Getting to zero: micro-foci of malaria in the Solomon Islands requires stratified control

Russell, Tanya L.; Grignard, Lynn; Apairamo, Alan; Kama, Nathan; Bobogare, Albino; Drakeley, Chris

doi:10.1186/s12936-021-03779-y

Cited by 6 publications

(5 citation statements)

References 34 publications

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“…Extraction from whole blood results in better sensitivity compared to dried blood spots [ 47 ]. The corresponding volume of blood screened by qPCR ranges from < 0.1 µL [ 48 ] to ≥ 200 µL [ 49 ] when DNA is concentrated during extraction. Multi-copy genes such as var ATS offer superior sensitivity compared to single copy genes [ 50 ].…”

Section: Discussionmentioning

confidence: 99%

Accuracy of diagnosis among clinical malaria patients: comparing microscopy, RDT and a highly sensitive quantitative PCR looking at the implications for submicroscopic infections

Afriyie

Addison

Gebre

et al. 2023

Malar J

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Background The World Health Organization recommends parasitological confirmation of all suspected malaria cases by microscopy or rapid diagnostic tests (RDTs) before treatment. These conventional tools are widely used for point-of-care diagnosis in spite of their poor sensitivity at low parasite density. Previous studies in Ghana have compared microscopy and RDT using standard 18S rRNA PCR as reference with varying outcomes. However, how these conventional tools compare with ultrasensitive varATS qPCR has not been studied. This study, therefore, sought to investigate the clinical performance of microscopy and RDT assuming highly sensitive varATS qPCR as gold standard. Methods 1040 suspected malaria patients were recruited from two primary health care centers in the Ashanti Region of Ghana and tested for malaria by microscopy, RDT, and varATS qPCR. The sensitivity, specificity, and predictive values were assessed using varATS qPCR as gold standard. Results Parasite prevalence was 17.5%, 24.5%, and 42.1% by microscopy, RDT, and varATS qPCR respectively. Using varATS qPCR as the standard, RDT was more sensitive (55.7% vs 39.3%), equally specific (98.2% vs 98.3%), and reported higher positive (95.7% vs 94.5%) and negative predictive values (75.3% vs 69.0%) than microscopy. Consequently, RDT recorded better diagnostic agreement (kappa = 0.571) with varATS qPCR than microscopy (kappa = 0.409) for clinical detection of malaria. Conclusions RDT outperformed microscopy for the diagnosis of Plasmodium falciparum malaria in the study. However, both tests missed over 40% of infections that were detected by varATS qPCR. Novel tools are needed to ensure prompt diagnosis of all clinical malaria cases.

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Section: Discussionmentioning

confidence: 99%

Accuracy of diagnosis among clinical malaria patients: comparing microscopy, RDT and a highly sensitive quantitative PCR looking at the implications for submicroscopic infections

Afriyie

Addison

Gebre

et al. 2023

Malar J

View full text Add to dashboard Cite

show abstract

“…Extraction from whole blood results in better sensitivity compared to dried blood spots (45). The corresponding volume of blood screened by qPCR ranges from <0.1 µL (46) to ≥200 µL (47) when DNA is concentrated during extraction. Multi-copy genes such as varATS offer superior sensitivity compared to single copy genes (48).…”

Section: Discussionmentioning

confidence: 99%

Accuracy of diagnosis among clinical malaria patients: comparing microscopy, RDT, and a highly sensitive quantitative PCR and the implication of submicroscopic infections

Afriyie

Addison

Gebre

et al. 2022

Preprint

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Background: The World Health Organization recommends parasitological confirmation of all suspected malaria cases by microscopy or rapid diagnostic tests (RDTs) before treatment. These conventional tools are widely used for point-of-care diagnosis in spite of their poor sensitivity at low parasite density. Several studies have compared the diagnostic accuracy of microscopy and RDT using standard 18S rRNA PCR as reference with varying outcomes. Here, we present for the first time in Ghana, the accuracy of diagnosis of microscopy and RDT using highly sensitive varATS qPCR as reference in a clinical setting.Methods: 1,040 febrile patients were recruited from two primary health care centers in the Ashanti Region of Ghana and tested for malaria by microscopy, RDT, and varATS qPCR. The sensitivity, specificity, and predictive values were assessed using qPCR as gold standard.Results: Parasite prevalence was 17.5%, 24.5%, and 42.1% by microscopy, RDT, and varATS qPCR respectively. Using qPCR as the standard, RDT was more sensitive (55.7% vs 39.3%), marginally less specific (98.2% vs 98.3%), and had higher positive (95.7% vs 94.5%) and negative predictive values (75.3% vs 69.0%) than microscopy. Parasite prevalence and density was higher among the 5-14 age group than the <5, 15-30, and >30 age groups across all the tests.Conclusions: RDT outperformed microscopy for the diagnosis of P. falciparum malaria in the study area. However, both diagnostic methods missed over 40% of infections that were detected by varATS qPCR. Novel tools are needed to ensure prompt diagnosis of all clinical malaria cases.

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“…Concurrently, 3 × 50 μl blood spots were placed onto cellulose chromatography papers (2 × 7 cm; Whatman Grade 3MM) and dried under ambient conditions. The malaria data has been analysed elsewhere [ 43 ].…”

Section: Methodsmentioning

confidence: 99%

Seroprevalence of dengue, Zika, chikungunya and Ross River viruses across the Solomon Islands

et al. 2022

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Across the Pacific, and including in the Solomon Islands, outbreaks of arboviruses such as dengue, chikungunya, and Zika are increasing in frequency, scale and impact. Outbreaks of mosquito-borne disease have the potential to overwhelm the health systems of small island nations. This study mapped the seroprevalence of dengue, Zika, chikungunya and Ross River viruses in 5 study sites in the Solomon Islands. Serum samples from 1,021 participants were analysed by ELISA. Overall, 56% of participants were flavivirus-seropositive for dengue (28%), Zika (1%) or both flaviviruses (27%); and 53% of participants were alphavirus-seropositive for chikungunya (3%), Ross River virus (31%) or both alphaviruses (18%). Seroprevalence for both flaviviruses and alphaviruses varied by village and age of the participant. The most prevalent arboviruses in the Solomon Islands were dengue and Ross River virus. The high seroprevalence of dengue suggests that herd immunity may be a driver of dengue outbreak dynamics in the Solomon Islands. Despite being undetected prior to this survey, serology results suggest that Ross River virus transmission is endemic. There is a real need to increase the diagnostic capacities for each of the arboviruses to support effective case management and to provide timely information to inform vector control efforts and other outbreak mitigation interventions.

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Getting to zero: micro-foci of malaria in the Solomon Islands requires stratified control

Cited by 6 publications

References 34 publications

Accuracy of diagnosis among clinical malaria patients: comparing microscopy, RDT and a highly sensitive quantitative PCR looking at the implications for submicroscopic infections

Accuracy of diagnosis among clinical malaria patients: comparing microscopy, RDT and a highly sensitive quantitative PCR looking at the implications for submicroscopic infections

Accuracy of diagnosis among clinical malaria patients: comparing microscopy, RDT, and a highly sensitive quantitative PCR and the implication of submicroscopic infections

Seroprevalence of dengue, Zika, chikungunya and Ross River viruses across the Solomon Islands

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