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Diseases Associated with Hunting and Trapping

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Hazards

The hazards associated with hunting and trapping are numerous—falls, drownings, frostbite, animal trap injuries, animal bites, reactions to insect bites and stings, wood-cutting wounds, sun glare and many others. However, it is usually the less experienced who suffer such mishaps. The most important factors contributing to the severity of these occupational hazards are isolation and distance. Hunters and trappers frequently work alone in rugged areas remote from any medical treatment centre, and their exact locations may often be unknown to anyone for weeks at a time. A wound, animal bite or other accident that would otherwise be a minor matter can have serious consequences under such circumstances.

Accidents

Since professional trappers work mainly in the winter season in northern climates, sun glare from snow can produce eye injuries, and cold temperatures can produce frostbite and a dangerous lowering of body temperature, known as hypothermia; symptoms of hypothermia include euphoria and lethargy, with fatal consequences if not recognized in time. Crossing frozen lakes and rivers requires extreme caution because breaking through a thin layer of ice can result in drowning or hypothermia in a matter of minutes. Prolonged exposure to even moderately cold weather without adequate clothing can lead to hypothermia. Other accidents include gunshot wounds, snowmobile mishaps, wounds from skinning and wood-chopping, the accidental tripping of traps, and bites or injuries from trapped animals, snakes or other animal encounters. In addition to risk of wounds becoming infected, there is also the possibility of contracting certain diseases from animals.

Diseases

Hunters and trappers are potentially exposed to a great variety of infectious agents that can cause illnesses. Among them are zoonotic diseases, transmitted from animals to people. Zoonotic diseases are caused by numerous types of bacteria, viruses, parasites and fungi. The risk of acquiring any zoonotic disease varies with location, season and living conditions. A person can become infected directly (e.g., from an animal bite or from contact with blood while skinning an animal) or indirectly (e.g., from an insect bite that transmits the disease from another animal to a human).

Rabies is one of the most serious diseases that can be contracted from wild animals, usually from a bite wound, because it is essentially 100% fatal without medical treatment. Rabies is endemic in many areas and can infect most warm-blooded animals, including foxes, dogs, cats, bats, raccoons, skunks, wolves, bears and beaver as well as larger animals such as caribou, moose, cattle and horses. The rabies virus affects the brain; therefore, any wild animal which appears to lose its fear of man or to show any other unusual behaviour should be considered hazardous. Because the rabies virus, as well as a number of other viruses and bacteria, is transmitted in saliva, all animal bites should be washed thoroughly with soap and water. Any hunter or trapper who is bitten by an animal suspected to be rabid should seek medical assistance immediately and should try to obtain the head of the animal for testing.

Tularaemia, also known as deer fly fever and rabbit fever, is a bacterial disease that can be transmitted indirectly (by ticks, deer flies and other biting flies) or directly (by bites of infected animals or by handling carcasses, furs and hides of infected animals). It can also infect water supplies and contaminate meat. Its symptoms, similar to those of undulant fever and plague, include fever, chills, fatigue and swollen lymph nodes. In areas in which the disease is suspected, water supplies should be disinfected. Wild game should be thoroughly cooked before eating. Arms and hands should be kept clean and disinfected. Rubber gloves should be worn if there are any cuts or abrasions. The area in which carcasses, hides and pelts are handled should be kept clean and disinfected.

Anthrax is another bacterial disease that may infect trappers and hunters, since it is endemic in both wild and domesticated animals in most parts of the world. A skin infection from contact with contaminated skins and hides is the most frequent form of anthrax; however, people are also infected by eating contaminated meat. Disease caused by inhalation is less common. Treatment should be sought at once.

Tuberculosis is an increasingly significant problem in many areas. Many species of animals can be a source of tuberculosis infection for hunters. Although most cases of human tuberculosis are due to exposure to coughs and sneezes from infected humans, many species of animals, including birds and cold-blooded animals, can be infected with the bacillum. Tuberculosis is also transmitted by consuming unpasteurized dairy products. It is also possible to become infected by inhaling airborne respiratory droplets or by eating the meat of infected animals. People who are immune suppressed (e.g., due to medication or human immunodeficiency virus infection) are at particular risk for the more common agents of tuberculosis, as well as those found in soil and water.

Hunters and trappers may also suffer from several fungal diseases carried by animals as well as soil fungi. Trichophyton verrucosum and T. mentagrophytes are the main ringworm agents affecting man. Also, dogs serve as a reservoir for Microsporum canis, the principal cause of animal ringworm in man. Hunters and trappers may be exposed to fungi that reside in soil and decaying vegetation, especially soils contaminated with bird or bat droppings; these fungi, which are not zoonotic diseases, inhabit specific habitats. Coccidioides immitis is common only in arid and semi-arid areas, whereas Blastomyces dermatitidis prefers moist soils along waterways and undisturbed areas. Cryptococcus neoformans and Histoplasma capsulatum are more common and live in soils enriched with bird and bat droppings. When inhaled, these fungi can cause pneumonia-like symptoms as well as serious systemic diseases in both people and animals.

Tetanus is another serious disease that infects both humans and animals. The tetanus bacteria are also very common in soils and other parts of the environment, and are normal inhabitants of many animals’ digestive tracts. Wounds, particularly deep puncture wounds, that are contaminated with dirt are the most likely to become infected. Prevention includes proper wound care and routine vaccination.

Wood ticks, mosquitoes, fleas and other biting insects often transmit infections from animals to man. Bubonic plague is an example of a bacterial disease transmitted by flea bites. A flea becomes infected when it takes a blood meal from an infected animal—usually a rodent, rabbit or hare, but also various carnivores. The flea then transmits the infection to the next animal it feeds on, including man. People can also become infected by handling tissues of infected animals, or by inhaling airborne droplets from humans or animals, usually cats, with pneumonic form of plague. The initial symptoms of bubonic plague are non-specific and include fever, chills, nausea and prostration. Later, the lymph nodes may become swollen and inflamed (the buboes for which the disease is named).

A more common disease transmitted by the bite of an insect is Lyme disease. Lyme disease is one of many transmitted by ticks. The first symptom is often a bull’s-eye rash, a red circle with a pale centre at the site of the bite. The rash disappears; however, without treatment, the disease can progress to arthritis and more serious complications.

Hantaviruses infect rodents worldwide, and human infections have been described for decades, most typically affecting the kidneys. In 1993, hantavirus pulmonary syndrome was newly recognized in the United States. This virus caused a rapidly fatal respiratory failure. Transmission of these viruses is likely to be via aerosolized rodent urine and faeces. It is thought that infected people were exposed to mice that contaminated cabins and houses.

In addition, hunters and trappers may be exposed to a wide variety of other viral, bacterial, fungal and parasitic infections that are at times found in wild animals (table 1). Standard reference works may be consulted for details.

Table 1. Examples of diseases potentially significant to hunters and trappers

Agent

Disease

Reservoir

Mode of transmission

Occurrence

Bacterial diseases

Bacillus anthracis

Anthrax

Animals, hides, hair, bone, soil

Direct and indirect contact,
insect bites, inhalation,
ingestion

Americas, Europe, Asia, Africa

Borellia spp.

Lyme disease, relapsing fever

Rodents, small mammals, deer, ticks

Tick and louse bites

Worldwide except Australia

Brucella spp.

Brucellosis, undulant fever

Animals

Contact, ingestion, inhalation

Worldwide

Campylobacter spp.

Enteritis

Animals

Ingestion

Worldwide

Coxiella burnetii

Q fever

Animals

Inhalation, contact

Worldwide

Clostridium tetani

Tetanus

Soil

Contact

Worldwide

Ehrlichia spp.

Ehrlichiosis

Unknown

Tick bite

North America, Africa, Asia

Francisella tularensis

Tularemia

Animals

Insect bites, contact, ingestion,
inhalation

Worldwide except Australia

Leptospira spp.

Leptospirosis

Animals

Contact, ingestion, inhalation

Worldwide

Listeria monocytogenes

Listeriosis

Soil, animals, humans

Ingestion

USA

Mycobacterium spp.

Tuberculosis

Humans, mammals, birds,
cold-blooded animals,
environment

Inhalation, ingestion, wound
contamination

Worldwide

Rickettsia spp.

Tick-borne rickettsioses
(spotted fever group)

Ticks, rodents

Tick and mite bites

Worldwide

Salmonella spp.

Salmonellosis

Mammals, birds, cold-blooded
animals

Ingestion

Worldwide

Vibrio cholera

Cholera

Humans

Ingestion

Worldwide

Yersinia pestis

Plague, bubonic plague

Rodents, hares, rabbits, humans,
carnivores

Flea bites, inhalation, contact

Worldwide

Viral diseases

Arboviruses
(over 100 types)

Fevers, rash, haemorrhagic fevers,
encephalitis (includes Dengue, Yellow fever, viral encephalitides, Rift Valley fever, tick fevers)

Humans, animals, insects

Insect bites: mosquitoes, ticks, midges, sandflies, others

Worldwide

Ebola/Marburg viruses

Haemorrhagic fevers

Unknown, monkeys

Unknown, body-fluid contact

Africa, exposure to monkeys

Hantaviruses

Haemorrhagic fever, renal and pulmonary syndromes

Rodents

Inhalation

Asia, former Soviet Union,
Americas

Lassa virus

Lassa fever

Rodents

Inhalation, body-fluid contact

West Africa

Rabies virus

Rabies

Mammals

Virus in saliva, usually a bite
wound or scratch, occasionally
inhalation, organ transplants

Worldwide except some island
countries

Fungal diseases

Blastomyces dermatitidis

Blastomycosis

Soil

Inhalation

Africa, India, Israel, North
America, Saudi Arabia,
South Africa

Coccidioides immitis

Coccidioidomycosis, valley fever, desert fever

Soil

Inhalation

Argentina, Paraguay, Colombia,
Venezuela, Mexico, Central
America, USA

Cryptococcus neoformans

Cryptococcosis

Soil, bird and bat droppings

Inhalation

Worldwide

Histoplasma capsulatum

Histoplasmosis

Soil, bird and bat droppings

Inhalation

Americas, Africa, eastern Asia,
Australia

Microsporum spp.,
Trichophyton spp.

Ringworm

Humans, animals, soil

Direct or indirect contact

Worldwide

Parasitic diseases

Babesia spp.

Babesiosis

Rodents, cattle

Tick bites

Europe, Mexico, Russia,
Yugoslavia, USA

Baylisascaris spp.

Baylisascaris larva migrans

Racoons, badgers, skunks,
fishers, martens, bears

Ingestion

North America

Cryptosporidium parvum

Cryptosporidiosis

Humans, cattle, domestic animals

Ingestion

Worldwide

Diphyllobothrium latum

Tapeworm infection

Humans, dogs, bears, fish-eating
mammals

Ingestion

Lake regions

Echinococcus spp.

Echinococcosis

Animals

Ingestion

Worldwide

Giardia spp.

Giardiasis

Humans, animals

Ingestion

Worldwide

Leishmania spp.

Leishmaniasis

Humans, animals

Sandfly bite

Tropical and sub-tropical areas

Trichinella spiralis

Trichinellosis

Animals

Ingestion

Worldwide

Trypanosoma spp.

Trypanosomiasis

Humans, animals

Insect bites

Africa, Americas

 

Most zoonotic diseases and other infectious agents can be avoided by using common sense and some general precautions. Water should be boiled or chemically treated. All foods should be adequately cooked, especially those of animal origin. Meats from all wild animals should be cooked to 71°C (160°F). Foods eaten raw should be thoroughly washed. Insect bites and stings should be avoided by tucking trousers into boots; wearing long-sleeved shirts; using repellants and mosquito netting as necessary. Ticks should be removed as soon as possible. Direct contact with animal tissues and bodily fluids should be avoided. Wearing gloves is recommended, particularly if one’s hands are cracked or abraded. Hands should be washed with soap and water after animal handling and always prior to eating. Bites and wounds should be washed with soap and water as soon as possible, with follow-up medical treatment especially if exposure to a rabies-infected animal is suspected. Hunters and trappers should be vaccinated against diseases common to their location. Having emergency first aid supplies on hand and a basic knowledge of first aid procedures may make the difference between a major and a minor incident.


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Contents

Hunting References

Alaska Trappers Association (ATA). 1991. Alaska Trappers Manual. Fairbanks, AK: ATA.

Herscovici, A. 1985. Second Nature: The Animal Rights controversy. Toronto: CBC Enterprises.

Hinnis, HA. 1973. The Fur Trade in Canada: An Introduction to Economic History. Toronto: University of Toronto Press.

International Hunter Education Association (IHEA). 1995. 1995 Hunting Accident Report. Wellington, CO: IHEA.

Novak, M, JA Baker, ME Obbard, and B Malloch (eds.). 1987. Wild Furbearer Management and Conservation in North America. Toronto: Ontario Trappers Association.

Ortega y Gasset, J. 1985. Meditations on Hunting. New York: Scribner’s.

US Department of the Interior, Fish and Wildlife Service, and US Department of Commerce, Bureau of the Census. 1993. 1991 National Survey of Fishing, Hunting and Wildlife-associated Recreation. Washington DC: US Government Printing Office.