HAV Quantification Kit Using Mengo Virus Control
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Solution Overview
Problem
Current methods for detecting Hepatitis A virus (HAV) in clinical, food, and environmental samples lack sensitivity and reliability, particularly in quantifying viral genomic copies, which is crucial for disease prognosis and safety control in industries like blood banks and agro-alimentary sectors.
Innovation Solution
A standardized method using RT-PCR with specific primers and probes for the 5' non-coding region of HAV, along with a non-pathogenic mutant Mengo virus as a control, to accurately quantify HAV by comparing standard curves and determining reaction efficiencies, ensuring precise detection and quantification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional RT-PCR methods are used for HAV detection, then the detection process is simple, but the sensitivity and reliability are insufficient leading to false negatives
Solution Approach 1:
The patent applies preliminary action by adding a known concentration of Mengo virus to the sample before nucleic acid extraction. This internal control is incorporated into the sample matrix early, allowing it to experience the same extraction and amplification conditions as the target HAV, thereby enabling accurate efficiency assessment and compensation for losses throughout the process.
Solution Approach 2:
The patent implements feedback mechanisms through multiple control systems: (1) Mengo virus as an internal extraction control providing real-time feedback on extraction efficiency, (2) synthetic RNA controls monitoring RT-PCR amplification efficiency, and (3) standard curves generating quantitative feedback for accurate HAV genome copy calculation. This multi-layered feedback system continuously monitors and corrects for variations in each step.
2Measurement precision
If sensitivity is increased to detect low viral loads, then detection capability improves, but the risk of false negatives increases without proper controls
Solution Approach 1:
The patent uses feedback through standard curves generated from known concentrations of HAV genomes and synthetic RNA. These curves provide a reference framework that allows accurate quantification of unknown samples, enabling precise measurement even at low viral loads while maintaining reliability through comparative analysis against calibrated standards.
Solution Approach 2:
The patent replaces direct mechanical detection of viral particles with molecular-level detection using RT-PCR amplification of viral genomes. This substitution allows detection of extremely low viral loads by amplifying genetic material, achieving high measurement precision through biochemical amplification rather than physical detection methods.
3Measurement precision
If multiple controls are added to monitor extraction and RT-PCR efficiency, then quantification accuracy improves, but the procedure complexity increases
Solution Approach 1:
The patent merges multiple control functions into a unified assay system. The Mengo virus serves dual purposes as both an extraction control and a process monitor, while synthetic RNA controls are integrated into the RT-PCR reaction mix. This consolidation allows simultaneous monitoring of extraction efficiency, amplification efficiency, and target quantification within a single workflow, reducing the number of separate procedures needed.
Solution Approach 2:
The patent applies universality through the Mengo virus control, which functions as a universal internal standard for monitoring nucleic acid extraction efficiency across different sample types and conditions. This single control element provides multi-functional information about process performance, reducing the need for multiple specialized controls and simplifying the overall procedure.
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
The method provides highly sensitive and reliable detection and quantification of HAV, reducing the risk of false negatives and enabling effective disease prognosis and safety control in clinical and food samples, ensuring the quality of blood and food products.
Implementation Method 1
The three subsamples are analyzed by RT-PCR with a reaction mixture comprising primers that specifically bind to regions of the 5′ non coding region (5′NCR) of the HAV genome, and a detectable labeled probe that specifically binds to the amplimer resulting from the RT-PCR
Implementation Method 2
The acronym 'RT-PCR' means 'reverse transcription polymerase chain reaction' as used commonly in the art
Implementation Method 3
a detectable labeled probe that specifically binds to the amplimer resulting from the RT-PCR
Data Source
AI summary
The present invention provides a standardized method and a kit for an accurate quantification of HAV in clinical and food samples. The general approach is based on the use of several controls to measure the efficiency of those critical steps of the quantification: the nucleic acids extraction and the RT-PCR reactions. The kit comprises: a Mengo virus mutant strain with the same growth properties than those of the wild-type Mengo virus and with no pathogenic capacity; a single stranded RNA molecule corresponding to a fragment of the HAV genome; primers that specifically bind to regions of the 5′ non coding region of the HAV genome; a detectable labeled probe that specifically binds to the amplimer resulting from the RT-PCR; and an appropriate molecule to generate an standard curve for the quantification of HAV.