Rev. Inst. Med. trop. S. Paulo 46(5):287-290, September-October, 2004
CASE REPORT ENVENOMATION BY NEOTROPICAL OPISTOGLYPHOUS COLUBRID Thamnodynastes cf. pallidus LINNĂ, 1758 (SERPENTES:COLUBRIDAE) IN VENEZUELA
Fresnel DIAZ(1), Luis F. NAVARRETE(2) Jaime PEFAUR(1) & Alexis RODRIGUEZ-ACOSTA(2)
SUMMARY This is a case report of a ânon-venomousâ snake bite in a herpetologist observed at the Sciences Faculty of the Universidad de los Andes (MĂ©rida, Venezuela). The patient was bitten on the middle finger of the left hand, and shows signs of pronounced local manifestations of envenomation such as bleeding from the tooth imprint, swelling and warmth. He was treated with local care, analgesics, and steroids. He was dismissed from the hospital and observed at home during five days with marked improvement of envenomation. The snake was brought to the medical consult and identified as a Thamnodynastes cf. pallidus specimen. This report represents the first T. pallidus accident described in a human. KEYWORDS: Envenomation; Opisthoglyphous; Rear-fanged; Thamnodynastes pallidus; Venom.
INTRODUCTION
CASE REPORT
Colubrids constitute the ophidians family that involves the higher number of ânon-venomousâ snakes species4,13,14,20,30. Nevertheless, envenomation by colubrids has already been reported10-12,15,17-23,26-28,31,3437 . Thamnodynastes cf. pallidus LinnĂ©, 1758 known as âsaperasâ, âcandelillasâ or âcandelitasâ16,33 is an opisthoglyphous (rear-fanged) snake belonging to the Colubridae family, found in South America from Peru, Brazil, Guayanas, Uruguay, Paraguay, Argentina, Ecuador, Bolivia, Trinidad and Venezuela8,24,25.
On March 21st 2003, during the collection activities carried out by the Animal Ecology of the Universidad de los Andes project (Envenomation in humans), leading a tour at the 20.00 hours by the âSanta Cruz del Zulia (Venezuela) route toward âSanta BĂĄrbara del Zuliaâ, Zulia state, Venezuela, two specimens of Thamnodynastes pallidus were located on the borders of the highway in a pasture and marshy environment (08Âș 54' 10" North latitude; 72Âș 08' 40" West longitude). At the moment of the capture, one of the researchers was bitten in the middle finger of the left hand by a male specimen of 57 cm and 25 g (Fig. 1), being accomplishing an effective attach during nearly 40 seconds, requiring help to detach the animal from the finger. The snake was take over and thereinafter it was moved to the laboratory located in MĂ©rida city, for its maintenance, registered as sample No. ZUJP1053RE257V483, Animal Ecology Collection No. 0654 (Science Faculty of the Universidad de los Andes), and confirmed its identification.
This genus is taxonomically complex, therefore in Venezuela is not totally clarified. Nowadays, seven species have been reported in the country. This species is aggressive at the moment of capturing them, habitually feeds on amphibians, gekonids, lizards and occasionally nursing mice. Predominantly inhabit in areas of chaparral vegetation, with semi-arboreal habits, very active in crepuscular hours. It is found from the sea level to 2,000 m of altitude. This paper represents the first record in the literature of a human snakebite caused by a Thamnodynastes pallidus specimen.
After the arrival at the Hospital, fang marks were evident in the middle finger of the left hand as well as bleeding (Fig. 2) from the tooth imprint, swelling and warmth. The patient had pronounced oedema and pain irradiated in few minutes to the entire extremity, ecchymotic lesions, and high local temperature of the bitten finger. The oedema reached its
(1) Sciences Faculty, Animal Ecology, Proyecto Emponzoñamiento en Humanos. Apartado 5101, Mérida, Venezuela. (2) Tropical Medicine Institute of the Universidad Central de Venezuela, Caracas, Venezuela. Correspondence to: Alexis Rodriguez-Acosta, E-mail: rodriguf@ucv.ve