**2.** *Lonomia* **spp. Epidemiology and Impact on Public Health**

The occurrence of hemorrhage after contact with South American caterpillars was first reported by Alvarenga and collaborators [11]. Although 26 species of the genus *Lonomia* (Saturniidae family) are distributed in the American continent, the most studied species are *L. obliqua* (Figure 2a) and *Lonomia achelous* caterpillars; both are capable of inducing hemorrhagic effects in humans after contact with their broken spines [8,12–20].

Accidents involving *L. achelous* caterpillars have been reported in Venezuela since 1967 [21] and in Brazil since 1982, in the state of Amapá and Ilha de Marajó (state of Pará) [15,22]. Accidents related to *L. achelous* have been characterized by a hemorrhagic syndrome attributed to the fibrinolytic activity of the venom [23]. On the other hand, accidents involving *L. obliqua* specimens have been reported since 1989 in southern Brazil

in Santa Catarina, Rio Grande do Sul, and Paraná, also affecting states in the southeast region [10,15,16,24–26].

In Brazil, accident notifications are registered and informed by the Brazilian Ministry of Health through the Information System for Notification of Diseases (SINAN). Data from SINAN between 2007 and 2017 [10] indicate that most cases of accidents involving caterpillars occurred in southern and southeast states during the warm and rainy season [9,10], representing ideal conditions for the hatching of eggs and subsequent development of larvae. A study performed with 105 patients in the State of Santa Catarina (between December 1998 and June 2000), showed that most accidents occur in rural areas (85%), during work activities (55%) [8]. Envenoming by *L. obliqua* caterpillars is considered a public health problem in southern Brazil [10,27,28]. The relevance of the accident is due not only to the increase in the number of accidents, but also to the expansion of the caterpillar population to other areas of the country and to the hemorrhagic syndrome that affects the victims.

#### **3. Clinical Manifestations and Complications**

Immediately after contact with the caterpillar bristles (Figure 2b), an urticating dermatitis occurs, accompanied by pain and swelling. Some general and nonspecific manifestations may appear later, such as holocranial headache, general malaise, nausea and vomiting, anxiety, myalgia, and, less frequently, abdominal pain, hypothermia, and hypotension. After a period that can vary from 1 to 48 h, blood dyscrasia appears, accompanied or not by hemorrhagic manifestations that usually appear 8 to 72 h after contact [7,8,27–30]. Ecchymoses can be found, which can reach extensive hemorrhagic dysfunctions, hematomas caused by trauma or healed lesions, hemorrhages from mucosal cavities (gingivorrhagia, epistaxis, hematemesis, and enterorrhagia), macroscopic hematuria, bleeding from recent wounds, intraarticular, abdominal (intra- and extraperitoneal), pulmonary, and glandular (thyroid, salivary glands) hemorrhages, and intraparenchymal cerebral hemorrhage [15–19,27,28] (Figure 2b). Lonomism is the term used to designate the severe hemorrhagic disease related to *Lonomia* accidents [31].

The main complication of *L. obliqua* envenomation is acute renal failure, which can occur in up to 12% of the cases, being frequent in patients over 45 years old and in those with heavy bleeding [24,28–30,32]. Moreover, some deaths related to hemorrhage and renal failure have been reported [9,10,15,16,29]. However, the early diagnosis and proper treatment with ALS within 12 h of contact can prevent severe coagulopathy and hemorrhage events [8,15,19,33–35].

Considering that caterpillars have gregarious habits, the severity of symptoms may be influenced by the number of caterpillars crushed on contact, the extent of the exposed body area, the depth of wound, and the amount of venom inoculated [31].

According to the intensity of the hemostatic disturbances [8,27,28], accidents can be classified as follows:


**Figure 2.** *L. obliqua* and clinical manifestations. (**a**) *L. obliqua* caterpillar. This photograph shows a caterpillar at the sixth stage or instar; and (**b**) Initial symptoms. This photograph shows some clinical manifestation that begin 12 to 24 h after the accident involving contact with broken bristles. Edema (hands), erythema, heat, and blisters (arm), in addition to systemic symptoms, have been reported. Ecchymosis, after 3 days of contact, of variable intensity and hematuria (abdominal bruises, after 24 h), may occur (Photographs: (**a**) Dr. Miryam P. Alvarez-Flores; (**b**) Dr. Marlene Zannin).
