Increasing of the Presence of Tityus trivittatus in Buenos Aires City

BLANCO G; LASKOWICZ R; SCARLATO E; CASAS N; COSTA DE OLIVEIRA V; LANARI N; LAGO N; DE ROODT, A

Hawai

Congreso; 17th World Congress of the International Society on Toxinology; 2012

International Society on Toxinology (IST)

Background: Tityus trivittatus is the scorpion of highest medical importance in Argentina. It is present in the majority of the big cities of the country favouring the contact man ? scorpion due its characteristic of adapting to live in human constructions and environments. In the last years the number of notification of scorpion findings increased as well the number of accidents in the country. To determine if the population of Tityus trivittatus has expanded its geographical area of influence during the last decade in Buenos Aires city and whether or not there is also an increase in the frequency of cases within the affected geographical areas. Methods: the reported cases recorded in our institutions during 2001-201 were classified by date and location, further geo-referenced in a digital map and analyzed in a geographic information system (GIS). Reported cases were modeled as points and buffer areas were created 250 m around each case to define an arbitrary measure of geographical influence. When reported Tityus events occurred close to each other (less than 500m), overlapping areas became merged into a single area containing all points representing those events. These areas were differentially plotted for increasing time intervals from 2001 to 2011. The total area associated with reported cases in square km and the number of events per square km was computed for each time interval. Results: Time interval (Years) Compromised Area (km2) Reported findings Reported findings/km2 2001-2002 0.78 16 20.49 2001-2004 2.43 60 24.68 2001-2006 3.03 82 27.08 2001-2008 3.63 126 34.68 2001-2011 6.00 251 41.81 Discussion: the geographical area within Buenos Aires city where some Tityus trivittatus findings have been reported, has increased at about 0.5 km2 per year since 2001. The incidence of findings of scorpions computed by area has also persistently increased since 2001suggesting the species has become permanent. Despite the increasing number of findings of Tityus trivittatus, the number of cases in Buenos Aires city did not increase in the last five years and no deaths and only a moderate envenoming occurred in the city. The toxicity of the venom of these scorpions in the city of Buenos Aires is lower regarding that from other regions of the country. However, the increase of the area where these scorpions can be find, indicates the need to focus the attention to prevent potential accidents in zones of the city where the presence of T. trivittatus was not historically registered.