Diseases Associated with Bites and Stings Flashcards
Envenomation - Snakes Geographic risk, prevention, transmission, possible symptoms and appropriate referral/triage of:
Poisonous snakes are hazards in many locations, although deaths from snakebites are rare. Snakebites usually occur in areas where dense human populations coexist with dense snake populations, such as Southeast Asia, sub-Saharan Africa, and tropical areas in the Americas.
Prevention Common sense is the best precaution. Most snake bites result from startling, handling, or harassing snakes. Therefore, all snakes should be left alone. Travelers should be aware of their surroundings, especially at night and during warm weather when snakes tend to be more active. For extra precaution, when practical, travelers should wear heavy, ankle-high or higher boots and long pants when walking outdoors in areas possibly inhabited by venomous snakes.
Management Travelers should be advised to seek immediate medical attention any time a bite wound breaks the skin or when snake venom is ejected into their eyes or mucous membranes. Immobilization of the affected limb and application of a pressure bandage that does not restrict blood flow are recommended first aid measures while the victim is moved as quickly as possible to a medical facility. Incision of the bite site and tourniquets that restrict blood flow to the affected limb are not recommended. Specific therapy for snakebites is controversial and should be left to the judgment of local emergency medical personnel. Specific antivenoms are available for some snakes in some areas, so trying to ascertain the species of snake that bit the victim may be critical.
Envenomation - Marine Animals Geographic risk, prevention, transmission, possible symptoms and appropriate referral/triage of:
Most marine animals are generally harmless unless threatened. Most injuries are the result of chance encounters or defensive maneuvers. Resulting wounds have many common characteristics: bacterial contamination, foreign bodies, and occasionally venom. Venomous injuries from marine fish and invertebrates are increasing with the popularity of surfing, scuba diving, and snorkeling. Most species responsible for human injuries, including stingrays, jellyfish, stonefish, sea urchins, and scorpionfish, live in tropical coastal waters.
Prevention Travelers should be advised to maintain vigilance while engaging in recreational water activities. Prevention is the best defense: Avoid contact. This may be difficult in conditions of poor visibility, rough water, currents, and confined areas. Do not attempt to feed, handle, tease, or annoy marine animals. Wear protective clothing, such as protective footwear. Make an effort to find out which animals may be encountered at the destination and learn about their characteristics and habitats before engaging in recreational water activities.
Management In case of injury, identifying the species involved can help determine the best course of treatment. Signs and symptoms may not appear for hours after contact, or the animal may not have been seen or recognized at the time of injury. In such cases treatment is based on the injury presentation. Symptoms of venomous injuries can range from mild swelling and redness at the site to more severe symptoms, such as difficulty breathing or swallowing, chest pain, or intense pain at the site of the sting, for which immediate medical treatment should be sought. Management will vary according to the severity of symptoms and can include medications, such as diphenhydramine, steroids, pain medication, and antibiotics.
Herpes B Geographic risk, prevention, transmission, possible symptoms and appropriate referral/triage of:
Macaques are native to Asia and North Africa. Additionally, descendants of North African populations of Barbary macaques inhabit Gibraltar, the only place that wild populations of macaques are found in Europe. They are also housed in research facilities, zoos, and wildlife or amusement parks and are kept as pets in private homes throughout the world. Monkey bites occasionally occur in certain urban sites, such as temples in Nepal or India. Macaque bites can transmit herpes B virus, a virus related to the herpes simplex viruses that cause oral and genital ulcers. Herpes B infection is rare in humans. The virus was discovered in 1933, and since that time approximately 50 human cases have been reported, with an 80% case-fatality ratio. No cases of herpes B infection have been reported in people exposed to monkeys in the wild. Most documented cases have resulted from occupational exposures. However, travelers to areas where macaques range freely should be aware of the potential risk. A monkey infected with herpes B may appear completely healthy.
Documented routes of human infection with herpes B virus include animal bites and scratches, exposure to infected tissue or body fluids from splashes, and in one instance, human-to-human transmission. Even minor scratches or bites should be considered potential exposures, because, experimentally, herpes B virus has been isolated from surfaces for up to 2 weeks after it was applied. The incubation period ranges from <1 week to 1 month or longer. Neurologic symptoms develop as the virus infects the central nervous system and may lead to ascending paralysis and respiratory failure. Increased public and clinician awareness about the risks associated with an injury from a macaque, improved first aid after exposure, the availability of better diagnostic tests, and improved antiviral therapeutics have decreased the case-fatality ratio to 20% in treated people. As a result, from 1987 through 2004 only 5 infections were fatal.
Although only macaque bites pose a herpes B virus threat, any monkey bite may pose a threat for rabies.
Prevention
Travelers should never attempt to feed, pet, or otherwise handle any monkeys.
Management
After a monkey bite or scratch, travelers should be advised to thoroughly clean the wound and seek medical care immediately to be evaluated for possible rabies and herpes B postexposure prophylaxis.
Rabies Geographic risk, prevention, transmission, possible symptoms and appropriate referral/triage of:
Rabies is found on all continents, except Antarctica. Regionally, different viral variants are adapted to various mammalian hosts and perpetuate in dogs and wildlife, such as bats and some carnivores, including foxes, jackals, mongooses, raccoons, and skunks. In certain areas of the world, canine rabies remains enzootic, including, but not limited to, parts of Africa, Asia, and Central and South America
Countries and political units that reported no indigenous cases of rabies during 2012:
- Africa Cape Verde, Mauritius, Réunion, São Tomé and Príncipe, and Seychelles
- Americas North: Bermuda, Saint Pierre and Miquelon
- Caribbean: Antigua and Barbuda, Aruba, The Bahamas, Barbados, Cayman Islands, Dominica, Guadeloupe, Jamaica, Martinique, Montserrat, Netherlands Antilles, Saint Kitts (Saint Christopher) and Nevis, Saint Lucia, Saint Martin, Saint Vincent and Grenadines, Turks and Caicos, and Virgin Islands (UK and US)
- Asia and the Middle East Hong Kong, Japan, Kuwait, Malaysia (Sabah), Qatar, Singapore, Taiwan, United Arab Emirates
- Europe Albania, Austria, Belgium, Corsica, Cyprus, Czech Republic, Denmark, Finland, France, Germany, Gibraltar, Greece, Hungary, Iceland, Ireland, Isle of Man, Liechtenstein, Luxembourg, Monaco, Netherlands, Norway (except Svalbard), Portugal, Slovakia, Slovenia, Spain(except Ceuta and Melilla), Sweden, Switzerland, and United Kingdom
- Oceania Australia,3 Cook Islands, Fiji, French Polynesia, Guam, Hawaii, Kiribati, Micronesia, New Caledonia, New Zealand, Northern Mariana Islands, Palau, Papua New Guinea, Samoa, Solomon Islands, and Vanuatu
prevention: Vaccine Avoiding Animal Bites Travelers to rabies-enzootic countries should be warned about the risk of acquiring rabies and educated in animal bite-prevention strategies. Travelers should avoid feral animals, be aware of their surroundings so that they do not accidentally surprise a dog, and avoid contact with bats and other wildlife. A particular risk for a bite exposure is from monkeys who live near temples and other urban areas of Asia. Tourists to these sites should not carry any food on their person or in their backpack, purse, or other bag and should be careful not to approach or otherwise interact with monkeys. Casual exposure to cave air is not a concern, but visitors should be educated not to handle bats or other wildlife. Many bats have tiny teeth, and not all wounds may be apparent, compared with the lesions caused by carnivores. Any suspected or documented bite or scratch from a bat should be grounds for seeking PEP. Children are at higher risk for rabies exposures because of their smaller stature, which makes extensive bites more likely; their curiosity and attraction to animals; and the possibility that they may not report a possible exposure. Although licks to fresh wounds or mucus membranes are a theoretical risk of acquiring rabies and PEP should be considered, there are no documented examples of rabies in travelers who were exposed in this manner.
Transmission Virus is present in the saliva of the biting rabid mammal. Transmission almost always occurs by an animal bite that inoculates virus into wounds. Virus inoculated into a wound does not enter the bloodstream but is taken up at a nerve synapse to travel to the central nervous system, where it causes encephalitis. Virus may enter the nervous system fairly rapidly or may remain at the bite site for an extended period. The approximate density of nerve endings in the region of the bite may increase the risk of developing encephalitis more rapidly. The hands and face, because of the relative density of nerve endings, are considered higher-risk exposures. Rarely, virus has been transmitted by exposures other than bites that introduce the agent into open wounds or mucous membranes. All mammals are believed to be susceptible to infection, but major reservoirs are carnivores and bats. Although dogs are the main reservoir in developing countries, the epidemiology of the disease from one region or country to another differs enough to warrant the medical evaluation of all mammal bites. Bat bites anywhere in the world are a cause of concern and an indication for prophylaxis.
Symptoms: Most patients will present after a documented, highly suspected, or likely exposure from a rabid animal. Clinical illness is compatible with acute, progressive encephalitis. After infection, the incubation period is highly variable, but it lasts approximately 1–3 months. The disease progresses acutely from a nonspecific, prodromal phase with fever and vague symptoms, to a neurologic phase, characterized by anxiety, paresis, paralysis, and other signs of encephalitis; spasms of swallowing muscles can be stimulated by the sight, sound, or perception of water (hydrophobia); and delirium and convulsions can develop, followed rapidly by coma and death. Once clinical signs manifest, most patients die in 7–14 days.
Treatment: Post-exposure prophylaxis RIG and/or vaccine
