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EPIDEMIOLOGICAL CLINICAL STUDY OF ENVENOMING BY Bothrops leucurus WAGLER, 1824 (Serpentes; Viperidae) IN THE METROPOLITAN AREA OF SALVADOR, BAHIA, BRAZIL

THESIS: R. M. Lira-da-Silva submitted this dissertation to obtain the degree of Master of Collective Health in Epidemiology, publicly examined at the Institute of Collective Health of the Federal University of Bahia, Salvador, Bahia, Brazil, in December 1996.

Advisor: Professor Fernando Martins Carvalho

ABSTRACT. The present investigation is a descriptive study about clinical and epidemiological aspects of snake envenoming caused by Bothrops leucurus in the metropolitan area of Salvador, Bahia, Brazil, from January 1982 to April 1996. These accidents were notified to the Information Center of Antivenom (CIAVE). This study is based on medical records of 126 patients and on questionnaires filled by the author who interviewed 13 patients or the persons accompanying them during the prospective phase of the study (from January 1995 to April 1996). None of the cases resulted in death. The 126 accidents occurred mainly in the cities of Salvador (29.3%) and Camaçari (26.1%). However, the highest incidences were reported in the cities of Itanagra (119.1/100,000 inhabitants), Mata de São João (26.8/100,000 inhabitants) and Camaçari (25.7/100,000 inhabitants). The accidents occurred mainly in March, May, June, September and October. Most of them took place in rural areas (56.7%) and during diurnal period (60.0%). Most of the patients were adult male rural workers, 10 to 49 years old, and 65.4% of the accidents occurred during work. The accidents involved the feet (65.9%) and the hands (25.4%). Time elapsed between the snakebite and medical care, snakebite and serotherapy, and admission to the CIAVE and serotherapy was less than six hours in 84.2%, 87.0% and 82.6% of the cases, respectively. Envenomation by B. leucurus is mainly characterized by local manifestations such as pain (80.9%), edema (79.8%), heat (26.3%), numbness (20.2%), erythema (16.7%), ecchymosis (13.2%) and phlycthena (10.5%), and coagulation manifestations such as period of altered coagulation and blood incoagulability (58.2%). General manifestations such as headache (14.0%) and dizziness (7.9%), vomiting (4.4%) and nausea (3.5%), oliguria (3.5%), hemorrhage (3.5%), hypotension (1.8%) reduced vision acuity (1.8%) and tremors (1,8%) were observed with less frequency. Proportionally, female snakes were responsible for more severe accidents than male snakes. Adult B. leucurus accounted for more local manifestations such as edema, plycthena and necrosis than young snakes. Consequently, adult snakes were responsible for more severe accidents (7.6% young and 22.4% adult snakes) and were less capable of causing blood coagulation alteration according to information about venom action of other Bothrops species. Most of the envenomation cases were mild (52.1%) and all evolved to cure. This might have direct relation to time elapsed between snakebite and medical care; therefore, severity of the envenomation increased with time. The high frequency of mild cases may also be related to the length of the snake, although most of the accidents were caused by young snakes. The high severity of the case was not associated to stomach content (11.1% of severe accidents by snakes with full stomach and 13.3% by snakes with empty stomach). On average, 7.5 ampoules/patient were used, as the majority of the patients received 1 to 4 ampoules (50.5%). The patients were administered, on average, 5.0 ampoules in mild cases, 7.4 ampoules in moderate cases and 8.8 ampoules in severe cases. The patients bitten by adult snakes received, on average, a higher dose of bothropic antivenom than those bitten by young snakes, not only when antivenom was first administered (5.6 and 7.2 ampoules, respectively), but also when antivenom was administered additionally (1.2 and 1.6 ampoules, respectively). These results demonstrated that local manifestations commonly related to accidents involving large snakes required treatment with high dose of antivenom. This information has already been reported in clinical studies with other Bothrops species. The frequency of reactions after antivenom administration (67.5%) may be considered one of the highest in Brazil if compared with that reported in other regions. The absence of lethality and the high frequency of mild cases with no sequelae suggest that treatment with bothropic antivenom effectively neutralized the venom action, indicating the efficiency of this treatment in the metropolitan area of Salvador.

CORRESPONDENCE TO:

R. M. LIRA-DA-SILVA - Departamento de Zoologia, Instituto de Biologia, Universidade Federal da Bahia, Campus Universitário de Ondina, CEP 40.170-210, Salvador, Bahia, Brasil. Tel: (071) 247-3744, Fax: (071) 245.6909, E-mail: rejane@ufba.br

Publication Dates

  • Publication in this collection
    27 Nov 1998
  • Date of issue
    1998
Centro de Estudos de Venenos e Animais Peçonhentos - CEVAP, Universidade Estadual Paulista - UNESP Caixa Postal 577, 18618-000 Botucatu SP Brazil, Tel. / Fax: +55 14 3814-5555 | 3814-5446 | 3811-7241 - Botucatu - SP - Brazil
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