Top Infectious Disease Threats to Watch in 2025

The emergence of COVID-19 was abrupt; its rapid spread resulted in the tragic loss of millions of lives worldwide. In the aftermath, it is reasonable to assert that there exists a pervasive unease regarding the potential arrival of the next significant infectious disease, regardless of whether it manifests as a virus, bacterium, fungus, or parasite.

With COVID-19 gradually receding—thanks largely to highly effective vaccines—public health officials are increasingly concerned about three predominant infectious diseases: malaria (caused by a parasite), HIV (a virus), and tuberculosis (a bacterium). Collectively, these diseases account for the deaths of approximately two million individuals annually.

Additionally, priority pathogen watchlists continue to grow, particularly highlighting those organisms that have developed resistance to conventional treatment methods, such as antibiotics and antivirals.

Scientists are mandated to remain vigilant for potential threats. While pathogens may arise in various forms, certain families, such as influenza viruses, hold a higher propensity for swift outbreaks.

Currently, one strain of influenza—specifically, subtype H5N1—raises significant alarm as it nears the threshold of becoming a serious health menace in 2025. Widely disseminated among both wild and domestic birds, including poultry, it has recently begun infecting dairy cattle in certain US states and has been reported in horses in Mongolia.

A surge in influenza cases among avian species inevitably raises concerns about potential transmission to humans. This year alone, the US has recorded 61 cases, primarily involving farm workers who have come into contact with infected animals or have consumed raw milk.

When juxtaposed against the mere two cases reported in the Americas over the preceding two years, this notable increase is concerning. Moreover, considering that infections in humans present a daunting 30 percent mortality rate, H5N1 bird flu is swiftly ascending the priority list for public health officials.

Fortunately, the H5N1 strain does not exhibit efficient human-to-human transmission, significantly mitigating the risk of a pandemic. The process of viral entry into host cells relies on specific molecular structures called sialic acid receptors, and while human-adapted influenza viruses bind effectively to these receptors, H5N1 shows a marked preference for avian receptor structures, resulting in limited human transmissibility.

Nevertheless, recent research indicates that a mere single mutation in the H5N1 genome could enhance its ability to transmit between humans, potentially triggering a pandemic scenario.

Should this strain acquire the capacity for human transmission, swift and decisive governmental actions will be essential in curbing its proliferation. Global health authorities have proactively established pandemic preparedness plans targeting bird flu and other emergent diseases.

An example of this proactive approach is the UK’s procurement of 5 million doses of H5 vaccine, aimed at enhancing pandemic readiness in anticipation of potential risks in 2025.

Even without imminent human transmission capabilities, H5N1 is poised to impact animal health significantly in 2025, leading to serious animal welfare implications and potential disruptions in food supply chains, alongside economic repercussions.

Interconnectedness of Health

This multifaceted approach aligns with the concept of “One Health,” which emphasizes the interconnectedness of human, animal, and environmental health. By comprehensively understanding and addressing disease dynamics in our ecosystems and animal populations, we can enhance our preparedness against zoonotic diseases poised to enter human populations. Conversely, monitoring and mitigating infectious diseases among humans can safeguard animal and environmental health.

Nevertheless, it is crucial not to overlook the ongoing ‘slow pandemics’ affecting human populations, such as malaria, HIV, and tuberculosis. Addressing these diseases remains imperative, even as vigilance for novel pathogens continues.

Conor Meehan, Associate Professor of Microbial Bioinformatics, Nottingham Trent University

This article is republished from The Conversation under a Creative Commons license. Read the original article.