#18,757
Rats and rodents have long been associated with the spread of zoonotic diseases (e.g. Plague, Hantaviruses, Lassa Fever, poxviruses, Leptospirosis, etc.), but in recent years we've seen a a bit of a renaissance in research into more exotic pathogens they may carry (see Viruses Review - The Hidden Threat: Rodent Borne Diseases).
Two years ago, in mBio: SARS-CoV-2 Exposure in Norway Rats (Rattus norvegicus) from New York City, we saw that rats were excellent hosts for COVID, while just over a year ago (June 4th, 2024) the USDA first added the House Mouse (n=11) to their mammalian wildlife with H5N1 list, all from New Mexico.Since then, deer mice, black & Norway rats have been added, and now make up > 20% of all H5N1 infected wild mammals reported in the United States.
Similar studies have found natural IAV infection in rats around the world, including Emer. Microbe & Inf.: HPAI Virus H5N1 clade 2.3.4.4b in Wild Rats in Egypt during 2023.
Last March, in Experimental Infection of Rats with Influenza A Viruses: Implications for Murine Rodents in Influenza A Virus Ecology, we saw evidence that rats are competent hosts for a wide variety of IAVs.
Over the past few years we've seen several studies from Chinese scientists on the virome (overall assemblage of viruses) in rat and rodent populations across Asia.
In late 2023, in V. Sinica: Diversity and Independent Evolutionary Profiling of Rodent-borne Viruses in Hainan, China, we looked at a report, published by Chinese scientists that describes the discovery of 8 previously unknown pathogens with zoonotic potential circulating in rodents on Hainan Island, China.
Sixteen months ago, we looked at a preprint (see Virome Characterization of Field-Collected Rodents in Suburban Beijing), which has now been updated, peer-reviewed, and published in the journal Nature.
This sampling was conducted between May 2017 and October 2018, across three suburban districts of Beijing (Fangshan, Mentougou, and Miyun). Briefly they report:
- 142 viral species were detected
- 75 of the identified viruses were novel while 67 were known viruses
- 25 viruses were classified as high-risk,
- including 8 previously recognized zoonotic viruses and
- 17 viruses posing spillover risk to humans or other animals
This review is quite detailed, and lengthy, and admittedly may not be everyone's cup of tea. But for those looking for a deep-dive into this topic, it is well worth following the link to read it in its entirety.
Virome characterization of field-collected rodents in suburban city
Zhen-Yu Hu, Fang Tang, Mei-Qi Zhang, Jing-Tao Zhang, Yun-Fa Zhang, Guang-Qian Si, Bo-Kang Fu, Gang Wang, Shuang Li, Lei Zhang, Cong Peng, Xiao-Fang Ma, Yan-Tao Liu, Hong Su, Peng-Tao Bao, Xiao-Ai Zhang & Wei Liu
npj Biofilms and Microbiomes volume 11, Article number: 103 (2025) Cite this article
Abstract
Rodents serve as natural reservoirs and vectors for a multitude of zoonotic viruses. Analyzing the viral diversity in rodents is crucial for predicting the emergence of infectious diseases. Through high-throughput sequencing, we characterized the RNA virome of nine rodent species from the families Cricetidae and Muridae, collected from suburban Beijing (n = 432).The composition of the virome exhibited significant variation at the virus family level across the nine rodent species and three types of natural habitats. A total of 142 viral species were identified, including 133 associated with vertebrates and 9 associated with invertebrates, spanning 26 families. Notably, 75 of these viruses were novel while 67 were known viruses.Twenty-five viruses were classified as high-risk, including eight zoonotic viruses and 17 spillover-risk viruses. Additionally, nine known viruses were identified for the first time in China. Thirty-three viruses demonstrated potential for cross-species transmission. Understanding the virome characterization of field-collected rodent might provide valuable insights into the potential risk of zoonotic spillover to humans.
(SNIP)
In conclusion, our research reveals that rodents in Beijing host an extensive and highly diverse array of viruses, offering significant insights into the remarkable diversity of RNA viruses within the two largest families of the Rodentia order. Cross-species analysis utilizing extensive sequencing data establishes a foundation for evaluating the risk of future emergence of rodent-borne zoonotic diseases in other wildlife or humans. These findings enhance our understanding of the virome of diverse rodent species, and underscore the potential threat from undiscovered viruses that could spill over to humans.
Eighteen months ago, in BMJ Global: Historical Trends Demonstrate a Pattern of Increasingly Frequent & Severe Zoonotic Spillover Events, we looked the rise of zoonotic disease spillover events (and resultant deaths) since the early 1960s, and the author's conclusion that their rate has steadily increased over time.
Should those trends continue, they calculate `. . . these pathogens to cause four times the number of spillover events and 12 times the number of deaths in 2050, compared with 2020.'
Studies, like today's, suggest where some of those future spillovers may come from.
