Biochemical and biological properties of Lonomia obliqua bristle extract

Abstract

Lonomia obliqua caterpillar is frequently seen in accidents with humans especially in the south of Brazil. Patients develop a hemorrhagic syndrome that can be treated with specific antilonomic serum. A consumptive coagulopathy was found to be the main cause of bleeding complications observed in patients after contact with L. obliqua. Studies revealed that L. obliqua caterpillar bristle extract (LOCBE) displays a procoagulant activity that leads to intravascular thrombin formation, resulting in a special form of disseminated intravascular coagulation (DIC). Fibrinolysis seems to be secondary to the fibrin production, since no direct fibrinolytic activity was found in LOCBE. Two procoagulant toxins, a factor X activator (Losac) and a prothrombin activator (Lopap), were isolated from LOCBE and characterized. Infusion of Lopap into experimental animals triggered a condition similar to that observed in human envenomation

Caterpillar-induced bleeding syndrome in a returning traveller

“…Decreased levels of factor XIII are more common with L. achelous than with L. obliqua. 1,6 Decreased plasminogen, α2-antiplasmin and protein C levels have also been documented. 1 Traditionally, patients were treated with fresh frozen plasma and cryoprecipitate.…”

“…1,3,4 Complications of Lonomia envenomation include alveolar hemorrhage, acute renal failure and intracranial hemorrhage. 5,6 Generally, patients with this syndrome have normal platelet and hemoglobin levels, minimal hemolysis and red blood cell fragmentation, and normal levels of factors II, VII, IX, X, XI, XII and antithrombin. Rarely, clinically significant hemolysis has also been reported.…”

“…1,6 L. obliqua is native to southern Brazil, and L. achelous is more commonly found in Venezuela and northern Brazil. Both caterpillars induce a consumptive coagulopathy and bleeding syndrome that is similar in presentation.…”

“…Two procoagulant toxins have been identified in the venom of L. obliqua. 1,6 Losac is an activator of factor X, and Lopap is an activator of prothrombin. The mechanism of L. obliqua-induced bleeding syndrome is a consequence of systemic intravascular activation of coagulation, which leads to a consumptive coagulopathy and secondary fibrinolysis in which the extent of fibrinogen depletion correlates with the severity of bleeding manifestations.…”

“…1,3 Owing to increasing numbers of caterpillar envenomations in southern Brazil, the Butantan Institute in Sao Paulo has produced an equine-derived antivenin against L. obliqua toxins. 6 It has proven very effective if administered within 12-24 hours after envenomation. The antivenin prevents further complications of bleeding and acute renal failure.…”