Journal Article > ResearchFull Text
Malar J. 2017 October 28; Volume 16 (Issue 1); 449.; DOI:10.1186/s12936-017-2094-3
Oyet C, Roh ME, Kiwanuka G, Orikiriza P, Wade M, et al.
Malar J. 2017 October 28; Volume 16 (Issue 1); 449.; DOI:10.1186/s12936-017-2094-3
BACKGROUND
Early diagnosis of suspected malaria cases with a rapid diagnostic test (RDT) has been shown to be an effective malaria control tool used in many resource-constrained settings. However, poor quality control and quality assurance hinder the accurate reporting of malaria diagnoses. Recent use of a portable, battery operated RDT reader (Deki Reader™, Fio Corporation) has shown to have high agreement with visual inspection across diverse health centre settings, however evidence of its feasibility and usability during cross sectional surveys are limited. This study aimed to evaluate the performance of the Deki Reader™ in a cross-sectional survey of children from southwestern Uganda.
METHODS
A two-stage, stratified cluster sampling survey was conducted between July and October 2014 in three districts of southwestern Uganda, with varying malaria transmission intensities. A total of 566 children aged 6-59 months were included in the analysis. Blood samples were collected and tested for malaria using: the SD Bioline Malaria Ag Pf/Pan RDT and microscopy. Results were compared between visual inspection of the RDT and by the Deki Reader™. Diagnostic performance of both methods were compared to gold-standard microscopy.
RESULTS
The sensitivity and specificity of the Deki Reader™ was 94.1% (95% CI 69.2-99.6%) and 95.6% (95% CI 93.4-97.1%), respectively. The overall percent agreement between the Deki Reader™ and visual RDT inspection was 98.9% (95% CI 93.2-99.8), with kappa statistic of 0.92 (95% CI 0.85-0.98).
CONCLUSIONS
The findings from this study suggest that the Deki Reader™ is comparable to visual inspection and performs well in detecting microscopy-positive Plasmodium falciparum cases in a household survey setting. However, the reader's performance was highly dependent on ensuring adequate battery life and a work environment free of dirt particles.
Early diagnosis of suspected malaria cases with a rapid diagnostic test (RDT) has been shown to be an effective malaria control tool used in many resource-constrained settings. However, poor quality control and quality assurance hinder the accurate reporting of malaria diagnoses. Recent use of a portable, battery operated RDT reader (Deki Reader™, Fio Corporation) has shown to have high agreement with visual inspection across diverse health centre settings, however evidence of its feasibility and usability during cross sectional surveys are limited. This study aimed to evaluate the performance of the Deki Reader™ in a cross-sectional survey of children from southwestern Uganda.
METHODS
A two-stage, stratified cluster sampling survey was conducted between July and October 2014 in three districts of southwestern Uganda, with varying malaria transmission intensities. A total of 566 children aged 6-59 months were included in the analysis. Blood samples were collected and tested for malaria using: the SD Bioline Malaria Ag Pf/Pan RDT and microscopy. Results were compared between visual inspection of the RDT and by the Deki Reader™. Diagnostic performance of both methods were compared to gold-standard microscopy.
RESULTS
The sensitivity and specificity of the Deki Reader™ was 94.1% (95% CI 69.2-99.6%) and 95.6% (95% CI 93.4-97.1%), respectively. The overall percent agreement between the Deki Reader™ and visual RDT inspection was 98.9% (95% CI 93.2-99.8), with kappa statistic of 0.92 (95% CI 0.85-0.98).
CONCLUSIONS
The findings from this study suggest that the Deki Reader™ is comparable to visual inspection and performs well in detecting microscopy-positive Plasmodium falciparum cases in a household survey setting. However, the reader's performance was highly dependent on ensuring adequate battery life and a work environment free of dirt particles.
Journal Article > CommentaryFull Text
Lancet Infect Dis. 2023 April 1; Volume 23 (Issue 4); 388-390.; DOI:10.1016/S1473-3099(22)00724-1
Boum Y II, Moukoko CEE, Parikh S
Lancet Infect Dis. 2023 April 1; Volume 23 (Issue 4); 388-390.; DOI:10.1016/S1473-3099(22)00724-1
Journal Article > ResearchFull Text
Lancet Infect Dis. 2017 July 1; Volume 17 (Issue 7); 754-762.; DOI:10.1016/S1473-3099(17)30170-6
Parikh S, Newbold L, Slater S, Moschioni M, Lucidarme J, et al.
Lancet Infect Dis. 2017 July 1; Volume 17 (Issue 7); 754-762.; DOI:10.1016/S1473-3099(17)30170-6
BACKGROUND
The UK introduced 4CMenB-a multicomponent vaccine against serogroup B meningococcal disease-into the national infant immunisation programme in September, 2015. The Meningococcal Antigen Typing System (MATS) was used to estimate coverage by 4CMenB of invasive meningococcal group B isolates obtained during 2007-08 in England and Wales (MATS coverage). We aimed to repeat the MATS survey for invasive meningococcal group B isolates obtained during 2014-15, before 4CMenB introduction; compare strain coverage between 2007-08 and 2014-15; and investigate associations between MATS coverage, age, region, and disease outcomes.
METHODS
Invasive serogroup B meningococcal isolates from cases in England, Wales, and Northern Ireland during 2014-15 were assayed using MATS and compared with 2007-08 data. MATS coverage was assessed by geographical region and age group. Clinical characteristics, risk factors, and outcomes were assessed according to MATS coverage for 2014-15 English cases.
FINDINGS
In 2014-15, 165 of 251 (66%; 95% CI 52-80) meningococcal group B isolates were estimated by MATS to be covered by 4CMenB, compared with 391 of 535 (73%; 95% CI 57-87) in 2007-08. The proportion of MATS-positive isolates with one vaccine antigen increased from 23% (122 of 535) in 2007-08 to 31% (78 of 251) in 2014-15, whereas the proportion with more than one antigen fell from 50% (269 of 535) to 35% (87 of 251). This effect reflected changes in circulating strains, particularly ST-269 clonal complex strains. MATS coverage increased with age, varied by geographical region, and was associated with more severe disease.
INTERPRETATION
In 2014-15, two-thirds of meningococcal group B isolates were predicted to be covered by 4CMenB. Temporal changes in MATS coverage underscore the need for continued monitoring of antigen expression and diversity, particularly in countries with 4CMenB programmes.
FUNDING
Public Health England, GlaxoSmithKline.
The UK introduced 4CMenB-a multicomponent vaccine against serogroup B meningococcal disease-into the national infant immunisation programme in September, 2015. The Meningococcal Antigen Typing System (MATS) was used to estimate coverage by 4CMenB of invasive meningococcal group B isolates obtained during 2007-08 in England and Wales (MATS coverage). We aimed to repeat the MATS survey for invasive meningococcal group B isolates obtained during 2014-15, before 4CMenB introduction; compare strain coverage between 2007-08 and 2014-15; and investigate associations between MATS coverage, age, region, and disease outcomes.
METHODS
Invasive serogroup B meningococcal isolates from cases in England, Wales, and Northern Ireland during 2014-15 were assayed using MATS and compared with 2007-08 data. MATS coverage was assessed by geographical region and age group. Clinical characteristics, risk factors, and outcomes were assessed according to MATS coverage for 2014-15 English cases.
FINDINGS
In 2014-15, 165 of 251 (66%; 95% CI 52-80) meningococcal group B isolates were estimated by MATS to be covered by 4CMenB, compared with 391 of 535 (73%; 95% CI 57-87) in 2007-08. The proportion of MATS-positive isolates with one vaccine antigen increased from 23% (122 of 535) in 2007-08 to 31% (78 of 251) in 2014-15, whereas the proportion with more than one antigen fell from 50% (269 of 535) to 35% (87 of 251). This effect reflected changes in circulating strains, particularly ST-269 clonal complex strains. MATS coverage increased with age, varied by geographical region, and was associated with more severe disease.
INTERPRETATION
In 2014-15, two-thirds of meningococcal group B isolates were predicted to be covered by 4CMenB. Temporal changes in MATS coverage underscore the need for continued monitoring of antigen expression and diversity, particularly in countries with 4CMenB programmes.
FUNDING
Public Health England, GlaxoSmithKline.
Journal Article > Meta-AnalysisFull Text
PLOS Med. 2018 June 12; Volume 15 (Issue 6); DOI:10.1371/journal.pmed.1002579
Kloprogge F, Workman L, Borrmann S, Tekete M, Lefevre G, et al.
PLOS Med. 2018 June 12; Volume 15 (Issue 6); DOI:10.1371/journal.pmed.1002579
The fixed dose combination of artemether-lumefantrine (AL) is the most widely used treatment for uncomplicated Plasmodium falciparum malaria. Relatively lower cure rates and lumefantrine levels have been reported in young children and in pregnant women during their second and third trimester. The aim of this study was to investigate the pharmacokinetic and pharmacodynamic properties of lumefantrine and the pharmacokinetic properties of its metabolite, desbutyl-lumefantrine, in order to inform optimal dosing regimens in all patient populations.
Journal Article > CommentaryFull Text
PLOS Glob Public Health. 2023 January 18; Volume 3 (Issue 1); e0001418.; DOI:10.1371/journal.pgph.0001418
Hodson DZ, Etoundi YM, Parikh S, Boum Y
PLOS Glob Public Health. 2023 January 18; Volume 3 (Issue 1); e0001418.; DOI:10.1371/journal.pgph.0001418
Interest in “global health” among schools of medicine, public health, and other health disciplines in high-income countries (HIC) continues to rise. Persistent power imbalances, racism, and maintenance of colonialism/neocolonialism plague global health efforts, including global health scholarship. Scholarly projects conducted in low- and middle-income countries (LMIC) by trainees at these schools in HIC often exacerbate these problems. Drawing on published literature and shared experiences, we review key inequalities within each phase of research, from design through implementation and analysis/dissemination, and make concrete and practical recommendations to improve equity at each stage. Key problems facing global health scholarship include HIC-centric nature of global health organizations, paucity of funding directly available for LMIC investigators and trainees, misplaced emphasis on HIC selected issues rather than local solutions to local problems, the dominance of English language in the scientific literature, and exploitation of LMIC team members. Four key principles lie at the foundation of all our recommendations: 1) seek locally derived and relevant solutions to global health issues, 2) create paired collaborations between HIC and LMIC institutions at all levels of training, 3) provide funding for both HIC and LMIC team members, 4) assign clear roles and responsibilities to value, leverage, and share the strengths of all team members. When funding for global health research is predicated upon more ethical and equitable collaborations, the nature of global health collaborations will evolve to be more ethical and equitable. Therefore, we propose the Douala Equity Checklist as a 20-item tool HIC and LMIC institutions can use throughout the conduct of global health projects to ensure more equitable collaborations.
Journal Article > Meta-AnalysisFull Text
PLOS Med. 2020 May 14; Volume 17 (Issue 5); DOI:10.1371/journal.pmed.1003084
Pfeffer DA, Ley B, Howes RE, Adu P, Alam MS, et al.
PLOS Med. 2020 May 14; Volume 17 (Issue 5); DOI:10.1371/journal.pmed.1003084
Journal Article > ResearchFull Text
Am J Trop Med Hyg. 2016 September 26; Volume 95 (Issue 5); 1094-1099.; DOI:10.4269/ajtmh.16-0552
Roh ME, Oyet C, Orikiriza P, Wade M, Mwanga-Amumpaire J, et al.
Am J Trop Med Hyg. 2016 September 26; Volume 95 (Issue 5); 1094-1099.; DOI:10.4269/ajtmh.16-0552
Despite the potential benefit of primaquine in reducing Plasmodium falciparum transmission and radical cure of Plasmodium vivax and Plasmodium ovale infections, concerns over risk of hemolytic toxicity in individuals with glucose-6-phosphate dehydrogenase deficiency (G6PDd) have hampered its deployment. A cross-sectional survey was conducted in 2014 to assess the G6PDd prevalence among 631 children between 6 and 59 months of age in southwestern Uganda, an area where primaquine may be a promising control measure. G6PDd prevalence was determined using three detection methods: a quantitative G6PD enzyme activity assay (Trinity Biotech(®) G-6-PDH kit), a qualitative point-of-care test (CareStart(™) G6PD rapid diagnostic test [RDT]), and molecular detection of the G6PD A- G202A allele. Qualitative tests were compared with the gold standard quantitative assay. G6PDd prevalence was higher by RDT (8.6%) than by quantitative assay (6.8%), using a < 60% activity threshold. The RDT performed optimally at a < 60% threshold and demonstrated high sensitivity (≥ 90%) and negative predictive values (100%) across three activity thresholds (below 60%, 30%, and 40%). G202A allele frequency was 6.4%, 7.9%, and 6.8% among females, males, and overall, respectively. Notably, over half of the G202A homo-/hemizygous children expressed ≥ 60% enzyme activity. Overall, the CareStart(™) G6PD RDT appears to be a viable screening test to accurately identify individuals with enzyme activities below 60%. The low prevalence of G6PDd across all three diagnostic modalities and absence of severe deficiency in our study suggests that there is little barrier to the use of single-dose primaquine in this region.
Journal Article > ResearchFull Text
Emerg Infect Dis. 2016 August 1; Volume 22; DOI:10.3201/eid2208.160619
Roh ME, Oyet C, Orikiriza P, Wade M, Kiwanuka G, et al.
Emerg Infect Dis. 2016 August 1; Volume 22; DOI:10.3201/eid2208.160619
A survey of asymptomatic children in Uganda showed Plasmodium malariae and P. falciparum parasites in 45% and 55% of microscopy-positive samples, respectively. Although 36% of microscopy-positive samples were negative by rapid diagnostic test, 75% showed P. malariae or P. ovale parasites by PCR, indicating that routine diagnostic testing misses many non–P. falciparum malarial infections.
Journal Article > ResearchFull Text
Nat Commun. 2024 October 25; Volume 15 (Issue 1); 9228.; DOI:10.1038/s41467-024-53243-z
Yadem AC, Armstrong JN, Sarimollaoglu M, Kiki Massa C, Ndifo JM, et al.
Nat Commun. 2024 October 25; Volume 15 (Issue 1); 9228.; DOI:10.1038/s41467-024-53243-z
Current malaria diagnostics are invasive, lack sensitivity, and rapid tests are plagued by deletions in target antigens. Here we introduce the Cytophone, an innovative photoacoustic flow cytometer platform with high-pulse-rate lasers and a focused ultrasound transducer array to noninvasively detect and identify malaria-infected red blood cells (iRBCs) using specific wave shapes, widths, and time delays generated from the absorbance of laser energy by hemozoin, a universal biomarker of malaria infection. In a population of Cameroonian adults with uncomplicated malaria, we assess our device for safety in a cross-sectional cohort (n = 10) and conduct a performance assessment in a longitudinal cohort (n = 20) followed for 30 ± 7 days after clearance of parasitemia. Longitudinal cytophone measurements are compared to point-of-care and molecular assays (n = 94). Cytophone is safe with 90% sensitivity, 69% specificity, and a receiver-operator-curve-area-under-the-curve (ROC-AUC) of 0.84, as compared to microscopy. ROC-AUCs of Cytophone, microscopy, and RDT compared to quantitative PCR are not statistically different from one another. The ability to noninvasively detect iRBCs in the bloodstream is a major advancement which offers the potential to rapidly identify both the large asymptomatic reservoir of infection, as well as diagnose symptomatic cases without the need for a blood sample.