Significant envenomation from a preserved rattlesnake head (in a patient with a history of immediate hypersensitivity to antivenin)

Identifying the snake: First scoping review on practices of communities and healthcare providers confronted with snakebite across the world

BACKGROUND

Snakebite envenoming is a major global health problem that kills or disables half a million people in the world's poorest countries. Biting snake identification is key to understanding snakebite eco-epidemiology and optimizing its clinical management. The role of snakebite victims and healthcare providers in biting snake identification has not been studied globally.

OBJECTIVE

This scoping review aims to identify and characterize the practices in biting snake identification across the globe.

METHODS

Epidemiological studies of snakebite in humans that provide information on biting snake identification were systematically searched in Web of Science and Pubmed from inception to 2nd February 2019. This search was further extended by snowball search, hand searching literature reviews, and using Google Scholar. Two independent reviewers screened publications and charted the data.

RESULTS

We analysed 150 publications reporting 33,827 snakebite cases across 35 countries. On average 70% of victims/bystanders spotted the snake responsible for the bite and 38% captured/killed it and brought it to the healthcare facility. This practice occurred in 30 countries with both fast-moving, active-foraging as well as more secretive snake species. Methods for identifying biting snakes included snake body examination, victim/bystander biting snake description, interpretation of clinical features, and laboratory tests. In nine publications, a picture of the biting snake was taken and examined by snake experts. Snakes were identified at the species/genus level in only 18,065/33,827 (53%) snakebite cases. 106 misidentifications led to inadequate victim management. The 8,885 biting snakes captured and identified were from 149 species including 71 (48%) non-venomous species.

CONCLUSION

Snakebite victims and healthcare providers can play a central role in biting snake identification and novel approaches (e.g. photographing the snake, crowdsourcing) could help increase biting snake taxonomy collection to better understand snake ecology and snakebite epidemiology and ultimately improve snakebite management.

Clinically Significant Envenomation From Postmortem Copperhead (Agkistrodon contortrix)

Over 14,000 copperhead (Agkistrodon contortrix) bites were reported to United States poison centers between 1983 and 2008, and 1809 cases were reported to poison centers in 2014. The copperhead is primarily found in the southeastern United States and belongs to the pit viper subfamily Crotalinae, which also includes the water moccasin (Agkistrodon piscivorus) and rattlesnakes (Crotalus and Sistrurus genera). Postmortem rattlesnakes have been reported to cause clinically significant envenomation; we report a case of a postmortem copperhead causing clinically significant envenomation after inadvertent puncture with the deceased copperhead fang. The copperhead was transected twice, leaving the snake in 3 separate pieces. While handling the snake head, an inadvertent puncture occurred on the right index finger followed by pain and swelling in the affected extremity necessitating antivenom administration. Care should be taken when handling deceased pit vipers due to the continued risk of envenomation.

Public perceptions of snakes and snakebite management: implications for conservation and human health in southern Nepal

BACKGROUND

Venomous snakebite and its effects are a source of fear for people living in southern Nepal. As a result, people have developed a negative attitude towards snakes, which can lead to human-snake conflicts that result in killing of snakes. Attempting to kill snakes increases the risk of snakebite, and actual killing of snakes contributes to loss of biodiversity. Currently, snake populations in southern Nepal are thought to be declining, but more research is needed to evaluate the conservation status of snakes. Therefore, we assessed attitudes, knowledge, and awareness of snakes and snakebite by Chitwan National Park's (CNP) buffer zone (BZ) inhabitants in an effort to better understand challenges to snake conservation and snakebite management. The results of this study have the potential to promote biodiversity conservation and increase human health in southern Nepal and beyond.

METHODS

We carried out face-to-face interviews of 150 randomly selected CNP BZ inhabitants, adopting a cross-sectional mixed research design and structured and semi-structured questionnaires from January-February 2013.

RESULTS

Results indicated that 43 % of respondents disliked snakes, 49 % would exterminate all venomous snakes, and 86 % feared snakes. Farmers were the most negative and teachers were the most ambivalent towards snakes. Respondents were generally unable to identify different snake species, and were almost completely unaware of the need of conserve snakes and how to prevent snakebites. Belief in a snake god, and the ability of snakes to absorb poisonous gases from the atmosphere were among many superstitions that appeared to predispose negativity towards snakes of BZ residents.

CONCLUSION

People with predisposed negativity towards snakes were not proponents of snake conservation. Fear, negativity, ambivalence towards, and ignorance about, snakes and the need for snake conservation were strong indicators of the propensity to harm or kill snakes. It seems that if wanton killing of snakes continues, local snake populations will decline, and rare and endangered snake species may even become locally extirpated. Moreover, inappropriate perception and knowledge about snakes and snakebites may put BZ people at increased risk of venomous snakebite. Therefore, intensive, pragmatic educational efforts focused on natural history and ecology of snakes and prevention of snakebite should be undertaken in communities and at schools and universities.

Venomous snakebite in mountainous terrain: prevention and management

The prevention and management of venomous snakebite in the world's mountains present unique challenges. This paper presents a series of practical, clinically sound recommendations for management of venomous snakebite in a mountain environment. The authors performed an extensive review of current literature using search engines and manual searches. They then fused the abundant knowledge of snakebite with the realities of remote first aid and mountain rescue to develop recommendations. A summary is provided of the world's most troublesome mountain snakes and the mechanisms of toxicity from their bites. Preventive measures are described. Expected symptoms and signs are reviewed in lay and medical terms. A review of currently recommended first-aid measures and advanced medical management for physicians, paramedics, and other clinicians is included. Venomous snakebites in mountainous environments present unique challenges for management. This paper offers practical recommendations for managing such cases and summarizes the approach to first aid and advanced management in 2 algorithms.

Most lay people can correctly identify indigenous venomous snakes

We attempted to determine how accurately members of the public can identify venomous snakes. Six different snakes indigenous to southern California were displayed in cages for 265 people to view at a street fair. These included 4 nonvenomous snakes and 2 venomous snakes. People were asked whether the snake was venomous and the name of the snake, if they knew it. Overall, people recognized whether a snake was venomous or nonvenomous 81% of the time. They were most accurate at identifying rattlesnakes as being venomous (95%) but incorrectly identified nonvenomous snakes as being venomous 25% of the time. Men were more accurate than women, and adults were more accurate than children. Subjects were less well able to identify the exact species of snakes. The results suggest that there may be no need to capture, kill, or bring a snake to the hospital for identification, at least in this geographic area.

Crotalid snake envenomation

Over 5000 Americans suffer from snake bites annually, and of these, nearly one quarter are from poisonous species. Although these cases are undeniably reported, death appears to occur in only a few cases each year, and often reflects delay in obtaining medical care. Two families of venomous snake indigenous to the United States account for most envenomations: Crotalidae (pit vipers or new world vipers) and Elapidae. This article focuses on the snakes of the Crotalidae family.

Emergency Management of Poisonous Snakebites

In brief Though 42 snake species in the United States can inflict a poisonous bite, management is the same for 99% of bites because 99% of bites are inflicted by pit vipers. First aid instructions stressing rapid transit to a hospital apply to all bites. Surgical intervention has no place in acute snakebite treatment. Antivenin therapy is appropriate except in cases of mild pit viper envenomation. Pit viper antivenin is the right choice for any pit viper envenomation, and the patient history will guide the choice of coral snake antivenin. For any antivenin administration, care must be taken to prevent allergic reactions. Basic supportive care involves pain control, correcting metabolic and hematologic complications, keeping the patient comfortable, and preventing serum sickness.