The Journal of Venomous Animals and Toxins including Tropical Diseases ISSN 1678-9199 | 2012 | volume 18 | issue 2 | pages 130-143 Scorpionism in Central America, with special reference to the case of Panama TICLE R A Borges A (1, 2, 3, 4), Miranda RJ (4), Pascale JM (3) EVIEW R (1) Laboratory of Molecular Biology of Toxins and Receptors, Institute of Experimental Medicine, Faculty of Medicine, Central University of Venezuela, Caracas, Venezuela; (2) Faculty of Medicine, University of Panama, Panama City, Republic of Panama; (3) Department of Genomics and Proteomics, Gorgas Memorial Institute for Health Studies, Panama City, Republic of Panama; (4) Department of Medical Entomology, Gorgas Memorial Institute for Health Studies, Panama City, Republic of Panama. Abstract: Scorpionism in the Americas occurs mainly in Mexico, northern South America and southeast Brazil. This article reviews the local scorpion fauna, available health statistics, and the literature to assess scorpionism in Central America. Notwithstanding its high toxicity in Mexico, most scorpion sting cases in Guatemala, Belize, El Salvador, Nicaragua, and Costa Rica are produced by species in the genus Centruroides that are only mildly toxic to humans despite the existence of ion channel-active toxins in their venoms. Regional morbidity is low with the exception of Panama, where an incidence of 52 cases per 100,000 inhabitants was recorded for 2007, with 28 deaths from 1998 to 2006. Taxa belonging to the genus Tityus (also present in the Atlantic coast of Costa Rica) are responsible for fatalities in Panama, with Tityus pachyurus being the most important species medically. Most Tityus species inhabiting Panama are also found in northern South America from which they probably migrated upon closure of the Panamanian isthmus in the Miocene era. Incorporation of Panama as part of the northern South American endemic area of scorpionism is thereby suggested based on the incidence of these accidents and the geographical distribution of Panamanian Tityus species. Key words: scorpionism, Central America, Tityus, Centruroides, scorpions. SCORPION ENVENOMATION IN THE complications that result from the direct and/or AMERICAS indirect effect of low molecular weight toxins on the gating mechanism of voltage-sensitive Scorpionism, or the accidental envenomation sodium (Nav) and potassium (Kv) channels and of humans by toxic scorpions, is a global the subsequent release of neurotransmitters problem, but mainly restricted to tropical from presynaptic terminals and inflammatory and subtropical areas. Most of the scorpions mediators from affected tissues including the capable of inflicting deadly stings belong lung and pancreas (1, 3). Although the action to the family Buthidae, the only exception mode of toxins targeting excitable tissues is being Hemiscorpius lepturus, in Iran (family very similar regardless of the scorpion species, Hemiscorpiidae) (1, 2). The syndrome derived clinical manifestations vary depending on the from envenoming by toxic buthids is very scorpion involved in the accident, as observed complex. It usually involves cardiorespiratory in South America (4). Higher molecular Borges A, et al. Scorpionism in Central America, with special reference to the case of Panama weight components, such as proteolytic and THE CENTRAL AMERICAN SCORPION connective-tissue degrading enzymes (i.e. FAUNA hyaluronidase) may contribute synergistically with neurotoxins to the pathophysiology of According to the most recent accounts of the scorpion envenoming (5, 6). Central American scorpion fauna, 37 species As reviewed recently by Chippaux inhabit the region, belonging to the families and Goyffon (7), the American continent Buthidae (genera Ananteris, Centruroides, encompasses several endemic areas of Tityus, and Isometrus), Chactidae (genera scorpionism with incidence rates at over 50 Broteochactas, Chactas, and Plesiochactas), cases per 100,000 inhabitants, in Mexico and Diplocentridae (genera Diplocentrus and the southwestern United States, northern Dydimocentrus), Hemiscorpiidae (genus South America (including Ecuador, Colombia, Opistachanthus) and Vejovidae (genus Venezuela, and the Guianas) and southeast Vejovis) (20, 21). Scorpions from the families Brazil. Chactidae, Diplocentridae and Vejovidae Probably due to the scarcity of data for the are not considered noxious to humans and region, scorpionism in Central America had produce only localized symptoms upon not previously been assessed despite several accidental stings, as their species synthesize countries being inhabited by the genera toxins that are mainly active against insects Centruroides and Tityus, both of which contain (e.g. Opisthacanthus cayaporum) and also species that have proven lethal to humans cytotoxic peptides with the ability to form elsewhere in the Americas. For instance, six plasma membrane pores, which act as potent Centruroides species are highly toxic in Mexico bactericides that prevent contamination of the (C. infamatus, C. limpidus limpidus, C. limpidus venom gland (22, 23). tecomanus, C. suffusus suffusus, C. noxius) and Epidemiological importance in the region the United States (C. sculpturatus), while Tityus is restricted to buthid scorpions in the includes at least twenty species of medical genera Centruroides (Table 1) and Tityus importance throughout South America and (Table 2), with 12 and 8 species, respectively. the Caribbean, including T. discrepans, T. Two species of the genus Centruroides are zulianus, and T. nororientalis (Venezuela), T. widely distributed in the region, namely C. trinitatis (Trinidad and Tobago), T. pachyurus, margaritatus, found in six countries, and C. T. asthenes, and T. fuhrmani (Colombia), gracilis, found in four countries (Table 1). Both T. serrulatus, T. stigmurus, and T. bahiensis species also inhabit South America (24). There (southeast Brazil), T. obscurus (formerly T. is controversy regarding the actual geographic paraensis/T. cambridgei, Brazilian Amazon, distribution of C. margaritatus given that some French Guiana and Guyana), T. metuendus Panamanian populations identified historically (the Peruvian and Brazilian Amazon), and T. in this species have now been assigned to C. trivitattus and T. confluens (Argentina) (4, granosus (25). C. gracilis and C. margaritatus 8-18). are followed in range of distribution by C. In this paper, we endeavor to review the koesteri (three countries), C. limbatus (four scorpionism problem in the Central American countries) and C. schmidti (three countries). region with particular emphasis on Panama, Some species are only known from their type where scorpion envenomation has acquired locality, such as C. mahnerti and C. ochraceus. increasing epidemiological importance in The evolutionary relationships of Centruroides recent years (19). The reasons for the restriction species inhabiting Central America to those of lethal cases in Central America to the prevalent in Mexico, which are responsible for Panamanian isthmus are discussed in light of the severe scorpionism mainly in the Pacific the biogeography and toxinology of Tityus and area, have not been determined thus far. Centruroides species. The distribution of species from the genus Tityus range from the Darién region in Panama J Venom Anim Toxins incl Trop Dis | 2012 | volume 18 | issue 2 131 Borges A, et al. Scorpionism in Central America, with special reference to the case of Panama Table 1. Distribution of species belonging to the genus Centruroides in Central American countries Centruroides El Costa References and Guatemala Honduras Belize Nicaragua Panama species Salvador Rica comments C. bicolor X X 20, 21, 26, 27 C. exilimanus X X 28, 29 C. fallassisimus X X 25 C. gracilis X X X X 28 C. granosus X 25 C. koesteri X X X 20, 21, 26, 28 20, 21, 26, 30, C. limbatus X X X X 31 Armas & Maes (20) considered this species as a possible C. mahnerti X synonym of C. koesteri but did not provide reasons for it 20, 21, 26, 27, C. margaritatus X X X X X X 28 C. ochraceus X 20, 21 C. schmidti X X X 28, 32 C. tapachulaensis X 33 Table 2. Distribution of species belonging to the genus Tityus in Central American countries El Costa References and Tityus species Guatemala Honduras Belize Nicaragua Panama Salvador Rica comments 26, 27 (as T. T. asthenes X X championi) T. cerroazul X X 34-36 T. dedoslargos X 26 T. festae X 27, 37 T. ocelote X X 26, 30 T. pachyurus X X 26, 27 T. tayrona X 38, 39 as far as northern Costa Rica, with two endemic having, respectively, six and five of the seven Central American species: T. cerroazul (first species described in this region (Table 2). Of these, described for Panama and also found in Costa four are shared with South American countries: Rica) and T. dedoslargos (inhabiting southern T. pachyurus (Colombia), T. asthenes (Colombia, Costa Rica in the Punta Arenas province) (26, Ecuador and Peru), T. festae (Colombia), and T. 34-36, 40). Until the present time, Tityus species tayrona (Colombia). Accounts of the Panamanian in Central America have been identified only Tityus (and also Centruroides) fauna have been in Panama and Costa Rica, with each country published recently (38, 39). J Venom Anim Toxins incl Trop Dis | 2012 | volume 18 | issue 2 132 Borges A, et al. Scorpionism in Central America, with special reference to the case of Panama Without doubt, T. pachyurus, a species T. festae is the largest Panamanian Tityus, described by Reginald Pocock from Colombia reaching 90 to 100 mm in adults, in comparison in 1897, is the most amply distributed