Snowshoe hare virus infection

Snowshoe hare virus infection (SSHV) is a neglected mosquito-borne illness that can cause neuroinvasive disease in humans. SSHV was first detected in the blood of a snowshoe hare in 1959 found in the US state of Montana,[1] and has since been classified as one of the 18 California serogroup (CSG) viruses.[2] Cases of SSHV have been geographically reported in Canada and the northern USA.

It is speculated that snowshoe hares and possibly other small mammals are the primary or amplifying hosts of the virus.[3] Other animals have demonstrated SSHV antibody positivity, including lemmings and red-backed voles in Alaska,[3] ground squirrels in Montana,[4] and larger animals like foxes, caribou and bears in northern Canada.[5]

Signs and symptoms

SSHV infection in humans can range from subclinical symptoms to more severe neurological disease like encephalitis and meningitis.[3] Commonly reported symptoms include fever, nausea, vomiting, headache, and confusion. Some cases have been found to present with a diffuse macular rash on the face, trunk, and upper and lower extremities, with conjunctival injection and mucocutaneous desquamation.[6] Due to these nonspecific febrile symptoms, many cases go undiagnosed. Serologic studies from the 1980s have reported antibody positivity rates around 40%, which signifies a considerable number of undetected human infections.[3]

Virology

SSHV is from the orthobunyavirus genus, peribunyaviridae family, and bunyavirales order.[1] As part of the orthobunyarius genus, SSHV is enveloped and contains a single-stranded negative sense tripartite genome. Moreover, as part of the orthobunyavirus genus, there is concern with reassortment of the viral genome, especially in areas where both LaCross virus (LACV) and SSHV are prevalent.[3]

Diagnosis

SSHV can be detected using IgM antibody-capture ELISA (MAC-ELISA) or a competitive enzyme-linked immunosorbent assay (cELISA), followed by a confirmatory plaque reduction neutralization test (PRNT). Usually MAC-ELISA and PRNT are run in parallel.[6][1]

Prevention

No vaccine has been developed yet. Since there is no formal treatment developed yet, the main focus is on disease prevention through mosquito-bite prevention. This includes wearing Insect repellent when outdoors, wearing long protective clothing, using air conditioning while indoors,[4] and avoiding the hours of dawn and dusk when mosquitoes are most prevalent.

Treatment

At this time, treatment of SSHV is supportive and focuses on management of symptoms and potential complications.[4]

Epidemiology

Reports of SSHV in animals and humans have been localized to northern latitude regions of Canada and the northern US. Within the US, SSHV has been detected in animals from Alaska, Montana, Wyoming, North Dakota, Wisconsin, Ohio, New York, and Massachusetts.[1]

In Canada, mosquito season lasts from May to October, and peaks in the late summer from July to early September.[4] Since SSHV is able to survive through harsh winters, there is a theory that the virus survives through winter due to transovarial transmission, survival in reservoir species, or overwintering in mosquitos.[3]

One health

It is important to talk about neglected and emerging infectious diseases, especially mosquito-borne diseases, as they are expected to become more prevalent due to the effects of climate change.[7] Due to the warming effects of climate change, the Arctic tree line has been shifting northwards, which affects the prevalence of mosquito populations by providing more habitats for hosts and vectors to breed in.[5] One study from Newfoundland found that snowshoe hares captured from closed-canopy environments had higher SSHV seropositivity than snowshoe hares captured from open-canopy environments.[8] This indicates a relationship between habitats and animal health, as closed-canopy environments may increase mosquito breeding and increase prevalence of CSG viruses. Though the majority of cases have been limited to North America, one study in Japan had tested for JCV seropositivity and found a 44% cross-reactivity to SSHV.[9]

History

SSHV was first discovered in a blood sample from a snowshoe hare covered in ticks in 1959 by Willy Burgdorfer in western Montana.[1] It was later found that SSHV was not transmitted by ticks, but rather mosquitos.[10] SSHV has been recovered from the Aedes genus of mosquitos, as well as Culiseta impatiens and Culiseta inornata mosquitos.[1] A 2024 study concluded that Culex pipiens mosquitoes are also capable of transmitting SSHV.[3]

Reported cases

The vast majority of SSHV cases are thought to be asymptomatic or undetected, however there are several reported neuroinvasive cases of SSHV in humans. Between 1978-1989 there was approximately one symptomatic case with a CSG virus per year, with the majority of cases found to be SSHV.[11] A study in New Brunswick, Canada has shown increasing prevalence of SSHV, with a relationship between seropositivity and male sex and older age.[4] Between 1978 and 1981, there were ten reported cases of human meningoencephalitis related to SSHV in Quebec, Ontario, and Nova Scotia, Canada.[1] Three of these were pediatric cases of SSHV encephalitis identified in young boys, ages 6–10 from Quebec.[12] Another case of acute meningitis was diagnosed in a 30-year-old male from Ontario, Canada in 1978.[13] In 2007, a 3-year-old boy from Nova Scotia was diagnosed with SSHV-related meningoencephalitis.[14][1] In 2015, a case of CSG viral encephalitis with SSHV and Jamestown Canyon virus (JCV) positivity was reported in a 73-year-old man from Grand Manan Island in New Brunswick.[15] In 2017, there was a case of meningoencephalitis in northern Manitoba in a 24-year-old Aboriginal male.[6] In 2019, there were 19 reported cases or exposures to CSG in Winnipeg, Manitoba, with one positive for SSHV.[4] Most recently, there were three cases of pediatric encephalitis with JCV and SSHV positivity in August 2024 in Whistler, British Columbia.[16]

References

  1. ^ a b c d e f g h Walker, Edward D; Yuill, Thomas M (2023-11-14). Faraji, Ary (ed.). "Snowshoe hare virus: discovery, distribution, vector and host associations, and medical significance". Journal of Medical Entomology. 60 (6): 1252–1261. doi:10.1093/jme/tjad128. ISSN 0022-2585. PMC 10645420. PMID 37862052.
  2. ^ Evans, Alyssa B.; Peterson, Karin E. (2019-08-29). "Throw out the Map: Neuropathogenesis of the Globally Expanding California Serogroup of Orthobunyaviruses". Viruses. 11 (9): 794. doi:10.3390/v11090794. ISSN 1999-4915. PMC 6784171. PMID 31470541.
  3. ^ a b c d e f g Jansen, Stephanie; Höller, Patrick; Helms, Michelle; Lange, Unchana; Becker, Norbert; Schmidt-Chanasit, Jonas; Lühken, Renke; Heitmann, Anna (2024-01-31). "Mosquitoes from Europe Are Able to Transmit Snowshoe Hare Virus". Viruses. 16 (2): 222. doi:10.3390/v16020222. ISSN 1999-4915. PMC 10893336. PMID 38399996.
  4. ^ a b c d e f Mincer, Jacqueline; Materniak, Stefanie; Dimitrova, Kristina; Wood, Heidi; Iranpour, Mahmood; Dibernardo, Antonia; Loomer, Courtney; Drebot, Michael A; Lindsay, L Robbin; Webster, Duncan (2021-09-30). "Jamestown Canyon and snowshoe hare virus seroprevalence in New Brunswick". Journal of the Association of Medical Microbiology and Infectious Disease Canada. 6 (3): 213–220. doi:10.3138/jammi-2021-0009. PMC 9615463. PMID 36337757.
  5. ^ a b Buhler, K. J.; Dibernardo, A.; Pilfold, N. W.; Harms, N. J.; Fenton, H.; Carriere, S.; Kelly, A.; Schwantje, H.; Aguilar, X. F.; Leclerc, L. M.; Gouin, G. G.; Lunn, N. J.; Richardson, E. S.; McGeachy, D.; Ortiz, A. H.; Samelius, G.; Lindsay, L. R.; Drebot, M. A.; Gaffney, P.; Leighton, P.; Alisauskas, R.; Jenkins, E. (2023). "Widespread Exposure to Mosquitoborne California Serogroup Viruses in Caribou, Arctic Fox, Red Fox, and Polar Bears, Canada". Emerging Infectious Diseases. 29 (1): 54–63. doi:10.3201/eid2901.220154. PMC 9796188. PMID 36573538.
  6. ^ a b c Lau, Lawrence; Wudel, Beverly; Kadkhoda, Kamran; Keynan, Yoav (2017-07-01). "Snowshoe Hare Virus Causing Meningoencephalitis in a Young Adult From Northern Manitoba, Canada". Open Forum Infectious Diseases. 4 (3) ofx150. doi:10.1093/ofid/ofx150. ISSN 2328-8957. PMC 5597862. PMID 28948178.
  7. ^ Delwel, Isabel O; Mordecai, Erin A (2025-09-01). "Molecules to spillover: how climate warming impacts mosquito-borne viruses". Current Opinion in Virology. 72 101473. doi:10.1016/j.coviro.2025.101473. ISSN 1879-6257. PMC 12212916. PMID 40570812.
  8. ^ Goff, Gregory; Whitney, Hugh; Drebot, Michael A. (2012-09-15). "Roles of Host Species, Geographic Separation, and Isolation in the Seroprevalence of Jamestown Canyon and Snowshoe Hare Viruses in Newfoundland". Applied and Environmental Microbiology. 78 (18): 6734–6740. Bibcode:2012ApEnM..78.6734G. doi:10.1128/AEM.01351-12. PMC 3426688. PMID 22798366.
  9. ^ Kato, Hirofumi; Satoh, Masaaki; Kawahara, Madoka; Kitaura, Satoshi; Yoshikawa, Tomoki; Fukushi, Shuetsu; Dimitrova, Kristina; Wood, Heidi; Saijo, Masayuki; Takayama-Ito, Mutsuyo (2020-10-23). "Seroprevalence of Jamestown Canyon virus in the Japanese general population". BMC Infectious Diseases. 20 (1): 790. doi:10.1186/s12879-020-05517-2. ISSN 1471-2334. PMC 7585186. PMID 33096994.
  10. ^ Newhouse, V.F.; Burgdorfer, W.; Mckiel, J.A.; Gregson, J.D. (1963). "California encephalitis virus. Serologie survey of small wild mammals in northern United States and southern Canada and isolation of additional strains". American Journal of Hygiene. 78: 123–129. PMID 14043542.
  11. ^ Rhyan, Jack; Tyers, Dan; Zimmer, Jeremy; Lewandowski, Kristen; Hennager, Steve; Young, John; Pappert, Ryan; Panella, Amanda; Kosoy, Olga (July 2015). "Serologic Survey of Snowshoe Hares ( Lepus americanus ) in the Greater Yellowstone Area for Brucellosis, Tularemia, and Snowshoe Hare Virus". Journal of Wildlife Diseases. 51 (3): 769–773. doi:10.7589/2015-01-021. ISSN 0090-3558. PMC 8812672. PMID 26161724.
  12. ^ Fauvel, M.; Artsob, H.; Calisher, C.H. (1980). "California group virus encephalitis in three children from Quebec: clinical and serologic findings". Can Med Assoc J. 122 (1): 60–64. PMC 1801601. PMID 7363197.
  13. ^ Artsob, H.; Spence, L.; Caughey, W.C.; Wherrett, J.R. (1981). "Aseptic meningitis in Ontario". Can Med Assoc J. 125 (9): 958–962. PMC 1862506. PMID 7332894.
  14. ^ Meier-Stephenson, V.; Langley, J. M.; Drebot, M.; Artsob, H. (2007-10-01). "Encephalitis in the summer: a case of snowshoe hare (California serogroup) virus infection in Nova Scotia". Canada Communicable Disease Report = Releve des Maladies Transmissibles Au Canada. 33 (11): 23–26. ISSN 1481-8531. PMID 18161204.
  15. ^ Webster, D.; Dimitrova, K.; Holloway, K.; Makowski, K.; Safronetz, D.; Drebot, M. A. (2017). "California Serogroup Virus Infection Associated with Encephalitis and Cognitive Decline, Canada, 2015". Emerging Infectious Diseases. 23 (8): 1423–1424. doi:10.3201/eid2308.170239. PMC 5547809. PMID 28726628. Retrieved 2025-10-27.
  16. ^ Vancouver Coastal Health. (2024). Physician's and Nurse Practitioners' Update: Encephalitis Cluster in Whistler Area due to California Serogroup Virus. Vancouver Coastal Health. https://www.vch.ca/en/media/29736
This article is issued from Wikipedia. The text is available under Creative Commons Attribution-Share Alike 4.0 unless otherwise noted. Additional terms may apply for the media files.