Part 1

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VENOMOUS ARTHROPOD HANDBOOK

Envenomization Symptoms/Treatment, Identification, Biology and Control

Terry L. Biery, Captain, USAF, BSC

Disease Surveillance Branch Epidemiology Division USAF School of Aerospace Medicine Aerospace Medical Division (AFSC) Brooks Air Force Base, Texas 78235

For sale by the Superintendent of Documents. U.S. Government Printing Office Washington, DC. 20402

Stock No. 008-070-00397-0/Catalog No. D 301,35: 161/43 U.S. GOVERNMENT PRINTING OFFICE: 1977 O—251-048

PREFACE

The purpose of this handbook is to provide Air Force medical personnel with a quick reference on the problems caused by the more important venomous arthropods found in the United States. An attempt has been made to include the latest information available in the scientific literature.

The author would like to acknowledge the valuable assistance of Mr. Orville V. Anderson, USAFSAM Photographer; Captain Robert W. Clegern, USAF, BSC, Medical Entomologist; and Lieutenant Colonel John C. Moseley, USAF, MC, Dermatologist.

CONTENTS

INTRODUCTION 1 BITING/PIERCING ARTHROPODS 4 1. Black Widow Spider (_Latrodectus mactans_) 4 2. Brown Recluse Spider (_Loxosceles reclusa_) 6 3. Centipedes (Class: Chilopoda) 8 4. Conenose or Kissing Bugs (_Triatoma_ spp.) 10 5. Wheel Bug (_Arilus cristatus_) 12 STINGING ARTHROPODS 14 1. Ants (Order: Hymenoptera; Family: Formicidae) 14 2. Bees (Order: Hymenoptera; Family: Apidae) 17 3. Scorpions (Class: Arachnida; Order: Scorpionida) 20 4. Velvet Ants (Order: Hymenoptera; Family: Mutillidae) 22 5. Wasps (Order: Hymenoptera; Family: Vespidae) 24 URTICATING/VESICATING ARTHROPODS 26 1. Blister Beetles (Order: Coleoptera; Family: Meloidae) 26 2. Urticating Caterpillars 28 a. Io Moth Caterpillar (_Automeris io_) 28 b. Puss Caterpillar (_Megalopyge opercularis_) 30 c. Saddleback Caterpillar (_Sibine stimulea_) 32 BIBLIOGRAPHY 34 APPENDIX: ARTHROPOD ENVENOMIZATION REACTIONS AND TREATMENT 39 Chart 1: Antihistamines 48 Chart 2: Treatment of Anaphylaxis—Shock 49

INTRODUCTION

Although most residents of the United States are aware of the pain and discomfort associated with contacting a venomous arthropod, many are not aware that these arthropods (such as ants, bees, wasps, spiders, and scorpions) are responsible for more human deaths in the United States each year than any other group of venomous animals, including snakes. In fact, a study by Parrish[15] showed that venomous arthropods accounted for more than 65% of the reported human fatalities caused by venomous animals in the United States from 1950 through 1959. His findings are summarized as follows:

_Venomous animal group_ _Human fatalities (1950-59)_

Hymenoptera (bees, wasps, and ants) 229/460 or 49.8% Poisonous snakes 138/460 or 30.0% Spiders 65/460 or 14.1% Scorpions 8/460 or 1.7% Others 20/460 or 4.4%

It would be incorrect, however, to assume from the above information that a high percentage of arthropod envenomizations are fatal. In actuality, the opposite is true. Of the estimated millions of people envenomized by arthropods in the United States each year, about 25,000 have severe reactions; and of these, approximately 30 result in reported deaths.[19] Therefore, the high number of fatalities caused by venomous arthropods, relative to other venomous animals, can be attributed to the high incidence of arthropod envenomizations rather than the efficient killing power of their venoms. This high-incidence rate is accounted for by the tremendous abundance of venomous arthropods and their ability to live in close proximity to man.

Air Force personnel stationed in the continental United States face a greater risk of contacting a venomous arthropod than the average United States resident because: (1) a large portion of bases are located in the southern half of the United States, where venomous arthropods are most numerous; (2) many facilities (such as radar, communications, security, and missile sites) are located in remote areas where venomous arthropods are not controlled; (3) numerous Air Force training and work activities must be performed outside; and (4) many military structures (such as older wooden buildings, storage buildings, and field training facilities) provide excellent habitats for venomous arthropods. It is important, therefore, that Air Force medical facilities have current information available concerning the most important venomous arthropods in their areas.

The venomous arthropods discussed in this handbook were selected for inclusion due to the relative severity of their envenomizations and/or the high frequency of their contact with humans. It should be stressed that other arthropods found in the United States are capable of producing envenomization reactions in humans. Regardless, all venomous arthropods found in the United States can be categorized under one of the three types of envenomization methods described in this handbook: (1) biting/piercing, (2) stinging, and (3) urticating/vesicating. The biting/piercing arthropods inject a toxin through an apparatus associated with or near their mouthparts; and the stinging arthropods, through a stinger located at the posterior end of the abdomen. Urticating and vesicating arthropods are grouped together because they both release their toxins on contact. They differ in that the urticating arthropods usually release their toxin through venomous hairs; and vesicating arthropods carry a toxic substance within their system, which is released through small body openings.

To facilitate the utilization of this handbook, each venomous arthropod presentation has been organized into the following information categories:

• Identification. Bringing the arthropod causing an envenomization to the medical facility treating the victim is most helpful. In most cases, an identification must be made before the proper form of treatment can be determined. To assist personnel with identification, the key characteristics and representative color photographs are provided for the venomous arthropods discussed.

• Distribution. Most arthropod envenomizations occur during the warm plant-growing season when venomous arthropods are most numerous. Since the Southern United States has the longest growing season, venomous arthropods are abundant for a longer period of time in this region. Also, the moderate climate of the Southern States, with fewer weather extremes, permits a greater variety of venomous arthropods to survive, propagate, and produce multiple generations each year. Specific regional occurrences are indicated.

• Biology/Behavior. Pertinent biological information is provided to help increase the reader’s awareness and understanding of venomous arthropods. These factors are essential in developing a good avoidance and control program.

• Avoidance/Control. To assist in preventing envenomization accidents, several means of avoidance are listed for each venomous arthropod. Since the status of insecticide recommendations is constantly changing, few specific recommendations are included. When insecticide control is necessary, an Air Force, County Extension Service, or United States Department of Agriculture entomologist should be consulted for current recommendations. Any insecticide must be applied according to the instructions on the container label.

In addition to the information presented in the text, a table on envenomization reactions and treatment is included as an appendix. The reactions listed in this table are “typical” and do not necessarily represent the entire range of reactions which might occur.

BITING/PIERCING ARTHROPODS

1. BLACK WIDOW SPIDER (Latrodectus mactans)

Identification. The female black widow has a shiny black body, approximately 1.5 cm (0.6 in) long, and usually a red hourglass-shaped marking on the underside of her globose abdomen. On some individuals the distinct hourglass marking is replaced with several triangles or spots or an irregular longitudinal blotch. She has slim black legs with a span of 4 cm (1.5 in). The male is considerably smaller than the female, usually a patterned brown color, and is not a threat to man.

Distribution. _Latrodectus mactans_ is found in every state except Alaska; however, most reported human fatalities have occurred in the Southeastern States.[14, 15]

Biology/Behavior. The black widow is generally found in its irregular-shaped web near the ground. Common web sites are under stones, loose bark, or water faucets or in wood piles, rodent burrows, garages, storage buildings, outhouses, and barns. Most human envenomizations occur when the spider is inadvertently trapped against part of the body or when the web is accidentally touched.

Avoidance/Control. Frequent cleaning to remove spiders and their webs from buildings and outdoor living areas will decrease the possibility of accidental bites. Routine hose washings of potential spider habitats, such as under steps and around windows and doors, will discourage the black widow from locating in these places. When working in spider-infested areas, wear gloves and a long-sleeved shirt. If warranted, the outside or inside of a building may be sprayed with an approved insecticide. Apply the spray around windows, stairs, closets, or other spider habitats in accordance with instructions on the manufacturer’s label.

Envenomization Reaction/Treatment. (See appendix.)

2. BROWN RECLUSE SPIDER (Loxosceles reclusa)

Identification. The brown recluse is a medium-sized spider with a 2- to 4-cm (0.8-1.6 in) legspan and a color range from yellow tan to dark brown. The most distinguishing characteristics are six eyes (most spiders have eight eyes) arranged in a semicircle of three pairs on top of the head, and a violin-shaped marking extending from the area of the eyes to the abdomen.

Distribution. Brown recluse spiders occur throughout an area of the Southcentral States, including Alabama, Arkansas, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Ohio, Oklahoma, Mississippi, Missouri, Tennessee, and Texas. Localized populations of this spider, probably imported from the Southcentral States, have been reported from Arizona, Wyoming, California, Florida, New Jersey, North Carolina, Pennsylvania, and Washington, D.C. Due to the mobility of the United States citizenry, specimens can be easily transported in household goods from the spider’s home range in the Southcentral United States to any other area of the country. Under favorable conditions the relocated spiders can survive for an extended period of time and possibly become established.

Biology/Behavior. Within its range, the brown recluse spider will readily establish populations inside parts of buildings which are generally dry, littered, and undisturbed for long periods of time. The spider also can be found outside in protected areas (under rocks and loose bark). Members of this species are nonaggressive and normally attempt to escape whenever they are threatened. Thus, most instances of bites occur when the spider is inadvertently trapped, such as when the victim puts on clothing in which the spider is hiding, steps on a wandering spider at night, or cleans closets or other storage areas where the spider resides.

Avoidance/Control. Any of the following actions will help prevent contact with the brown recluse spider: shake out clothing and bedding before use; eliminate collections of papers and unused boxes; thoroughly clean beneath and behind furniture; remove spiders, webs, and egg cases from living and storage areas; and properly use appropriate insecticides.

Envenomization Reaction/Treatment. (See appendix.)

3. CENTIPEDES (Class: Chilopoda)

Identification. Centipedes are multisegmented elongate arthropods with a distinct head and one pair of legs, or appendages, per segment. Size is species dependent, with body length ranging from approximately 2.5 to 25 cm (1-10 in) or more. The number of legs can therefore vary from 15 to 100 pairs or more, depending upon the species.

Distribution. The range of centipedes varies with the species; however, these arthropods are most numerous in the southern half of the United States.

Biology/Behavior. Throughout the day, centipedes hide under rocks, boards, or bark and in cracks, crevices, closets, basements, and other moist, protected locations. At night, they come out of hiding to hunt for prey which usually consists of insects and other small arthropods. Centipedes inject venom through two powerful claws located on the ventral side of the body immediately behind the head. Contrary to popular belief, centipedes cannot inject venom through their numerous legs. The majority of centipedes found in the United States are small and not a threat to man. Human centipede envenomizations occur when a relatively large centipede is accidentally picked up, stepped on, or otherwise trapped against the body.

Avoidance/Control. When camping in a centipede-infested area, carefully invert and shake out sleeping bags, clothes, or other items left in contact with the ground. Always wear shoes when walking about at night, and wear leather gloves when moving rocks or trash from the ground. Usually centipedes are not sufficiently numerous in any one location to warrant chemical control.

Envenomization Reaction/Treatment. (See appendix.)

4. CONENOSE OR KISSING BUGS (_Triatoma_ spp.)

Identification. Species of the genus _Triatoma_ have the elongate (cone-shaped) head which is characteristic of the family Reduviidae. Hence, the name “conenose bugs” is often used to describe these insects. Orange and black markings are usually present where the abdomen extends laterally past the folded wings. These insects are flattened dorsally, and this trait allows them to effectively hide in small cracks and crevices. The size of mature adults varies from approximately 1 to 3 cm (0.4-1.2 in) depending upon the species.

Distribution. _Triatoma_ species that attack humans are generally located in the southern half of the United States.

Biology/Behavior. Conenose bugs are nocturnal insects. They take their blood meals at night and hide in any available crack or crevice between feedings. _Triatoma_, as a group, normally feed on small mammals; but in the absence of their preferred hosts, several species will readily feed on humans. They are commonly referred to as “kissing bugs” because their blood meals are occasionally taken from the area around the human lips. Some of the common sites of human attack, in order of frequency, are the hands, arms, feet, head, and trunk. This feeding pattern can be expected since kissing bugs have not been found to feed through clothing.[30]

Avoidance/Control. Since these bugs can feed undetected on a sleeping victim, it is difficult to avoid their attack in heavily infested areas. Exposure to kissing bugs can be minimized, however, by destroying underbrush, rubbish, wood rats’ nests, and any other small-animal habitat located near a residence.[27] When an infestation is detected inside a house, two or three treatments with an appropriate insecticide at 10-day intervals should provide control. To obtain the best results, thoroughly treat all windows, baseboards, walls, cracks, crevices, and bedsprings.

Envenomization Reaction/Treatment. (See appendix.)

5. WHEEL BUG (_Arilus cristatus_)

Identification. _Arilus cristatus_ has the small narrow head characteristic of the Reduviidae family of Hemiptera (true bugs). This insect is mouse gray in color and approximately 2.5 to 4 cm (1-1.6 in) long. A cogwheel-like crest on the dorsal side of the prothorax is distinctive to this insect and accounts for its popular name, “wheel bug.”

Distribution. Wheel bugs are generally found in the southern two-thirds of the United States.

Biology/Behavior. Wheel bugs are predacious on soft-bodied insects. Human envenomizations are usually the result of accidental contact while handling vegetation, boards, or other objects. The bug penetrates the skin with its “beak,” or proboscis, and injects a salivary fluid normally used in killing its insect prey.[31]

Avoidance/Control. The best way to prevent wheel bug contact is to be able to identify this unusual insect and avoid it. Children should be instructed not to handle it. Wearing leather gloves while working outside will prevent bites which occur when the wheel bug is accidentally picked up with vegetation or other debris. Since wheel bugs are predacious on many harmful insects and are generally considered beneficial, control is not recommended.

Envenomization Reaction/Treatment. Wheel bug bites are characterized by immediate intense pain which usually subsides in 3 to 6 hours. Since all reported bite reactions have been localized and self-limiting, specific treatment measures are not provided for _A. cristatus_ bites. However, anaphylactic shock has resulted from the bite of other Hemiptera and should be considered a possibility with wheel bug bites.[12]

STINGING ARTHROPODS

1. ANTS (Order: Hymenoptera; Family: Formicidae)

Identification. Like other Hymenoptera, females of dangerous ant species have a stinger at the posterior tip of the abdomen. Their constricted “waist” between the thorax and posterior abdomen and their elbowed antennae distinguish them from similar insects. The dangerous United States species belong to genera _Solenopsis_ (fire ants) or _Pogonomyrmex_ (harvester ants). The easiest way to distinguish these ants is by their mounds. Fire ants build elevated earthen mounds 8-90 cm (3-36 in) high, leaving the surrounding vegetation relatively undisturbed. In contrast, harvester ant mounds are usually flat or slightly elevated and are surrounded by a defoliated area 0.6-3 m (2-10 ft) or more in diameter. Also, harvester ants are 2 to 3 times larger than fire ants.

Distribution. The Florida harvester ant, _P. badius_, distributed throughout the Southeastern States, is the only harvester ant known to occur east of the Mississippi River. West of the Mississippi, the red harvester ant (_P. barbatus_), the California harvester ant (_P. californicus_), and the western harvester ant (_P. occidentalis_) are found in different individualized distribution areas. The two most important fire ant species were introduced into the United States from South America. The red imported fire ant (_S. invicta_) was introduced about 1940 and is well established in the Southeastern States. Currently, this ant infests Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, North and South Carolina, and Texas. The black imported fire ant (_S. richteri_) was introduced about 1918; its distribution is limited to an area in northeastern Mississippi and northwestern Alabama. Two less important native species, _S. geminata_ (tropical or native fire ant) and _S. xyloni_ (southern fire ant), occur in localized areas of a few southern states.

Biology/Behavior. Ants of the _Solenopsis_ and _Pogonomyrmex_ genera are diurnal soil-inhabiting insects that prefer to nest in open areas. These ants are social insects; their colonies consist of at least one reproductive queen, several males, and many nonreproductive female workers. Fire and harvester ants are particularly dangerous because workers defending their nest can inflict repeated stings, and multiple human envenomizations may occur when a victim comes in contact with a mound.

Avoidance/Control. Familiarization with the appearance of the ant mounds is necessary in order to avoid them and prevent accidental envenomizations. Since small children are often the victims of multiple stings, parents should insure that the mounds of dangerous ant species are not present in play areas. This is particularly important where the red imported fire ant occurs. Mound treatments with mirex have been effective in controlling _Solenopsis_ and _Pogonomyrmex_ ants. The Environmental Protection Agency limits the use of this insecticide, and it must be applied in strict accordance with EPA and product label instructions.

Envenomization Reaction/Treatment. (See appendix.)

2. BEES (Order: Hymenoptera; Family: Apidae)

Identification. Two families of bees are commonly associated with human envenomization: Apidae (honey bees and bumble bees) and Halictidae (sweat bees). Only the honey bees and bumble bees are considered dangerous. Both are robust hairy insects with two pairs of membranous wings which they hold at an angular position over the body when at rest. Microscopic examination shows that bee thoracic hairs are individually “feathered.” In contrast, wasp thoracic hairs are smooth.

Distribution. Dangerous species of bees are distributed throughout the United States.

Biology/Behavior. 1. Honey Bees. Since these insects are not native to this continent, north of Mexico, all original honey bee colonies in the United States were imported. _Apis mellifera_, the cosmopolitan bee of commerce, is responsible for most bee stings and many deaths.[10] This species is separated into several races, with the gold Italian and the black or gray Caucasian races making up the majority of the bees found in this country.[5] The aggressive Brazilian (hybrid African) bee is currently restricted to the South American continent. Honey bees are highly social insects. Their colony consists of an egg-laying queen, drones to fertilize the queen, and workers to gather food and care for the young. Honey bees can release “alarm odors” associated with the sting gland, which cause other bees in the vicinity of an odor-marked victim to attack and inflict multiple stings. Unlike other hymenopterous insects, the honey bee worker has a barbed stinger and can sting only once; to escape, the bee must leave its entire stinging apparatus attached to the skin of its victim. As important pollinators of crops, honey bees are very beneficial to man.