Operational Medicine Medical Education and Training

Environmental Diseases and Injuries I





This subcourse on environmental disease and injuries includes sections on venomous snake bites, spider bites, insect stings and bites, anaphylactic shock, poisonous marine animals, and hepatitis.

The identification of types of snake bites and types of venoms is the main concern of the section on snakes. The snakes described here will be found mainly in the United States. For those soldiers assigned to other parts of the world, supplementary information will be provided by proper persons when an assignment is made. It is not possible to include all species of snakes and their varieties in this subcourse. A LAC-USC Guide for Snake Venom Poisoning is included at the end of the first lesson.

The spiders that are identified can be as lethal as some types of snakes, but many of the insects are not. These insects are included because they are medically important in terms of pain and the possibility of an allergic reaction. Many people can show an allergy that will progress to anaphylactic shock. Some types of marine life can emit a poison that is more lethal than that of any snake, and many military personnel are stationed at or near the habitats of these animals.

The lesson on hepatitis identifies the various types of this disease. The routes of person to person transmission, and disease precautions, will be of special interest.


Length: 91 Pages

Estimated Hours to Complete: 6

Format: PDF file

Size: 1.2 MB


Anyone may take this course. However, to receive credit hours, you must be officially enrolled and complete an examination furnished by the Nonresident Instruction Branch at Fort Sam Houston, Texas. Enrollment is normally limited to Department of Defense personnel. Others may apply for enrollment, but acceptance is not guaranteed.




Environmental Diseases and Injuries I

Distance Learning Course
91 Pages
Est. 6 Hours
1.2 MB pdf file

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Section I. Spiders

Section II. Insects

Section III. Fire Ants, Scorpions, Centipedes & Millipedes

Section IV. Injuries From Marine Life





Section I. General

Section II. Type A Hepititis

Section III. Type B Hepititis

Section IV Other Types of Hepititis


Appendix A Snake Venom Poisoning and Antivenins

Appendix B Glossary





An emergency that can occur, that is not directly related to a combat area, is the bite of a snake. As a Medical NCO responsible for caring for a variety of patients, the information contained in this lesson concerning snakebites is invaluable because a snakebite can occur almost anyplace. A snake will avoid mankind usually, unless it is injured, trapped or somehow disturbed: n these cases, it will defend itself. An aggressive type of snake may attack without apparent provocation. Snakes tend to display more aggressiveness during their breeding season. Although there are over 2,500 known species of snakes in the world, less than 200 are potentially dangerous. All species of snakes can swim, and many of the snakes can remain under water for long periods without drowning. A bite sustained in water is just as dangerous as one on dry land. Often the thought of a snakebite creates fear and confusion, combined with anxiety about what to do, but this is needless and groundless when first aid for snakebites is understood.


a. Family Helodermatidae. The two lizards of the Helodermatidae family are the Gila monster (Heloderma suspectum) and the beaded lizard, scorpion (H. horridum). These lizards are unique because they have grooved teeth and venom glands. They can be found in the southwestern part of the United States and in Mexico.

The Gila monster is a large, corpulent, relatively slow-moving and largely nocturnal reptile, and may reach an overall length of 550 mm. Its life span is 10 to 25 years, and some records have noted even as many as 27 years. The location of the Gila monster's venom glands is on either side of the lower jaw. The glands consist of several lobes, and there is a separate duct for each gland to carry the venom to the mucous membrane between the lower jaw and the lip and the lip near the base of the tooth. Through capillary action, the venom travels from the duct to the grooves of the lower teeth, then the venom is drawn into the puncture wound made by the tooth.

It is relatively rare that a Gila monster bites unless there has been careless handling of it during captivity, it may not always expel venom. The venom has local irritant hemotoxic and neurotoxic effects.

b. Family Colubridae. Of the over 1000 species of snakes in the Colubridae family, there are some 200 venomous species. The boomslang (Dispholidus typhus) of South Africa and the bird snake (Thelotornis kirtlandii) are found in this group. They are found in mostly tropical and subtropical areas and have grooved fangs on the posterian maxillae (rear fangs). Although little is known concerning the venoms, some are powerfully hemorrhagic. This venom has been implicated in fatal envenomations.

c. Family Elapidae. The snakes of this family are referred to as the elapids and include over 150 species of coral, (Figure 1-3) and venomous snakes of Australia. The coral snakes have bright rings of red, white or yellow, and black across their bodies to make them the most beautifully colored of the venomous snakes. Corals are relatively small snakes and their secretive and burrowing habits keep contact with humans rather rare and bites even rarer. The eastern coral snake (Micrurus fulvius), the Texas coral snake (M. Tenere), and the Arizona or Sonoran coral snake (Micruroides euryxanthus) are found in the United States. They are fixed fangs on the anterior ends of the maxillae and the venom is predominately neurotoxic and potent.

d. Family Hydrophidae. There are approximately 100 species in this family. The words "adder" and "viper" are commonly used in literature and in a few areas of the world. "Adder" may be used to described nonvenomous snakes (i.e., hognose and milk snake in North America). These snakes can be found in Southeast Asia, the southwest Pacific Islands and one species reaches the western coasts of tropical America. They have short fangs and the venoms act primarily on skeletal muscle. The venom of these snakes is often extremely potent but small in quantity.

e. Family Crotalidae. There are approximately 100 species of Crotalidae. Many are pit vipers. The best-known pit vipers are the rattlesnakes. Rattlesnakes are found in North, South, and Central America and all of them are venomous. With the exception of Crotalus catalinensis, all rattlesnakes have rattles. They are relatively heavy bodied, have broad heads and are marked with blotches or cross bands over the back. In addition to the rattlesnake, some common names of snakes in the family.

Crotalidae are moccasins, new world pit vipers, bushmasters, massasaugas and pygmy rattlesnakes. There is also the Asiatic pit viper found in Asia. These snakes have single large fangs on short and their otherwise toothless maxillae rotate which permits the fangs to be erected or folded against the roof of the mouth (hinged). The venom usually causes local necrosis and hemorrhage.

f. Family Viperinae. There are approximately 50 species in this family. These snakes can be found in Africa, Asia, and Europe. They have large hinged fangs and the venom is extremely necrotic and hemorrhagic. One of the deadliest members of this family is the Gaboon viper.

From Environmental Diseases and Injuries I


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