Trends in Parasitology
ReviewThe essential role of infection-detection technologies for malaria elimination and eradication
Section snippets
Malaria diagnostic priorities
Malaria control efforts have yielded substantial progress toward reducing the burden of malaria. In the past decade, cases of malaria fell by an estimated 274 million and malaria-related deaths were reduced by 1.1 million compared with the previous decade [1]. However, the emergence of multiple forms of resistance, the cost of sustained control efforts, and the long history of malaria resurgence [2] following near elimination have fueled recent policies, guidance [3], and funding dedicated to
Elimination and eradication goals
The WHO has established a clear distinction between the programmatic goals of malaria control, elimination, and eradication [9]. Although the goal of malaria control is to reduce morbidity and mortality, the goal of malaria elimination is to reduce malaria transmission to zero in a given geographic region. Sustained elimination in all regions over an extended period of time is a prerequisite for malaria eradication, defined as the permanent reduction to zero of the worldwide incidence [1].
The dynamic epidemiology of elimination
Malaria has often been described as heterogeneous to address wide variations in phenotype, vector–host reactions, and spatial distribution of disease [14]. Despite this variability, some general themes about the epidemiology of low-prevalence malaria can be inferred: (i) there is an increased contribution to transmission from subclinical individuals and from infections that are undetectable by microscopy and RDTs; (ii) defined parasite reservoirs, a bellwether of elimination, represent both
Distinguishing use-scenarios
In light of the dynamic epidemiology of malaria elimination and the tactics under development to most efficiently identify and treat infection, use-scenarios present a useful, outcome-oriented framework for classifying and distinguishing ID methods. A thorough understanding of each use-scenario, including identifying the probable location, user, training, infrastructure, and other constraints, is essential to subsequently assigning attribute requirements for hypothetical tools that provide the
Target product profiles
A TPP [77] is a strategic planning tool that is used to facilitate communication among all product-development stakeholders. TPPs drive product-development thinking by beginning with the end goal in mind [78]. This review of the use-scenarios categorized in Figure 1 suggests that various technical improvements can be made to existing malaria ID technologies to adapt them to E&E tactics. Yet the distinct use-scenarios described in Figure 1 each correspond to a unique set of performance and user
Concluding remarks and future perspectives
The ability to accurately detect malaria infection in all individuals and in all populations is fundamental to achieving E&E goals. However, the detection of low-level infections is notoriously inaccurate with currently available RDTs and microscopy, and PCR is expensive and infeasible for field use [5]. This suggests that new diagnostic tools are needed with user requirements and performance attributes that are appropriate for application within the continuum of malaria elimination
Glossary
- Active infection detection (active ID)
- the detection of malaria (clinical and subclinical) infections at community and household levels in population groups that are considered to be high risk.
- Border testing
- a proactive ID tactic aimed at preventing cross-border transmission at checkpoints. Border testing may be preceded by fever screening followed by testing of all patients with a recent history of malaria symptoms.
- Community testing
- a reactive ID tactic to identify and treat infected persons
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Cited by (38)
Malaria cross-sectional surveys identified asymptomatic infections of Plasmodium falciparum, Plasmodium vivax and Plasmodium knowlesi in Surat Thani, a southern province of Thailand
2020, International Journal of Infectious DiseasesA focus on improving molecular diagnostic approaches to malaria control and elimination in low transmission settings: Review
2019, Parasite Epidemiology and ControlCitation Excerpt :Elimination is attaining malaria transmission at zero level in each geographic region and elimination in all regions leads to malaria eradication which is the permanent reduction to zero incidence globally (World Health Organization, 2018a). The context of malaria elimination goals paves a way for changing diagnostic tools and since the prevalence of malaria is declining, its management is focused on subclinical infections and on geographically as well as demographically concentrated human reservoirs (Tietje et al., 2014). There is no universal definition for asymptomatic parasitemias but most of the definitions involve detection of sexual or asexual parasites in the absence of symptom of malaria (mostly fever) and it excludes the dormant liver stage (Lindblade et al., 2013).
Asymptomatic plasmodial infection in Colombian pregnant women
2017, Acta TropicaCitation Excerpt :Asymptomatic plasmodial infection (API) has been recognized since many decades ago, but only now, it is receiving attention because of the current antimalarial program goals (control, elimination, eradication) (Tietje et al., 2014).
New molecular detection methods of malaria parasites with multiple genes from genomes
2016, Acta TropicaCitation Excerpt :Hence it is very important to have a rapid, sensitive and specific method for the detection of malaria parasites in febrile patients as well as in asymptomatic individuals. Precise identification of malaria disease may play a key role in planning, targeting and evaluating malaria control efforts in low, medium and high malaria endemic areas (Alonso et al., 2011; Tietje et al., 2014; Sturrock et al., 2013). We have developed methods using the real-time PCR based assays for the diagnosis of malaria caused by Pf and Pv, which have shown good threshold sensitivity value in the blood samples even with low parasitemia (Figs. 3 and 4).
Impact of Malaria in Pregnancy as Latin America Approaches Elimination
2016, Trends in ParasitologyCitation Excerpt :For the context of Latin America, it will be important to include species identification with any diagnostic test for malaria in order to guide treatment. Pregnant women are among the more accessible populations for active case detection and can be considered one of the so-called ‘hot pops’ (target populations) for interventions directed toward elimination [76]. Support for women to attend antenatal clinics ensures better care, and in turn can provide opportunities for screening women during pregnancy by sensitive methods to identify asymptomatic sub-microscopic infections.