The position of different diagnostic approaches/tests in relation to morbidity, parasite prevalence, densities, and different stages towards malaria elimination.

<p>Image credit: Fusión Creativa.</p

Target product profiles for malaria diagnostics.

<p>D, desirable; E, essential; O, optional.</p>a<p>Analytic sensitivity<i>:</i> detection threshold against the marker of the infective agent (target) in controlled conditions. Diagnostic sensitivity<i>:</i> proportion (percent) of target cases detected by the test in the setting of intended use. The sensitivity required for <i>P. vivax</i> is generally at least that required for <i>P. falciparum</i>, and the parameters here should be applied to both. To achieve the required diagnostic sensitivity in low-prevalence settings, a greater analytic sensitivity (lower threshold of detection) may be required in some cases.</p>b<p>Not required for febrile case management, but in an elimination setting, it would be desirable to detect incidental parasitemia at this level.</p>c<p>Essential where stored in the field in ambient temperatures that frequently reach this level. Ambient temperature of prolonged storage in place of use should be considered the essential temperature stability requirement for a particular product.</p>d<p>Areas in which infections are almost exclusively monospecies or mixed species <i>P. falciparum</i> infections. It is likely that many such infections have subpatent coinfections with other species. Where this represents a minority of infections, treatment on the basis of <i>P. falciparum</i> alone is likely to be acceptable from a programmatic and public health point of view. Non<i>-P. falciparum</i> infections are likely to become relatively more prominent as <i>P. falciparum</i> infections decline in prevalence, making the detection of non-<i>P. falciparum</i> species more desirable.</p>e<p>May be of importance in areas undergoing certification for elimination.</p>f<p>All inner (individual test) packaging should display, at a minimum: manufacturer name, product name, expiry date, lot number, target use (malaria).</p>g<p>Outcome of temperature stability and integrity of packaging (ability to exclude moisture).</p>h<p>Rapidity of results: For case management, results must be available before a patient is likely to leave the clinic. For surveillance, result availability in time for finding and managing cases is highly desirable.</p

Community participation for malaria elimination in tafea province, vanuatu: part ii. social and cultural aspects of treatment-seeking behaviour

Background: Early diagnosis and prompt effective case management are important components of any malaria elimination strategy. Tafea Province, Vanuatu has a rich history of traditional practices and beliefs, which have been integrated with missionary efforts and the introduction of modern constructions of health. Gaining a detailed knowledge of community perceptions of malarial symptomatology and treatment-seeking behaviours is essential in guiding effective community participation strategies for malaria control and elimination

Modelling the contribution of the hypnozoite reservoir to Plasmodium vivax transmission

Plasmodium vivax relapse infections occur following activation of latent liver-stages parasites (hypnozoites) causing new blood-stage infections weeks to months after the initial infection. We develop a within-host mathematical model of liver-stage hypnozoites, and validate it against data from tropical strains of P. vivax. The within-host model is embedded in a P. vivax transmission model to demonstrate the build-up of the hypnozoite reservoir following new infections and its depletion through hypnozoite activation and death. The hypnozoite reservoir is predicted to be over-dispersed with many individuals having few or no hypnozoites, and some having intensely infected livers. Individuals with more hypnozoites are predicted to experience more relapses and contribute more to onwards P. vivax transmission. Incorporating hypnozoite killing drugs such as primaquine into first-line treatment regimens is predicted to cause substantial reductions in P. vivax transmission as individuals with the most hypnozoites are more likely to relapse and be targeted for treatment

Highly sensitive detection of malaria parasitemia in a malaria-endemic setting: performance of a new loop-mediated isothermal amplification kit in a remote clinic in Uganda.

BACKGROUND: Current malaria diagnostic tests, including microscopy and antigen-detecting rapid tests, cannot reliably detect low-density infections. Molecular methods such as polymerase chain reaction (PCR) are highly sensitive but remain too complex for field deployment. A new commercial molecular assay based on loop-mediated isothermal amplification (LAMP) was assessed for field use. METHODS: Malaria LAMP (Eiken Chemical, Japan) was evaluated for samples from 272 outpatients at a rural Ugandan clinic and compared with expert microscopy, nested PCR, and quantitative PCR (qPCR). Two technicians performed the assay after 3 days of training, using 2 alternative blood sample-preparation methods and visual interpretation of results by fluorescence assay. RESULTS: Compared with 3-well nested PCR, the sensitivity of both LAMP and single-well nested PCR was 90%; the microscopy sensitivity was 51%. For samples with a Plasmodium falciparum qPCR titer of ≥ 2 parasites/µL, LAMP sensitivity was 97.8% (95% confidence interval, 93.7%-99.5%). Most false-negative LAMP results involved samples with parasitemia levels detectable by 3-well nested PCR but very low or undetectable by qPCR. CONCLUSIONS: Malaria LAMP in a remote Ugandan clinic achieved sensitivity similar to that of single-well nested PCR in a United Kingdom reference laboratory. LAMP dramatically lowers the detection threshold achievable in malaria-endemic settings, providing a new tool for diagnosis, surveillance, and screening in elimination strategies