Despite its questionable historical veracity, the asp has been inextricably linked to Cleopatra’s death throughout history. What’s more, it is claimed Cleopatra tested the venoms of various lethal snakes on condemned prisoners to determine the different ways they would die [1]. It could be said that she was studying the clinical features of envenomation following a snakebite… Which is just what this blog post will address, after a breakdown of how snakes are classified and an overview of the global effects of snakebites. CLASSIFICATION The box on the right shows that snakes belong under the Squamata (reptilian) order, and under that, in the Serpentes sub-order. Below this level snakes are broken down into family, genus, species and sometimes even subspecies. As with all animals, their classification is not binary and is constantly developing. Just 20 years ago it was estimated that there were around 3,000 different species of snakes around the world. Now, the number has risen to 3,400 [2]. This variety of snakes may seem surprising, especially considering that their distinguishing features are often not as obvious to the general population as they are to herpetologists. Some of the most obvious common features of snakes are their scales, limbless bodies, forked tongues, and their lack of ear openings and eyelids. Their differences, such as geographic range, appearance and habits, that used to categorise them into different families, sub-families, species and sub-species.This includes their size, which can vary from the length of a pencil to that of a school bus, their diet, whether it is rodents or larger prey, their habitat, ranging from tropical rainforests to dry deserts, and whether they are oviparous (laying eggs) or viviparous (giving birth to live young) [3]. Of course, the classic distinction being whether they are venomous or not. SNAKEBITES GLOBALLY Of the 16-20 distinct families of snakes, there are only four families that contain venomous snakes, and only two of these families have members

inhabiting Australia, as shown by the box on the left. Within the family of Elapidae are the Australian elapids that contains three of the world’s most lethal snakes: The Inland taipan, Eastern Brown snake and Coastal taipan. This tends to affirm the wide-spread perception of Australia of being one of the most dangerous countries. It’s a reasonable assumption to make that the injuries and deaths as a result of snakebites in Australia would reflect this. However, Australia’s 1,000 – 3,000 snake bites per year and 1 – 4 deaths a year following envenomations, is minor in comparison to the global scale [4].

Cleopatra and… an Australian Elapid?

Kingdom: Animalia Phylum: Chordata Class: Reptilia Order: Squamata Suborder: Serpentes

Astractaspididae Colubridae (presence in Aus) Viperidae Elapidae (presence in Aus)

Australia is infamous for its some of the most venomous snakes, but not for the number of snakebites or deaths as a result.

It is estimated that 5.4 million people each year around the world are bitten by snakes, with around 2.7 million of those being envemonings [5]. A figure between 81,000 and 138,000 people die each year from snake bites globally, and around three times this figure is the number of people that sustain permanent disabilities or require amputations as a result of snake bites. These figures predominantly come from areas like Sub-Saharan Africa, South and South East Asia and Latin America where many barriers to effective treatment exist [6].

One of the major challenges contributing to the public health threat in these nations is the limited availability of medical resources [7]. This includes poverty which prevents many from being able to access appropriate treatment and antivenoms following a snakebite; and rural location where poor transport creates delays in treatment, and there is often a lack of properly trained medical staff in the area. In

addition to this, there are social and cultural practices and beliefs that may compound the issue by diverting snakebite victims to traditional healers that cannot provide effective treatments [8]. The issue is multifactorial, however, and a lot of research has been carried out and much discussion surrounds the different aspects contributing to this public health threat. If this interests you, links to some websites that delve into the global effect of snakebites have been attached at the bottom of this post. CLINICAL FEATURES OF ENVENOMATION It is important to note, as indicated by the ratio of bites to deaths by Australian elapids above, that most snakebites in Australia do not actually result in clinical envenoming either because the snake is non-venomous, or because there is an insufficient injection of venom [9]. Where it does occur, some of the clinical features of envenoming can include local effects such as bleeding, swelling or blistering close to the bite area; systemic effects, such as nausea, diarrhoea, and headaches; and major toxin syndromes some of which are listed and briefly described below.

These clinical features are not specific to envenomations by Australian elapids but are common to many snake families. Some Australian elapid envenomations result in all of the above being exhibited, whereas others will only result in a few of these toxin syndromes [10]. Despite there being distinct differences in Australian elapids and asps, Cleopatra, as legend has it, would likely have experienced some of the same clinical features when she was envenomed by an asp.

Venom-Induced Consumption Coagulopathy (VICC): Coagulation factors in the blood are activated by particular toxins. Coagulopathy results due to exhaustion of these factors and is characterised by excessive bleeding.

Neurotoxicity: Damage to the nervous system caused by toxins which can result in flaccid paralysis extending from the eye muscles to respiratory muscles and to the limbs.

Myotoxicity: Local or generalised muscle pain and tenderness as a result of toxins causing muscle necrosis.

Thrombotic microangiopathy: Blood clotting in capillaries especially those in the brain and kidney which can often lead to renal failure and various neurological symptoms. [4]

Envenomation: The act of injecting venom by sting, spine, bite, or other venom apparatus. thefreedictionary.com

REFERENCES Image 1: Shea, G., Shine, R., Covacevich, J.C. 1995, ‘Family Elapidae - Fauna of Australia. Vol. 2A. Amphibia & Reptilia’, Australian Govenrment Publishing Service, pp. 261–279.

Image 2: ‘The Global Scale of Snakebite’, 2018, University of Melbourne School of Biomedical Sciencesd<https://biomedicalsciences.unimelb.edu.au/departments/pharmacology/engage/avru/discover/snakebite-envenoming-a-neglected-tropical-disease>. [1] ‘The dramatic death of Cleopatra – was it really Suicide?’ 2014, Ardizoni, S., Ancient Origins <http://www.ancient-origins.net/history-important-events/dramatic-death-cleopatra-was-it-really-suicide-002117>. [2] White, J. 1991, ‘Snakebite: An Australian Perspective’ Journal of Wilderness Medicine, vol. 2, pp. 219-244.

[3] Shea, G., Shine, R., Covacevich, J.C. 1995, ‘Family Elapidae - Fauna of Australia. Vol. 2A. Amphibia & Reptilia’, Australian Govenrment Publishing Service, pp. 261–279. [4] Isbister, G.K. et al, 2013, ‘Snakebite in Australia: a practical approach to diagnosis and treatment’ The Medical Journal of Australia, vol. 199, no. 11, pp. 763-768. [5] ‘Snakebite Envenoming’ 2018, World Health Organisation, <http://www.who.int/en/news-room/fact-sheets/detail/snakebite-envenoming>. [6] Chippaux, J.P. 1998, ‘Snake-bites: appraisal of the global situation’ Bulletin of the World Health Organisation, vol. 76, no. 5, pp. 515-524. [7] Kasturiratne, A., Wickremasinghe, A.J., de Silva, N., et al, 2008, ‘The Global Burden of Snakebite: A Literature Analysis and Modelling Based on Regional Estimates of Envenoming and Deaths’ PLoS, vol. 5, no. 11, e218 <https://www.ncbi.nlm.nih.gov/pubmed/18986210>. [8] White, J. 2018, ‘Snakebites worldwide: Clinical manifestations and diagnosis’ UpToDate, viewed 21 May 2018 <https://www.uptodate.com/contents/snakebites-worldwide-clinical-manifestations-and-diagnosis?topicRef=93182&source=see_link>. [9] ‘Clinical Toxinology Resources – Family Elapidae’ 2018, University of Adelaide, <http://www.toxinology.com/fusebox.cfm?staticaction=snakes/ns-elapid1.htm> [10] Maduwage, K., and Isbister, G.K. 2014, ‘Current Treatment for Venom-Induced Consumption Coagulopathy Resulting from Snakebite’ Neglected Tropical Diseases – PloS, vol 8, No. 10, e 3220 <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4207661/>.

Read more: The global effect of snakebites 1.https://biomedicalsciences.unimelb.edu.au/departments/pharmacology/engage/avru/discover/snakebite-envenoming-a-neglected-tropical-disease 2. http://www.who.int/neglected_diseases/integrated_media_snakebite/en/ 3. http://www.who.int/en/news-room/fact-sheets/detail/snakebite-envenoming