Development (DFID).
Responding to the unexpected
11. Commencing in 1997, WHO put in place
a system for rapid and systematic outbreak alert (intelligence,
verification, and dissemination of information) and co-ordinated
international response (field investigation, case finding/contact
tracing, case management, vaccine supply, logistics and security
support). From 1 January 1998 to 31 March 2002, 538 outbreaks
of international concern were verified in 132 countries with a
median duration to verification of one day. A total of 117 of
these events involved Category A biological agents including eight
events initially reported as smallpox and all refuted rapidly
(eg the most recent rumour of smallpox in Pakistan was investigated
and refuted within 24 hours). Other agents revealed through this
process included viral haemorrhagic fevers (83), anthrax (13)
plague (11), tularaemia (2) and botulism (1).
12. In April 2000, WHO established the Global
Outbreak Alert and Response Network (GOARN) as a technical partnership
of 110 institutions and other relevant networks that have come
together to pool resources for epidemic containment. GOARN provides
a global mechanism for the international co-ordination of response
and has agreed "Guiding principles for International Outbreak
Alert and Response" supported by detailed operational protocols
under development in technical working groups and the Network
Steering Committee. Recent examples of co-ordinated international
responses include Ebola in Uganda, Gabon and Congo (550 cases
detected and 7,500 contacts traced), urban yellow fever in Cóte
d'Ivoire (2.8 million people vaccinated over a 10 day period)
and influenza in Madagascar (initially reported as an unknown
disease with high case fatality and rapid spread, later confirmed
as influenza).
13. A number of UK institutions are active
in the network including the PHLS Communicable Disease Surveillance
Centre (CDSC), PHLS Central Public Health Laboratory (CPHL), Medical
Emergency Relief International (MERLIN) and the Infectious Diseases
Unit of North Manchester Hospital. UK physicians, epidemiologists
and laboratory experts have been involved in supporting international
outbreak responses including Ebola in Uganda and Gabon, Lassa
fever in Sierra Leone, Congo Crimean Haemorrhagic Fever in Kosovo
and most recently influenza in Madagascar. The PHLS is represented
on the Steering Committee of the Network by Dr Angus Nicoll, Director
of CDSC. Furthermore, DFID has provided significant funding in
support of outbreak responses, notably for Ebola in Uganda and
Gabon, and for meningitis in Burkina Faso and Ethiopia.
Improving preparedness
14. Throughout the development of the WHO
strategy for global health security, significant gaps have been
identified in global, regional and national infrastructure. Critically,
these gaps are most profound in the areas of epidemiology and
essential public health laboratory services. These gaps were also
identified in the recent reports on global surveillance from the
US General Accounting Office.
15. WHO's activities in assisting Member
States to improve national preparedness for alert and response
to epidemic-prone and emerging infections include:
— Assessment of national communicable
disease surveillance systems (including early warning and response
systems) to identify gaps, define priorities, and to identify
areas of synergy for integrated disease surveillance;
— Assistance to countries to develop
national plans of action to strengthen the above systems;
— Assistance to countries to implement
these plans of action through training in field epidemiology,
strengthening laboratory skills and infrastructure, providing
specific technical advice, improving information technology skills
and electronic communications, and promoting networking both nationally
and internationally.
The International Health Regulations (IHR)
16. A regulatory framework for global health
security activities is provided through the IHR and will be further
strengthened by the revision of these regulations currently under
way. The revised IHR will be based on the understanding that the
best way to prevent international spread of diseases is to detect
and contain them rapidly. International co-ordination is necessary
since many countries may need assistance during serious disease
events. The revised IHR will include a broader scope to include
the notification of "public health emergencies of international
concern"; a communications mechanism between affected countries
and WHO to verify unofficially reported outbreaks; rapid international
risk assessment and assistance; and maintenance of national core
capacity for early warning and response.
17. The revision process involves the nomination
of national focal points and a series of consultations with Member
States; a process within which the UK has actively participated.
CONCLUSION
18. The globalisation of threats to health
security mean that no country can ignore the international perspective.
The goal is that the world is alert and ready to respond rapidly,
both locally and globally, to epidemic-prone and emerging disease
threats as and when they arise, be they natural or intentional
in origin, minimising their impact on the health and economy of
the world's populations. The UK already assists WHO in working
towards this goal and in so doing improves its national health
security as well as contributing to the improved surveillance,
alert and response capacity in resource-poor countries. WHO would
welcome proposals to strengthen the mechanisms by which such contributions
can be facilitated.
October 2002
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