Identification.The puss caterpillar is the larva of a lepidopterous group commonly referred to as “flannel moths.” In some parts of the United States the larva is incorrectly referred to as an “asp.” When fully mature, the larvae are near white to dark gray in color, 2 to 3 cm (0.8-1.2 in) long, and completely covered dorsolaterally with hairs that cause them to resemble elongate tufts of cotton. Some of the hairs are venomous, and when they penetrate the skin a “toxin” passes from an underlying gland through the hairs at the points of contact. The color variation of the larvae in this species is dependent upon larval age, locality, and time of year. In Texas, where this species is most abundant, the spring/summer generation of caterpillars is usually lighter in color than the fall generation.
Distribution.This species has been recorded primarily from the Southeastern States, including Alabama, Arkansas, Florida, Georgia, Louisiana, Maryland, Mississippi, Missouri, North Carolina, South Carolina, Texas, and Virginia.
Biology/Behavior.In most of the southern area of its range, the puss caterpillar is thought to have two generations per year. The first generation develops in the spring and early summer, while the second generation develops in the fall. After emerging from a cocoon and mating, the female moth lays her eggs on a suitable host plant. In a few days the eggs hatch into larvae, which develop by feeding on the leaves of a wide range of trees and shrubs. The natural enemies of the puss caterpillar usually keep its numbers under control; however, every 4 or 5 years the caterpillars become more numerous, and the number of envenomizations associated with them increases.66
Avoidance/Control.Always wear protective clothing such as gloves and a long-sleeved shirt when working in areas heavily infested with puss caterpillars. During periods ofM. opercularisabundance, children should be instructed to stay away from infested trees and shrubs and not to handle caterpillars. If necessary, heavy puss caterpillar infestations may be treated with an appropriate insecticide.
Envenomization Reaction/Treatment.(Seeappendix.)
Identification.The saddleback caterpillar is easy to recognize since its brown sluglike body is covered mid-dorsally with markings that resemble a brown or purplish saddle sitting on a green and white saddle blanket. Upon close examination, stout spines can be observed along the caterpillar’s lateral body margin and on its four tubercles. Many of these spines are hairs that are connected at their bases with individual poison glands. Just prior to pupation and subsequent development into a moth, the caterpillar is 2-3 cm (0.8-1.2 in) long.
Distribution.In general, the saddleback caterpillar in the United States is distributed southeast of a diagonal line drawn from Massachusetts through the middle of Texas.68
Biology/Behavior.From May to November,Sibine stimuleacaterpillars may be found feeding on the leaves of a large variety of trees, shrubs, and other plants. Envenomization usually occurs when the victim accidentally contacts vegetation infested with these caterpillars. At the instant the victim’s skin contacts the caterpillar, the spine tips break off, thus allowing toxin to flow out of the hollow spines and into or onto the skin.
Avoidance/Control.When working in infested areas, wear gloves, a long-sleeved shirt, and long pants to prevent accidental envenomization. During periods of local heavy infestations, children should be instructed to avoid trees, shrubs, and other vegetation commonly infested with these caterpillars. Local entomologists may be contacted to obtain information on the most effective insecticide for saddleback caterpillar control in a given area.
Envenomization Reaction/Treatment.(Seeappendix.)
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The material presented in this appendix was prepared by Lt Col John C. Moseley, USAF, MC, Dermatologist, Wilford Hall USAF Medical Center, Lackland AFB, Texas.
IMMEDIATE:Pinprick sensation from the bite
LOCAL:Dull numbing pain; two red puncture marks at bite site. Pain peaks at 1-3 hours and persists 12-48 hours
REGIONAL:
GENERAL:
DEATHS:4-5% of untreated cases due to neurotoxic effect of the venom
LOCAL FIRST AID:Ineffective and unnecessary
SYSTEMIC:
IMMEDIATE:Very little pain, if any
LOCAL:
SYSTEMIC:
DEATHS:Reported; usually in children, due to renal failure and hematological abnormalities.
LOCAL FIRST AID:None effective or necessary
LOCAL:Within 4 hours of the bite, locally excise bite site
SYSTEMIC:
IMMEDIATE:Pain, often intense
LOCAL:1-4 hours—A two-puncture wound at the site with redness, swelling, and a burning aching pain that subsides in 4-5 hours
REGIONAL:Rare—Purpura of an entire limb
ANAPHYLAXIS AND DEATH:None reported in the United States
LOCAL FIRST AID:
SYSTEMIC:Analgesics for pain
IMMEDIATE:Usually no sensation, occasionally mild pain
LOCAL:(Four distinct reactions depending on degree of sensitivity):
ANAPHYLACTIC SHOCK:Rare, but reported
DEATHS:None reported
LOCAL FIRST AID:Wash with soap and water
SYSTEMIC:Oral antihistamines (Chart 1)
IMMEDIATE:Fierce burning pain lasting minutes
LOCAL:(Fire Ants)
SYSTEMIC:Due to allergic sensitization; severity and speed of onset related to degree of sensitivity. May see wheezing, urticaria, abdominal cramps, generalized edema, nausea, vomiting, dizziness, confusion, shock
ANAPHYLAXIS AND DEATH:Rare, but reported
LOCAL FIRST AID:
SYSTEMIC:
IMMEDIATE:Pain
LOCAL:Within 1-4 hours—Appearance and subsidence of wheal and red flare; may see intense local swelling in region of sting
SYSTEMIC:
ANAPHYLAXIS AND SUDDEN DEATH:Many cases reported, usually in adults
LOCAL FIRST AID:
SYSTEMIC:
LONG-TERM MANAGEMENT:(for hypersensitive patients)
IMMEDIATE:Severe sharp pain
LOCAL:
SYSTEMIC(neurotoxic species only—within 1-3 hours):
ANAPHYLAXIS:Rare, but reported with non-neurotoxic species
DEATHS:Occasional; due to neurotoxic species
LOCAL FIRST AID:
SYSTEMIC:
IMMEDIATE:Severe burning pain
LOCAL:
SYSTEMIC:
DEATHS:None reported
LOCAL FIRST AID:
SYSTEMIC: