Field Guide to Venomous and Medically Important Invertebrates ...

The ultimate outcome can include inflamed nasal membranes and sinuses which obstruct
breathing, destruction of red blood cells, hemorrhage, and necrosis. Other serious systemic
complications known to occur include swelling of lymph nodes in the underarm and groin areas,
headache, nausea, fever, difficulty in breathing, and prostration. Reactions depend on individual
sensitivities, the part of the body contacted, time and pressure of contact, and the size of the
caterpillar. Several families and species of moths known to have urticating properties are shown
in Appendix 1.
Figure 132. Urticating setae embedded in a finger. Photo: Richard C. Russell.
Figure 133. Marks from a puss caterpillar sting. Photo: source unknown.
Figure 134. Urticarial reaction caused by caterpillar in the Family Lymantriidae. Photo:
Richard C. Russell.
Among the most dangerous of the urticating caterpillars belong to the genus Lonomia in South
America. A bleeding syndrome induced by contact with Lonomia achelous caterpillars was first
described in Venezuela, and similar reactions have been reported for Lonomia obliqua from
Brazil. Symptoms are similar in all cases starting with burning pain after the initial contact
followed by reddened skin with a feeling of heat, swelling, blisters, headache, and vomiting. The
onset of hemorrhagic syndrome occurs within about 12 hours and manifests as hematoma
throughout the body, hemorrhage from the nose, and other bleeding. An intense dissolution of
fibrin which allows blood clots to form has been detected in the blood of the patients, but the
mechanism of this activity is unknown. Another group of dangerous caterpillars are the puss
caterpillars (Megalopyge spp.) whose painful stings have been known to produce hemorrhagic
lesions with significant swelling, swollen lymph nodes, and shock with low blood pressure.
Species in this genus are sometimes referred to as stinging asps.