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He W, Sendor R, Potlapalli VR, Kashamuka MM, Tshefu AK, Phanzu F, Kalonji A, Ngasala B, Thwai KL, Juliano JJ, Lin JT, Parr JB. A novel duplex qualitative real-time PCR assay for the detection and differentiation of Plasmodium ovale curtisi and Plasmodium ovale wallikeri malaria. medRxiv 2023:2023.10.31.23297819. [PMID: 37961397 PMCID: PMC10635243 DOI: 10.1101/2023.10.31.23297819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Background P. ovale spp. infections are endemic across multiple African countries and are caused by two distinct non-recombining species, P. ovale curtisi (Poc) and P. ovale wallikeri (Pow). These species are thought to differ in clinical symptomatology and latency, but existing diagnostic assays have limited ability to detect and distinguish them. In this study, we developed a new duplex assay for the detection and differentiation of Poc and Pow that can be used to improve our understanding of these parasites. Methods Repetitive sequence motifs were identified in available Poc and Pow genomes and used for assay development and validation. We evaluated the analytical sensitivity and specificity of the best-performing assay using a panel of samples from Tanzania and the Democratic Republic of the Congo (DRC), then validated its performance using 55 P. ovale spp. samples and 40 non-ovale Plasmodium samples from the DRC. Poc and Pow prevalence among symptomatic individuals sampled across three provinces of the DRC were estimated. Results The best-performing Poc and Pow targets had 9 and 8 copies within the reference genomes, respectively. Our duplex assay had 100% specificity and 95% confidence lower limits of detection of 4.2 and 41.2 parasite genome equivalents/μl for Poc and Pow, respectively. Species was determined in 80% of all P. ovale spp.-positive field samples and 100% of those with >10 parasites/μl. Most P. ovale spp. field samples from the DRC were found to be Poc infections. Conclusions We identified promising multi-copy targets for molecular detection and differentiation of Poc and Pow and used them to develop a new duplex real-time PCR assay that performed well when applied to diverse field samples. Though low-density Pow infections are not reliably detected, the assay is highly specific and can be used for high-throughput studies of P. ovale spp. epidemiology among symptomatic cases in malaria-endemic countries like the DRC.
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Affiliation(s)
- Wenqiao He
- Division of Infectious Diseases and Institute for Global Health and Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- Department of Epidemiology, School of Public Health, Guangdong Provincial Key Laboratory of Tropical Disease Research, Southern Medical University, Guangzhou, China
| | - Rachel Sendor
- Department of Epidemiology, Gillings School of Global Public Health, Chapel Hill, NC, United States
| | - Varun R. Potlapalli
- Division of Infectious Diseases and Institute for Global Health and Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | | | | | | | | | - Billy Ngasala
- Muhimbili University of Health and Allied Sciences, Dar Es Salaam, Tanzania
| | - Kyaw Lay Thwai
- Division of Infectious Diseases and Institute for Global Health and Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Jonathan J. Juliano
- Division of Infectious Diseases and Institute for Global Health and Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- Department of Epidemiology, Gillings School of Global Public Health, Chapel Hill, NC, United States
| | - Jessica T. Lin
- Division of Infectious Diseases and Institute for Global Health and Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Jonathan B. Parr
- Division of Infectious Diseases and Institute for Global Health and Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
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Puggioni V, Chiesa O, Panini M, Mazzoni E. Qualitative Sybr Green real-time detection of single nucleotide polymorphisms responsible for target-site resistance in insect pests: the example of Myzus persicae and Musca domestica. Bull Entomol Res 2017; 107:96-105. [PMID: 27444359 DOI: 10.1017/s0007485316000675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Chemical insecticides have been widely used to control insect pests, leading to the selection of resistant populations. To date, several single nucleotide polymorphisms (SNPs) have already been associated with insecticide resistance, causing reduced sensitivity to many classes of products. Monitoring and detection of target-site resistance is currently one of the most important factors for insect pest management strategies. Several methods are available for this purpose: automated and high-throughput techniques (i.e. TaqMan or pyrosequencing) are very costly; cheaper alternatives (i.e. RFLP or PASA-PCRs) are time-consuming and limited by the necessity of a final visualization step. This work presents a new approach (QSGG, Qualitative Sybr Green Genotyping) which combines the specificity of PASA-PCR with the rapidity of real-time PCR analysis. The specific real-time detection of Cq values of wild-type or mutant alleles (amplified used allele-specific primers) allows the calculation of ΔCqW-M values and the consequent identification of the genotypes of unknown samples, on the basis of ranges previously defined with reference clones. The methodology is applied here to characterize mutations described in Myzus persicae and Musca domestica and we demonstrate it represents a valid, rapid and cost-effective technique that can be adopted for monitoring target-site resistance in field populations of these and other insect species.
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Affiliation(s)
- V Puggioni
- Department of Sustainable Crop Production,Section Sustainable Crop and Food Protection,Università Cattolica del Sacro Cuore,Via Emilia Parmense,84, I-29122 Piacenza,Italy
| | - O Chiesa
- Department of Sustainable Crop Production,Section Sustainable Crop and Food Protection,Università Cattolica del Sacro Cuore,Via Emilia Parmense,84, I-29122 Piacenza,Italy
| | - M Panini
- Department of Sustainable Crop Production,Section Sustainable Crop and Food Protection,Università Cattolica del Sacro Cuore,Via Emilia Parmense,84, I-29122 Piacenza,Italy
| | - E Mazzoni
- Department of Sustainable Crop Production,Section Sustainable Crop and Food Protection,Università Cattolica del Sacro Cuore,Via Emilia Parmense,84, I-29122 Piacenza,Italy
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