Glossary

acute respiratory infections (ARIs)

Bacterial or viral infections of the respiratory tract, including pneumonia and influenza, lasting less than 14 days. ARIs cause a larger total number of deaths than TB, HIV/AIDS and malaria combined, with the highest mortality among children under five years of age.

Care Quality Commission (CQC)

Independent regulatory authority inspecting all health and social care services in England to ensure they meet set quality standards.

case containment

A public health approach to infectious disease outbreaks, in which infected people (cases) are prevented from transmitting the pathogen, e.g. they may be ‘contained’ at home or in a special healthcare course. In extreme cases (e.g. smallpox, dengue fever) infected communities may be sealed off until all patients recover or die, all known or suspected contacts have been vaccinated (if a vaccine exists), or the disease incidence has fallen to zero.

Clostridium difficile infection (CDI)

Symptomatic infection with Clostridium difficile bacteria. CDI occurs mainly in hospitals and nursing homes in people over 65 years after treatment with broad-spectrum antibiotics, which destroy commensal gut bacteria, allowing C. difficile to proliferate in the large intestine. CDI causes severe ulceration of the gut lining, pain and persistent diarrhoea.

combined (or combination) vaccines

Vaccines containing the antigens of more than one type of pathogen, so immunisation protects against more than one infectious disease (e.g. the MMR vaccine against measles, mumps and rubella).

dracunculiasis

See guinea worm disease.

DTP3 coverage

The percentage of infants (i.e. in the first year of life) vaccinated with three spaced injections of a combined vaccine to protect them from diphtheria, tetanus and pertussis. This percentage is taken as one measure of the effectiveness of routine vaccination campaigns, particularly in low- and middle-income countries. NB: some sources refer to ‘DPT3’ (the terms are interchangeable).

eradication

Reduction of the number of infections to zero, with no known source of reinfection. Eradication of specific infectious diseases is confirmed by the World Health Organization (WHO) initially for a country, then for all countries in a WHO Region, and ultimately (as in the case of smallpox) for the whole world.

Global Outbreak Alert and Response Network

The main coordinating body of the World Health Organization’s infectious disease surveillance and response system. See also International Health Regulations (IHRs).

guinea worm disease

A disease caused by a nematode worm, Dracunculus medinensis, the largest tissue parasite to affect humans and the only exclusively waterborne pathogen. The worm larvae are ingested by aquatic Cyclops, consumed by humans in drinking water and, after a complex maturation cycle, emerge as adult worms usually from the person’s lower leg, causing pain and inflammation. (Also known as ‘dracunculiasis’.)

healthcare-associated infections (HCAIs)

Infections that develop as a direct result of medical or surgical treatment or contact in a healthcare setting, such as a hospital, residential care home or nursing home.

health-related behaviour modification

Long-lasting changes in behaviour that result in health gains, reduction in health risks or an increase in disease prevention.

herd immunity level

The herd immunity level is reached in a population when the ratio of immune (vaccinated or recovered) individuals to non-immune (susceptible) individuals is high enough to stop the infection circulating in the population; the pathogen ceases to circulate because there are too few susceptible individuals to sustain its numbers.

hygiene behaviour

The wide range of actions taken by individuals to maintain a standard of cleanliness of their bodies, domestic environments and workplaces, which prevents or reduces the risk of transmitting infectious agents to others.

incidence

The number of new cases of a disease arising in a given period, usually a year, expressed as a proportion of the population at risk (the incidence rate).

International Health Regulations (IHRs)

The IHRs (updated in 2005) aim to ensure early warning and prompt action to contain any public health emergency of international concern. The obligations on member states include national disease prevention, surveillance, control and response systems, public health security in travel and transport, particularly at designated airports, sea ports and ground crossings, and ‘real time’ reporting of disease outbreaks to WHO via round-the-clock communication channels.

methicillin-resistant Staphylococcus aureus (MRSA)

Strains of Staphylococcus aureus bacteria that resist treatment with methicillin (or meticillin in the UK), the antibiotic generally used to treat staphylococcal infections. MRSA commonly causes infection of surgical sites and the bloodstream. VRSA strains have also been identified that are resistant to another antibiotic, vancomycin.

Millennium Development Goals (MDGs)

The United Nations (UN) Millennium Development Goals were adopted by world leaders at a UN summit meeting in September 2000. The initiative includes the following targets, to be achieved by 2015: halving extreme poverty and hunger; providing productive employment and access to primary education for all; eliminating gender disparity in education; reducing the under-five mortality rate by two-thirds and the maternal mortality rate by three-quarters; achieving universal access to reproductive health; halting the spread of HIV/AIDS, malaria and tuberculosis and providing universal access to prevention and treatment; ensuring environmental sustainability and reducing biodiversity loss; halving the proportion of people without access to improved water and sanitation; achieving significant improvement in the lives of at least 100 million slum dwellers; and developing global partnerships for development, debt reduction, access to affordable drugs and the benefits of new technologies. (Source: United Nations (UN) (2010) ‘Millennium Development Goals (MDGs)’ [online], http://www.un.org/ millenniumgoals/ [Tip: hold Ctrl and click a link to open it in a new tab. (Hide tip)] (accessed 22 October 2012).)

prevalence

The proportion of the population with a particular infection or disease at a particular point in time, or during a given period.

primary prevention

Public health strategies that seek to prevent new cases of infection from occurring, e.g. vaccination, promotion of personal hygiene, food safety legislation, installation of infrastructures that reduce infection risks, such as sewerage and piped water supplies.

quarantine

A period of enforced isolation, or restriction of travel or activity, in order to prevent the spread of an infectious disease.

reference laboratories

Designated laboratories in countries around the world that collect and analyse infectious agents (e.g. influenza viruses) sent by detection centres to give early warning of new variants that could pose a major risk to global health.

screening programmes

The systematic application of a test or investigation to large numbers of individuals to identify those at risk of developing a particular disease, or (in the case of infectious disease) those who are already infected.

secondary prevention

Public health strategies that aim to detect new cases of infectious disease at the earliest possible stage and intervene in ways that prevent or reduce the risk of infection from spreading further in the population.

tertiary prevention

Medical treatment to prevent the worst outcomes of a disease in an individual.