Digital PCR for ebolavirus research

The Bundibugyo ebolavirus (BDBV) outbreak in the Democratic Republic of the Congo and Uganda has the global virology community on alert. This epidemic presents a particular hurdle, because unlike the Zaire strain, there are currently no approved vaccines or targeted therapies for Bundibugyo.

Labs working to develop countermeasures face a common technical issue: They need absolute certainty in their results, but they’re often working right at the lower limit of detection, where traditional reverse-transcription qPCR (RT-qPCR) results can be ambiguous. At single-digit viral copy numbers, the baseline noise of a qPCR amplification curve makes it impossible to reliably separate true low-titer samples from background artifacts.

In contrast, reverse-transcription digital PCR (RT-dPCR) provides absolute quantification of ebolavirus RNA by partitioning samples into thousands of individual reactions. Because each partition is counted as positive or negative, digital PCR doesn't require standard curves. This shift offers extreme sensitivity at single-digit copy numbers and a higher tolerance to the PCR inhibitors that are often in complex sample matrices. (1) 

Applications of digital PCR in ebolavirus research

Advanced virology research pipelines like those used for Ebola and other filoviruses demand deep analytical precision. While RT-qPCR works well for field diagnostics, it lacks the resolution required for upstream development and quantification. So researchers across multiple fronts are using RT-dPCR to overcome these limitations and confidently measure near-zero viral loads.

Validating novel therapeutics and vaccines

Digital PCR supports the development of novel Ebola countermeasures by providing highly reproducible viral replication kinetics. For labs evaluating candidate vaccines, monoclonal antibodies or small-molecule antivirals, tracking minute changes in viremia is critical.

Under the FDA Animal Rule, the critical challenge is attributing changes in viral load to your therapeutic rather than to measurement error. (2)  Because RT-dPCR provides absolute counts without run-to-run drift, (3) observed drops in viremia can be confidently attributed to the drug and documented to support regulatory filings. For non-human primate challenge studies evaluating candidate vaccines or therapeutics, this reproducibility is the difference between a statistical claim and background noise.

Quantifying viral persistence in Ebola survivors

Identifying low-level ebolavirus shedding in immune-privileged sites like semen and ocular fluid can help us understand how persistent viral reservoirs trigger unexpected outbreak flare-ups. (4) Clinical samples from disease survivors can contain endogenous inhibitors and are often precious or low volume. RT-dPCR's partitioning approach offers an advantage in detecting persistent virus and helping us better understand the clinical importance of these reservoirs.

Calibrating Ebola diagnostic reference materials

Reference labs use digital PCR to establish baseline copy numbers for master Ebola reference standards. (1) When diagnostic kits are manufactured globally, developers must test them against these standards to ensure specificity and sensitivity. The challenge is if the value obtained for the standard drifts between plates, you can't distinguish between a kit that's failing and a kit that's meeting a moving target. RT-dPCR solves this by delivering an absolute, verifiable copy number that remains stable across sites and timepoints. These biological rulers keep global diagnostic thresholds uniform.

Digital PCR assays for ebolavirus species

QIAGEN offers predesigned and custom digital PCR microbial detection assays for ebolavirus targets on the QIAcuity platform. These assays support research detection workflows where the question is the virus itself: quantifying viral load, characterizing strains across the six ebolavirus species and developing sensitive detection methods for low-copy targets.

If you're working across more than one pathogen, you can find the rest of the dPCR microbial detection range under digital PCR applications.

1. Sancha Dominguez L, Cotos Suárez A, Sánchez Ledesma M, Muñoz Bellido JL. Present and future applications of digital PCR in infectious diseases diagnosis. Diagnostics (Basel). 2024;14(9):931. https://doi.org/10.3390/diagnostics14090931
2. St Claire MC, Ragland DR, Bollinger L, Jahrling PB. Animal models of Ebolavirus infection. Comp Med. 2017;67(3):253–262. https://pubmed.ncbi.nlm.nih.gov/28662754
3. Matson MJ, Ricotta E, Feldmann F, et al. Evaluation of viral load in patients with Ebola virus disease in Liberia: a retrospective observational study. Lancet Microbe. 2022;3(7):e533–e542. https://doi.org/10.1016/S2666-5247(22)00065-9
4. Varkey JB, Shantha JG, Crozier I, et al. Persistence of Ebola virus in ocular fluid during convalescence. N Engl J Med. 2015;372(25):2423–2427. https://doi.org/10.1056/NEJMoa1500306
5. Huang Y, Xiao S, Yuan Z. Comparison and evaluation of real-time TaqMan PCR for detection and quantification of ebolavirus. Viruses. 2021;13(8):1575. https://doi.org/10.3390/v13081575
6. World Health Organization. Emergency Guidance on the Use of Licensed Ebola Virus Vaccines during Outbreaks of Bundibugyo Virus Disease. Geneva: WHO; 2026. https://www.who.int/publications/i/item/B09772