Snakebites: Anti-venom and Envenoming Information

Author: Thomas C. Weiss
Published: 2015/09/10 - Updated: 2021/07/30
Topic: Pharmaceuticals - Publications List

Page Content: Synopsis - Introduction - Main

Synopsis: Information regarding snake anti-venoms, the only effective treatment to prevent or reverse most of the venomous effects of snakebites. Anti-venom, antivenin or antivenene, is defined as a biological product used in the treatment of venomous bites or stings. Anti-venom is created by milking venom from a relevant snake, spider, insect, or fish.

Introduction

Snake anti-venom immunoglobulins or, 'anti-venoms,' are the only specific form of treatment for envenoming by snakebites. Anti-venoms may prevent or reverse the majority of snakebite envenoming effects and play an important role in decreasing mortality and morbidity. The preparations are included in the World Health Organization's List of Essential Medicines and needs to be part of any primary health care package where snakebites happen. At this time, there is an urgent need to ensure availability of safe, affordable and effective anti-venoms, especially in developing countries and to improve the regulatory control over the manufacture, import and sale of anti-venoms.

Main Item

Anti-venom, antivenin or antivenene, is defined as a biological product used in the treatment of venomous bites or stings. Anti-venom is created by milking venom from a relevant snake, spider, insect, or fish. The venom is then diluted and injected into a horse, sheep, rabbit, or goat. The subject animal will undergo an immune response to the venom, producing antibodies against the venom's active molecules which can then be harvested from the animal's blood and used to treat envenomation. Internationally, anti-venoms must conform to the standards of pharmacopoeia and the World Health Organization (WHO).

Snakebite Risk and Envenoming

The risk of snakebite envenoming is a public health hazard that a number of people in rural tropics face daily. In these areas, snakebite envenoming is a common cause of occupational injury affecting agricultural workers and hunters with important socioeconomic implications. Open-plan housing and sleeping on the floor, common in regions that are tropical, also exposes people to bites from snakes that are nocturnal. Overall, women, children and farmers are the most at risk populations for snakebites. Children often times suffer more severe effects than adults do because of their smaller body mass.

Bites by venomous snakes may cause severe paralysis that might also prevent breathing. Bleeding disorders may lead to fatal haemorrhage, severe local tissue destruction and irreversible kidney failure and may cause permanent disability. Bites by venomous snakes may also result in amputation of a limb.

Knowledge of which species of venomous snakes present the highest risks to people in any particular region or country is crucial to addressing snakebite issues. If venom from the wrong species of snake is selected, the anti-venom produced might not be effective against the effects of bites by snakes in regions or countries where the product is sold.

Important Facts Concerning Snakebites

• At least 100,000 people die due to snakebites every year
• Children and agricultural workers are the most affected populations
• Venomous snakebites may cause paralysis that might prevent breathing
• Snakebites may cause bleeding disorders that can lead to a fatal haemorrhage
• Children often experience more severe effects than adults because of their smaller body mass
• Approximately three times as many amputations and other forms of permanent disabilities are caused by snakebites each year
• While the exact number of snakebites is not known, it is estimated that 5 million people are bitten every year with up to 2.5 million envenomings
• Bites by venomous snakes can cause irreversible kidney failure and tissue damage that may cause permanent disability and might result in amputation of a limb

The Snakebite Situation Around the World

Snakebite is a neglected public health issue in a number of subtropical and tropical countries. As mentioned, around 5 million snakebites happen every single year. The result is up to 2.5 million envenomings, approximately 100,000 deaths and about three times as many amputations and other forms of disabilities.

The majority of snakebites occur in Asia, Africa and Latin America. In Africa alone there are an estimated 1 million snakebites each year, with around half of those affected requiring treatment. Snakebite injury is often found among children, women and farmers in poor rural communities in low and middle-income countries. The injuries happen most in countries where health systems are weakest and medical resources are sparse.

Bites by venomous snakes may cause acute medical emergencies involving severe paralysis that might prevent breathing as well as irreversible kidney failure, bleeding disorders that may lead to fatal haemorrhage, as well as severe local tissue destruction that can cause permanent disability and might result in amputation of a person's limb. Children experience more severe effects than adults because of their smaller body mass.

In contrast to several other serious health conditions, a highly effective treatment exists for snakebite. The majority of serious consequences and deaths from snakebites are totally preventable by making anti-venom more widely available. Snake anti-venoms are the only effective treatment to prevent or reverse most of the venomous effects of snakebites. Anti-venoms are in the World Health Organization's List of Essential Medicines and need to be a part of any primary health care package in locations around the world where snakebites happen.

Challenges Related to the Production of Anti-venoms

A notable challenge in the manufacture of anti-venoms is the preparation of the right immunogens, or snake venoms. At this time, very few countries produce snake venoms of adequate quality for the manufacture of anti-venom. Lack of regulatory capacity for the control of anti-venoms in countries with significant snake bite issues results in an inability to assess the quality and appropriateness of the anti-venoms as well.

A combination of factors has led to the crisis that currently exists. Poor information regarding the number of types of snakebites has lead to difficulties with estimating needs, combined with deficient distribution policies, has contributed to manufacturers ceasing the production of anti-venom or an increase in the prices of anti-venoms. Poor regulation and marketing of inappropriate anti-venoms has led to a loss of confidence in the available anti-venoms by health managers, clinicians and people affected by snakebites, leading to erosion of demand for the products.

Lack of Information, Weak Health Systems and Low Manufacture of Anti-venoms

Health systems in a number of countries where snakebites are common do not have the resources and infrastructure to collect strong statistical information on the issue. Assessing the real impact is also complicated by the fact that instances reported to health ministries by hospitals and clinics are often times only a minor part of the actual burden because many of those affected by snakebites never reach primary care facilities and due to this remain unreported. For example; in Nepal, where 90% of the population lives in rural areas, the Ministry of Health reported 480 snakebites which result in 22 deaths in the year 2000 alone. Yet figures for the same year collected in a community based study of one region, Eastern Nepal, detailed 4,078 snakebites and 396 deaths.

The poor quality and amount of information on snakebites is reflected in the poor availability of anti-venoms. Poor information results in the under-estimation of the need for anti-venoms by national health authorities, leading to low demand for manufacturers to produce anti-venom products, as well as the implementation of inappropriate procurement and medicine distribution strategies in countries.

A number of manufacturers of anti-venoms have stopped production of products due to low demand. Meanwhile, the cost of some anti-venoms has increased dramatically over the last two decades, making treatment unaffordable for most of the people who need it. Increasing prices have further suppressed demand, to the point where treatment has declined significantly, or disappeared entirely in some areas. Entry into some markets of inappropriate, untested, or fake anti-venom products has also undermined confidence in anti-venom therapy in general. Anti-venom supply failure is imminent in Africa and some countries in Asia. Plainly, the need for anti-venoms that are appropriate is very great indeed.

Author Credentials: Thomas C. Weiss is a researcher and editor for Disabled World. Thomas attended college and university courses earning a Masters, Bachelors and two Associate degrees, as well as pursing Disability Studies. As a CNA Thomas has providing care for people with all forms of disabilities. Explore Thomas' complete biography for comprehensive insights into his background, expertise, and accomplishments.