RESUMO
The Loxosceles genus represents one of the main arachnid genera of medical importance in Brazil. Despite the gravity of Loxosceles-related accidents, just a handful of species are deemed medically important and only a few have undergone comprehensive venom characterization. Loxosceles amazonica is a notable example of a potentially dangerous yet understudied Loxosceles species. While there have been limited reports of accidents involving L. amazonica to date, accidents related to Loxosceles are increasing in the North and Northeast regions of Brazil, where L. amazonica has been reported. In this work, we provide a complementary biochemical and immunological characterization of L. amazonica venom, considering its most relevant enzymatic activities and its immunorecognition and neutralization by current therapeutic antivenoms. Additionally, a cDNA library enriched with phospholipase D (PLD) sequences from L. amazonica venom glands was built and subsequently sequenced. The results showed that L. amazonica venom is well immunorecognised by all the tested antibodies. Its venom also displayed proteolytic, hyaluronidase, and sphingomyelinase activities. These activities were at least partially inhibited by available antivenoms. With cDNA sequencing of PLDs, seven new putative isoforms were identified in the venom of L. amazonica. These results contribute to a better knowledge of the venom content and activities of a synanthropic, yet understudied, Loxosceles species. In vivo assays are essential to confirm the medical relevance of L. amazonica, as well as to assess its true toxic potential and elucidate its related pathophysiology.
RESUMO
The spider's genus Loxosceles (also known as "brown spiders") is one of the few ones of medical importance in Brazil, being Loxosceles anomala a species of common occurrence in the Southeast region. This species is usually smaller in size than the other members of the Loxosceles group. A single human accident involving L. anomala was reported to date and the clinical picture shared similar characteristics with accidents caused by other Loxosceles species. Despite the potential relevance of L. anomalafor loxocelism in Minas Gerais state, its venom activity has never been characterized. In this work, we provide a preliminary characterization of L. anomala venom, considering its most relevant enzymatic activities and its venom immunorecognition by current therapeutic antivenoms. The results showed that L. anomala venom is immunorecognised by therapeutic antivenoms and by anti-phospholipase D antibodies. Its venom also shows enzymatic activities (sphingomyelinase activity, fibrinogenolytic) described for other Loxosceles venoms. This work contributes to a better knowledge on the venom content and activities of synanthropic Loxosceles species that have the potential of causing relevant human accidents.
Assuntos
Venenos de Aranha , Aranhas , Animais , Humanos , Antivenenos , Diester Fosfórico Hidrolases/toxicidade , BrasilRESUMO
Introdução: Dentre as aranhas-marrons, Loxosceles laeta é responsável por casos de loxoscelismo de maior gravidade, com maior taxa de letalidade. A espécie é invasora, sinantrópica e encontra-se amplamente disseminada, incluindo alguns estados brasileiros. Objetivos: São apresentados novos registros geográficos de L. laeta em Minas Gerais e dados epidemiológicos de loxoscelismo. Metodologia: Os registros foram obtidos com amostragens faunísticas e análise de coleção científica e foi consultado o banco de dados epidemiológicos do Sinan Net. Resultados e Discussão: Loxosceles laeta foi registrada na região do Quadrilátero Ferrífero (extremo sul da Serra do Espinhaço), nos municípios de Ouro Preto e Belo Horizonte (registro prévio em literatura); e na Serra da Mantiqueira (incluindo seu extremo noroeste e o sul do estado), nos municípios de Barbacena, Carandaí e Jacutinga. Em todas as coletas as aranhas estavam no intradomicílio e as localidades de registro compartilham características ambientais, especialmente elevadas altitudes (acima de 1.000 m). Loxosceles laeta é apontada como espécie de elevada importância médica nas serras do Quadrilátero e da Mantiqueira. Acerca da epidemiologia dos acidentes, ao longo de nove anos foram notificados 446 casos de loxoscelismo nos cinco municípios de ocorrência de L. laeta, incluindo um óbito em Jacutinga e outro nas proximidades de Barbacena. É possível que ao menos parte desses caso tenha sido causada por L. laeta, especialmente os óbitos. Conclusão: Conclui-se que L. laeta foi introduzida e encontra-se estabelecida em regiões serranas do sudeste e sul de Minas Gerais, onde há risco de graves casos de loxoscelismo. (AU)
Introduction: Among brown spiders, Loxosceles laeta is responsible for the most severe cases of loxoscelism and the highest lethality rate. The species is invasive, synanthropic and widely disseminated, including occurrences in some Brazilian states. Objectives: We present new geographical records of L. laeta for the state of Minas Gerais, and epidemiological data on cases of loxoscelism. Methods: The records were obtained from faunistic sampling and analysis of scientific collections, while epidemiological data were acquired from consulting the Sinan Net database. Results and Discussion: Loxosceles laeta was recorded in the Iron Quadrangle, municipalities of Ouro Preto and Belo Horizonte; and the Mantiqueira Mountain Range (including its extreme northwest, and southern extensions of the State), municpalities of Barbacena, Carandaí and Jacutinga. In all cases the spiders were inside houses, and the recorded localities shared a set of environmental characteristics, especially being at high elevations (over 1,000 m). Loxosceles laeta is considered to be a species of high medical importance in the Iron Quadrangle and Mantiqueira mountains. Over a period of nine years, 446 cases of loxoscelism were reported from the five municipalities where L. laeta occurs, including a death in Jacutinga and another in the vicinity of Barbacena. It is possible that at least some of these cases were caused by L. laeta, but particularly the deaths. Conclusion: We conclude that L. laeta was introduced to the mountainous regions of southeastern and southern Minas Gerais, where it has become established and now poses a is a risk of severe cases of loxoscelism. (AU)
Assuntos
Animais , Aranhas , Epidemiologia , Aranha Marrom Reclusa , Zoologia , Brasil , Distribuição AnimalRESUMO
Introdução: as espécies de Loxosceles, conhecidas como aranhas-marrons, são consideradas de importância médica, sendo responsáveis pela forma mais grave de araneísmo no Brasil. Loxosceles amazonica é uma espécie ainda pouco estudada e com ampla distribuição geográfica no Norte, Nordeste e Centro-Oeste do Brasil, embora seja reportada em poucas localidades. Objetivos: neste trabalho são apresentados novos registros geográficos de L. amazonica no Nordeste do Brasil. Métodos: foram obtidos registros ocasionais da aranha em coletas herpetológicas ou fortuitamente em ambientes urbanos, entre setembro de 2011 e outubro de 2012. Resultados: foram encontrados espécimes nos estados da Paraíba (Matureia e Serra Branca), Pernambuco (Serra Talhada) e Maranhão (Itapecuru Mirim, Santa Inês, Arari, Buriticupu e Bom Jesus das Selvas) de forma sinantrópica, associados a residências e em áreas alteradas, e de forma autóctone em matas secundárias, nos domínios da Amazônia e da Caatinga. Conclusões: há poucas informações sobre a epidemiologia de acidentes com L. amazonica, mas é provável que a espécie seja o principal agente etiológico de loxoscelismo em sua área de distribuição, o que permite reconhecê-la como de importância médica.
Introduction: Loxosceles species, known as brown-spiders, are considered to be of medical importance, being responsible for the most severe form of araneism in Brazil. Loxosceles amazonica is a still little studied species with wide geographic distribution in Northern, Northeastern, and Central-Western Brazil, although it is reported in a few localities. Objectives: new geographic records of L. amazonica are reported in northeastern Brazil in this study. Methods: occasional records for this spider were obtained in herpetological studies or fortuitously in urban environments, between September of 2011 and August of 2012. Results: specimens were found in the States of Paraíba (Maturéia and Serra Branca), Pernambuco (Serra Talhada), and Maranhão (Itapecuru Mirim, Santa Inés, Arari, Buriticupu, and Bom Jesus das Selvas) in a synanthropic form associated with houses in altered areas, and in an autochthonous form in secondary forests, in Amazon and the Caatinga domains. Conclusions: there is little information about the epidemiologyof accidents with L. amazonica, however, it is likely that the species is the primary etiological agent of loxoscelism in its distribution area, which allows recognizing the species as of medical importance
RESUMO
Loxosceles laeta is the species of brown spider of greatest medical importance. It causes accidents of great severity and presents synanthropic habits. In this paper, the first synanthropic record of Loxosceles laeta in the municipality of Rio de Janeiro, RJ, Brazil, is presented. This came from occasional encounters and sampling of specimens between August 2005 and June 2009. The species was recorded in a building of the Museu Nacional/UFRJ, located in the Quinta da Boa Vista park, in the urban area of the northern zone of the city of Rio de Janeiro. The focus was considered to be localized and restricted. Loxosceles laeta is adaptable to the climatic conditions of the metropolitan region of Rio de Janeiro, which makes possible for new foci of the species to become established, with occurrences of loxoscelism in the region.
Assuntos
Aranhas/classificação , Animais , Brasil , Feminino , Masculino , Aranhas/anatomia & histologiaRESUMO
Loxosceles laeta é a espécie de aranha-marrom de maior importância médica, causando acidentes de maior gravidade, além de apresentar hábito sinantrópico. No presente trabalho, é apresentado o primeiro registro sinantrópico de Loxosceles laeta no Município do Rio de Janeiro, RJ, Brasil, a partir de encontro e coleta ocasional de espécimes, no período de agosto de 2005 a junho de 2009. A espécie foi registrada em um prédio do Museu Nacional/UFRJ, localizado no parque da Quinta da Boa Vista, área urbana na Zona Norte da Cidade do Rio de Janeiro. O foco foi considerado localizado e restrito. Loxosceles laeta é adaptável às condições climáticas da região metropolitana do Rio de Janeiro, o que torna possível o estabelecimento de novos focos da espécie e a ocorrência de loxoscelismo na região.
Loxosceles laeta is the species of brown spider of greatest medical importance. It causes accidents of great severity and presents synanthropic habits. In this paper, the first synanthropic record of Loxosceles laeta in the municipality of Rio de Janeiro, RJ, Brazil, is presented. This came from occasional encounters and sampling of specimens between August 2005 and June 2009. The species was recorded in a building of the Museu Nacional/UFRJ, located in the Quinta da Boa Vista park, in the urban area of the northern zone of the city of Rio de Janeiro. The focus was considered to be localized and restricted. Loxosceles laeta is adaptable to the climatic conditions of the metropolitan region of Rio de Janeiro, which makes possible for new foci of the species to become established, with occurrences of loxoscelism in the region.