Nyanja Health Research Institute, PO Box 579, Salima, Malawi.
Sainte Innocence, Dordogne, France.
Toxicon. 2023 Nov;235:107324. doi: 10.1016/j.toxicon.2023.107324. Epub 2023 Oct 12.
Proatheris superciliaris, the lowland swamp viper, has a limited distribution along lakeshores and rivers in Malawi, Southern Tanzania, and central Mozambique. Its venom is known to be procoagulant. Only five P. superciliaris bites have been reported, all inflicted by captive snakes, and none was fatal. Here we present a case of sudden death following a bite by Proatheris superciliaris in rural Malawi that cannot be attributed to envenoming. A healthy 32-year-old woman was planting rice in a flooded rice paddy field when she suddenly told her sister in a quiet voice that she had been bitten by a snake. She then collapsed face-upwards into the ankle-deep water. She remained motionless while her sister and uncle carried her out of the rice paddy onto dry land a few meters away. The victim did not regain consciousness. Her uncle heard one exhalation but no further breathing. The snake responsible was killed by a friend. Although the venom of this species can cause life-threatening coagulopathy, this woman's death occurred too rapidly to be attributable to envenoming. Only two explanations seem plausible: anaphylaxis, or vasovagal shock triggered by fear. In the present case, the victim died within minutes of the bite, closely observed by her anxious relatives, but showed no features of anaphylaxis. In Malawi, as in much of sub-Saharan Africa, many people are reportedly terrified of snakes, believing that bites by almost any species can cause rapid death. In this case, death occurred less than 2 min after a bite from Proatheris superciliaris. We believe that the cause of death was most likely a severe vasovagal attack, in response to the fear and pain of the snakebite that triggered vasodilatation, bradycardia, and hypotension leading to cardiac arrest.
西里伯斯眼镜蛇，又名低地沼泽蝰蛇，分布于马拉维、坦桑尼亚南部和莫桑比克中部沿湖和河流的有限区域。其毒液已知具有促凝血作用。仅报告了五例西里伯斯眼镜蛇咬伤病例，均由圈养蛇引起，且均无致命。在这里，我们报告了一例在马拉维农村发生的西里伯斯眼镜蛇咬伤后突然死亡的病例，不能归因于中毒。一名 32 岁健康女性在淹没的稻田里插秧时，突然用平静的声音告诉她的妹妹她被蛇咬了。然后她脸朝上摔倒在齐脚踝深的水中。当她的妹妹和叔叔把她从稻田里抱到几码外的干地上时，她一动不动。受害者没有恢复意识。她的叔叔听到一次呼气，但没有再呼吸。咬人的蛇被一个朋友打死了。尽管该物种的毒液会导致危及生命的凝血功能障碍，但该女性的死亡发生得太快，不能归因于中毒。只有两种解释似乎合理：过敏反应，或因恐惧引起的血管迷走性休克。在本例中，受害者在被咬伤后的几分钟内死亡，被她焦虑的亲属密切观察，但没有出现过敏反应的特征。在马拉维，就像在撒哈拉以南非洲的许多地区一样，据报道，许多人非常害怕蛇，他们认为被几乎任何种类的蛇咬伤都会导致迅速死亡。在这种情况下，死亡发生在西里伯斯眼镜蛇咬伤不到 2 分钟后。我们认为死亡的原因很可能是严重的血管迷走性发作，这是对蛇咬伤的恐惧和疼痛的反应，导致血管扩张、心动过缓和低血压，最终导致心脏骤停。
