Biodefence research two decades on: worth the investment?

Smallpox lesion characterization in placebo-treated and tecovirimat-treated macaques using traditional and novel methods

Smallpox was the most rampant infectious disease killer of the 20th century, yet much remains unknown about the pathogenesis of the variola virus. Using archived tissue from a study conducted at the Centers for Disease Control and Prevention we characterized pathology in 18 cynomolgus macaques intravenously infected with the Harper strain of variola virus. Six macaques were placebo-treated controls, six were tecovirimat-treated beginning at 2 days post-infection, and six were tecovirimat-treated beginning at 4 days post-infection. All macaques were treated daily until day 17. Archived tissues were interrogated using immunohistochemistry, in situ hybridization, immunofluorescence, and electron microscopy. Gross lesions in three placebo-treated animals that succumbed to infection primarily consisted of cutaneous vesicles, pustules, or crusts with lymphadenopathy. The only gross lesions noted at the conclusion of the study in the three surviving placebo-treated and the Day 4 treated animals consisted of resolving cutaneous pox lesions. No gross lesions attributable to poxviral infection were present in the Day 2 treated macaques. Histologic lesions in three placebo-treated macaques that succumbed to infection consisted of proliferative and necrotizing dermatitis with intracytoplasmic inclusion bodies and lymphoid depletion. The only notable histologic lesion in the Day 4 treated macaques was resolving dermatitis; no notable lesions were seen in the Day 2 treated macaques. Variola virus was detected in all three placebo-treated animals that succumbed to infection prior to the study's conclusion by all utilized methods (IHC, ISH, IFA, EM). None of the three placebo-treated animals that survived to the end of the study nor the animals in the two tecovirimat treatment groups showed evidence of variola virus by these methods. Our findings further characterize variola lesions in the macaque model and describe new molecular methods for variola detection.

Integrating research infrastructures into infectious diseases surveillance operations: Focus on biobanks

Technological advances in the first two decades of the 21st century have profoundly impacted medical research in many ways, with large population cohorts, biological sample collections and datasets through biobanks becoming valued global resources to guide biomedical research, drug development, and medical practice. However, in order for biobanks to maximize their impact and scientific reach of their resources, they would need to act within a complex network of infrastructures and activities. Therefore, different ways have emerged in which biobanks, including those for infectious diseases, can emerge as (part of) infrastructures, integrate within existing ones, or become an independent, yet an interoperable component of the existing infrastructural landscape. However, there has been a limited understanding and study of such mechanisms to date. This perspective aims to address this knowledge gap and illustrates these three high-level ways in which such infrastructures could integrate their activities and identifies the necessary key pre-conditions for doing so, while drawing from specific examples.

An introduction to the Marburg virus vaccine consortium, MARVAC

The emergence of Marburg virus (MARV) in Guinea and Ghana triggered the assembly of the MARV vaccine "MARVAC" consortium representing leaders in the field of vaccine research and development aiming to facilitate a rapid response to this infectious disease threat. Here, we discuss current progress, challenges, and future directions for MARV vaccines.

Development and evaluation of a multiplex droplet digital polymerase chain reaction method for simultaneous detection of five biothreat pathogens

Biothreat agents pose a huge threat to human and public health, necessitating the development of rapid and highly sensitive detection approaches. This study establishes a multiplex droplet digital polymerase chain reaction (ddPCR) method for simultaneously detecting five high-risk bacterial biothreats: Yersinia pestis, Bacillus anthracis, Brucella spp., Burkholderia pseudomallei, and Francisella tularensis. Unlike conventional multiplex real-time PCR (qPCR) methods, the multiplex ddPCR assay was developed using two types of probe fluorophores, allowing the assay to perform with a common two-color ddPCR system. After optimization, the assay performance was evaluated, showing a lower limit of detection (LOD) (0.1–1.0 pg/μL) and good selectivity for the five bacteria targets. The multiplex assay’s ability to simultaneously detect two or more kinds of targets in a sample was also demonstrated. The assay showed strong sample tolerance when testing simulated soil samples; the LOD for bacteria in soil was 2 × 10²–2 × 10³ colony-forming unit (CFU)/100 mg soil (around 5–50 CFU/reaction), which was 10-fold lower than that of the single-target qPCR method. When testing simulated soil samples at bacterial concentrations of 2 × 10³–2 × 10⁴ CFU/100 mg soil, the assay presented a higher sensitivity (100%, 35/35) than that of the qPCR method (65.71%, 23/35) and a good specificity (100%, 15/15). These results suggest that the developed 5-plex ddPCR method is more sensitive than conventional qPCR methods and is potentially suitable for rapidly detecting or screening the five selected bacterial biothreats in suspicious samples.

A Hierarchy of Medical Countermeasures Against Biological Threats

INTRODUCTION

Emerging biological threats represent a serious challenge for force health protection (FHP). Against a novel biological threat, medical countermeasures are the first line of defense. However, as exposed by global pandemic conditions, there are significant complications when administering medical countermeasures against novel threats. One such limitation involved the lack of any guiding structure to discuss and deliberate upon the relative value of employing different countermeasures either alone or in tandem. For example, both personal protective equipment and prophylactic medication can provide some protection, but how are individual protections weighed against operational capabilities and FHP initiatives? The goal of this review is to provide a hierarchical organizing structure to the different medical countermeasures available in response to emerging biological threats.

MATERIALS AND METHODS

This review used no explicit inclusion or exclusion criteria for its literature review. References are provided for illustrative purposes to represent different components of the medical hierarchy.

DISCUSSION

The hierarchy presented here is organized around a resource-durability structure that functions as a push-pull mechanism. Specifically, lower levels of the hierarchy require more resources to sustain FHP conditions while also providing less durable protection. These countermeasures require continual reapplication, and so resources become conceived as much in time and effort to apply as in exhaustible supplies. Higher-order countermeasures require less resources investment as a single application can provide weeks, months, or years of protection. Moreover, higher-order protections are less likely to interfere with military operational capabilities, which further support their classification as superior countermeasures to sustain FHP. The five levels of the hierarchy are presented here as follows, organized from lowest to highest value as a medical countermeasure: (1) Sanitization, (2) personal protective equipment, (3) prophylaxis, (4) vaccines, and (5) optimized immune system. Rationale and descriptions identify how each higher-order countermeasure is superior to its lower-order counterparts while noting that optimizing FHP will likely require employing multiple countermeasures at different levels. The discussion concludes with an overview as to how different countermeasures were employed to various degrees during a novel global pandemic.

CONCLUSIONS AND FUTURE USES

Identifying medical countermeasures is important to optimizing FHP. Different countermeasures have different advantages, and the hierarchy distinguishes between inferior and superior countermeasures through the push-pull style mechanism of resource-durability assessment. Future deployment and development should focus on superior countermeasures to maximize medical protections and operational readiness while understanding the relative value and complications inherent with different countermeasures.

Q Fever Vaccine Development: Current Strategies and Future Considerations

Q fever is a zoonotic disease caused by the intracellular pathogen Coxiella burnetii. This disease typically manifests as a self-limiting, febrile illness known as acute Q fever. Due to the aerosol transmissibility, environmental persistence, and infectivity of C. burnetii, this pathogen is a notable bioterrorism threat. Despite extensive efforts to develop next-generation human Q fever vaccines, only one vaccine, Q-Vax®, is commercially available. Q-Vax® is a phase I whole-cell vaccine, and its licensed use is limited to Australia, presumably due to the potential for a post-vaccination hypersensitivity response. Pre-clinical Q fever vaccine development is a major area of interest, and diverse approaches have been undertaken to develop an improved Q fever vaccine. Following a brief history of Q fever vaccine development, current approaches will be discussed along with future considerations for an improved Q fever vaccine.