Factores asociados al conocimiento y medidas preventivas de mordedura de Loxosceles laeta en la población de la Encuesta Nacional de Programas Presupuestales (ENAPRES) en el Perú 2017-2019

Introducción: Las enfermedades metaxénicas y zoonóticas, son consideradas prioridades nacionales de investigación en salud en Perú 2019-2023. De estas, los casos reportados por loxoscelismo han ido aumentando progresivamente. Objetivo: Determinar los factores asociados al conocimiento y medidas preventivas de mordedura de Loxosceles laeta en la población de la ENAPRES en el Perú 2017-2019. Métodos: Estudio de tipo observacional, transversal, analítico y retrospectivo, basado en la información de la ENAPRES. Resultados: Se analizó una muestra total de 285.354 personas. De estas, aquellos con 60 a más años (RPa=1,48; IC95%: 1,45-1,51), los costeños (RPa=1,37; IC95%: 1,33-1,40), las mujeres (RPa=1,12; IC95%: 1,11-1,13), con primaria o secundaria (RPa=1,12; IC95%: 1,09-1,15), con viviendas inadecuadas [techo (RPa=1,07; IC95%: 1,05-1,10), piso (RPa=1,02; IC95%: 1,00-1,04)], se asociaron con mayor posibilidad de tener más conocimiento sobre mordedura de L. laeta. Por otra parte, los encuestados de 60 a más años (RPa=1,49; IC95%: 1,46-1,52), los costeños (RPa=1,39; IC95%: 1,35-1,43), con estudios superiores no universitarios (RPa=1,19; IC95%: 1,15-1,22), las mujeres (RPa=1,13; IC95%: 1,12-1,14) y con viviendas con techos inadecuados (RPa=1,07; IC95%: 1,05-1,10) se asociaron con mayor posibilidad de realizar adecuadas medidas preventivas. En ambas, se halló asociación con el desechar los residuos orgánicos en calle o vía pública (RPa=0,97; IC95%: 0,96-0,99). Conclusiones: Se encontró aquellos factores asociados a conocimientos y a las medidas preventivas de mordedura de L. laeta.

Background: Metaxenic and zoonotic diseases are one of the ten national priorities for health research in Peru 2019-2023. Of these, the cases reported by loxoscelism have been increasing progressively. Aim: To determine the factors associated with the knowledge and preventive measures of Loxosceles laeta bite in the population of the ENAPRES in Peru 2017-2019. Methods: Observational, cross-sectional, analytical and retrospective study, based on information from ENAPRES. Results: A total sample of 285,354 people was analyzed. Of these, those aged 60 or over (PRa=1,48; 95%CI: 1,45-1,51), those from the coast (PRa=1,37; 95%CI: 1,33-1,40), women (PRa=1,12; 95%CI: 1,11-1,13), with primary or secondary education (PRa=1,12; 95%CI: 1,09-1,15), with inadequate housing [ceiling (PRa=1,07; 95%CI: 1,05-1,10), floor (PRa=1,02; 95%CI: 1,00-1,04)], were associated with higher possibility ofhaving more knowledge about L. laeta bite. On the other hand, those aged 60 or over (PRa=1,49; 95%CI: 1,46-1,52), those from the coast (PRa=1,39; 95%CI: 1,35-1,43), with non-university higher education (PRa=1,19; 95%CI: 1,15-1,22), women (PR a=1,13; 95%CI: 1,12-1,14) and with inadequate housing ceilings (PRa=1,07; 95%CI 1,05-1,10) were associated with a greater possibility of taking adequate preventive measures. In both, an association was found between disposing of organic waste on the street or on public roads (RPa=0.97; 95%CI: 0.96-0.99) Conclusions: It were found factors associated with knowledge and preventive for L. laeta bite.

Heterophilic antibodies in sera from individuals without loxoscelism cross-react with phospholipase D from the venom of Loxosceles and Sicarius spiders

Background Loxoscelism is a severe human envenomation caused by Loxosceles spider venom. To the best of our knowledge, no study has evaluated the presence of antibodies against Loxosceles venom in loxoscelism patients without treatment with antivenom immunotherapy. We perform a comparative analysis for the presence of antibodies capable of recognizing Loxosceles venom in a group of patients diagnosed with loxoscelism and in a group of people without loxoscelism. Methods The detection of L. laeta venom, Sicarius venom and recombinant phospholipases D from Loxosceles (PLDs) in sera from people with loxoscelism (Group 1) and from healthy people with no history of loxoscelism (Group 2) was evaluated using immuno-dot blot, indirect ELISA, and Western blot. Results We found naturally heterophilic antibodies (IgG-type) in people without contact with Loxosceles spiders or any clinical history of loxoscelism. Either serum pools or single sera from Group 1 and Group 2 analyzed by dot blot tested positive for L. laeta venom. Indirect ELISA for venom recognition showed titles of 1:320 for Group 1 sera and 1:160 for Group 2 sera. Total IgG quantification showed no difference in sera from both groups. Pooled sera and purified IgG from sera of both groups revealed venom proteins between 25 and 32 kDa and the recombinant phospholipase D isoform 1 (rLlPLD1), specifically. Moreover, heterophile antibodies cross-react with PLDs from other Loxosceles species and the venom of Sicarius spider. Conclusions People without contact with the spider venom produced heterophilic antibodies capable of generating a cross-reaction against the venom of L. laeta and Sicarius spiders. Their presence and possible interference should be considered in the development of immunoassays for Loxosceles venom detection.

de araña marrón (Loxosceles laeta). presentación de un caso / Brown spider (Loxosceles laeta) bite. presentation of a case

Se presentó un caso tratado en la Unidad Básica de Salud del poblado Pedras municipio Matoes Do Norte estado Maranhao Brasil, de una gestante de 32.4 semanas con lesión necrótica en la cara interna del muslo derecho provocado por la picadura de una araña marrón. Con el propósito de informar un caso de lesión producida por la picadura de este insecto y revisar la literatura médica se presentó este reporte sobre una gestante de 19 años donde el diagnóstico se estableció mediante estudio epidemiológico y características de la lesión siendo diagnosticada finalmente de loxoscelismo cutáneo, lesión producida por la picadura de araña marrón(AU)

It was presented a case in the Basic Health Unit of Pedras municipality Matoes Do Norte Maranhao Brazil, from a pregnant woman of 32.4 weeks with a necrotic lesion on the inner side of her right thigh caused by the bite of a brown spider. In order to report a case of injury caused by the brown spider bite and review the medical literature, this report is presented on a pregnant woman of 19 years where the diagnosis was established by epidemiological study and characteristics of the lesion being the final diagnosis of Loxoscelism cutaneous lesion produced by the brown spider bite(AU)

Heterophilic antibodies in sera from individuals without loxoscelism cross-react with phospholipase D from the venom of Loxosceles and Sicarius spiders

Loxoscelism is a severe human envenomation caused by Loxosceles spider venom. To the best of our knowledge, no study has evaluated the presence of antibodies against Loxosceles venom in loxoscelism patients without treatment with antivenom immunotherapy. We perform a comparative analysis for the presence of antibodies capable of recognizing Loxosceles venom in a group of patients diagnosed with loxoscelism and in a group of people without loxoscelism. Methods The detection of L. laeta venom, Sicarius venom and recombinant phospholipases D from Loxosceles (PLDs) in sera from people with loxoscelism (Group 1) and from healthy people with no history of loxoscelism (Group 2) was evaluated using immuno-dot blot, indirect ELISA, and Western blot. Results We found naturally heterophilic antibodies (IgG-type) in people without contact with Loxosceles spiders or any clinical history of loxoscelism. Either serum pools or single sera from Group 1 and Group 2 analyzed by dot blot tested positive for L. laeta venom. Indirect ELISA for venom recognition showed titles of 1:320 for Group 1 sera and 1:160 for Group 2 sera. Total IgG quantification showed no difference in sera from both groups. Pooled sera and purified IgG from sera of both groups revealed venom proteins between 25 and 32 kDa and the recombinant phospholipase D isoform 1 (rLlPLD1), specifically. Moreover, heterophile antibodies cross-react with PLDs from other Loxosceles species and the venom of Sicarius spider. Conclusions People without contact with the spider venom produced heterophilic antibodies capable of generating a cross-reaction against the venom of L. laeta and Sicarius spiders. Their presence and possible interference should be considered in the development of immunoassays for Loxosceles venom detection.(AU)

Experiencia en loxoscelismo cutáneo y cutáneo visceral de manejo hospitalario: clínica, evolución y propuesta terapéutica / Experience in visceral cutaneous and cutaneous loxoscelism of hospital management: clinical, evolution and therapeutic proposal

Resumen Introducción: El loxoscelismo es una patología frecuente en nuestro medio con un amplio espectro de presentaciones y diagnósticos diferenciales, con complicaciones potencialmente graves, e incluso con riesgo de muerte. A la fecha no existe un tratamiento estándar para estos pacientes. Objetivo: Describir las manifestaciones clínicas, principales complicaciones, manejo terapéutico y evolución de pacientes internados por loxoscelismo en un hospital terciario en Chile. Pacientes y Método: Se analizaron todos los pacientes consultantes e internados por loxoscelismo en el Hospital Clínico de la Pontificia Universidad Católica de Chile entre los años 2014 y 2017, evaluados en interconsulta por Dermatología. Revisión de los registros clínicos incluyendo semiología, imágenes, informes de laboratorio y tratamientos efectuados. Resultados: Se registraron 17 casos de loxoscelismo de manejo hospitalario, cuya presentación responde al patrón epidemiológico nacional. La mayoría de los casos fue manejada con antimicrobianos, corticosteroides sistémicos, antihistamínicos y dapsona. De ellos, 11,8% correspondieron a loxoscelismo cutáneo visceral, manejados exitosamente con medidas de soporte, corticosteroides sistémicos y antihistamínicos. El 59% presentó resolución de las lesiones al mes de tratamiento, con cicatriz residual leve o hiperpigmentación postinflamatoria, sin mortalidad en nuestra serie. Discusión: La mayoría de los casos de loxoscelismo cutáneo presentó excelente respuesta y rápida resolución del cuadro tras el tratamiento asociado de corticosteroides sistémicos, antimicrobianos y dapsona, sugiriendo que el uso de estas terapias podría detener la progresión de la necrosis cutánea y prevenir las complicaciones asociadas al loxoscelismo.

Background: Loxoscelism is a common pathology in our environment with a broad spectrum of differential diagnoses and presentations, with potentially serious complications, even to the point of death. To date, there is no standard treatment for these patients. Aim: To describe the clinical manifestations, main complications, therapeutic management, and evolution of loxoscelism in an inpatient setting from a tertiary hospital in Chile. Methods: All patients consulting and hospitalized in the hospital of the Pontificia Universidad Católica de Chile with diagnosis of loxoscelism between 2014 to 2017 and evaluated by dermatologist were included. Review of clinical files, including symptoms, images, laboratory parameters and treatment. Results: We evaluated seventeen inpatient with loxoscelism, whose presentation responds to the national epidemiological pattern. Most cases were managed with antibiotics, systemic corticosteroids, antihistamines, and dapsone. From these, 11.8% corresponded to viscerocutaneous loxoscelism, successfully managed with supportive measures, systemic corticosteroids and antihistamines. Fifty-nine percent healed their cutaneous lesions after one month of treatment, with slight residual scarring or post inflammatory hyperpigmentation, without associated mortality in our series. Discussion: Most cases of cutaneous loxoscelism presented excellent response and rapid resolution of the disease after combined therapy with systemic corticosteroids, antibiotics and dapsone, suggesting that the use of these therapies could stop the progression of cutaneous necrosis and prevent complications associated with loxoscelism.

Loxoscelismo cutáneo predominantemente edematoso: a propósito de un caso / Cutaneous loxoscelism mainly edematous: a case report

In Chile, loxoscelism is caused by the bite of the Loxosceles laeta spider. The clinical presentation has two different forms: cutaneous loxoscelism (CL) and vicero-cutaneous loxoscelism, which is less frequent. Cutaneous loxoscelism includes an uncommon clinical variation (4%), called CL with edematous predominance (CLEP). We present a 5-year-old patient with sudden pain and edema on his right eyelid associated with fever, which progressed rapidly involving the right hemifacial area, frontal region, and left eyelid. Angioedema and pre-orbital cellulitis were discarded and CLEP was suspect. Cutaneous loxoscelism with an edematous predominance is self-limited, benign and with little or no necrotic injury due to the edema, which dilutes the toxin-induced enzymatic process causing necrosis. As in the reported cases it usually responds well to medical treatment and does not cause visceral involvement.

El loxoscelismo en Chile es un cuadro producido por la mordedura de la araña Loxosceles laeta. Las formas de presentación son: loxoscelismo cutáneo (LC) y loxoscelismo cutáneo-visceral (LCV), el último menos frecuente. Dentro del LC existe una variante poco común (4%) conocida como loxoscelismo cutáneo predominantemente edematoso (LCPE). Nuestro caso es un paciente de 5 años que consultó por cuadro de inicio súbito de dolor y edema palpebral derecho, asociado a fiebre el cual evolucionó con rápida progresión extendiéndose en la hemicara derecha, región frontal y párpado izquierdo. Se descartó un angioedema y una celulitis periorbitaria, sospechándose un LCPE. Se manejó con hidrocortisona y clorfenamina. El LCPE es un cuadro benigno, autolimitado, en que no está presente la lesión necrótica o ésta es insignificante. Predomina el edema, el cual abortaría la necrosis al diluir el proceso enzimático producido por el veneno. Tiene buena respuesta al tratamiento médico, con ausencia de compromiso visceral.

Loxoscelismo cutáneo visceral: actualización en el manejo a propósito de un caso / Viscerocutaneous loxoscelism: case report and update on management

Loxoscelism is a condition produced by the bite of Loxosceles laeta. It can present as cutaneous loxoscelism with only vascular dermal manifestations or as viscerocutaneus loxoscelism with systemic compromise and a mortality rate of 1 to 3%. We report the case of an adult patient presenting viscerocutaneus loxoscelism, who was evolving with macrohematuria, edema, and progressive blisters, requiring treatment in the intensive care unit. He was treated according to the actual scientific evidence with antihistamines, corticosteroids, and dual antibiotic therapy covering Streptococcus spp., Staphylococcus spp., and anaerobes, particularly penicillin and tetracycline resistant C. perfringens. The use of dapsone and antiloxosceles-serum was avoided. The patient showed a favorable clinical evolution.

El loxoscelismo es producido por la mordedura de la araña Loxosceles laeta. Puede ser cutáneo, con alteraciones vasculares o cutáneo-visceral, con manifestaciones sistémicas y una mortalidad de 1 a 3%. Se presenta el caso de un paciente adulto con loxoscelismo cutáneo-visceral, que evolucionó con hematuria macroscópica, edema y aparición de flictenas en forma progresiva en antebrazo, requiriendo ser trasladado a la Unidad de Tratamiento Intermedio. Fue manejado según la evidencia científica actual que recomienda el uso de antihistamínicos, corticoesteroides y terapia antibacteriana asociada para la cobertura de Streptococcus spp., Staphylococcus spp. y bacterias anaerobias, especialmente C. perfringens resistente a penicilina y tetracilina, evitando el uso de dapsona y de suero anti-loxosceles. Evolucionó de manera favorable.

Desarrollo de cohortes y parámetros poblacionales de la araña del rincón Loxosceles laeta / Development and population parameters of cohorts of the Chilean recluse spider Loxosceles laeta

Background: Despite the abundant eco-epidemiological knowledge of the Chilean reclusive spider, Loxosceles laeta, which causes all forms of loxoscelism in Chile, the main characteristics of this species its stages of development remains poorly known especially in the medical area. Objective: In this study we address these issues with the goal of providing clear images of the development of this species and for the first time on population projections as well as the relationship between mature and immature instars, useful data for the control and prevention of accidental bites. Results: We found that L. laeta is an r-selected species, with R0 = 2.1, a generation time of G = 2.1 years, with a concentration of the reproductive value of females between the first and second year of life. We determined the average sizes and development times of all instars. The first vary between 2.3 mm at birth and about 13 mm at adulthood. The total development time was about 1 year. Discussion: The population projection by Leslie matrix suggested great capacity for growth and dispersal with clear seasonal population fluctuations associated with reproduction. It also showed that the proportion of immature varied seasonally between 80 and 90 %, which means that a house with three or four visible adult spiders actually has a population between 20 and 40 spiders in total.

Introducción: A pesar del abundante conocimiento eco-epidemiológico de la araña del rincón, Loxosceles laeta, causante de todos los cuadros de loxoscelismo en Chile, sigue siendo una especie poco conocida en el ambiente médico, especialmente las características y tiempos de sus estados de desarrollo. Objetivo: En este estudio abordamos estos aspectos con el objetivo de aportar imágenes claras del desarrollo de esta especie y por primera vez de sus características y proyecciones poblacionales y de la relación entre estados maduros e inmaduros, datos útiles para el control y prevención de los accidentes por mordedura. Resultados: Loxosceles laeta es una especie r-estratega, con un R0 = 2,1, un tiempo generacional G = 2,1 años y con concentración del valor reproductivo de las hembras entre el primer y segundo año de vida. Determinamos los tamaños promedio y los tiempos de desarrollo de todos los estados. Los primeros varían entre los 2,3 mm al nacer y alrededor de 13 mm al estado adulto. Los tiempos totales de desarrollo son de aproximadamente un año. Discusión: La proyección de la población con matriz de Leslie sugiere una gran capacidad de crecimiento y dispersión, pero con claras fluctuaciones poblacionales estacionales asociadas a la reproducción. Además se muestra que la proporción de estados inmaduros fluctúa estacionalmente entre 80 y 90%, lo que implica que una casa con tres o cuatro arañas adultas visibles, en realidad tiene una población entre 20 y 40 arañas en total.

First report of in vitro selection of RNA aptamers targeted to recombinant Loxosceles laeta spider toxins

BACKGROUND: Loxoscelism is the envenomation caused by the bite of Loxosceles spp. spiders. It entails severe necrotizing skin lesions, sometimes accompanied by systemic reactions and even death. There are no diagnostic means and treatment is mostly palliative. The main toxin, found in several isoforms in the venom, is sphingomyelinase D (SMD), a phospholipase that has been used to generate antibodies intended for medical applications. Nucleic acid aptamers are a promising alternative to antibodies. Aptamers may be isolated from a combinatorial mixture of oligonucleotides by iterative selection of those that bind to the target. In this work, two Loxosceles laeta SMD isoforms, Ll1 and Ll2, were produced in bacteria and used as targets with the aim of identifying RNA aptamers that inhibit sphingomyelinase activity. RESULTS: Six RNA aptamers capable of eliciting partial but statistically significant inhibitions of the sphingomyelinase activity of recombinant SMD-Ll1 and SMD-Ll2 were obtained: four aptamers exert ~17% inhibition of SMD-Ll1, while two aptamers result in ~25% inhibition of SMD-Ll2 and ~18% cross inhibition of SMD-Ll1. CONCLUSIONS: This work is the first attempt to obtain aptamers with therapeutic and diagnostic potential for loxoscelism and provides an initial platform to undertake the development of novel anti Loxoscelesvenom agents.

Primeiro registro sinantrópico de Loxosceles laeta (Nicolet, 1849) (Araneae, Sicariidae) no Município do Rio de Janeiro, Estado do Rio de Janeiro / First synanthropic record of Loxosceles laeta (Nicolet, 1849) (Araneae, Sicariidae) in the municipality of Rio de Janeiro, State of Rio de Janeiro

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.