CLINICAL AND EPIDEMIOLOGICAL CHARACTERISTICS OF INJURIES CAUSED BY VENOMOUS SNAKES OBSERVED AT THE HOSPITAL FOR TROPICAL DISEASES OF ARAGUAÍNA , TOCANTINS STATE , BRAZIL , FROM 1995 TO 2000

Injuries caused by venomous snakes are considered a problem of public health in Brazil, and further studies for a better knowledge are very important. The aim of this work is to describe clinical and epidemiological characteristics that were observed from 1995 to 2000 in the Hospital for Tropical Diseases of Araguaína, Tocantins State, Brazil, which is a unit of health that takes care of patients suffering from tropical diseases. We studied 440 individuals and the most common characteristics observed were masculine sex, age among 15-45 years, bite in low members, and injuries caused by snakes of the Bothrops genus. The signs and symptoms more frequently observed were edema, pain, erythema, and bleeding. The most observed systemic manifestation was alteration of blood coagulation. The most frequent complications were abscess, necrosis, bacterial infection, and renal failure. The mortality rate was 3%. These data are very important for the evaluation of the problem.


RESULTS
Out of the 440 cases of injuries by venomous snakes, 307 (69.77%) were identified as being caused by the Bothrops genus, 80 (18.18%) by the Crotalus genus, and 53 (12.04%) were identified or considered as injuries caused by non-venomous snakes.
There were no records of accidents caused by Micrurus and Lachesis genera (Figure 7).

Goiatins
The highest number of accidents -276 cases (62.71%) -happened during the day, between 6 a.m. and 6 p.m.In the night period, 64 cases (25.9%) occurred.From the accidents, 234 (53.18%) happened during work in the rural area, 97 (22.04%) during leisure, and 109 (24.77%) in other activities.Regarding the time of the year, the period of highest incidence of accidents was between the months of December and April (54%); and the lowest incidence occurred from July to September (15%) (Figures 8 and 9).In relation to the clinical data, the most affected corporal segments were the feet in 268 cases (60.9%) and the legs in 92 cases (20.9%), followed by the hands in 25 cases (5.68%).With regard to the cases evolution, 401 patients (91.13%) obtained cure, 11 patients (2.5%) were transferred to another hospital for surgical procedures or for hospitalization in the Intensive Therapy Unit, 14 patients (3.18%) were at death, and there was no evolutionary segment for 14 patients (3.18%).Among the deaths, 3 cases (0.68%) were due to Bothrops genus bites and 11 cases (2.5%) due to Crotalus genus.
Considering the treatment, 361 patients (82.5%) received serum therapy.The same was applied to cases with clinical and/or laboratorial signs of envenomation either without previous serum therapy or with previous serum therapy administered at the patient's district by an inadequate route (intramuscular) and/or in doses inferior to the case severity.
The administration route was the intravenous in all the cases.The number of flasks used varied according to the case severity and the accident type.For secondary bacterial infection, analgesics, anti-inflammatory and antibiotics, as well as tetanus prevention and nursing of the wound site, were used in cases where there was no history of previous inoculation.Surgical treatment was applied to patients who developed abscesses in the bite site.

DISCUSSION
The results obtained, in spite of not reflecting all the accidents in Tocantins State, demonstrate a larger number of Crotalus bites when compared to the data notified and recorded all over the national territory according to the Ministry of Health (7%).
However, most of the accidents are caused by the Bothrops genus (69.77%), what coincides with the data from the Ministry of Health (75%) (Figure 7).
Most bites occurred in the municipal district of Araguaína, located to the north of Tocantins State, characterized by 2 much defined seasons, a rainy one and a dry According to the time of the year, the bites were more frequent from December to April, which are the rainy months in the region, when the planting period begins and, consequently, there is movement of people and also of snakes in the fields.Another practice in the area is the deforestation for subsequent planting, which causes the man to be in contact with the snakes of the area (Figure 8).The accidents happened, in their majority (62.7%), during the day, which is the period of higher human activity.
With regard to the sex, there was a higher incidence of attacks on men than on women, which shows a similarity to other Brazilian studies.This fact could be explained by the male's larger presence in agricultural activities.
The predominant age group (67.89%) was composed of youths and young adults (11 to 45 years), who constitute the primary share of manpower in the rural area.It was observed that 12% of the bites occurred in children up to 10 years old, who could have been in the area working or accompanying their parents at work.In relation to the circumstances of the accidents, 53.1% happened during the patients' professional activities and the remaining in leisure activities and others.
A high number of patients lived in the rural area, and the distance from the urban centers determined the medium time of medical assistance after the accident, which was between 3 and 7 hours (67.49%).The bites happened in more distant municipal districts, especially those out of Tocantins State, and contributed to the medical aid only 7 hours after the accident (Figure 9).
Confirming previous works and the statistics already existent, this study showed that the most affected anatomical sites in the accidents were the feet (60.9%), legs (20.9%), and hands (5.68%).It is interesting to notice that the bites in the hands occurred during the hunt of animals like armadillo, which lives in pits in the ground where there are also snakes, especially of the Bothrops genus.
Considering the clinical aspects, in cases of Bothrops bites there was prevalence of local alterations, characteristic of these kinds of accidents.However, in Crotalus

Figure 1 :
Figure 1: A specimen of Bothrops captured near Araguaína after causing envenomation in a man.This genus caused most of the injuries in this study.

Figure 2 :
Figure 2: Crotalus durissus.The rattlesnakes were responsible for a number of injuries in the study area greater than that from the Ministry of Health for all the country.

Figure 3 :
Figure 3: The arm of a victim bitten by a Bothrops snake.Note the edema, erythema and ecchymosis.

Figure 4 :
Figure 4: A severe accident with prominent bleeding (uncoagulable blood) caused by a Bothrops snake in a child.

Figure 5 :
Figure 5: Palpebral ptosis is a prominent aspect in envenoming by snakes of the Crotalus genus.This patient was observed during this study.

Figure 6 :Figure 7 :Figure 8 :
Figure 6: This child showed intense neurotoxicity with palpebral ptosis after being bitten by a Crotalus snake.

Figure 9 :
Figure 9: Distribution of accidents according to the time elapsed between the bite and the medical aid.
b) Crotalus genus: pain in the bite site in 65 cases (81.25%), edema in 45 cases (56.25%), erythema in 18 cases (22.5%), and local bleeding in 10 cases (12.5%).J J. B. Paula Neto et al.CLINICAL AND EPIDEMIOLOGICAL CHARACTERISTICS OF INJURIES CAUSED BY VENOMOUS SNAKES OBSERVED AT THE HOSPITAL FOR TROPICAL DISEASES OF ARAGUAÍNA, TOCANTINS STATE, BRAZIL, FROM 1995 TO 2000.J. Venom.Anim.Toxins incl.Trop.Dis., 2005, 11, 4, p. 430 one, besides two types of vegetation: forests and open areas (savannahs) composed of arboreal vegetation.Other areas with a high number of bites by Bothrops were the municipal districts of Santa Fé do Araguaia and Aragominas, which present as geoclimatic characteristics a rainy climate and exuberant vegetation formed by forests.
J. B. Paula Neto et al.CLINICAL AND EPIDEMIOLOGICAL CHARACTERISTICS OF INJURIES CAUSED BY VENOMOUS SNAKES OBSERVED AT THE HOSPITAL FOR TROPICAL DISEASES OF ARAGUAÍNA, TOCANTINS STATE, BRAZIL, FROM 1995 TO 2000.J. Venom.Anim.Toxins incl.Trop.Dis., 2005, 11, 4, p. 431 bites, pain was observed at the bite site in 65 cases (14.7%) and edema in 45 cases (10.2%), what generally are not described because local alterations produced by Crotalus venom have small expression.Death was present in 3% of the total cases (14), with prevalence in Crotalus envenomations (78% of the deaths).