Briefing Document: Unique Virome of Arctic Mosquitoes in Greenland

Source:https://doi.org/10.1038/s41598-025-01086-z: “Metagenomic analysis of mosquitoes from Kangerlussuaq, Greenland reveals a unique virome” by Schilling, Jagdev, Thomas, & Johnson (2025). 

Date: Received – 17 January 2025 | Accepted – 02 May 2025 | Published – 17 May 2025

Subject: Metagenomic analysis of mosquito viromes in Kangerlussuaq, Greenland and implications in the context of climate change.

Summary: This study provides the first metagenomic analysis of the virome of two prevalent Arctic mosquito species, Aedes impiger and Aedes nigripes, sampled near Kangerlussuaq, Greenland. The research employed next-generation sequencing (NGS) to identify viruses present in pooled mosquito samples collected in July 2022 and July 2023. The findings reveal a diverse and, importantly, a unique virome in these Arctic mosquitoes compared to other Aedes species. The study highlights the critical need to understand these viromes in light of climate change, which is significantly impacting Arctic ecosystems and potentially increasing the risk of vector-borne disease emergence and spread.

Key Findings and Themes:

1. Dominance of Aedes impiger: Contrary to previous assumptions that Aedes nigripes was the sole mosquito species in western Greenland, this study found Aedes impiger to be the predominant species collected at the Kangerlussuaq site.

• Fact: “Where a definitive identification could be made, A. impiger was the most frequently sampled mosquito at the Kangerlussuaq site.”
• Fact: In 2023, “49 mosquitoes were identified as A. impiger (70%) and 16 as A. nigripes (23%).”

1. Novel and Diverse Arctic Mosquito Virome: Metagenomic analysis identified a range of RNA viruses belonging to various families in both Aedes impiger and Aedes nigripes. Many of these viruses are novel and exhibit low sequence identity (sometimes as low as 34% at the amino acid level) when compared to previously published virus sequences from other mosquito species.

• Quote: “Metagenomic analysis of RNA extracted from species pools detected a number of novel RNA viruses belonging to a range of different virus families, including Flaviviridae, Orthomyxoviridae, Bunyavirales, Totiviridae and Rhabdoviridae.”
• Quote: “However, the sequence identities when compared to previously published, were as low as 34% at the amino acid level.”
• Fact: “Within the family of Flaviviridae, two novel flavi-like virus sequences were identified, with their polyproteins displaying 35% similarity to the nearest published polyprotein…”
• Fact: “Similarly, two novel orthomyxo-like sequences were identified within the family of Orthomoyxoviridae… Their nucleoprotein comprised only 36% identity to that of Byreska virus…”
• Fact: “Within the order of Bunyavirales, we discovered two novel phasiviruses as well as two novel phasmaviruses.”

1. Uniqueness of the Arctic Mosquito Virome: A significant finding is the distinct virome of Aedes impiger and Aedes nigripes compared to other Aedes species, particularly Aedes aegypti, which has the most well-characterized virome. Only a small percentage of the identified viruses overlapped with those found in other Aedes species.

• Quote: “To emphasize the uniqueness of the virome of A. impiger and A. nigripes, we compared our findings to a database of viruses published for other Aedes species… The heatmap… reveals that the majority of sequences derived from Greenland mosquitoes were unique to A. impiger and A. nigripes…”
• Fact: “…only 36 (of a total of 94, 38%) assigned viruses overlapping with viruses published for other Aedes spp.”
• Fact: “Only 22 (23%) overlapped with Aedes aegypti…”
• Quote: “This makes the virome composition of A. cantans the most similar published virome composition to that of the mosquitoes we sampled near Kangerlussuaq.”

1. Influence of Climate Change on Arctic Vector Ecology: The study explicitly links its findings to the dramatic effects of climate change on Arctic ecosystems, including the potential for shifts in vector distribution and an increased likelihood of vector-borne disease emergence in previously unaffected areas.

• Quote: “Climate change is dramatically affecting vector ecology in extreme environments such as the Arctic.”
• Quote: “Global changes in climate are causing a shift in the distribution of vectors and increasing the likelihood of vector-borne disease outbreaks in regions that have not experienced such disease emergence.”
• Quote: “With rapid environmental change, and warming at twice the global average the ecology of Arctic insects will be dramatically affected.”

1. Potential for Zoonotic Transmission Risk: While the detected viruses are likely insect-specific, the study highlights the potential for Aedes impiger and Aedes nigripes to replicate viruses belonging to families with known zoonotic potential. The documented human feeding behavior of Aedes impiger further underscores this risk.

• Quote: “Our findings further support the capability of A. nigripes and A. impiger to replicate viruses belonging to a range of different virus families, including (-)ssRNA, (+)ssRNA, dsRNA and retroviruses.”
• Quote: “Aedes impiger is known to feed on humans and can productively produce eggs and oviposit after a human blood meal. These observations indicate a realistic risk that these Arctic mosquitoes are capable of transmitting viruses with zoonotic potential.”
• Quote: “However, none of the viruses detected are closely related to known viruses with zoonotic potential and are likely insect-specific.”

1. Importance of Continued Research: The study emphasizes the limited knowledge about Arctic mosquito viromes and the need for further research, including larger datasets and functional characterization of the identified viruses, to better understand their potential impact on animal and public health in a changing climate.

• Quote: “However, surprisingly little is known about the viruses harboured by this and other indigenous mosquito species.”
• Quote: “Due to our limited sample size, future studies are needed to explore the differences and similarities with the virome of other Aedes species in more depth, and to determine how significant the virome difference between A. impiger and A. nigripes is.”
• Quote: “Further studies will need to functionally characterise the viruses we detected, with regard to their replicative capabilities, potential to cause disease and impact on the replication and transmission of other, better characterized arboviruses.”

Implications:

The discovery of a unique and diverse virome in Arctic mosquitoes in Greenland has significant implications for understanding the current and future risks of vector-borne diseases in the region. As climate change continues to alter Arctic ecosystems, the potential for the introduction…