Niche modelling of the Chilean recluse spider Loxosceles laeta and araneophagic spitting spider Scytodes globula and risk for loxoscelism in Chile.

In Chile, all necrotic arachnidism is attributed to the Chilean recluse spider Loxosceles laeta (Nicolet) (Araneae: Sicariidae). It is predated by the spitting spider Scytodes globula (Nicolet) (Araneae: Scytodidae). The biology of each of these species is not well known and it is important to clarify their distributions. The aims of this study are to elucidate the variables involved in the niches of both species based on environmental and human footprint variables, and to construct geographic maps that will be useful in estimating potential distributions and in defining a map of estimated risk for loxoscelism in Chile. Loxosceles laeta was found to be associated with high temperatures and low rates of precipitation, whereas although S. globula was also associated with high temperatures, its distribution was associated with a higher level of precipitation. The main variable associated with the distribution of L. laeta was the human footprint (48.6%), which suggests that this is a highly invasive species. Similarly to other species, the distribution of L. laeta reaches its southern limit at the Los Lagos region in Chile, which coincides with high levels of precipitation and low temperatures. The potential distribution of L. laeta in Chile corresponds to the distribution of cases of loxoscelism.

Accident caused by Centruroides testaceus (DeGeer, 1778) (Scorpiones, Buthidae), native to the Caribbean, in Brazilian airport / Acidente causado por Centruroides testaceus (DeGeer, 1778) (Scorpiones, Buthidae), nativo do Caribe, em aeroporto brasileiro

Describes the case of a 6-year-old girl who was stung by a Centruroides testaceus, a scorpion native to the Lesser Antilles, in the Guarulhos International Airport, São Paulo, Brazil, as she disembarked from a flight coming from the Caribbean. The patient presented only local symptoms (a small area of erythema and pain at the sting site), which were resolved after a few hours with analgesics, without the need for antivenom. Physicians who treat patients stung by scorpions should be alert to the possibility of such accidents being caused by non native species, especially those cases that occur near airports or ports.

Descreve-se um caso de menina de 6 anos de idade picada por um Centruroides testaceus, escorpião nativo das Antilhas, no interior do Aeroporto Internacional de Guarulhos, São Paulo, Brasil, após ter desembarcado de um vôo vindo do Caribe. A paciente apresentou apenas sintomas locais (pequena área de eritema e dor no local da picada), resolvidos em algumas horas com uso de analgésicos, não necessitando receber soro antiveneno. Os médicos que tratam pacientes picados por escorpiões devem estar precavidos quanto à possibilidade dos acidentes serem causados por espécies não-nativas, especialmente nos que ocorrem próximos a aeroportos ou portos.

Cutaneous loxoscelism caused by Loxosceles anomala.

A previously healthy 35-year-old female was bitten on the anterior right thigh by a brown spider while dressing her trousers; the spider was stored and later identified as an adult female Loxosceles anomala. Clinical evolution involved a relatively painless bite with mild itching, followed by local, indurated swelling and a transient, generalized erythrodermic rash at 24 h post-bite. The local discomfort was progressive, and involved changes in the lesion pattern, with pain of increasing intensity. The patient was admitted 60 h post-bite, showing an irregular blue plaque surrounded by an erythematous halo lesion, located over an area of indurated swelling. Considering the presumptive diagnosis of cutaneous loxoscelism, she was treated with five vials of anti-arachnidic antivenom i.v. without adverse effects. There was progressive improvement, with no dermonecrosis or hemolysis; complete lesion healing was observed by Day 55. The clinical features and outcome were compatible with cutaneous loxoscelism and similar to those reported for other Loxosceles species.

Loxoscelism: From basic research to the proposal of new therapies.

Loxoscelism is caused by envenomation by spiders from Loxosceles genus. Clinical symptoms only appear a few hours after envenomation and can evolve in local reactions, such as dermonecrosis, and systemic reactions, such as intravascular haemolysis, intravascular coagulation and renal failure. Current therapies are not effective, often not based in scientific research and can be even detrimental. A lack of understanding of the mechanism of action of the venom of the Loxosceles spider had thus far prevented development of effective therapies. In this review we aim to give an overview of our contributions to the understanding of the mechanism of action of the Loxosceles venom and propose targets and therapeutics for medical intervention.

Activities against hemostatic proteins and adrenal gland ultrastructural changes caused by the brown widow spider Latrodectus geometricus (Araneae: Theridiidae) venom.

Brown widow spider (BrWS) (Latrodectus geometricus) venom produces intense systemic reactions such as cramps, harsh muscle nociceptive, nauseas, vomiting and hypertension. The proposed pathogenic mechanisms resulting in these accidents have principally been damages occurring at the nervous system. However, it is suspected that there is also damage of the adrenal glands, as a result of the experimental animal's clinical manifestations, which developed symptoms compatible with acute adrenal insufficiency. We have currently found that the adrenal gland is damaged by this venom gland homogenates (VGH) producing severe alterations on cortex cells resulting in death by acute adrenal insufficiency. In general, the ultrastructural study on the glands of mice under transmission electronic microscopy observations showed alterations in the majority of the intracellular membranes within 3 to 24h. BrWSVGH also showed specific actions on extracellular matrix proteins such as fibronectin, laminin and fibrinogen. In addition, zymogram experiments using gelatin as substrates detected gelatinolytic activity. The molecular exclusion fractionation of crude BrWSVGH resulted in 15 fractions, of which F1 and F2 presented alpha/beta-fibrinogenase and fibronectinolytic activities. Fractions F6, F14 and F15 showed only alpha-fibrinogenase activity; in contrast, the gelatinolytic action was only observed in fraction F11. Only metalloproteinase inhibitors abolished all these proteolytic activities. Our results suggest that adrenal cortex lesions may be relevant in the etiopathogenesis of severe brown widow spider envenoming. To our knowledge, this is the first report on adrenal gland damages, fibrinogenolytic activity and interrelations with cell-matrix adhesion proteins caused by L.geometricus VGH. The venom of this spider could be inducing hemostatic system damages on envenomed patients.

Scorpionism due to Tityus neoespartanus (Scorpiones, Buthidae) in Margarita Island, northeastern Venezuela

The first two cases of scorpion envenoming caused by Tityus neoespartanus (Buthidae) are described. The accidents took place within human environments (one inside a home and the other inside a school), in the village of La Sierra, Margarita Island, State of Nueva Esparta, northeastern Venezuela. Both cases were moderately severe and developed pancreatic involvement and electrocardiographic abnormalities. This report allows inclusion of Margarita Island among the endemic areas of scorpionism in Venezuela.

Descrevem se os dois primeiros casos de escorpionismo por Tityus neoespartanus (Scorpiones, Buthidae). Os acidentes ocorreram no ambiente antrópico (um no domicilio e outro na escola) na aldeia de La Sierra, Ilha de Margarita, Estado de Nueva Esparta, nordeste da Venezuela. Os dois acidentes, moderadamente graves, cursaram com acometimento pancreático e alterações eletrocardiografias. Este reporte permite incluir à Ilha de Margarita entre as áreas endêmicas de escorpionismo na Venezuela.

Síndrome compartamental de extremidad superior: experiencia con el uso de un sistema aspirativo contínuo para el manejo de una herida mayor / Compartmental syndrome of upper extremity

Presentamos a un menor de 9 años de edad quien a raíz de una mordedura de araña de rincón en su extremidad superior derecha (antebrazo) desarrolló un cuadro grave de loxoscelismo cutáneo-visceral rápidamente progresivo, que lo llevó a una insuficiencia renal aguda, además de un síndrome compartamental de la extremidad afectada, donde fue necesario efectuar una fasciotomía de descarga amplia, y varios aseos quirúrgicos con resecciones de tejido necrótico, que dejó una lesión cruenta mayor, la que fue tratada con una curación hermética aspirativa, para finalmente realizar un injerto dermoepidérmico, logrando su recuperación después de 19 días en unidad de cuidados intermedios y de 24 días totales de hospitalización, egresando sin complicaciones precoces.

[Spider bites: araneidism of medical importance]. / Morsures d'araignées: les aranéismes d'importance médicale.

LIMITED RISKS: Although most species of spiders are venomous, only ten or so are able to induce human envenomations. From a systematic point of view, it is possible to distinguish the araneomorph spiders - or "true" spiders - from the mygalomorph spiders. Dangerous species for humans can be found in both groups. Regarding "true' spiders, two kinds of envenomation are frequent, ubiquitous and potentially severe: latrodectism (neurotoxic symptomatology) due to the Widow spiders of the Latrodectus species,and loxoscelism (viscero-cutaneous symptomatology). Regarding the mygalomorph spiders, the Australian species responsible for atraxism (neurotoxic symptomatology) are considered as the most dangerous. Most of the other mygalomorph spiders, when they bite, only provoke benign loco regional problems. A supplementary defensive weapon exists in certain South-American species: urticating hairs which may induce severe ocular damage.

Molecular cloning and expression of a functional dermonecrotic and haemolytic factor from Loxosceles laeta venom.

The bite of spiders of the genus Loxosceles can induce a variety of biological effects, including dermonecrosis and complement-dependent haemolysis. The aim of this study was to generate recombinant proteins from the Loxosceles spider gland to facilitate structural and functional studies in the mechanisms of loxoscelism. Using "Expressed Sequencing Tag" strategy of aleatory clones from, L. laeta venom gland cDNA library we have identified clones containing inserts coding for proteins with significant similarity with previously obtained N-terminus of sphingomyelinases from Loxosceles intermedia venom [1]. Clone H17 was expressed as a fusion protein containing a 6x His-tag at its N-terminus and yielded a 33kDa protein. The recombinant protein was endowed with all biological properties ascribed to the whole L. laeta venom and sphingomyelinases from L. intermedia, including dermonecrotic and complement-dependent haemolytic activities. Antiserum raised against the recombinant protein recognised a 32-kDa protein in crude L. laeta venom and was able to block the dermonecrotic reaction caused by whole L. laeta venom. This study demonstrates conclusively that the sphingomyelinase activity in the whole venom is responsible for the major pathological effects of Loxosceles spider envenomation.

Loxoscelismo cutáneo de predominio edematoso / Cutaneous loxoscelism with edema predominance

Loxoscelism in the clinical condition produced by the venom of spiders belonging to the genus loxosceles, human cases of loxoscelism have been observed in diverse countries of different continents in temperate and tropical regions. In Chile loxoscelism is caused by loxosceles laeta, spider with domestic habits. Loxoscelism can be observed into two well definited clinical variants: cutaneous loxoscelism (CL) and systemic or viscerocutaneous loxoscelism (VCL) which occur in around 83,3 and 16,7 percent cases respectively. Within the universe of CL patients a clinical modality in which necrotic lesion is not present or is insignificant, but presenting a remarkable edema, particularly when the bite is on the face, which as received the name of CL with an edematous predominance (CLEP). In this paper the individual description and the assambled analysis of 10 cases, four males and six females, age ranging from 6 to 68 years, of CLEP are presented. Nine cases occurred in warm periods spring through fall and one in winter. In six cases the accident causing spider was seen and two of these were identified as L. laeta adult females. In all cases the patients went or were transported to emergency medical services 4-24 h after the bite. The predominant initial symptom was a burning stinging sensation at the site of the bite, followed by intensive pain which expanded the neighbour areas concomitantly with the emerging and progressive edema. In four of the nine patients in who the bite was on the face, the edema envolved all of it, closed both eyelids and expanded to the neck and upper part of the thorax. In three cases the enormous edema was the only signicant clinical manifestation, whereas in the remaining seven conjunctly with the edema, a small violaceous plaque or a blister of serous content gave place to a little livedoid plaque (diameter 0,3-0,8 cm) which evolved to desquamation without leaving any scarring. The edema was characterized by its brilliant rose color, painful and hard which is not accompanied by regional adenopathy. Treatment of the 10 patients depended on the moment in they were seen by us. It consisted on parenteral administration, according to age and weight, of 5-10 mg of chloroprofenpyridamine maleate every 8 hours for be continued every 12-24 hours until the patient was discharged. Parenteral route was preferred in order that it was going to be adequately absorbed

[Report of a case of latrodectism occurring in Manaus, Amazonas, Brazil]. / Relato de um caso de latrodectismo ocorrido em Manaus, Amazonas, Brasil.

In July 2, 1995 arrived at the Instituto de Medicina Tropical do Amazonas as eleven-year-old male with complaining of spider bite on his right retroauricular region, presenting typical findings of latrodectism. The accident was reported as having occurred in the suburbs of Manaus. The patient was given neostigmine preceded by atropine, calcium gluconate, cimetidine, diazepan and hydrocortisone. Within three days the patient showed improvement, and was aware, orientated and with significant palpebral oedema reduction. Muscle spasms are still present, as well as fever, shivering, and intense sweating. In spite of a daily progressive improvement, at the fifth day appeared a spotted papular erythema. The patient was discharged without symptoms after the 13th day. This is the first such reported case which took place in Amazonian region, it might have been happened a consequence of the urban sprawl which has characterized the growth of the city of Manaus, in the last twenty years. It is not possible at this point to evaluate the epidemiological resound of the event, but in any case, it seems plausible to recommend that black widow antivenom become available.

Relato de um caso de latrodectismo ocorrido em Manaus, Amazonas, Brasil / Report of a case of latrodectism occurring in Manaus, Amazonas, Brazil

Em 02/07/1995, foi atendido no Instituto de Medicina Tropical do Amazonas, paciente masculino, 11 anos, acidentado em Manaus, por picada na região retroauricular direita, clínicamente compatível com aquele causado por Latrodectus. Observavam-se abalos musculares, febre, calafrios e sudorese intensa. Instituída terapêutica com neostigmine precedido de atropina, gluconato de cálcio, cimetidina, diazepam e hidrocortisona. No terceiro dia apresentava-se melhorado, consciente, orientado e com diminuição importante do edema palpebral. A despeito de uma melhora progressiva diária, no quinto dia surgiu eritema máculo-pápulo-vesiculoso. Em 14/07/1995 teve alta, assintomático. O caso relatado é o primeiro descrito na região Amazônica, ocorrido na periferia de Manaus e pode ter sido uma consequência da expansão urbana das duas últimas décadas.

In July 2, 1995 arrived at the Instituto de Medicina Tropical do Amazonas as eleven-year-old male with complaining of spider bite on his right retroauricular region, presenting typical findings of latrodectism. The accident was reported as having occurred in the suburbs of Manaus. The patient was given neostigmine preceded by atropine, calcium gluconate, cimetidine, diazepan and hydrocortisone. Within three days the patient showed improvement, and was aware, orientated and with significant palpebral oedema reduction. Muscle spasms are still present, as well as fever, shivering, and intense sweating. In spite of a daily progressive improvement, at the fifth day appeared a spotted papular erythema. The patient was discharged without symptoms after the 13th day. This is the first such reported case which took place in Amazonian region, it might have been happened a consequence of the urban sprawl which has characterized the growth of the city of Manaus, in the last twenty years. It is not possible at this point to evaluate the epidemiological resound of the event, but in any case, it seems plausible to recommend that black widow antivenom become available.

Loxosceles y loxoscelismo en Piura / Loxosceles and loxoscelism in Piura

Los autores presentan dos casos con loxocelismo cutaneo y mordedura de araña del género Loxoceles sp. en la casa de uno de los pacientes. Estos son uno de los primeros caos de loxocelismo y Loxoceles en Piura