Primer registro de una picadura causada por un macho de Latrodectus geometricus C. L. Koch, 1841 (Araneae: Theridiidae) / First record of a bite produced by a male of Latrodectus geometricus C. L. Koch, 1841 (Araneae: Theridiidae)

Latrodectus geometricus (Araneae: Theridiidae), es una araña llamada vulgarmente "viuda marrón". Originaria de África, es una especie sinantrópica y cosmopolita, muy frecuente en varias ciudades del centro y norte de Argentina. A diferencia de otras especies del género no suele causar envenenamientos graves, habiéndose registrado en el mundo muy pocos casos que requirieron tratamiento los cuales evolucionaron siempre de forma favorable. Todos los casos registrados hasta la fecha fueron atribuidos a hembras, asumiendo que los machos no causan casos clínicos e incluso serían incapaces de atravesar con sus quelíceros la piel humana debido a su pequeño tamaño. Este trabajo presenta el primer registro de un accidente causado por un macho de L. geometricus describiendo los síntomas. El accidente ocurrió a una mujer de 21 años en Villa Gobernador Gálvez (33°01'31" S, 60°38'01" O), Santa Fe, Argentina, en marzo 2016. El ejemplar murió en el momento siendo conservado y luego identificado según su genitalia como un macho adulto de L. geometricus. Los síntomas se relevaron desde el accidente hasta el cese de las manifestaciones sin intervención terapéutica. En el momento la joven advirtió una sensación punzante seguida inmediatamente de ardor y eritema. Luego de 10 minutos el ardor aumentó, disminuyendo a los 20 minutos. Luego de una hora el ardor y el eritema disminuyó considerablemente. Los resultados observados respaldan que L. geometricus no reviste peligrosidad en Argentina y evidencian que los quelíceros de los machos pueden atravesar la piel humana, al menos en zonas de piel delgada.

Latrodectus geometricus (Araneae: Theridiidae) is a spider commonly known as "Brown widow". Originally from Africa, is a synanthropic and cosmopolitan spider, very common in several cities in central and northern Argentina. Unlike other species of the genus, this spider does not cause serious poisoning, very few have been registered that required treatment and always evolved favorably. All cases listed to date were attributed to females, assuming that males do not cause clinical cases and would even be unable to pass through human skin due to the small size of their chelicerae. This work presents the first record of an accident by a male of L. geometricus and describes the symptoms. The accident occurred to a 21 year old woman from Villa Gobernador Gálvez (33°01'31" S, 60°38'01" W), Santa Fe, Argentina, in March 2016. The specimen died at the time, being preserved and then identified as an adult male of L. geometricus according to its genitalia. The symptoms were relieved from the accident to its end without applying treatments. At the time, the woman felt a sting followed immediately by burning sensation and erythema in the area. After 10 minutes the burning increased, decreasing at 20 minutes. One hour later, burning sensation disappeared and the erythema diminished considerably. The observed results support L. geometricus as not dangerous in Argentina and show that males actually are able to penetrate the human skin, at least in areas of thin skin.

Lactrodectismo en Costa Rica / Latrodectism in Costa Rica

ResumenSe reporta un accidente causado por la araña Latrodectus geometricus, incluida en el grupo conocido como “viudas negras”, en Costa Rica. El accidente le ocurrió a una mujer de 27 años vecina de la ciudad de Cartago, en su casa de habitación. Los síntomas mostrados cursaron la siguiente secuencia: dolor intenso en el área del piquete, enrojecimiento y aumento en la temperatura al tacto alrededor de ese punto, ampliación del área del dolor, sudoración, dolor de espalda, arritmia, taquicardia y aumento de la presión arterial. Los síntomas mostrados en este caso son muy similares a los descritos por personas picadas por la misma u otras especies de viudas negras en Suramérica y Centroamérica.

AbstractWe here report a case of human lactrodectism in Costa Rica, caused by the spider Latrodectus geometricus, included in the group known as “black widows”. A 27 year-old woman was bitten by a Brown Widow spider in her home in Cartago city. She showed a moderately severe case with the following sequence of symptoms: an acute, intense local pain begins just after being bitten, and this irradiates to the entire affected limb, redness, increase in temperature around the bitten area, sweating and backache. At the cardiovascular level, she showed tachycardia and hypertension. The symptoms showed in this case are quite similar to those cases described for the Brown Widow spider and for other Black Widow spiders, in Central and South America.

First report of brown widow spider sightings in Peninsular Malaysia and notes on its global distribution

Background:The brown widow spider (Latrodectus geometricus Koch, 1841) has colonised many parts of the world from its continent of origin, Africa. By at least 1841, the species had successfully established populations in South America and has more recently expanded its range to the southern states of North America. This highly adaptable spider has been far more successful in finding its niche around the world than its famous cousins, the black widow, Latrodectus mactans, found in the south-eastern states of North America, and the red-back, Latrodectus hasselti, found mostly in Australia, New Zealand and Japan.Methods:We performed an extensive web search of brown widow sightings and mapped the location of each sighting using ArcGIS. Specimens reputedly of the species L. geometricus were collected at three localities in Peninsular Malaysia. The spiders were identified and documented based on an examination of morphological characteristics and DNA barcoding.Results:The spiders found in Peninsular Malaysia were confirmed to be Latrodectus geometricus based on their morphological characteristics and DNA barcodes. We recorded 354 sightings of the brown widow in 58 countries, including Peninsular Malaysia.Conclusion:Reports from the Americas and the Far East suggest a global-wide invasion of the brown widow spider. Herein we report the arrival of the brown widow spider in Peninsular Malaysia and provide notes on the identification of the species and its recently expanded range.(AU)

First report of brown widow spider sightings in Peninsular Malaysia and notes on its global distribution

Background: The brown widow spider (Latrodectus geometricus Koch, 1841) has colonised many parts of the world from its continent of origin, Africa. By at least 1841, the species had successfully established populations in South America and has more recently expanded its range to the southern states of North America. This highly adaptable spider has been far more successful in finding its niche around the world than its famous cousins, the black widow, Latrodectus mactans, found in the south-eastern states of North America, and the red-back, Latrodectus hasselti, found mostly in Australia, New Zealand and Japan. Methods: We performed an extensive web search of brown widow sightings and mapped the location of each sighting using ArcGIS. Specimens reputedly of the species L. geometricus were collected at three localities in Peninsular Malaysia. The spiders were identified and documented based on an examination of morphological characteristics and DNA barcoding. Results: The spiders found in Peninsular Malaysia were confirmed to be Latrodectus geometricus based on their morphological characteristics and DNA barcodes. We recorded 354 sightings of the brown widow in 58 countries, including Peninsular Malaysia. Conclusion: Reports from the Americas and the Far East suggest a global-wide invasion of the brown widow spider. Herein we report the arrival of the brown widow spider in Peninsular Malaysia and provide notes on the identification of the species and its recently expanded range.

Habitat, redescription and distribution of Latrodectus geometricus in Uruguay (Araneae: Theridiidae) / Hábitat, redescripción y distribución de Latrodectus geometricus en Uruguay (Araneae: Theridiidae)

This study provides the first accurate records of Latrodectus geometricus C. L. Koch, 1841 for Uruguay and extends the known distribution of this species to the Southeastern region of South America. Data and figures of the genitalic morphology for the recognition of the species and natural history in this country are indicated. In Uruguay L. geometricus was mainly restricted to urban areas at the west of this country and it is associated with locations with high human activity.

Este estudio reporta los primeros registros precisos de Latrodectus geometricus C. L. Koch, 1841 en Uruguay y extiende la distribución conocida de esta especie para la región sureste de Sudamérica. Datos y figuras de las estructuras genitales para el reconocimiento de la especie e historia natural en este país son indicados. En Uruguay L. geometricus se encuentra principalmente restringida a áreas urbanas del oeste de este país y asociada a sitios con elevada actividad humana.

Envenomation caused by Latrodectus geometricus in São Paulo state, Brazil: a case report

Widow spiders (Latrodectus spp.), also known as "black widows", have a worldwide distribution and can cause latrodectism. To the best of our knowledge, in Brazil, only one case of Latrodectus geometricus (Koch, 1841) envenomation in a human has been reported. The aim of the present report is to describe a spider bite caused by Latrodectus geometricus in a patient who lives in Paranapanema, São Paulo state, Brazil.(AU)