Fighting Invisible Foes: Role of Animal Models in Infectious Disease Research

By Jamshed Arslan, Pharm D, PhD

Infectious diseases remain a significant global health challenge. They underscore an intricate game of cat and mouse between the pathogen and host, revealing interactions that can only be properly deciphered through the application of suitable biological models.¹ Animal models, being the critical players in this pursuit, serve as the magnifying glass enabling us to delve into the microscopic world of host-pathogen interactions.

In the Heart of the Labyrinth: Mouse Models in the Spotlight 

Mouse models have long been the linchpin of infectious disease research, primarily due to their genetic malleability and striking physiological similarities to humans. The use of these models has been paramount for understanding how pathogens cause disease, defining the role of specific host genes in disease development, and identifying potential targets for prevention or treatment of a variety of infectious agents.¹ Diverse mouse strains, ranging from inbred to gene knockout and even humanized mice, offer an invaluable canvas for exploring a wide spectrum of infectious diseases. 

Beyond the Beaten Path: The Rise of Unconventional Animal Models 

While mice have dominated the field of infectious disease research, there has been an increasing trend in the utilization of more unconventional animal models. This shift has been driven by advancements in genetic manipulation, allowing researchers to modify both the host and pathogen as needed throughout the course of the studies. Examples of such models include non-human primates, Guinea pigs, ducks, chickens, Drosophila melanogaster (fruit fly), zebrafish, and mosquitoes, each offering unique perspectives on host-pathogen interactions. For instance, zebrafish embryos are gaining popularity for unravelling disease pathogenesis, particularly related to human bacterial infections.²

In Pursuit of Cure: Towards Treatment Development and Vaccine Discovery

The central role of animal models extends well beyond disease comprehension to the crucial spheres of vaccine discovery and treatment development. Animal models, particularly murine, have proven instrumental in designing strategies with drugs and vaccines at a preclinical level. They have made substantial contributions to understanding the pharmacokinetics and pharmacodynamics of antimicrobial drugs, informing optimal drug exposures that can be translated from the model to humans.³

Moreover, these models have been pivotal in uncovering novel therapeutic avenues. A well-designed animal model, selected based on its biological relevance to the human disease, can contribute to creating translatable scientific data, facilitating the development of effective therapies and interventions.⁴  

A Necessary Trade-off: Ethical Considerations 

The immense utility of animal models, however, comes with an ethical price tag. Guidelines like the 3R principles (reduce, refine, replace) proposed by Russell & Burch, provide a roadmap for researchers to minimize the number of animals used, alleviate their suffering, and seek alternatives where possible.³ Emphasizing ethical and responsible use of animals in research is as significant as the research outcomes themselves. 

Concluding Thoughts 

In this complex journey of understanding infectious diseases, animal models serve as our compass, leading us towards answers and solutions. These models, traditional or unconventional, open windows into the intricate world of host-pathogen interactions, advancing our understanding and aiding in the discovery of treatments and vaccines. The ethical considerations surrounding their use remind us of the need to continuously seek balance between scientific advancement and animal welfare.