About Lonomia obliqua Walker, 1855
Description: The caterpillars of Lonomia obliqua Walker, 1855 measure around 4.1 to 6.7 centimeters (approximately 2 inches) in length, and their base body color ranges from green to brown. They are well camouflaged, and have rows of tubercles; each tubercle is crowned with whorls of easily detachable spines that come in different sizes.
Toxicity: Lonomia obliqua produces toxic venom that triggers disseminated intravascular coagulation and consumptive coagulopathy, which can develop into a hemorrhagic syndrome. The toxins are stored in sacs located at the base of each spine. When the spines pierce a victim's skin, venom moves through the hollow bristles and into the puncture wound. Research has found that the toxin in the caterpillar's skin contains potent anti-clotting agents. This anti-clotting agent attaches to a protein in the body's cells, causing the cells to leak because blood cannot clot. This internal bleeding fills surrounding tissue with "bruised blood", spreads through internal organs, and eventually leads to compression and brain death. This mechanism accounts for at least 500 deaths from human contact with L. obliqua caterpillars.
Of the 26 Lonomia genus species found on the American continent, only Lonomia obliqua and Lonomia achelous have caused severe reactions that lead to hemorrhagic syndrome. Since 1989, the number of human accidents caused by these caterpillars has been rising in the southern region of Brazil. Demographic data from reported cases shows 63% of victims were male, 45% were between 0 and 21 years old, and 41% of lesions occur especially on the fingers. The overall reported death rate for these accidents is 2.5%. A 2021 study recorded 42,264 confirmed cases of Lonomia obliqua-related caterpillar accidents in Brazil between 2009 and 2017; out of 248 severe cases, five resulted in death. While severe incidents are uncommon, a vaccine company based in Sao Paulo has started producing antivenom for L. obliqua envenomation. During venom extraction, after all spicules are removed, each caterpillar yields approximately 2.4 mg of venom. The total amount of venom that can be injected into a 70 kg individual can reach up to 1.4–1.7 mg per kg of body weight.
Medical applications: The toxin of L. obliqua caterpillars has been the focus of many studies investigating its potential medical value. One specific component, called "Lopap" (L. obliqua prothrombin activator protease), has been found to exhibit anticoagulant and anti-apoptotic properties.
