EPIDEMIC RISKS AND SURVEILLANCE ( Writing Sample)
An epidemic can be described as an increase (mostly sudden) in disease cases of what is
normally expected in a population in the area which they inhabit (1). Epidemics normally occur
when the right conditions presents itself i.e. the presence of the agent and a susceptible host. If
these are present in large numbers within a population in a given area the chances of an
epidemic increases. Throughout history there have been epidemics dating back decades, an
example of this would be the spread of influenza in the United States in 1918. Epidemics can put
sudden pressure on the demands of both national and international healthcare systems and if
not handled properly can bring both social and health systems to collapse.
There are certain factors that drive the risk of epidemics on both national and international
levels. Some of these factors on a national level include population growth, urbanisation,
mobility, environmental changes which includes intensification of agriculture and livestock
production, deforestation which can lead to a breach in the species barrier and also climate
change can be a driver of an epidemic risk(2). Most of the drivers of epidemic risk are
interlinked with each other and in most cases one leads to the other.
Population growth and urbanisation are important predictors of emerging infectious diseases
and spread of epidemics(3) and this is not solely down to the fact that an increase in population
density helps the spread of infectious disease because of the close human to human contact but
also due to the pressure it puts on systems around it. Rise in population brings about increased
demands for livestock and other agricultural produce and this leads to intensification of
farming. To cope with this there are human induced changes in land use (deforestation to make
space for farming) which sometimes can lead to breaking of the species barrier or human
encroachment of the ecosystem and this enhances interaction between wildlife, livestock, and
human beings thus increasing the likelihood of pathogens crossing the species barrier(2) and
also the possibilities new infectious diseases emerging, which could also alter the genetic make-
up of endemic viruses making them more virulent. Intensive farming of different livestock in a
small farm to meet demands sometimes gives rise to viruses jumping species e.g. a virus in birds
is transferred to pigs and re-assortment takes place and it is then transferred to humans.
Urbanisation brings about changes in social structures (4); it drives some vector-borne diseases
because urbanisation brings about the establishment of urban slums and peri-urban areas
which have very poor hygiene and sanitation.
Climate has become one of the important drivers of epidemic risk due to the current changes in
climate that is occurring. Vector-borne diseases especially arthropod vectors tend to thrive in
warm temperatures and recent El Niño was a predictor of dengue fever outbreak in Thailand(5).
On an international scale the major driver of epidemics is globalisation in the sense that the
constant travel of people and the trade of animals and their produce on the international
market. Business travellers and frequent fliers tend to mix with each other either by favouring
particular airport lounges or staying in particular hotels, with this sort of mixing amongst
people from different parts of the world respiratory infections could potentially spread quickly
in this group of people and thus between countries creating a pandemic. The SARS outbreak is a
really good example of how infections can spread quickly amongst travellers, where 6 of the 16
people infected in the Metropole hotel in Hong Kong took international flights to Australia,
Canada, Singapore, Vietnam and the Philippines leading to out brakes in Hanoi, Toronto and
Singapore within days of the first case in Hong Kong (CDC). In addition to human movement
cross border trade of livestock could also be considered an international risk as most trading
centres can act as a mixing zone of humans and other species which are then shipped off to
other countries.
Surveillance is the on-going systematic process of collecting, collating, and analysing of data so it
can be disseminated to the necessary authorities for action to be taken(6). The purpose of
surveillance is to provide a scientific and factual basis for policy decisions in public health
practice and also allocation of resources or we can simply say surveillance is the gathering
information in order for public health to take proper action. Surveillance systems serve
numerous functions in the sense that they can predict the emergence of diseases, support
response during an outbreak, and help in evaluating the response.
Some basic ingredients of effective surveillance include a good team of motivated people with
basic sound epidemiological tools and efficient communication systems. For surveillance to be
effective at the national level it has to begin at the local and state ministries of health, these
ministries mostly work closely with a range of healthcare providers including laboratories,
hospitals, and private healthcare providers to obtain reports on a lot of infectious diseases. In
Ireland for example there are a number of diseases that are notifiable to the Health Protection
Surveillance Centre (HPSC) if a case is discovered in a laboratory, acute hospital or general
practice. There should also be a standard set of criteria to determine if an individual should be
classified as having the condition of interest which should be a simple and clear. Together with
an efficient reporting mechanism this will help in swift reporting and makes gathering of
surveillance data more effective. There also has to be coordination between public health and
animal health professionals to get updates on the health of animals as regards outbreaks of
illness in different species. It is also advisable to have an operational diagnostic laboratory as
full partners of a national surveillance and monitoring system and if need be an international
reference laboratory can be used to support surveillance by doing confirmatory diagnostic
tests(7). Also the dissemination of information to those who need it in a quick manner for action
to be taken is another component of an effective surveillance. For all these to function properly
the key people and institutions have to be identified in advance and put together in a structured
manner so there is a flow of information and all roles are well defined.
The other aspect of surveillance is to have a proper response system should the need arise for
action to be taken based on the data gotten from surveillance. At a national level a generic
response plan should be available in event of an outbreak. The plan should have detailed
descriptions of what should be done in case of an emergency and by whom, it should include the
roles of all stakeholders and a clear chain of command should be stated. An effective response
system should also include active case finding, case management, case isolation and also
voluntary home quarantine. As part of the plan it is important that quarantine procedures be
included, the where and how it will be implemented should be stated clearly. Depending on the
nature of the disease it is important to identify existing control measures e.g. vaccination
against the disease, contact should be established to determine vaccine stocks or as part of the
plan there should be a vaccine bank ready in the event of an emergency. Having all these
components in place would make response system to a potential outbreak both a large and
small scale effective and with everyone knowing what roles to play the health and social
systems would not be overwhelmed by most events.
Globalization has made disease spread across countries and continents fairly easy due to
international travel and trade. A health crisis or disease outbreak in one country can affect the
livelihoods and economies of countries in many parts of the world by posing a public health risk.
To combat the spread of infectious diseases on an international level the World Health
Organisation has the Global Alert and Response System (GAR) which helps detect outbreaks (8).
It is an integrated global alert response system for epidemics and other public health
emergencies based on strong coordination with national public health systems and an effective
international system for coordinated response in a case of emergency. The GAR supports
member states in implementing national capacities and preparedness in response to potential
epidemics, including laboratory capacities and early alert and ability to respond when alerted.
The Global alert and response system also helps nations in strengthening biosafety, biosecurity
and readiness for potential outbreaks of dangerous emerging infectious diseases and pathogens
e.g. (ebola, viral haemorrhagic fevers). It is a system that maintains and further develops a
global operational stage to aid outbreak responses and also support regional offices to help
implementation at the regional level. They also help develop standardized coordinated
approaches for response systems to major epidemic-prone diseases such as meningitis and
yellow fever. Member states get support in coordination for pandemic and seasonal influenza
preparedness and response.
The coordination between countries from different regions is made possible by the
International health Regulations 2005 (IHR) which is a legal document that binds 194 countries
across the world and all member countries of the World Health Organisation (9). The purpose of
the document is to help the international community prevent and respond to acute public health
risk with potential to cross borders and cause a worldwide pandemic. The IHR 2005 expands
the scope of regulation applications, gives more strength to the WHO’s authority on surveillance
and response, includes more demanding surveillance and response requirements, and puts into
use human rights principles to public health interventions(10). The IHR requires member
countries bound to the regulations report all health related events under surveillance to the
WHO meaning that state should notify the WHO of all health related events that may constitute
public health risk and an emergency of international concern. The regulations also require
member states to report potential public health risks identified outside their regions when
practicable to the world health organisation. This should be done when there is a possibility
that the risk could lead to an international outbreak, as evidenced by exported or imported
human cases, vectors that may carry infections or by contaminated goods crossing borders.
WHO is working closely with the countries and partners signed up to the international health
regulations 2005 to provide technical guidance and support to mobilize the resources needed to
implement the new rules in an effective and timely manner(10).
The global alert response system together with the international health regulations 2005
document binding the member states of the world health organisation makes surveillance of
infectious diseases very effective and enables prompt response in event of an outbreak. The
enhanced surveillance and communication between nations from different regions of the world
makes identification of potential threats quicker and countries when alerted can begin to take
steps to limit the potential spread of the illness. This international mechanism ensures timely
and open reporting of events with potential risk to public health, thus making helping to make
the world that more secure when it comes to new emerging illnesses and other infectious
diseases.
REFERENCES
1.
Gordis L. Epidemiology, 3rd Edition. Philadelphia: Elsevier Saunders, 2004, 18.
2.
Coker RJ, Hunter BM, Rudge JW, Liverani M, Hanvoravongchai P. Emerging Infectious
Diseases in Southeast Asia: regional challenges to control. Lancet, 2011; 377(9765):599-609.
3.
Jones KE, Patel NG, Levy MA, Storeygard A, Balk D, Gittleman JL, et al. Global trends in
emerging infectious diseases. Nature, 2008; 451(7181):990-3.
4.
Weiss RA, McMichael AJ. Social and environmental risk factors in the emergence of
infectious diseases. Nat Med. 2004; 10(12 Suppl):S70-6.
5.
Tipayamongkholgul M, Fang CT, Klinchan S, Liu CM, King CC. Effects of the El Nino-
southern oscillation on dengue epidemics in Thailand, 1996-2005. BMC Public Health. 2009; 9:
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6.
Thacker SB, Choi K, Brachman PS. The surveillance of infectious diseases. JAMA: the
journal of the American Medical Association. 1983; 249(9):1181-5.
7.
Jebara KB. Surveillance, Detection and Response: managing emerging diseases at
national and international levels. Rev Sci Tech. 2004; 23(2):709-15.
8
World Health Organization. Global Alert and Response (GAR). Current WHO phase of
pandemic alert. [cited 2014 January 2 ]. Available from http://www.who.int/csr/en/
9
World Health Assembly Revision of the International Health Regulations, WHA58.3. 2005.
[cited 2014 January 2]. Available from http://www.who.int/gb/ebwha/pdf_files/WHA58REC1/english/Resolutions.pdf.
10.
Baker MG, Fidler DP. Global Public Health Surveillance Under New International Health
Regulations. Emerging Infectious Diseases. 2006; 12(7):1058.