The Role of Acanthamoeba in Preserving Ancient Viruses and Their Potential Spread Due to Climate Change

Climate change is a multifaceted crisis that extends far beyond rising temperatures, posing a significant threat to both biological and ecological balance. One of the most concerning aspects of this crisis is the accelerated thawing of glaciers that have remained frozen for thousands of years enabling the reintroduction of microorganisms that have remained isolated for millennia into modern ecosystems (1). During this thawing process, particularly in permafrost layers, samples have revealed the presence of ancient giant viruses, such as Mollivirus sibericum and Pithovirus sibericum, alongside remnants of the 1918 Spanish flu-causing influenza virus (2, 3). These findings are not only of historical significance but also highlight the potential for novel biological threats to modern societies. One of the most critical agents in the environmental circulation of these viruses is Acanthamoeba. This free-living amoebae protects giant viruses by engulfing them through phagocytosis and facilitating their transmission into various environments. Moreover, the remarkable resilience of Acanthamoeba in extreme environmental conditions positions it not only as a host but also as a biological vector. This characteristic directly links the release of ancient viruses to their potential activation and dissemination. This review explores the mechanisms by which giant viruses released through glacial melting are transported via Acanthamoeba, assesses the potential infectious risks emerging in the context of climate change, and examines the broader consequences of this process. Additionally, the potential protective role of virophages in mitigating such risks is evaluated.