A Phi29-based unbiased exponential amplification and genotyping approach improves pathogen detection in tick samples.

Area of Science:

• Veterinary Entomology
• Molecular Biology
• Infectious Diseases

Background:

• Ticks transmit significant infectious diseases like spotted fever group rickettsioses and borreliosis.
• Limited DNA quantity from individual ticks hinders comprehensive pathogen screening and genotyping.
• Unbiased DNA amplification is crucial for ecological surveys and tick-borne disease research.

Purpose of the Study:

• To develop and evaluate a Phi29-based unbiased exponential amplification (PEA) assay for tick DNA.
• To assess the assay's efficacy in enabling pathogen detection and genotyping from single ticks.
• To demonstrate the assay's utility in identifying novel tick-borne pathogen genotypes.

Main Methods:

• Extraction of DNA from single ticks.
• Application of the Phi29-based unbiased exponential amplification (PEA) assay for DNA amplification.
• Utilizing amplified DNA for tick-borne pathogen detection and genotyping.

Main Results:

• The PEA assay achieved up to 10⁵-fold amplification of tick DNA.
• Amplified DNA successfully supported pathogen screening and genotyping.
• Detected and genotyped *Rickettsia* from single tick samples, identifying a new genotype in Northeast China.

Conclusions:

• The developed PEA assay effectively generates sufficient tick DNA for genetic analysis.
• This method is highly valuable for tick-borne pathogen surveillance and discovery.
• The PEA assay is a versatile tool applicable to various low-input DNA scenarios.