Enhanced light microscopy visualization of virus particles from Zika virus to filamentous ebolaviruses

Light microscopy is a powerful tool in the detection and analysis of parasites, fungi, and prokaryotes, but has been challenging to use for the detection of individual virus particles. Unlabeled virus particles are too small to be visualized using standard visible light microscopy. Characterization of virus particles is typically performed using higher resolution approaches such as electron microscopy or atomic force microscopy. These approaches require purification of virions away from their normal millieu, requiring significant levels of expertise, and can only enumerate small numbers of particles per field of view. Here, we utilize a visible light imaging approach called Single Particle Interferometric Reflectance Imaging Sensor (SP-IRIS) that allows automated counting and sizing of thousands of individual virions. Virions are captured directly from complex solutions onto a silicon chip and then detected using a reflectance interference imaging modality. We show that the use of different imaging wavelengths allows the visualization of a multitude of virus particles. Using Violet/UV illumination, the SP-IRIS technique is able to detect individual flavivirus particles (~40 nm), while green light illumination is capable of identifying and discriminating between vesicular stomatitis virus and vaccinia virus (~360 nm). Strikingly, the technology allows the clear identification of filamentous infectious ebolavirus particles and virus-like particles. The ability to differentiate and quantify unlabeled virus particles extends the usefulness of traditional light microscopy and can be embodied in a straightforward benchtop approach allowing widespread applications ranging from rapid detection in biological fluids to analysis of virus-like particles for vaccine development and production.

Zika virus induced cellular remodelling

Zika virus (ZIKV) has been associated with morbidities such as Guillain-Barré, infant microcephaly, and ocular disease. The spread of this positive-sense, single-stranded RNA virus and its growing public health threat underscore gaps in our understanding of basic ZIKV virology. To advance knowledge of the virus replication cycle within mammalian cells, we use serial section 3-dimensional electron tomography to demonstrate the widespread remodelling of intracellular membranes upon infection with ZIKV. We report extensive structural rearrangements of the endoplasmic reticulum and reveal stages of the ZIKV viral replication cycle. Structures associated with RNA genome replication and virus assembly are observed integrated within the endoplasmic reticulum, and we show viruses in transit through the Golgi apparatus for viral maturation, and subsequent cellular egress. This study characterises in detail the 3-dimensional ultrastructural organisation of the ZIKV replication cycle stages. Our results show close adherence of the ZIKV replication cycle to the existing flavivirus replication paradigm.

Robust Visualization and Discrimination of Nanoparticles by Interferometric Imaging

Single-molecule and single-nanoparticle biosensors are a growing frontier in diagnostics. Digital biosensors are those which enumerate all specifically immobilized biomolecules or biological nanoparticles, and thereby achieve limits of detection usually beyond the reach of ensemble measurements. Here we review modern optical techniques for single nanoparticle detection and describe the single-particle interferometric reflectance imaging sensor (SP-IRIS). We present challenges associated with reliably detecting faint nanoparticles with SP-IRIS, and describe image acquisition processes and software modifications to address them. Specifically, we describe a image acquisition processing method for the discrimination and accurate counting of nanoparticles that greatly reduces both the number of false positives and false negatives. These engineering improvements are critical steps in the translation of SP-IRIS towards applications in medical diagnostics.

Disposable cartridge platform for rapid detection of viral hemorrhagic fever viruses

Light microscopy is a straightforward and highly portable imaging approach that is used for the detection of parasites, fungi, and bacteria. The detection of individual virus particles has historically not been possible through this approach. Thus, characterization of virus particles is typically performed using high-energy approaches such as electron microscopy. These approaches require purification of virions away from its normal milieu, significant levels of expertise, and only count a small number of particles at a time. To correct these deficiencies we created a platform that allows label-free, point-of-need virus imaging and counting. We adapted a multiplex-capable, interferometric imaging technique to a closed-system that allows real-time particle detection in complex mixtures. To maximize virus particle binding we constructed a disposable device with a constant flow rate of ∼3 μl min^-1. Biosafety was achieved by having a sealable sample addition port. Using this platform we were able to readily identify virus binding in a 20 minute experiment. Sensitivity was comparable to laboratory-based assays such as ELISA and plaque assay, and showed equal or better sensitivity against paper-based assays designed for point-of-need use. Our results demonstrate a platform that can be used for rapid multiplexed detection and visualization of whole virus particles. We envision this technology as a sample-to-answer platform for detection and visualization of viruses without the need for prior labeling. This would enable both research investigation of virus particle behavior and morphology and have the potential to be used in a diagnostic context, where direct imaging from samples such as blood and urine would be valuable.

Transcriptomic signatures differentiate survival from fatal outcomes in humans infected with Ebola virus

Background

In 2014, Western Africa experienced an unanticipated explosion of Ebola virus infections. What distinguishes fatal from non-fatal outcomes remains largely unknown, yet is key to optimising personalised treatment strategies. We used transcriptome data for peripheral blood taken from infected and convalescent recovering patients to identify early stage host factors that are associated with acute illness and those that differentiate patient survival from fatality.

Results

The data demonstrate that individuals who succumbed to the disease show stronger upregulation of interferon signalling and acute phase responses compared to survivors during the acute phase of infection. Particularly notable is the strong upregulation of albumin and fibrinogen genes, which suggest significant liver pathology. Cell subtype prediction using messenger RNA expression patterns indicated that NK-cell populations increase in patients who survive infection. By selecting genes whose expression properties discriminated between fatal cases and survivors, we identify a small panel of responding genes that act as strong predictors of patient outcome, independent of viral load.

Conclusions

Transcriptomic analysis of the host response to pathogen infection using blood samples taken during an outbreak situation can provide multiple levels of information on both disease state and mechanisms of pathogenesis. Host biomarkers were identified that provide high predictive value under conditions where other predictors, such as viral load, are poor prognostic indicators. The data suggested that rapid analysis of the host response to infection in an outbreak situation can provide valuable information to guide an understanding of disease outcome and mechanisms of disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s13059-016-1137-3) contains supplementary material, which is available to authorized users.

DNA-Directed Antibody Immobilization for Robust Protein Microarrays: Application to Single Particle Detection 'DNA-Directed Antibody Immobilization

Protein microarrays are emerging tools which have become very powerful in multiplexed detection technologies. A variety of proteins can be immobilized on a sensor chip allowing for multiplexed diagnostics. Therefore, various types of analyte in a small volume of sample can be detected simultaneously. Protein immobilization is a crucial step for creating a robust and sensitive protein microarray-based detection system. In order to achieve a successful protein immobilization and preserve the activity of the proteins after immobilization, DNA-directed immobilization is a promising technique. Here, we present the design and the use of DNA-directed immobilized (DDI) antibodies in fabrication of robust protein microarrays. We focus on application of protein microarrays for capturing and detecting nanoparticles such as intact viruses. Experimental results on Single-particle interferometric reflectance imaging sensor (SP-IRIS) are used to validate the advantages of the DDI method.

Generating Recombinant Vesicular Stomatitis Viruses for Use as Vaccine Platforms

The unique properties of vesicular stomatitis virus (VSV) make it a promising vaccine platform. With the advent of plasmid-based approaches to generate recombinant VSV viruses that express glycoproteins of other viruses, researchers now have the means to generate vaccine candidates targeting a variety of human pathogens. This chapter gives a general overview of the workings of VSV as a vaccine platform and provides a detailed protocol for the generation of recombinant VSV from plasmids.

Visualizing Ebolavirus Particles Using Single-Particle Interferometric Reflectance Imaging Sensor (SP-IRIS)

This chapter describes an approach for the label-free imaging and quantification of intact Ebola virus (EBOV) and EBOV viruslike particles (VLPs) using a light microscopy technique. In this technique, individual virus particles are captured onto a silicon chip that has been printed with spots of virus-specific capture antibodies. These captured virions are then detected using an optical approach called interference reflectance imaging. This approach allows for the detection of each virus particle that is captured on an antibody spot and can resolve the filamentous structure of EBOV VLPs without the need for electron microscopy. Capture of VLPs and virions can be done from a variety of sample types ranging from tissue culture medium to blood. The technique also allows automated quantitative analysis of the number of virions captured. This can be used to identify the virus concentration in an unknown sample. In addition, this technique offers the opportunity to easily image virions captured from native solutions without the need for additional labeling approaches while offering a means of assessing the range of particle sizes and morphologies in a quantitative manner.

In vivo Ebola virus infection leads to a strong innate response in circulating immune cells

BACKGROUND

Ebola virus is the causative agent of a severe syndrome in humans with a fatality rate that can approach 90 %. During infection, the host immune response is thought to become dysregulated, but the mechanisms through which this happens are not entirely understood. In this study, we analyze RNA sequencing data to determine the host response to Ebola virus infection in circulating immune cells.

RESULTS

Approximately half of the 100 genes with the strongest early increases in expression were interferon-stimulated genes, such as ISG15, OAS1, IFIT2, HERC5, MX1 and DHX58. Other highly upregulated genes included cytokines CXCL11, CCL7, IL2RA, IL2R1, IL15RA, and CSF2RB, which have not been previously reported to change during Ebola virus infection. Comparing this response in two different models of exposure (intramuscular and aerosol) revealed a similar signature of infection. The strong innate response in the aerosol model was seen not only in circulating cells, but also in primary and secondary target tissues. Conversely, the innate immune response of vaccinated macaques was almost non-existent. This suggests that the innate response is a major aspect of the cellular response to Ebola virus infection in multiple tissues.

CONCLUSIONS

Ebola virus causes a severe infection in humans that is associated with high mortality. The host immune response to virus infection is thought to be an important aspect leading to severe pathology, but the components of this overactive response are not well characterized. Here, we analyzed how circulating immune cells respond to the virus and found that there is a strong innate response dependent on active virus replication. This finding is in stark contrast to in vitro evidence showing a suppression of innate immune signaling, and it suggests that the strong innate response we observe in infected animals may be an important contributor to pathogenesis.

Polyamines and Hypusination Are Required for Ebolavirus Gene Expression and Replication

Ebolavirus (EBOV) is an RNA virus that is known to cause severe hemorrhagic fever in humans and other primates : EBOV successfully enters and replicates in many cell types. This replication is dependent on the virus successfully coopting a number of cellular factors. Many of these factors are currently unidentified but represent potential targets for antiviral therapeutics. Here we show that cellular polyamines are critical for EBOV replication. We found that small-molecule inhibitors of polyamine synthesis block gene expression driven by the viral RNA-dependent RNA polymerase. Short hairpin RNA (shRNA) knockdown of the polyamine pathway enzyme spermidine synthase also resulted in reduced EBOV replication. These findings led us to further investigate spermidine, a polyamine that is essential for the hypusination of eukaryotic initiation factor 5A (eIF5A). Blocking the hypusination of eIF5A (and thereby inhibiting its function) inhibited both EBOV gene expression and viral replication. The mechanism appears to be due to the importance of hypusinated eIF5A for the accumulation of VP30, an essential component of the viral polymerase. The same reduction in hypusinated eIF5A did not alter the accumulation of other viral polymerase components. This action makes eIF5A function an important gate for proper EBOV polymerase assembly and function through the control of a single virus protein.

IMPORTANCE

Ebolavirus (EBOV) is one of the most lethal human pathogens known. EBOV requires host factors for replication due to its small RNA genome. Here we show that the host protein eIF5A in its activated form is necessary for EBOV replication. We further show that the mechanism is through the accumulation of a single EBOV protein, VP30. To date, no other host proteins have been shown to interfere with the translation or stability of an EBOV protein. Activated eIF5A is the only protein in the cell known to contain the specific modification of hypusine; therefore, this pathway is a target for drug development. Further investigation into the mechanism of eIF5A interaction with VP30 could provide insight into therapeutics to combat EBOV.

New Approaches for Virus Detection through Multidisciplinary Partnerships

A critical requirement for controlling outbreaks of viral infection is sensitive and accurate diagnostics, which can be expensive and are frequently located in resource-intensive clinical laboratories. Outbreaks of many viral infections occur in countries where healthcare resources are limited and clinical laboratories scarce. This creates a fulfillment gap, one that could be filled through the development of inexpensive, sensitive, easy to use, and portable diagnostics. Here we describe our efforts to develop a diagnostic technology that detects viruses without needing to label the particle directly. Our approach has the advantage of speed and assay simplicity while maintaining high sensitivity. Essential in this approach has been the assembly of an integrated, diverse, and interdisciplinary team that worked together to evaluate technologies, spin-out a company, and produce a product for infectious disease diagnostics. The synergy of different individuals with complementary skills has been critical for the development of our transformative technology.

Real-Time Capture and Visualization of Individual Viruses in Complex Media

Label-free imaging of individual viruses and nanoparticles directly in complex solutions is important for virology research and biosensing applications. A successful visualization technique should be rapid, sensitive, and inexpensive, while needing minimal sample preparation or user expertise. Current approaches typically require fluorescent labeling or the use of an electron microscope, which are expensive and time-consuming to use. We have developed an imaging technique for real-time, sensitive, and label-free visualization of viruses and nanoparticles directly in complex solutions such as serum. By combining the advantages of a single-particle reflectance imaging sensor, with microfluidics, we perform real-time digital detection of individual 100 nm vesicular stomatitis viruses as they bind to an antibody microarray. Using this approach, we have shown capture and visualization of a recombinant vesicular stomatitis virus Ebola model (rVSV-ZEBOV) at 100 PFU/mL in undiluted fetal bovine serum in less than 30 min.

A Single-Vector, Single-Injection Trivalent Filovirus Vaccine: Proof of Concept Study in Outbred Guinea Pigs

The filoviruses, Marburg marburgvirus (MARV), Zaire ebolavirus (ZEBOV), and Sudan ebolavirus (SEBOV), cause severe and often fatal hemorrhagic fever in humans and nonhuman primates (NHPs). Monovalent recombinant vesicular stomatitis virus (rVSV)-based vaccine vectors, which encode a filovirus glycoprotein (GP) in place of the VSV glycoprotein, have shown 100% efficacy against homologous filovirus challenge in rodent and NHP studies. Here, we examined the utility of a single-vector, single-injection trivalent rVSV vector expressing MARV, ZEBOV, and SEBOV GPs to protect against MARV-, ZEBOV-, and SEBOV-induced disease in outbred Hartley guinea pigs where we observed protection from effects of all 3 filoviruses.

Advancing rapid point-of-care viral diagnostics to a clinical setting

ABSTRACT 

We discuss here critical factors in ensuring the success of a viral diagnostic at the point of care. Molecular and immunoassay approaches are reviewed with a focus on their ability to meet the infrastructure and workflow limitations in clinical settings in both the developed and developing world. In addition to being low cost, easy-to-use, accurate and adapted for the intended laboratory and healthcare environment, viral diagnostics must also provide information that appropriately directs clinical treatment decisions. We discuss the challenges and implications of linking diagnostics to clinical decision-making at the point of care using three examples: respiratory viruses in the developed world, differential fever diagnosis in the developing world and HPV detection in resource-limited settings.

Probing the virus host interaction in high containment: an approach using pooled short hairpin RNA

The study of viruses in high containment offers unique challenges for technology-intense approaches. These approaches include high-throughput screening for small-molecule antivirals and genetic perturbation-based screens for host factors required for viral replication. Here, we describe the use of whole-genome scale pooled short hairpin RNA (shRNA) libraries to screen for host factors necessary for viral infection at BSL2, and the transition of this technique into the BSL4 environment. Pooled screening provides a unique way to circumvent many of the technological challenges associated with other high-throughput screening approaches in high containment. Our pooled screening approach identified host factors involved in the replication of orthopoxviruses (Vaccinia and Monkeypox) and filoviruses (Ebola and Marburg) under conditions that enable straightforward screen-to-follow-up approaches.

Lassa and Marburg viruses elicit distinct host transcriptional responses early after infection

BACKGROUND

Lassa virus and Marburg virus are two causative agents of viral hemorrhagic fever. Their diagnosis is difficult because patients infected with either pathogen present similar nonspecific symptoms early after infection. Current diagnostic tests are based on detecting viral proteins or nucleic acids in the blood, but these cannot be found during the early stages of disease, before the virus starts replicating in the blood. Using the transcriptional response of the host during infection can lead to earlier diagnoses compared to those of traditional methods.

RESULTS

In this study, we use RNA sequencing to obtain a high-resolution view of the in vivo transcriptional dynamics of peripheral blood mononuclear cells (PBMCs) throughout both types of infection. We report a subset of host mRNAs, including heat-shock proteins like HSPA1B, immunoglobulins like IGJ, and cell adhesion molecules like SIGLEC1, whose differences in expression are strong enough to distinguish Lassa infection from Marburg infection in non-human primates. We have validated these infection-specific expression differences by using microarrays on a larger set of samples, and by quantifying the expression of individual genes using RT-PCR.

CONCLUSIONS

These results suggest that host transcriptional signatures are correlated with specific viral infections, and that they can be used to identify highly pathogenic viruses during the early stages of disease, before standard detection methods become effective.

Transcriptional correlates of disease outcome in anticoagulant-treated non-human primates infected with ebolavirus

Ebola virus (EBOV) infection in humans and non-human primates (NHPs) is highly lethal, and there is limited understanding of the mechanisms associated with pathogenesis and survival. Here, we describe a transcriptomic analysis of NHPs that survived lethal EBOV infection, compared to NHPs that did not survive. It has been previously demonstrated that anticoagulant therapeutics increase the survival rate in EBOV-infected NHPs, and that the characteristic transcriptional profile of immune response changes in anticoagulant-treated NHPs. In order to identify transcriptional signatures that correlate with survival following EBOV infection, we compared the mRNA expression profile in peripheral blood mononuclear cells from EBOV-infected NHPs that received anticoagulant treatment, to those that did not receive treatment. We identified a small set of 20 genes that are highly confident predictors and can accurately distinguish between surviving and non-surviving animals. In addition, we identified a larger predictive signature of 238 genes that correlated with disease outcome and treatment; this latter signature was associated with a variety of host responses, such as the inflammatory response, T cell death, and inhibition of viral replication. Notably, among survival-associated genes were subsets of genes that are transcriptionally regulated by (1) CCAAT/enhancer-binding protein alpha, (2) tumor protein 53, and (3) megakaryoblastic leukemia 1 and myocardin-like protein 2. These pathways merit further investigation as potential transcriptional signatures of host immune response to EBOV infection.

Discovery of a novel compound with anti-venezuelan equine encephalitis virus activity that targets the nonstructural protein 2

Alphaviruses present serious health threats as emerging and re-emerging viruses. Venezuelan equine encephalitis virus (VEEV), a New World alphavirus, can cause encephalitis in humans and horses, but there are no therapeutics for treatment. To date, compounds reported as anti-VEEV or anti-alphavirus inhibitors have shown moderate activity. To discover new classes of anti-VEEV inhibitors with novel viral targets, we used a high-throughput screen based on the measurement of cell protection from live VEEV TC-83-induced cytopathic effect to screen a 340,000 compound library. Of those, we identified five novel anti-VEEV compounds and chose a quinazolinone compound, CID15997213 (IC₅₀ = 0.84 µM), for further characterization. The antiviral effect of CID15997213 was alphavirus-specific, inhibiting VEEV and Western equine encephalitis virus, but not Eastern equine encephalitis virus. In vitro assays confirmed inhibition of viral RNA, protein, and progeny synthesis. No antiviral activity was detected against a select group of RNA viruses. We found mutations conferring the resistance to the compound in the N-terminal domain of nsP2 and confirmed the target residues using a reverse genetic approach. Time of addition studies showed that the compound inhibits the middle stage of replication when viral genome replication is most active. In mice, the compound showed complete protection from lethal VEEV disease at 50 mg/kg/day. Collectively, these results reveal a potent anti-VEEV compound that uniquely targets the viral nsP2 N-terminal domain. While the function of nsP2 has yet to be characterized, our studies suggest that the protein might play a critical role in viral replication, and further, may represent an innovative opportunity to develop therapeutic interventions for alphavirus infection.

Alphaviruses occur worldwide, causing significant diseases such as encephalitis or arthritis in humans and animals. In addition, some alphaviruses, such as VEEV, pose a biothreat due to their high infectivity and lack of available treatments. To discover small molecule inhibitors with lead development potential, we used a cell-based assay to screen 348,140 compounds for inhibition of a VEEV-induced cytopathic effect. The screen revealed a scaffold with high inhibitory VEEV cellular potency and low cytotoxicity liability. While most previously reported anti-alphavirus compounds inhibit host proteins, evidence supported that this scaffold targeted the VEEV nsP2 protein, and that inhibition was associated with viral replication. Interestingly, compound resistance studies with VEEV mapped activity to the N-terminal domain of nsP2, to which no known function has been attributed. Ultimately, this discovery has delivered a small molecule-derived class of potent VEEV inhibitors whose activity is coupled to the nsP2 viral protein, a novel target with a previously unestablished biological role that is now implicated in viral replication.

A single vertebrate DNA virus protein disarms invertebrate immunity to RNA virus infection

Virus-host interactions drive a remarkable diversity of immune responses and countermeasures. We found that two RNA viruses with broad host ranges, vesicular stomatitis virus (VSV) and Sindbis virus (SINV), are completely restricted in their replication after entry into Lepidopteran cells. This restriction is overcome when cells are co-infected with vaccinia virus (VACV), a vertebrate DNA virus. Using RNAi screening, we show that Lepidopteran RNAi, Nuclear Factor-κB, and ubiquitin-proteasome pathways restrict RNA virus infection. Surprisingly, a highly conserved, uncharacterized VACV protein, A51R, can partially overcome this virus restriction. We show that A51R is also critical for VACV replication in vertebrate cells and for pathogenesis in mice. Interestingly, A51R colocalizes with, and stabilizes, host microtubules and also associates with ubiquitin. We show that A51R promotes viral protein stability, possibly by preventing ubiquitin-dependent targeting of viral proteins for destruction. Importantly, our studies reveal exciting new opportunities to study virus-host interactions in experimentally-tractable Lepidopteran systems.

Digital sensing and sizing of vesicular stomatitis virus pseudotypes in complex media: a model for Ebola and Marburg detection

Rapid, sensitive, and direct label-free capture and characterization of nanoparticles from complex media such as blood or serum will broadly impact medicine and the life sciences. We demonstrate identification of virus particles in complex samples for replication-competent wild-type vesicular stomatitis virus (VSV), defective VSV, and Ebola- and Marburg-pseudotyped VSV with high sensitivity and specificity. Size discrimination of the imaged nanoparticles (virions) allows differentiation between modified viruses having different genome lengths and facilitates a reduction in the counting of nonspecifically bound particles to achieve a limit-of-detection (LOD) of 5 × 10(3) pfu/mL for the Ebola and Marburg VSV pseudotypes. We demonstrate the simultaneous detection of multiple viruses in a single sample (composed of serum or whole blood) for screening applications and uncompromised detection capabilities in samples contaminated with high levels of bacteria. By employing affinity-based capture, size discrimination, and a "digital" detection scheme to count single virus particles, we show that a robust and sensitive virus/nanoparticle sensing assay can be established for targets in complex samples. The nanoparticle microscopy system is termed the Single Particle Interferometric Reflectance Imaging Sensor (SP-IRIS) and is capable of high-throughput and rapid sizing of large numbers of biological nanoparticles on an antibody microarray for research and diagnostic applications.

Vaccinia reporter viruses for quantifying viral function at all stages of gene expression

Poxviruses are a family of double stranded DNA viruses that include active human pathogens such as monkeypox, molluscum contagiousum, and Contagalo virus. The family also includes the smallpox virus, Variola. Due to the complexity of poxvirus replication, many questions still remain regarding their gene expression strategy. In this article we describe the conceptualization and usage of recombinant vaccinia viruses that enable real-time measurement of single and multiple stages of viral gene expression in a high-throughput format. This is enabled through the use of spectrally distinct fluorescent proteins as reporters for each of three stages of viral replication. These viruses provide a high signal-to-noise ratio while retaining stage specific expression patterns, enabling plate-based assays and microscopic observations of virus propagation and replication. These tools have uses for antiviral discovery, studies of the virus-host interaction, and evolutionary biology.

An interferometric reflectance imaging sensor for point of care viral diagnostics

The use of in vitro diagnostic devices is transitioning from the laboratory to the primary care setting to address early disease detection needs. Time critical viral diagnoses are often made without support due to the experimental time required in today's standard tests. Available rapid point of care (POC) viral tests are less reliable, requiring a follow-on confirmatory test before conclusions can be drawn. The development of a reliable POC viral test for the primary care setting would decrease the time for diagnosis leading to a lower chance of transmission and improve recovery. The single particle interferometric reflectance imaging sensor (SP-IRIS) has been shown to be a sensitive and specific-detection platform in serum and whole blood. This paper presents a step towards a POC viral assay through a SP-IRIS prototype with automated data acquisition and analysis and a simple, easy-to-use software interface. Decreasing operation complexity highlights the potential of SP-IRIS as a sensitive and specific POC diagnostic tool. With the integration of a microfluidic cartridge, this automated instrument will allow an untrained user to run a sample-to-answer viral assay in the POC setting.