Appendix 2: Glossary
- Acquired immunity
- People residing in malaria-endemic regions over time acquire immunity to malaria through natural and continued exposure to malaria parasites. Acquired immunity to malaria parasites is not sterile, i.e. it generally protects against severe malaria although low level parasite infections may still occur.
- A substance that helps and enhances the pharmacological effect of a drug or increases the ability of an antigen to stimulate the immune system in a vaccine.
- Mosquito genus that transmits the disease.
- Substance that prompts the generation of antibodies and can cause an immune response; used in vaccines.
- Artemisinin-based combination therapy (ACT)
- A combination of artemisinin or one if its derivatives with an anti-malarial or anti-malarial drugs of a different class[a]Guidelines for the Treatment of Malaria. Geneva, World Health Organization, 2006.
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- Asymptomatic reservoir
- Group of individuals carrying Plasmodium infections without any clinical symptoms.
- Behavior Change Communication (BCC)
- BCC includes the basic components of IEC (please see IEC for definition), but employs a more participatory approach to engaging communities and focuses more on the end actions of the client in regard to the health intervention.
- Blood-stage infection
- The life-cycle of the malaria parasite in host red blood cells (intraerythrocytic development) from merozoite invasion to schizont rupture (merozoite → ring stage →trophozoite →schizont →merozoites). Duration approximately 48 h in Plasmodium falciparum, P. ovale and P. vivax; 72 h in P. malariae.[b]Guidelines for the Treatment of Malaria. Geneva, World Health Organization, 2006.
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- The morbidity and mortality impact of malaria. In the document, the text will refer to either the morbidity or mortality burden.
- Chloroquine (CQ)
- An anti-malarial drug that been used extensively for the treatment and prevention of malaria. Widespread resistance has now rendered it ineffective against P. falciparum infections in most parts of the world, although it still maintains considerable efficacy for the treatment of P. vivax, P. ovale and P. malariae infections.[c]Guidelines for the Treatment of Malaria. Geneva, World Health Organization, 2006.
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- Reduction of disease incidence, prevalence, morbidity or mortality to a locally acceptable level as a result of deliberate efforts; continued intervention measures are required to maintain the reduction.[d]Dowdle W. The principles of disease elimination and eradication from the 1997 Dahlem Workshop. WHO Bulletin, 1998, 76 (supplement 2)
For each of the following interventions, coverage is defined as:
- Long-Lasting Insecticidal Nets (LLINs): A household owns one long-lasting insecticidal bed net for every two people living there
- Indoor Residual Spraying (IRS): The interior walls of every house are routinely sprayed at appropriate intervals with an effective insecticide
- Intermittent Preventive Treatment (IPTp): A pregnant woman living in a high transmission setting receives at least 2 doses of an appropriate anti-malarial drug during her pregnancy
- Other vector control measures: Other targeted approaches (e.g. larviciding, environmental management, etc.) are applied wherever appropriate
- Diagnosis: A patient receives prompt parasitological confirmation by microscopy or rapid diagnostic tests (RDTs) of malaria diagnosis
- Treatment: An infected person receives appropriate anti-malarial drugs for uncomplicated or severe malaria within one day of onset of illness
Please note that not all interventions should be used in every setting. See Part II, Chapter 2: Control: Overcoming Malaria.
- Dichloro-Diphenyl-Trichloroethane (DDT) is an insecticide used in indoor residual spraying.
- Reduction to zero of the incidence of locally transmitted infection caused by Plasmodia in a defined geographical area as a result of deliberate efforts; continued intervention measures are required to prevent reintroduction.[e]Dowdle W. The principles of disease elimination and eradication from the 1997 Dahlem Workshop. WHO Bulletin, 1998, 76 (supplement 2)
- Permanent reduction to zero of the global incidence of infection caused by Plasmodia as a result of deliberate efforts; intervention measures are no longer needed.[f]Dowdle W. The principles of disease elimination and eradication from the 1997 Dahlem Workshop. WHO Bulletin, 1998, 76 (supplement 2)
- Sexual stages of malaria parasites present in the host red blood cells, which are infective to the Anopheles mosquito.[g]Guidelines for the Treatment of Malaria. Geneva, World Health Organization, 2006.
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- Glucose-6-phosphate dehydrogenase deficiency
- Genetic disorder that mainly affects red blood cells and occurs in 10-25% of sub-Saharan African populations. In affected individuals, a defect in an enzyme called glucose-6-phosphate dehydrogenase causes red blood cells to break down prematurely.
- Home management of malaria
- Coverage with malaria interventions provided at the community level, often to individual households.
- Humanitarian Crisis
- A humanitarian crisis is a situation which is triggered by either manmade disasters or natural disasters or even both. Crises affect large civilian populations by causing food shortages and population displacement, resulting in excess mortality and morbidity and high risks of malaria. Also known as Complex Emergency.
- Persistent liver stages of P. vivax and P. ovale malaria that remain dormant in host hepatocytes for a fixed interval before maturing to hepatic schizonts. These then burst and release merozoites, which infect red blood cells. Hypnozoites are the source of relapses.[h]Guidelines for the Treatment of Malaria. Geneva, World Health Organization, 2006.
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- Indoor Residual Spraying (IRS)
- Application of long-lasting chemical insecticides on the walls and roofs of all houses and domestic animal shelters in a given area, in order to kill adult mosquito vectors that land and rest on these surfaces.
- Information, Education, Communication (IEC)
- IEC is broadly defined as combining communication strategies, approaches and methods that provide knowledge to enable individuals, families, groups, organizations and communities to play active roles in achieving, protecting and sustaining their own health.
- Insecticide-Treated Nets (ITNs)
- Nets that have been treated with insecticides such as pyrethroids to protect from mosquito bites during the night. Insecticide-treated nets require regular re-treatment. Also see Long-Lasting Insecticidal Nets (LLINs).
- Integrated vector management (IVM)
- Integrated Vector Management is defined as a rational decision-making process for the optimal use of resources for vector control to make deliberate, evidence-based decisions to target and implement vector control operations including LLINs, and in some situations IRS, larval source management and other measures.
- Intermittent preventive treatment (IPT)
- The administration of a full course of an anti-malarial treatment to a population at risk at specified time points regardless of whether or not they are known to be infected. IPT in pregnancy (IPTp) is WHO recommended policy in high transmission settings. In IPTp, pregnant women, whether or not they show symptoms of malaria infection, receive at least two doses of an anti-malarial drug, currently sulphadoxine-pyrimethamine (SP), at each scheduled antenatal visit after the first trimester.
Research is currently ongoing to assess the benefits of providing IPT for children (IPTc) and infants (IPTi).
- Products used for malaria prevention or case management. Most common are Long-Lasting Insecticidal nets (LLINs), Indoor Residual Spraying (IRS), drugs (ACTs, CQ), microscopy, and Rapid Diagnostic Tests (RDTs)
- Destruction of mosquito larvae by measures such as treating mosquito larvae surfaces, intermittent irrigation, sluicing or biological control.
- Long-lasting insecticidal nets (LLINs)
- A long-lasting insecticidal net (LLIN) is a factory-treated mosquito net made with netting material that has insecticide incorporated within or bound around the fibers. The net must retain its effective biological activity without re-treatment for at least 20 WHO standard washes under laboratory conditions and three years of recommended use under field conditions.
- Monitoring and Evaluation (M&E)
- Monitoring is the routine tracking of the key elements of program performance through record keeping, regular reporting, surveillance systems or surveys. Evaluation is the episodic assessment of a program, and the extent to which a particular program intervention may be linked to a specific output or result.[i]Monitoring & Evaluation Toolkit - HIV/AIDS, Tuberculosis and Malaria. Geneva, World Health Organization, January 2006.
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- Malaria-free certification
- Process by which WHO certifies an entire country malaria-free following at least three consecutive years of no local transmission of any of the four human malaria species. Countries can still experience imported cases, as long as no onward transmission occurs due to intense surveillance and effective control.
- Anti-malarial treatment with a single medicine, either a single active compound or a synergistic combination of two compounds with related mechanism of action.[j]Guidelines for the Treatment of Malaria. Geneva, World Health Organization, 2006.
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- Morbidity refers to the incidence of malaria cases.
- Mortality refers to the deaths caused by malaria.
- Amount of blood-stage parasites that an individual has within their red blood cells. Often expressed as percentage of infected red blood cells to red blood cells counted.
- A genus of protozoan vertebrate blood parasites that includes the causal agents of malaria. Plasmodium falciparum, P. malariae, P. ovale and P. vivax cause malaria in humans.
- Viruses, bacteria, virosomes, and nanoparticles used in vaccines to increase breadth, magnitude, and duration of induced immunity.
- Population at risk
- Human population living in a geographical area where locally acquired malaria cases occur and they are at risk of being infected with the parasite.
- Malaria control program re-orientation period between the sustained control and elimination stages where emphasis on surveillance, reporting and information systems increases.
- Prevention of reintroduction
- The period following elimination once surveillance shows a reduction to zero of all locally acquired cases (this does not include imported cases). Countries must be in the stage at least three years before eligible for WHO malaria-free certification.
- Effective against intrahepatic forms of all types of malaria parasite. It is used to provide radical cure of P. vivax and P. ovale[k]Guidelines for the Treatment of Malaria. Geneva, World Health Organization, 2006.
Click for source malaria, in combination with a blood schizontocide for the erythrocytic parasites. Primaquine is also gametocytocidal against P. falciparum and has significant blood stage activity against P. vivax (and some against asexual stages of P. falciparum).
- Insecticide commonly used in insecticide-treated nets.
- Rapid Diagnostic Tests (RDTs)
- An antigen-based stick, cassette or card test for malaria in which a colored line indicates that plasmodial antigens have been detected.
- RBM Partnership
- The RBM Partnership is a mechanism to facilitate and coordinate the planning and implementation of activities of individual partners to avoid duplication and fragmentation and to ensure optimal use of resources. The RBM Partnership’s strength lies in its ability to form effective partnerships both globally and nationally. Partners are malaria-endemic countries, bilateral and multilateral development partners, the private sector, local and global nongovernmental organizations, community-based organizations, foundations, and research and academic institutions. Each one maintains its independent function while at the same time contributing to RBM.
- RBM Partnership bodies
- RBM Partnership bodies are the mechanisms within the RBM Partnership that coordinate and facilitate the activities of the Partnership, i.e. the RBM Board, the RBM Executive Committee, the RBM Partnership Secretariat, the Working Groups and the Sub-Regional Networks.
- Reproduction rate
- Measure describing how many new infections can occur from one infected case.
- Reduced susceptibility of the causal agent to a drug. WHO defines resistance to anti-malarials as the ability of a parasite strain to survive and/or multiply despite the administration and absorption of a medicine given in doses equal to – or higher than – those usually recommended but within the tolerance of the subject.[l]Malaria Elimination: A Field Manual for Low and Moderate Endemic Countries. Geneva, World Health Organization, 2007.
Click for source Insecticide resistance refers specifically to resistance against insecticides used for vector control of the malaria vector.
- The most clinically advanced vaccine candidate scheduled to enter Phase 3 in late 2008 or early 2009. It appears to diminish the capacity of the malaria parasite to infect, survive, and develop in the human liver.[m]Guidelines for the Treatment of Malaria. Geneva, World Health Organization, 2006.
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- Scale-up for impact (SUFI)
- Rapidly reach universal (100%) coverage for all populations at risk with locally appropriate malaria control interventions (i.e. LLINs, IRS, IPTp, drugs and diagnostics), supported by strengthened health systems. This will have a substantial impact on malaria burden.
- Slide positivity rate (SPR)
- The proportion of slides found positive among the slides examined.[n]Malaria Elimination: A Field Manual for Low and Moderate Endemic Countries. Geneva, World Health Organization, 2007.
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- Motile malaria parasites that are infective to humans, inoculated by a feeding female Anopheles mosquito. Sporozoites invade hepatocytes.
- Sulphadoxine-Pyremethanine[o]Guidelines for the Treatment of Malaria. Geneva, World Health Organization, 2006.
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- Combination treatment with sulphadoxine and pyremethanine. It targets the blood-stage infection and is also possibly active against pre-erythrocytic forms of the malaria parasite and inhibits sporozoite development in the mosquito vector. It is effective against all four human malarials, although resistance has emerged and is wide-spread.
- Surveillance is the regular collection, monitoring and analysis of information in a given population or subpopulation to detect the presence and any epidemiological changes of malaria.
- Sustained control
- Once universal coverage with appropriate malaria interventions is achieved, sustained control is the period during which malaria control measures are stabilized and universal coverage is maintained by continued strengthening of health systems, until local field research suggests that coverage can gradually be targeted to high risk areas and seasons only, without risk of a generalized resurgence.
- An 8-aminoquinoline drug manufactured by GlaxoSmithKline being investigated for both treatment and prevention. The main advantage of tafenoquine is that it has a long half-life and therefore does not need to be taken as frequently as primaquine.
- Transmission intensity
Rate at which people in a given area are infected with malaria parasites by mosquitoes (usually expressed by the annual entomological inoculation rate). There is as yet no clear consensus on criteria for determining the thresholds between high, and low to moderate transmission settings. In this report, transmission is defined in line with WHO World Malaria Report 2008[p]World Malaria Report 2008. Geneva, World Health Organization, 2008.
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- Areas of low transmission: the reported malaria case incidence from all species is less than 1 per 1000 population per year but greater than zero. Transmission in these areas is generally highly seasonal with or without epidemic peaks.
- Areas of high transmission: the reported malaria case incidence from all species is 1 or more per 1000 population per year
- Malaria-free areas: there is no continuing, local mosquito-borne malaria transmission, and all malaria cases are introduced
Guerra et al (2008)[q]Guerra CA et al. The limits and intensity of Plasmodium falciparum transmission: implications for malaria control and elimination worldwide. PLoS Medicine, 2008, 5(2):e38., uses stable vs. unstable to identify populations at risk. More specifically:
- Unstable risk was defined as P. falciparum API (Annual Parasite Incidence) < 0.1 per 1000 population per annum
- Stable risk was defined as P. falciparum API ≥ 0.1 per 1000 population per annum.
- Universal coverage
- 100% of the populations at risk are covered by appropriate malaria interventions. See definition for coverage above.
The appropriate usage of malaria interventions, e.g.
- All members of a household sleep under LLINs each night
- A house is sprayed appropriately each transmission cycle
- A pregnant woman takes at least 2 doses of IPTp during pregnancy
- Patients take the complete treatment cycle of anti-malarial drugs as recommended