AUTHOR=Hifumi Toru , Sakai Atsushi , Yamamoto Akihiko , Morokuma Kazunori , Otani Norio , Takahashi Motohide , Ato Manabu 

TITLE=Rhabdophis tigrinus (Yamakagashi) Bites in Japan Over the Last 50 Years: A Retrospective Survey

JOURNAL=Frontiers in Public Health

VOLUME=9

YEAR=2022

URL=https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2021.775458

DOI=10.3389/fpubh.2021.775458

ISSN=2296-2565

ABSTRACT=<p><bold>Introduction:</bold><italic>Rhabdophis</italic> snakes, which include 27 species, are rear-fanged venomous snakes that are widely distributed from India to East Asia and Russia. Severe envenomation by <italic>R. tigrinus</italic> (Yamakagashi snake) in Japan and <italic>R. subminiatus</italic> in Southeast Asia has been reported. The epidemiology of <italic>R. tigrinus</italic> bites, such as geographical features, the incidence, and changes in the number of bites over time have not been comprehensively examined. Hence, we intended to clarify the epidemiological features of <italic>R. tigrinus</italic> bites through a careful review of scientific data over the last 50 years in Japan.</p><p><bold>Methods:</bold> Patient records of <italic>R. tigrinus</italic> bites between 1971 and 2020 at the Japan Snake Institute were examined retrospectively. The following were ascertained: patient characteristics, clinical symptoms, laboratory data, treatment-related factors, and hospital mortality. These variables were compared in the antivenom and the without-antivenom groups.</p><p><bold>Results:</bold> Over the 50-year study period, 43 <italic>R. tigrinus</italic> bites, including five fatal cases, were encountered. Severe cases of <italic>R. tigrinus</italic> bites have been treated with antivenom since 1985; however, fatalities occurred in 2006 and 2020. <italic>R. tigrinus</italic> bite cases have been well-distributed in the western part of Japan since 2000. The mortality rate in the antivenom group was significantly lower in the patient group that was not administered the antivenom (0 vs. 23.8%, <italic>p</italic> = 0.048).</p><p><bold>Conclusion:</bold> This study clarified the epidemiology of <italic>R. tigrinus</italic> bites in Japan over a 50-year period. Almost all severe cases of <italic>R. tigrinus</italic> bites have been treated with the antivenom in the current situation, and fatalities occurred in cases not treated with the antivenom. It is important to diagnose <italic>R. tigrinus</italic> bites in the early phase of the clinical course. The antivenom, the definitive treatment for <italic>R. tigrinus</italic> bites, is an unapproved drug. Hence, approval needs to be obtained for the drug.</p>