Distinct pathophysiological mechanisms of Heterometrus laoticus and Lychas mucronatus scorpion venoms on cardiovascular and renal functions

Posted by
  Distinct pathophysiological mechanisms of Heterometrus laoticus and Lychas mucronatus scorpion venoms on cardiovascular and renal functions Abstract Background:    Heterometrus laoticus and Lychas mucronatus are widely distributed in Southeast Asia, yet their pathophysiological effects of both venoms remain poorly characterized due to low human fatality rates. This study compared their venom compositions and acute cardiovascular and renal effects. Methods:   Anesthetized male New Zealand White rabbits were monitored for blood pressure (BP), heart rate (HR), and renal clearance following intravenous administration of crude venom (0.5 mg/kg). Venom components were identified via LC-MS/MS, and hematological/biochemical parameters were assessed. Results:    H. laoticus venom induced a rapid, transient hypotension ( p < 0.05), followed by a mild, prolonged hypotensive phase (up to 120 min). Conversely, L. mucronatus venom elicited a biphasic response: ...

Keep calm and carry on: bites from Trichonephila clavata are unlikely and cause minimal discomfort

Posted by

 


Keep calm and carry on: bites from Trichonephila clavata are unlikely and cause minimal discomfort

Abstract

Arachnophobia is a widespread phenomenon, despite the fact that the vast majority of spiders pose no meaningful threat to people. The introduction and spread of an invasive spider (Trichonephila clavata L. Koch, 1878) to the United States has prompted questions about whether it should be considered dangerous. These questions are particularly relevant because the spider is large, builds webs on and near human structures, and has been documented to consume small vertebrate prey. To understand the realistic threat this species represents, we examined spider–human interactions in the field with escalating levels of contact intensity. During these interactions, spiders primarily moved to avoid human contact, and bites were incredibly rare, mainly occurring when spiders were forcibly restrained. To assess the medical significance of a bite by T. clavata, we conducted what we believe to be the first controlled study of spider bites. Spiders were induced to bite volunteers under controlled laboratory conditions while supervised by medical staff. Subjects who were bitten reported reliably low levels of pain and only localized physical symptoms (eg redness and swelling) that attenuated quickly. It is clear that this spider is unlikely to bite someone who encounters it in nature, and the symptoms are minor and fleeting in the event of a bite. Although T. clavata is spreading quickly in the United States, the risk of its bite or resulting symptoms should not be cause for fear.


David R Nelsen, Angela Chuang, Aaron G Corbit, Michael I Sitvarin, Hannah E Bergmann, Everaldo P De Araujo, Sarah R Hunter, Jared K Ing, Justin J Park, Kaitlyn A Vasquez, Amani S Wang, David R Coyle, Keep calm and carry on: bites from Trichonephila clavata are unlikely and cause minimal discomfort, Journal of Medical Entomology, 2025;, tjaf103, https://doi.org/10.1093/jme/tjaf103