Viperid venom glands with defective venom production. Morphological study Karina Cristina Giannotti a , Antonio Sesso b , Kathleen Fernandes Grego c , Wilson Fernandes c , Rubens Pinto Cardoso Jr. d , Gabriela Grilo Camargo a , Sylvia Mendes Carneiro a, * a Laboratório de Biologia Celular, Instituto Butantan, Av. Vital Brazil 1500, 05503-900 São Paulo, SP, Brazil b Setor de Biologia Estrutural, Laboratório de Imunopatologia, Instituto de Medicina Tropical, Universidade de São Paulo, São Paulo, SP, Brazil c Laboratório de Herpetologia, Instituto Butantan, Av. Vital Brazil 1500, 05503-900, São Paulo, SP, Brazil d Superintendência de Controle de Endemias, SUCEN Regional 08, Av. Philadelpho Manoel Gouveia Neto 3101, 15060-040 São José do Rio Preto, SP, Brazil article info Article history: Received 3 December 2012 Received in revised form 13 March 2013 Accepted 18 March 2013 Available online 9 April 2013 Keywords: Viperid snakes Venom gland pathology Venom production abstract The venom of viperid snakes is collected monthly at Butantan Institute for research pur- poses and production of antivenoms. Here we describe histological and ultrastructural changes on Crotalus durissus terrificus and Bothrops sp. venom glands with defective venom production. Secretory tubules commonly showed partial or total obliteration of their lumina by masses of necrotic cells and cellular debris. Secretory cells showed varying degrees of degenerative and/or metaplastic alterations seriously affecting the structures responsible for the synthesis and secretion of venom. The intertubular connective tissue presented fibroblast hyperplasia, inflammatory cells infiltration, vacuolated cells and blood vessels alterations. In two venom glands out of nineteen snakes examined, virus-like particles were found. The alterations observed in most of the glands could have been caused by excessive manual pressure, during venom extraction routine, causing disruption of the secretory tubules and leakage of venom to the intertubular connective tissue. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction Snakes of the genera Bothrops and Crotalus are the main responsible for human envenomation in Brazil. Antivenoms and immunological research are produced with venoms milked from snakes kept at the Laboratory of Herpetology (Belluomini, 1968). Snakes from different regions of Brazil are kept in quarantine in appropriate cages for sixty days, where they are physically examined, dewormed and bathed with an antiectoparasitic solution. Ill snakes are isolated and treated. After quarantine period, the snakes are transferred to Venom Production Rooms where they are monthly submitted to manually venom extraction. The quantity of venom extracted varies with the size of the snake, its physiological state and health condition. Crotalus durissus provides an average of 250 mL per animal and can live 8–15 years in captivity. Some snakes fail to produce venom or present a hemorrhagic or purulent secretion. Venom gland of viperid snakes is composed of a main gland, a primary duct, an accessory gland and a secondary duct that joins the fang sheath. The main gland is formed by * Corresponding author. Tel.: þ55 11 2627 9768; fax: þ55 11 2627 9324. E-mail addresses: giannotti.kc@gmail.com (K.C. Giannotti), antses88@ uol.com.br (A. Sesso), kgrego@butantan.gov.br (K.F. Grego), wilsonbut@ butantan.gov.br (W. Fernandes), rcardosojr@yahoo.com.br (R.P. Cardoso), gabigc@hotmail.com (G.G. Camargo), sycarneiro@butantan. gov.br, symcarneiro@gmail.com (S.M. Carneiro). Contents lists available at SciVerse ScienceDirect Toxicon journal homepage: www.elsevier.com/locate/toxicon 0041-0101/$ – see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.toxicon.2013.03.019 Toxicon 70 (2013) 32–43