Illustration of viral genetic exchange within a tick cell.

Tick-Borne Viruses: Are We on the Brink of a Viral Reassortment?

Theo Raines in Science & Nature September 2025 • 3 min read.

"New research sheds light on the potential for tick-borne phleboviruses to swap genetic material, raising concerns about the emergence of novel diseases."

In the world of viruses, the ability to adapt and evolve is key to survival. For bunyaviruses, a family of viruses known to cause diseases transmitted by arthropods like ticks, this adaptability takes a particularly intriguing form: reassortment. This is when two closely related viruses infect the same cell and exchange genetic material, potentially creating new hybrid viruses with altered characteristics.

Tick-borne phleboviruses, a group within the bunyavirus family, are increasingly recognized as emerging threats to human and animal health. With their capacity to cause severe febrile illnesses and spread across geographical regions, understanding their evolutionary potential is crucial for public health preparedness.

Now, a new study published in the Journal of Virology is offering insights into the reassortment potential of tick-borne phleboviruses. By developing innovative minigenome and virus-like particle assays, researchers are uncovering the rules that govern genetic exchange between these viruses, paving the way for better risk assessment and prevention strategies.

What is Viral Reassortment and Why Should We Care?

Illustration of viral genetic exchange within a tick cell.

Viral reassortment is a natural form of genetic shuffling that occurs when two or more related viruses infect the same host cell. Because bunyaviruses have a segmented genome (meaning their genetic material is divided into multiple pieces), they can swap these segments during co-infection. This is similar to shuffling cards in a deck; the resulting virus might have a combination of traits from its 'parent' viruses, making it different.

Why is this concerning? Reassortment can lead to several outcomes:

Increased virulence: The new virus might cause more severe disease.
Altered host range: The virus could jump to new animal species or even humans.
Drug resistance: The virus might become resistant to existing antiviral medications.
Immune evasion: The virus might be able to evade detection by the immune system, making vaccines less effective.

Given these possibilities, understanding the factors that facilitate or restrict reassortment is essential for predicting and mitigating potential outbreaks.

The Road Ahead: Predicting and Preventing Viral Reassortment

The study from Rezelja et al. provides a significant step forward in understanding the reassortment potential of tick-borne phleboviruses. By identifying compatible viral components and demonstrating the feasibility of genetic exchange in the lab, the researchers have opened new avenues for risk assessment and prevention.

About this Article -

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This article is based on research published under:

DOI-LINK: 10.1128/jvi.02068-18, Alternate LINK

Title: M Segment-Based Minigenomes And Virus-Like Particle Assays As An Approach To Assess The Potential Of Tick-Borne Phlebovirus Genome Reassortment

Subject: Virology

Journal: Journal of Virology

Publisher: American Society for Microbiology

Authors: Veronica V. Rezelj, Timothy J. Mottram, Joseph Hughes, Richard M. Elliott, Alain Kohl, Benjamin Brennan

Published: 2019-03-15

Everything You Need To Know

What is viral reassortment and how does it apply to tick-borne phleboviruses?

Viral reassortment is a process where two or more related viruses infect a single host cell and exchange genetic material. In the context of tick-borne phleboviruses, which belong to the bunyavirus family, this is particularly relevant because bunyaviruses have segmented genomes. This means their genetic information is divided into multiple pieces. During co-infection, these segments can be swapped, potentially creating new hybrid viruses with different characteristics. This can lead to changes in virulence, host range, drug resistance, or immune evasion. The study by Rezelja et al. highlights this process specifically for tick-borne phleboviruses.

What are the potential outcomes of viral reassortment in tick-borne viruses?

Viral reassortment can lead to several concerning outcomes. The new virus might exhibit increased virulence, causing more severe disease. It could also alter its host range, enabling it to infect new animal species or even humans, thus increasing the scope of potential outbreaks. Furthermore, reassortment can lead to drug resistance, rendering existing antiviral medications ineffective. Finally, the reshuffled virus might develop the ability to evade the immune system, making vaccines less effective. These outcomes emphasize the importance of understanding reassortment potential for effective public health strategies.

How does the segmented genome of bunyaviruses facilitate viral reassortment?

Bunyaviruses possess a segmented genome, meaning their genetic material is split into multiple segments. This structural characteristic is key to their reassortment potential. When two bunyaviruses infect the same host cell, the segments from each virus can mix and match during the replication process. This is analogous to shuffling a deck of cards; the resulting virus can have a unique combination of traits from its parental viruses, which can result in significantly altered characteristics, such as increased virulence or a change in host range.

What is the significance of the research by Rezelja et al. on tick-borne phleboviruses?

The research by Rezelja et al. represents a significant advancement in understanding the reassortment potential of tick-borne phleboviruses. The study used innovative minigenome and virus-like particle assays to uncover the rules that govern genetic exchange between these viruses. This is crucial because it provides insights into which viral components are compatible and likely to exchange genetic material. By demonstrating the feasibility of genetic exchange in the lab, the researchers have opened new avenues for risk assessment and developing effective prevention strategies against potential outbreaks of novel or more dangerous tick-borne diseases.

Why is it important to study the evolution of tick-borne phleboviruses, and what measures can be taken to mitigate the risks?

Studying the evolution of tick-borne phleboviruses is vital because these viruses are emerging threats to human and animal health. Understanding how they evolve, specifically through reassortment, allows for proactive risk assessment and the development of targeted prevention strategies. Measures to mitigate risks include enhanced surveillance to monitor viral evolution, development of diagnostic tools to detect novel viruses, and the research and development of vaccines and antiviral therapies. Additionally, public health strategies should focus on controlling tick populations, reducing human exposure to ticks, and raising awareness about tick-borne diseases.