ガラガラヘビで致死性感染症リスクが増大(Rattlesnakes Face Increased Risk of Deadly Infections)

2026-05-28 ジョージア大学(UGA)

米ジョージア大学(UGA)の研究チームは、米国南東部の野生ヘビ類において、真菌・寄生虫・細菌による複合感染が拡大し、一部のガラガラヘビ類が深刻な絶滅リスクに直面していることを明らかにした。研究ではジョージア州、フロリダ州、サウスカロライナ州で29種・500匹以上のヘビを調査し、7種類の病原体を解析した。その結果、40%以上の個体で複数病原体への同時感染が確認され、特にピグミーガラガラヘビでは、致死的な真菌症「ヘビ真菌病(Ophidiomycosis)」と肺寄生虫「ヘビ肺虫(Raillietiella orientalis)」の感染率が高かった。さらに、野生ヘビでは初めて薬剤耐性Mycoplasma属細菌も検出された。真菌感染個体では栄養失調や皮膚病変、顔面変形が見られ、一部は急激な体重減少の末に死亡した。研究者らは、外来種ビルマニシキヘビによる病原体持ち込みや環境ストレスが感染拡大に関与している可能性を指摘している。本研究は、ヘビ類の保全と病原体拡散防止に向けた重要な基礎資料となる成果である。

ガラガラヘビで致死性感染症リスクが増大(Rattlesnakes Face Increased Risk of Deadly Infections)

An up close look at a banded watersnake. UGA researchers studied more than 500 snakes for a recent paper.  (Photo courtesy of Taylor Miller)

<関連情報>

米国南東部に生息する野生ヘビの健康状態評価と多病原体監視 Health assessment and multipathogen surveillance of free-ranging snakes in the southeastern United States

Corinna M. Mishin ,Terence M. Farrell,Jenna N. Palmisano,Robert J. Ossiboff,Makaylah McCray,Ellen Haynes,John C. Maerz,Kristina Meichner,+5,Nicole M. Nemeth

Frontiers in Veterinary Science  Published:26 May 2026

DOI:https://doi.org/10.3389/fvets.2026.1754420

Abstract

Introduction:

Health assessments and pathogen surveys in wildlife are critical for gauging population-level risks. Recent concerns associated with ophidiomycosis, caused by the fungus Ophidiomyces ophidiicola (Oo), have brought needed attention to snake conservation.

Methods:

We evaluated the health of native snake species in the southeastern United States through physical examinations and multipathogen surveillance targeting Cryptosporidium spp., Hepatozoon spp., Mycoplasma spp., Oo, Raillietiella orientalis (Ro), Salmonella spp., and serpentoviruses. We hypothesized that apparent ophidiomycosis (skin lesions present and qPCR detection of Oo) would be positively associated with coinfection detection, and that pathogen detection prevalence would vary spatiotemporally and among snake species. We assessed pathogen and disease prevalence through monthly sampling from May 2022 to May 2024 (via full-body skin swabs, choanal swabs, cloacal swabs, blood, and fecal collection, and physical examinations) at wetland sites in Volusia County, Florida, and Jasper County, South Carolina. We opportunistically sampled snakes from a site in Athens-Clarke County, Georgia, and included diagnostic cases submitted to the Southeastern Cooperative Wildlife Disease Study from 2021 to 2024.

Results:

In total, we sampled 509 individuals with 49 recaptures, representing 29 species. We included 61 carcasses, comprising 56 individuals (33 collected opportunistically) and five recaptures. We detected Salmonella enterica in 62.6% (306/489), Hepatozoon spp. in 53.4% (205/384), Mycoplasma spp. in 17.5% (78/445), Oo in 16.1% (82/508), and Cryptosporidium spp. in 2.0% (10/489). Detection of Ro was limited to snakes in Florida, with a detection prevalence of 12.7% (37/292). No serpentoviruses were detected (n = 447). Overall coinfection prevalence was 44.0% (219/498) and was strongly predictive of apparent ophidiomycosis (p < 0.0001). Mycoplasma spp. and Cryptosporidium spp. were nearly exclusively detected in snakes from Florida. Seasonal trends were seen in the detection of Mycoplasma spp. (p = 0.0075), Oo (p = 0.0475), and S. enterica (p = 0.0295). Detection of Oo (p = 0.0002) or Ro (p = 0.0200) was negatively associated with nutritional condition scores. Increased detection risks of Oo (p = 0.0479) and apparent ophidiomycosis (p = 0.0148) were observed primarily in pygmy rattlesnakes (Sistrurus miliarius), supported by severe associated pathology, indicating increased conservation risks.

Discussion:

This health assessment enhances understanding of infectious agents circulating in free-ranging snakes in the southeastern United States and establishes baseline parameters to inform conservation management.

1903自然環境保全
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