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- Cotter, Chris
(författare)
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Evaluating and optimizing surveillance and response strategies for malaria elimination in the Asia Pacific region
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Malaria case investigation and reactive case detection (RACD) activities are widely implemented in low transmission settings to identify additional malaria infections and gather surveillance information, but with varying degrees of success. Challenges in conducting RACD include poor diagnostic sensitivity (particularly for low density and asymptomatic infections), knowledge gaps among those conducting RACD, financial and resource constraints, and operational and logistical difficulties. To improve infection detection and better target individuals at highest risk for infection, RACD strategies need to be evaluated and optimized to provide quality and nuanced surveillance information.To support more effective surveillance and response strategies, this PhD project focused on evaluating RACD strategies to improve and optimize malaria surveillance in low transmission settings in the Asia Pacific region. Using a standardized monitoring and evaluation (M&E) tool, case investigation and RACD indicators were assessed, including the knowledge and practices of the staff conducting RACD. This PhD project explored the utility of molecular diagnostics and genotyping and targeted sociobehavorial RACD strategies for increasing infection detection and to understand the relatedness of infections identified during RACD. Also, the acceptability and feasibility of a presumptive treatment-based strategy to reduce malaria (referred to as reactive drug administration (RDA)) was evaluated.Results revealed gaps in case investigation and RACD reporting completeness and timeliness and that staff were not always equipped with the appropriate documentation or have accurate knowledge on how to conduct RACD. Molecular diagnostics used in RACD in Thailand identified an additional 12 (0.6%) infections compared to no RACD-identified infections detected by microscopy. Of the four confirmed infections, only one (25%) was genetically related to the index case. In Indonesia, a sociobehavorial RACD strategy targeting high risk populations and work venues was able to identify 180 individuals for RACD yielding 8 infections compared to only one infection during household-based RACD. Shared risk factors between sociobehavorial RACD individuals and index patients include being male, 30-45 years of age, and occupation of logging or mining. In Thailand, an RDA strategy targeting within and around the household and forest-going co-workers was found to be acceptable by those that participated and feasible to be implemented by the malaria staff.The quality of malaria case investigation and RACD activities and the knowledge of those implementing it can be improved using a standardized M&E tool. The molecular and genotyping findings may be useful for malaria programs in low transmission settings to increase infection detection in persistent malaria foci or among high-risk populations and to characterize local transmission patterns. When the highest risk individuals for malaria can be identified, a strategy like RDA may be useful to target and eliminate malaria to accelerate elimination efforts.
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| 2. |
- Lin, Kangming, et al.
(författare)
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Evaluation of an Innovative Point-of-Care Rapid Diagnostic Test for the Identification of Imported Malaria Parasites in China
- 2023
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Ingår i: Tropical Medicine and Infectious Disease. - : MDPI. - 2414-6366. ; 8:6
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Tidskriftsartikel (refereegranskat)abstract
- Background: China was certified malaria-free by the World Health Organization on 30 June 2021. However, due to imported malaria, maintaining a malaria-free status in China is an ongoing challenge. There are critical gaps in the detection of imported malaria through the currently available tools, especially for non-falciparum malaria. In the study, a novel point-of-care Rapid Diagnostic Test designed for the detection of imported malaria infections was evaluated in the field. Methods: Suspected imported malaria cases reported from Guangxi and Anhui Provinces of China during 2018-2019 were enrolled to evaluate the novel RDTs. Diagnostic performance of the novel RDTs was evaluated based on its sensitivity, specificity, positive and negative predictive values, and Cohen's kappa coefficient, using polymerase chain reaction as the gold standard. The Additive and absolute Net Reclassification Index were calculated to compare the diagnostic performance between the novel RDTs and Wondfo RDTs (control group). Results: A total of 602 samples were tested using the novel RDTs. Compared to the results of PCR, the novel RDTs presented sensitivity, specificity, PPV, NPV, and diagnostic accuracy rates of 78.37%, 95.05%, 94.70%, 79.59%, and 86.21%, respectively. Among the positive samples, the novel RDTs found 87.01%, 71.31%, 81.82%, and 61.54% of P. falciparum, P. ovale, P. vivax, and P. malariae, respectively. The ability to detect non-falciparum malaria did not differ significantly between the novel and Wondfo RDTs (control group). However, Wondfo RDTs can detect more P. falciparum cases than the novel RDTs (96.10% vs. 87.01%, p < 0.001). After the introduction of the novel RDTs, the value of the additive and absolute Net Reclassification Index is 1.83% and 1.33%, respectively. Conclusions: The novel RDTs demonstrated the ability to distinguish P. ovale and P. malariae from P. vivax which may help to improve the malaria post-elimination surveillance tools in China.
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| 3. |
- Newby, Gretchen, et al.
(författare)
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Testing and treatment for malaria elimination : a systematic review
- 2023
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Ingår i: Malaria Journal. - : BioMed Central (BMC). - 1475-2875. ; 22:1
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Forskningsöversikt (refereegranskat)abstract
- Background Global interest in malaria elimination has prompted research on active test and treat (TaT) strategies.Methods A systematic review and meta-analysis were conducted to assess the effectiveness of TaT strategies to reduce malaria transmission.Results A total of 72 empirical research and 24 modelling studies were identified, mainly focused on proactive mass TaT (MTaT) and reactive case detection (RACD) in higher and lower transmission settings, respectively. Ten intervention studies compared MTaT to no MTaT and the evidence for impact on malaria incidence was weak. No intervention studies compared RACD to no RACD. Compared to passive case detection (PCD) alone, PCD + RACD using standard diagnostics increased infection detection 52.7% and 11.3% in low and very low transmission settings, respectively. Using molecular methods increased this detection of infections by 1.4- and 1.1-fold, respectively.Conclusion Results suggest MTaT is not effective for reducing transmission. By increasing case detection, surveillance data provided by RACD may indirectly reduce transmission by informing coordinated responses of intervention targeting.
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| 4. |
- Sun, Xiao-dong, et al.
(författare)
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Implementing a novel capture and ligation probe-PCR method in mass screen and treatment to support malaria elimination efforts in the China-Myanmar border region
- 2023
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Ingår i: Malaria Journal. - : BioMed Central (BMC). - 1475-2875. ; 22:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundMass screening and treatment (MSAT) for malaria elimination lacks an ideal diagnostic tool to allow sensitive and affordable test of the target population in the field. This study evaluated whether Capture and Ligation Probe-PCR (CLIP-PCR) could be used in a field MSAT in Laiza City, Myanmar.MethodsOn day 0, two dried blood spots were collected from each participant. On day 1, all samples were screened for Plasmodium in a 20 m(2) laboratory with workbench, a biosafety cabinet, a refrigerator, a benchtop shaking incubator and a qPCR machine, by four technicians using CLIP-PCR with sample pooling, at a health clinic of the Chinese bordering town of Nabang. On day 2, all positives were followed up and treated.ResultsOf 15,038 persons (65% of the total population) screened, 204 (1.36%) were CLIP-PCR positives. Among them, 188, 14, and 2 were infected with Plasmodium vivax, Plasmodium falciparum, and P. vivax/P. falciparum mix, respectively. The testing capacity was 538 persons/day, with a cost of US$0.92 /person. The proportion of submicroscopic infection was 64.7%. All positive individuals received treatment within 72 h after blood collection.ConclusionUsing CLIP-PCR in MSAT in low transmission settings can support the malaria elimination efforts in the China-Myanmar border region.
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| 5. |
- Suwannarong, Kanokwan, et al.
(författare)
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Assessing the acceptability and feasibility of reactive drug administration for malaria elimination in a Plasmodium vivax predominant setting : a qualitative study in two provinces in Thailand
- 2023
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Ingår i: BMC Public Health. - : BMC. - 1471-2458. ; 23
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Tidskriftsartikel (refereegranskat)abstract
- Background: Reactive case detection (RACD) or testing and treatment of close contacts of recent malaria cases, is commonly practiced in settings approaching malaria elimination, but standard diagnostics have limited sensitivity to detect low level infections. Reactive drug administration (RDA), or presumptive treatment without testing, is an alternative approach, but better understanding regarding community acceptability and operational feasibility are needed.Methods: A qualitative study was conducted as part of a two-arm cluster randomized-controlled trial evaluating the effectiveness of RDA targeting high-risk villages and forest workers for reducing Plasmodium vivax and P. falciparum malaria in Thailand. Key informant interviews (KIIs) and focus group discussions (FGDs) were conducted virtually among key public health staff, village health volunteers (VHVs), and household members that implemented or received RDA activities. Transcriptions were reviewed, coded, and managed manually using Dedoose qualitative data analysis software, then underwent qualitative content analysis to identify key themes.Results: RDA was well accepted by household members and public health staff that implemented it. RDA participation was driven by fear of contracting malaria, eagerness to receive protection provided by malaria medicines, and the increased access to health care. Concerns were raised about the safety of taking malaria medicines without having an illness, particularly if underlying health conditions existed. Health promotion hospital (HPH) staff implementing RDA noted its operational feasibility, but highlighted difficulty in traveling to remote areas, and requested additional travel resources and hiring more VHVs. Other challenges were highlighted including the need for additional training for VHVs on malaria activities and the inability of HPH staff to conduct RDA due to other health priorities (e.g., Covid-19). More training and practice for VHVs were noted as ways to improve implementation of RDA.Conclusions: To maximize uptake of RDA, regular education and sensitization campaigns in collaboration with village leaders on the purpose and rationale of RDA will be critical. To alleviate safety concerns and increase participant safety, a rigorous pharmacovigilance program will be important. To accelerate uptake of RDA, trust between HPH staff and VHVs and the communities they serve must continue to be strengthened to ensure acceptance of the intervention.
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