Flavivirus Nested PCR Assay for Co-infection Detection
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Solution Overview
Problem
Current diagnostic assays for flavivirus infections, such as those caused by Zika, often result in false positives and false negatives due to sequence similarity among Flaviviridae family members, leading to misdiagnosis and challenges in identifying co-infections, which is critical for public health monitoring and fetal development outcomes.
Innovation Solution
The development of nested amplification methods targeting a broadly conserved region of flaviviruses using specific PCR primer pairs and sequencing primers, allowing for accurate discrimination among family members and identification of mixed sample populations, particularly in the NS5 coding region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If qPCR methods are used for flavivirus detection, then diagnostic testing can be performed, but false positives and false negatives occur due to sequence similarity among Flaviviridae family members
Solution Approach 1:
The patent divides the detection process into multiple sequential steps: initial qPCR screening followed by nested PCR amplification of specific regions, and finally Sanger sequencing for definitive identification. This segmentation allows each method to perform its optimal function - qPCR for sensitivity, nested PCR for specificity, and sequencing for precise viral lineage identification - thereby resolving the contradiction between detection capability and identification accuracy
Solution Approach 2:
The patent introduces an intermediary sequencing step between qPCR and final diagnosis. The Sanger sequencing of the nested PCR amplicon serves as a mediator that verifies the qPCR results and provides definitive viral identification, eliminating false positives and negatives caused by sequence similarity among Flaviviridae family members
2Measurement precision
If broadly conserved region amplification is used, then cross-priming is reduced, but detection sensitivity may be compromised due to genetic divergence
Solution Approach 1:
The patent employs nested PCR where a second pair of primers amplifies a smaller, more conserved region within the larger amplicon generated by the first primer pair. This nesting strategy allows the outer primers to capture diverse viral sequences while the inner primers provide specific amplification of conserved regions, thereby maintaining both detection sensitivity and discrimination accuracy
Solution Approach 2:
The patent targets specific local regions within the viral genome that exhibit high conservation across Flaviviridae family members, particularly in the NS5 protein-coding region. By focusing amplification on these locally conserved sequences rather than attempting to amplify entire genomes, the method maintains high detection sensitivity while achieving accurate virus discrimination
3Device complexity
If single virus detection assays are used, then assay simplicity is maintained, but co-infection identification becomes impossible
Solution Approach 1:
The nested PCR and sequencing assay serves multiple functions: it identifies the presence of flavivirus, determines the specific viral lineage, and detects co-infections with multiple flavivirus species. This multi-functional capability is achieved through the universal nature of the conserved region primers that can amplify diverse flavivirus genomes, followed by sequencing that reveals all viral lineages present in the sample
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces false positive and negative rates, providing confident virus identification and enabling the detection of multiple flaviviruses in a single sample, including co-infections, thereby improving diagnostic accuracy and epidemiological monitoring.
Implementation Method 1
nested amplification of a broadly conserved region of the family of flaviviruses including family members often misdiagnosed as Zika
Implementation Method 2
PCR primer pairs and sequencing primers targeting a region in the flavivirus NS5 coding region or gene
Implementation Method 3
The sequencing procedures can use nucleic acid templates, such as cDNA or PCR amplicons, as a template for sequencing in medium to high throughput format
Data Source
AI summary
Certain embodiments of the invention include methods and compositions for evaluating flaviviruses, such as Zika virus, for the purpose of identifying, typing, and/or categorizing/speciation of virus in samples using nucleic acid sequencing.