Multiple genetic lineages of the invasive brown widow spider (Araneae: Theridiidae) from inland areas in the Kanto region, Japan

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  Multiple genetic lineages of the invasive brown widow spider (Araneae: Theridiidae) from inland areas in the Kanto region, Japan Abstract The brown widow spider, Latrodectus geometricus Koch, 1841, is a medically important invasive species that possesses neurotoxic venom capable of causing latrodectism in humans. This species has recently been found in inland areas of the Kanto region in Japan, raising concerns about its ongoing range expansion and associated public health risks. Here, we analyzed partial sequences of mitochondrial cytochrome c oxidase subunit I (cox1) and 16S ribosomal DNA from 99 individuals (3 males and 96 females) collected from multiple sites in Tokyo and Kanagawa prefectures, evaluating their phylogenetic positions and introduction history. The analysis revealed two major lineages, with six cox1 haplotypes (LGc1–LGc6) and five 16S rDNA haplotypes (LGs1–LGs5). One lineage comprised previously unreported basal haplotypes, including LGc5 and LGc6 in cox1 and L...

Envenomation by a Razi’s Viper, Macrovipera razii (Serpentes: Viperidae) in Iran: A Neglected Public Health Threat, Report of Two Cases, and Clinical Implications

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Envenomation by a Razi’s Viper, Macrovipera razii (Serpentes: Viperidae) in Iran: A Neglected Public Health Threat, Report of Two Cases, and Clinical Implications

Abstract

Snakebite envenomation remains a significant global health concern, with viperid snakes responsible for substantial mortality and disability. In Iran, the genus Macrovipera is of considerable medical importance. Macrovipera razii is an endemic Iranian species distributed across central and southern regions of the country; however, detailed clinical reports of envenomation by this species remain scarce. We report two cases of M. razii envenomation from Iran. The first case involved a 36-year-old male who sustained a bite to the middle finger in Nazmabad, Arak, Markazi Province, Iran, in 2017. He was admitted to hospital approximately 15 min after the bite and received six vials of polyvalent antivenom. Progressive local tissue injury developed, followed by severe necrosis of the affected finger, resulting in permanent deformity and severe functional impairment. The second case involved a 37-year-old male who sustained a bite to the dorsal aspect of the right hand in Sirjan, Kerman Province, in 2024. He received one vial of polyvalent antivenom during ambulance transport, followed by five additional vials after hospital admission and two further vials approximately two hours later, resulting in a total of eight vials during the initial treatment period. He developed severe and progressive hand edema with clinical features concerning for acute compartment syndrome and underwent emergency fasciotomy, followed by delayed wound closure, prolonged hospitalization, and persistent partial functional impairment. Both cases demonstrated severe local tissue injury following M. razii envenomation. The clinical manifestations were broadly consistent with severe local effects reported following envenomation by other medically important viperid species. However, the limited number of documented cases precludes conclusions regarding the typical clinical course, frequency, or severity of M. razii envenomation. These cases underscore the need for further clinical and experimental investigation of M. razii envenomation and its management. Clinical observations alone cannot establish antivenom efficacy or failure, particularly in the absence of venom–antivenom cross-reactivity and functional neutralization data. Further studies, including comprehensive venom characterization and functional venom–antivenom neutralization assays, are warranted to clarify antivenom recognition and coverage and to inform future antivenom development.
Kazemi, S. M., & Salabi, F. (2026). Envenomation by a Razi’s Viper, Macrovipera razii (Serpentes: Viperidae) in Iran: A Neglected Public Health Threat, Report of Two Cases, and Clinical Implications. Toxicon, 109315. https://doi.org/10.1016/j.toxicon.2026.109315