A snakebite is an injury caused by a bite from a snake, often resulting in puncture wounds inflicted by the animal’s fangs and sometimes resulting in envenomation. Although the majority of snake species are non-venomous and typically kill their prey with constriction rather than venom, venomous snakes can be found on every continent except Antarctica. The outcome of snake bites depends on numerous factors, including the species of snake, the area of the body bitten, the amount of venom injected, and the health conditions of the victim. Feelings of terror and panic are common after a snakebite and can produce a characteristic set of symptoms mediated by the autonomic nervous system, such as a racing heart and nausea, and death too.
Rabies is a zoonotic disease (a disease that is transmitted to humans from animals) that is caused by a virus called rhabdovirus that causes acute encephalitis (inflammation of the brain) in endotherms. Rabies virus, a rhabdovirus present in infected animal’s saliva is inoculated into the bite wound. This disease infects domestic and wild animals, and is spread to people through close contact with infected saliva via bites or scratches. For a human, rabies is almost invariably fatal if post exposure prophylaxis is not administered prior to the onset of severe symptoms. The rabies virus infects the central nervous system, ultimately causing disease in the brain and death. Once the rabies virus reaches the central nervous system and symptoms begin to show, the infection is effectively untreatable and usually fatal within days. Once symptoms of the disease develop, rabies is nearly always fatal.
Rabies occurs in more than 150 countries and territories. Worldwide, more than 55 000 people die of rabies every year. More than 95% of human deaths occur in Asia and Africa. Once symptoms of the disease develop, rabies is nearly always fatal. 40% of people who are bitten by suspect rabid animals are children under 15 years of age. Dogs are the source of 99% of human rabies deaths.Wound cleansing and immunization within a few hours after contact with a suspect rabid animal can prevent the onset of rabies and death. Every year, more than 15 million people worldwide receive a post-exposure preventive regimen to avert the disease – this is estimated to prevent 327 000 rabies deaths annually. Rabies is present on all most all continents, but more than 95% of human deaths occur in Asia and Africa. More than 99% of all human deaths from rabies occur in the developing world. Once symptoms of the disease develop, rabies is nearly always fatal.
Dog rabies potentially threatens over 3.3 billion people in Asia and Africa. People most at risk live in rural areas where human vaccines and immunoglobulin are not readily available or accessible. Poor people are at a higher risk.
Removing the rabies virus at the site of the infection by chemical or physical means is an effective means of protection. Therefore, prompt local treatment of all bite wounds and scratches that may be contaminated with rabies virus is important.Recommended first-aid procedures include immediate and thorough flushing and washing of the wound for a minimum of 15 minutes with soap and water, detergent, povidone iodine or other substances that kill the rabies virus.
There is a Vaccine and also Anti Rabies Serum (ARS) for the Rabies disease. But, Anti Rabies Vaccine alone may not save lives. W.H.O recommends ARS (Anti Rabies Serum) with ARV (Anti Rabies Vaccine) in all category III & immune-compromised category II patients. Anti Rabies Serum is a prepared from Human origin and Equine origin.Equine Rabies Immunoglobulin (ERIG) is obtained from the blood plasma of healthy equines that have been immunized against rabies by vaccination.Benefits of ERIG:
- Cheaper and safe (purified pepsin digested horse serum) equine immunoglobulin (ERIG) is availablePurification techniques can be used to reduce the risk of sensitization to ERIG.
- The objective is to maximize the specific activity and to minimize the allergenic substances in the product.
The incubation period for rabies is typically 1-3 months. This however could vary from 1 week to a year. Initial symptoms of rabies are usually nonspecific and suggest presence of fever and often pain or unusual or unexplained tingling, pricking or burning sensation (paraesthesia) at the wound site. As the virus spreads through the central nervous system, progressive, fatal inflammation of the brain and spinal cord develops. Two forms of the disease can follow:Furious rabies, during which people infected by the virus exhibit signs of hyperactivity, excited behavior, hydrophobia and sometimes aerophobia. After a few days, death occurs by cardio-respiratory arrest. Paralytic rabies accounts for about 30% of the total number of human cases. This form of rabies runs a less dramatic and usually longer course than the furious form. The muscles gradually become paralyzed, starting at the site of the bite or scratch. A coma slowly develops, and eventually death occurs. The paralytic form of rabies is often misdiagnosed, contributing to the underreporting of the disease.
Diphtheria is a bacterial disease caused by Corynebacterium diphtheriae. The infection commonly affects the throat and may lead to obstruction of the airways and death. Exotoxin-induced damage occurs on organs such as the heart. Nasal diphtheria may be mild, and chronic carriage of the organism frequently occurs; asymptomatic infections are common. Transmission occurs from person to person, through droplets and close physical contact, and is increased in overcrowded and poor socioeconomic conditions. A cutaneous form of diphtheria is common in tropical countries and may be important in transmission of the infection.
There are 20,000 to 30,000 reported cases of Diphtheria every year worldwide.
The symptoms of diphtheria usually begin two to seven days after infection. Symptoms of diphtheria include fever, chills, fatigue, bluish skin coloration, sore throat, hoarseness, cough, headache, difficulty swallowing, painful swallowing, difficulty breathing, rapid breathing, foul-smelling bloodstained nasal discharge and lymphadenopathy. Symptoms can also include cardiac arrhythmias, myocarditis, and cranial and peripheral nerve palsies.
Tetanus is a bacterial disease which is acquired through exposure to the spores of the bacterium Clostridium tetani which are universally present in the soil. The disease is caused by the action of apotent neurotoxin produced during the growth of the bacteria in dead tissues, e.g. in dirty wounds or in the umbilicus following non-sterile delivery. Tetanus is not transmitted from person toperson. A person usually becomes infected with tetanus when dirt enters a wound or cut. Tetanus germs are likely to grow in deep puncture wounds caused by dirty nails, knives, tools, wood splinters, and animal bites.
Tetanus is characterized by muscle spasms, initially in the jaw muscles. As the disease progresses, mild stimuli may trigger generalized tetanic seizure-like activity,
Tetanus antitoxin available which is prepared from hyper immunized animals (Equines) with tetanus toxoid / toxin. Plasma obtained from hyperimmunized horses is enzyme refined, purified and concentrated. The tetanus antitoxin has specific antitoxin globulins which neutralize the toxin formed by Clostridium tetani, the causative organism of tetanus infection.
Scorpions don’t bite, but scorpions sometimes sting. The last tail segment of Scorpion contains the stinger (also termed a telson) that transmits a toxin to the recipient of a sting. They can deliver enough venom to cause serious or lethal damage to humans.Contact with scorpions is usually accidental. Scorpion stings are painful, and they can be fatal, particularly to children. Scorpions may sting more than once; the stinger, located at the end of the tail segment is usually not lost or left in the person’s tissue after a sting.
Scorpion stings are a major public health problem in many underdeveloped tropical countries, especially Sahelian Africa, South India, the Middle East, Mexico, and South Latin America. The estimated annual number of scorpion stings is 1.2 million leading to 3250 deaths (0.27%). For every person killed by a poisonous snake, 10 are killed by a poisonous scorpion. In Mexico, 1000 deaths from scorpion stings occur per year
In general, the sting usually causes discomfort that slowly decreases over time. The discomfort, described below, usually ranges from moderate to severe.A person who has been stung by a scorpion may feel a painful, tingling, burning or numbing sensation at the sting site. The reaction at the sting site may appear mild. However, infrequently, a person experiencing a serious reaction may develop severe symptoms throughout the body. Severe symptoms include widespread numbness, difficulty swallowing, a thick tongue, blurred vision, roving eye movements, seizures, salivation, and difficulty breathing. These symptoms constitute a medical emergency. Death may occur.
Envenoming resulting from snake bites is a particularly important public health problem in rural areas of tropical and subtropical countries situated in Africa, Asia, Oceania and Latin America. A recent study estimates that at least 421,000 envenomings and 20,000 deaths occur worldwide from snakebite each year, but warns that these figures may be as high as 1,841,000 envenomings and 94,000 deaths. The highest burden of snakebites is in South Asia, Southeast Asia, and sub-Saharan Africa.
The major groups of snakes causing envenoming are the elapids (cobras, kraits, mambas etc.) and vipers, and in some regions, sea snakes. Snake venom is a complex mixture of many different compounds. The composition and effects of venom varies considerably between species to species, but can broadly be divided into categories which include i) cytotoxins causing local swelling and tissue damage, ii) hemorrhagins which disturb the integrity of blood vessels, iii) compounds which lead to incoagulable blood, iv) neurotoxins causing in neurotoxicity and iv) mycotoxins which cause muscle breakdown
The clinical features of the bites of venomous snakes reflect the effects of these venom components. These include, local tissue damage ranging from swelling of the bitten limb to skin and muscle necrosis, abnormal blood clotting and bleeding, hypotension and shock, neurotoxicity sometimes leading to paralysis of respiratory muscles requiring assisted ventilation, and renal toxicity. Although the most obvious explanation for a confirmed snake-bite with no clinical manifestations is a bite by a non-venomous species, bites by venomous species do not always cause symptoms, and only 50-70% of bites by a venomous species will actually cause envenoming.
Antivenom (or antivenin or antivenin) is a biological product used in the treatment of venomous bites or Stings. Antivenom is produced by injecting a small amount of the targeted venom into an animal such as a horse, sheep, goat, or rabbit, the subject animal will undergo an immune response to the venom, producing antibodies against the venom’s active molecule which can then be harvested from the animal’s blood and used to treat envenomation Internationally, antivenoms must conform to the standards of Pharmacopoeia and the World Health Organization (W.H.O).
Snake antivenom immunoglobulins are the only specific treatment for envenoming by snakebites Antivenom therapy is key to the medical management of snakebite and other venomous bites and stings.Antisera are essential because:
- No alternative successful therapy
- High degree of mortality and morbidity in the absence of treatment
- The diseases in which they are used represent a heavy toll of human suffering
- Largely affects children and farmers in rural communities
- Unfortunately there are a number of problems for developing countries in accessing and using antivenoms – W.H.O.
Like snakebite, dog bite is also a tropically neglected condition which requires more attention to improve the needful things. The solution to the lack of effective and safe antivenoms on a global basis demands the financial support of governments, non-governmental organizations and other international agencies. Without adequate financial support it will not be possible to pursue the objectives described in this plan of action. A concerted international effort, led by W.H.O will guarantee full international exposure of this problem thereby attracting the attention of agencies devoted to solutions for health problems in the developing world. Such a concerted international effort, involving producers, regulators, researchers, national and regional health authorities, international agencies and the community organizations, under the coordination of W.H.O can be expected to result in:Increased availability of safe and effective animal-derived antisera;
- Enhanced technical capacity of regulatory agencies and manufacturers;
- Guaranteed production of safe and effective antisera
- Improved clinical management of rabid bites and envenomingsOptimal clinical use of antisera
- Improved health programmes in the affected countries.
Patients with severe cases will be put in a hospital intensive care unit and be given a diphtheria antitoxin. Diphtheria antitoxin is hyperimmune serum produced in horses. Plasma obtained from healthy horses with diphtheria toxin is enzyme refined, purified and concentrated. The antitoxin has the specific capacity of neutralizing the toxin secreted by Corynebacterium diphtheriae, the causative organism of Diphtheria. Antitoxin will only neutralize circulating toxin that is not yet bound to tissue, thus prompt administration is critical. Delayed administration increases the risk of late effects such as myocarditis and neuritis.Before antitoxin is administered, the patient should be tested for sensitivity to horse serum and if necessary, desensitized. The dose of antitoxin to be administered depends upon the site and extent of the diphtheritic membrane, the degree of toxicity and the duration of illness. Prevention: Toxoid as DTP, DT or Td – at least three primary doses given by the intramuscular route.
Tetanus can be prevented by the administration of tetanus toxoid, which induces specific antitoxins. To prevent maternal and neonatal tetanus, tetanus toxoid needs to be given to the mother before or during pregnancy, and clean delivery and cord care needs to be ensured. Tetanus toxoid vaccine is available as single toxoid (TT), combined with diphtheria toxoid (DT) or low-dose diphtheria toxoid (Td), and combined with diphtheria and pertussis vaccines (whole pertussis wP or acellular pertussis aP) (DTwP, DTaP, or TdaP).
Continuously apply ice to the sting area.If there is no danger to other people, carefully collecting a dead or injured scorpion into a sealed container to show to the physician may be helpful.Antivenom therapy is available for the many scorpion species. The antivenom has been made by immunizing horses with the venom and then the antivenom (immunoglobulin) is harvested from horse blood. The antivenom may stop all symptoms within about 4 hours after administration. Other researchers are developing antivenom to other species of scorpions. All but the mildest of symptoms require hospital admission for 24 hours of observation, especially for children.
Snake bite is a tropically neglected public issue. The people most affected by snake bites, rabid dog bites and scorpion stings usually live in poor rural communities where medical resources are often sparse. The impact of these health issues, although dramatic and economically significant, does not appear as a priority in the design of national public health programmes. These are therefore the most neglected among today’s global health problems. The situation is particularly poignant because, in contrast to some other diseases, a highly effective treatment already exists: the timely administration of specific antiserum. Rabies, for instance, is entirely preventable even after severe exposure, provided post-exposure prophylaxis, completed with rabies immunoglobulin, can be given. Similarly, the mortality and morbidity of snake bites and scorpion stings can be reduced to very low levels by timely administration of appropriate antivenoms. The current situation of the management of potentially rabid mammal bites and envenomings by snake bites or scorpion stings worldwide is a global public health emergency. There is a lack of awareness of the magnitude of the problem by health authorities and politicians alike, due to both the scarcity of adequate statistics on the real impact of these diseases, and the lack of advocacy by and on behalf of the affected groups, mostly children and rural agricultural workers. Worldwide production of these antisera has declined, due to economic constraints that have forced the withdrawal of some private producers, and to the weakening of public-sector manufacturers in the public sector in many countries.Moreover, the poor quality of some antisera and the resulting deficiency in their efficacy and safety, together with deficient distribution policies and inadequate training of medical and nursing staff requires an urgent international action. The gravity of this problem, and the complexity of its causes, demands from the public health community, and especially from the W.H.O and humanitarian international agencies, a concerted, rapid and effective global response to reduce the burden of human suffering incurred by rabies, and snake and scorpion envenomings.
- A multi component scenario is required, involving producers and regulatory authorities at national, regional and global levels, with an appropriate coordination by WHO and with financial support of the international community.
- We need competence, collaboration and coordination more than competition.
