CHAPTER 2: BACKGROUND
AND REPORT STRUCTURE |
In this chapter we describe what infection is,
discuss the burden of infection and provide a brief overview of
how infection is currently treated and prevented in England and
Wales. We identify two key tasks necessary to tackle infection,
firstly, diagnosis and treatment, and, secondly, prevention and
We suggest that these tasks must be underpinned
by supporting components, namely surveillance, effective systems
for gathering and sharing information, education and training,
and research and development. In addition there should be clear
effective collaboration and communication both within and among
those who carry out the key tasks of an infection service. This
should extend to international collaboration. We will discuss
each of these tasks and supporting components in turn throughout
2.1 Infection causes illnesses of varying severity.
An infection may be mild and short-lived (e.g. the common cold);
serious and short-lived (e.g. meningitis); or may lead to chronic
conditions such as tuberculosis, cervical cancer and peptic ulcer
disease. In addition some people carry and transmit an infection
(e.g. meningitis bacteria) whilst remaining well.
2.2 The form an infection takes results from complex
interplay between micro-organisms (bacteria, viruses, protozoa
etc.), hosts (person or animal) and the environment. The likelihood
of an organism causing an infection depends on a variety of factors.
These include the immune status, age and general health of an
individual, the intrinsic capacity of a micro-organism to cause
disease (pathogenicity), its potential for causing severe disease
(virulence), and the relative ease with which it can establish
itself in a host (infectivity) and be passed from person-to-person
2.3 Some micro-organisms are the cause of infection,
but some are also essential for our well-being.
Each person has more bacteria on their skin and in their gut than
the number of people that have ever lived on the planet.
These bacteria play an important role in our defence against infection
and disturbing then, for example by using antibiotics, can allow
pathogens to flourish. Besides their role in protecting against
infection these beneficial micro-organisms are also important
in the metabolism of nutrients and vitamins.
2.4 The environment plays a significant role in infection
with some micro-organisms surviving better in dry climates, others
in the wet. Humans create settings such as doctors' waiting rooms
which may facilitate the transfer of infectious micro-organisms
from one person to another. Even attempts to treat infection,
for example by using antibiotics, can create new problems such
as antimicrobial resistance [Spec Ad Cttee Antimicrob Resist,
of infection: extent of the problem
2.5 In the United Kingdom around 70,000 people die
each year from an infection. Hospital acquired infections are
estimated to cost the NHS about £1 billion per year [BioIndustry
Assoc, I p25]. Forty percent of primary care consultations result
from infection and the health care system is often severely stretched
as a result of winter influenza epidemics [Stewart, II p316; Birmingham,
2.6 Notwithstanding significant scientific and medical
developments, such as the introduction of vaccines and antibiotics
and improved socio-economic conditions over the last century,
we cannot afford to adopt the position taken in the mid twentieth
century that infectious diseases were conquered [AcMedSci, II
2.7 Optimism in relation to infections has proven
to be untenable. In the recent past a number of new infections
have appeared and old infections which were thought to have been
under control have become problems again. This list of emerging
and re-emerging infections includes tuberculosis, new strains
of influenza, HIV/AIDS, EColi O157, Nipah Virus, West Nile virus,
malaria and, most recently, SARS [see Box 1].
2.8 Infections cannot be conquered. They can however
be controlled and prevented under many circumstances, but they
will continue to present challenges. Factors such as global travel,
antibiotic resistance and increases in numbers of people with
weak immune systems (following cancer treatment or organ transplantation)
all provide opportunities for infection to develop and spread
[Stewart, II p316]. Infections found in animals may directly infect
humans, as with anthrax, or they can mutate and pass on to humans,
as with avian flu (infections transmitted from animals are known
as zoonoses) [Stewart, II p318 Thorns, Q440]. The recent spectre
of bioterrorism (the deliberate release of infectious agents)
is also a possible threat [DoH, II p1].
to tackle infection
2.9 There are two key tasks that need to be carried
out in order to reduce incidence and spread of infection:
diagnosis and treatment; and
prevention and control.
2.10 These tasks are currently performed by a wide
variety of health professionals and scientists. Members of the
public must also play a part in any meaningful attempt to control
infection. In Boxes 2, 7 and 9 we provide a brief overview of
how infection is treated, how information is gathered and feeds
into prevention and control activity. In Boxes 3 and 4 we provide
a simplified representation of the main lines of responsibility
between different key organisations and health professionals and
the flow of information between them as relates to infection control.
Box 1: Examples
of infections that have emerged or been recognised over the last
refers to infections that are known to be zoonotic)
2.11 In order to be able to carry out the two key
tasks effectively there are four supporting components needed,
which in turn requires
systems for gathering and sharing information;
and training; and
2.12 In this report we highlight concerns with the
current arrangements and make recommendations for change. We examine
problems with the ways in which each of the two key tasks are
carried out, and then move on to look at how the four supporting
components can be improved in order to underpin the key tasks
effectively. We then consider ways in which to improve collaboration
and how to create a more integrated infection service.
How infection is controlled
Catching an infection
Most people with an infection, particularly mild acute conditions such as colds, remain unknown to the health system as they look after themselves. They may infect other people in the family, work colleagues or casual contacts.
Entering the healthcare system
Seeing a GP. In most cases if a person with an infection feels unwell and needs advice they consult a primary care doctorGP. GPs usually make a diagnosis and decide on treatment on the basis of symptoms. They advise the patient on suitable action (such as bed-rest, drinking plenty of fluids) and might prescribe a medicine (such as antibiotics). If they are uncertain of the diagnosis, if the patient is very unwell, or if the patient fails to improve after some days or following a course of treatment, the GP might send a sample (such as a throat swab or faecal sample) to the local microbiology laboratory to identify the problem .
Going to hospital. If a patient remains unwell with an infection or has severe illness GPs may refer them to hospital. In most hospitals the patient will be looked after by a general physician, paediatrician or geriatrician. In a few hospitals, mainly teaching hospitals, there are specialist infectious disease physicians who care for patients with infection. Hospital physicians will often send samples to a laboratory to be investigated.
Identifying the infectious organism: laboratories
Microbiology laboratories, managed by medical microbiologists (doctors specialising in laboratory investigation of infection), investigate samples and identify the infectious organism. Sometimes samples are sent on to a national reference laboratory for more detailed testing. The medical microbiologist then often advises the physician about how to best treat the infection, and thus the patient.
Acting to control further infection
Consultant in Communicable Disease Control (CCDC). The CCDC is responsible for prevention and control of infection in the community. In cases of infections which can be easily spread throughout the community and cause illness in many people (such as salmonella), the microbiologist or the physician may inform the CCDC who will then implement relevant control measures.
Environmental Health Officer (EHO). In the case of an infection of public health importance, such as salmonella, the CCDC (or GP) will often inform the EHO (employed by the local authority) about the outbreak of the infection. An EHO will visit the patient to ascertain from where they picked up the infection and whether they are likely to infect others easily and then will take action to try to prevent further spread of the infection.
Community infection control nurses (CICN). The CCDC may ask a CICN to identify and follow up all close family and friends of the patient to ensure that they are diagnosed and treated if necessary.
Reporting infections to the authorities. Physicians are legally obliged to inform the local authority, via the CCDC, of certain "notifiable" infections (e.g. TB and cholera).
Simplified lines of accountability and
Simplified lines of accountability and
6 House of Lords
Select Committee on Science and Technology, Resistance to Antibiotics,
7th Report, 1997-8, HL81-I ISBN 0 10 478998 0 Back
The Path of Least Resistance. Standing Medical Advisory
Committee, Department of Health, London 1998. Back
House of Lords Select Committee on Science and Technology,
Air Travel and Health, 5th Report, 1999-2000, HL 121 ISBN
0 10 444200 X Back
We thank Professor Stephen Palmer for providing information reproduced
in this table. Please note that this is not intended to be an
exhaustive list of all infections that have been described in
the last thirty years. Back