Management of Snakebite and Research Management of Snakebite ...

More documents

Recommendations

Info

Effect of the Snake’s Length and Recent Feeding on Venom Antigenaemia and Severity of Envenoming in Russell’s Viper (Daboia russelii siamensis) Bites Tun-Pe 1 , Ba-Aye 2 , Aye-Aye-Myint 1 , Tin-Nu-Swe 3 and D.A. Warrell 4 1 Venom Research Laboratory, Department of Medical Research 2 Medical Statistics Division, Department of Medical Research 3 Clinical Research Unit on Snake Bite, Department of Medical Research 4 Centre for Tropical Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford, OX3 9DU, UK Abstract An enzyme immunoassay technique was used for detection of venom antigen levels in the diagnosis of 311 suspected Russell’s viper bite cases in Myanmar, 181 of whom (58%) had systemic envenoming. Russell’s viper venom was detected in the sera of 175 (56.3%). Among 175 of these patients, who failed to bring the dead snake, EIA achieved a specific diagnosis of Russell’s viper envenoming in 101 (58%). Stomach contents were examined in 101 Russell’s vipers responsible for bites. The presence of prey, usually a rodent, in the snake’s stomach, indicating that it had eaten recently, did not influence the severity of envenoming, the initial venom level, or the percentage circumference increase and the extent of local swelling in the bitten limb. One hundred and fifty-five Russell’s vipers responsible for bites showed a bimodal distribution of total lengths. The smaller snakes had probably been born that year. Longer snakes were responsible for more severe envenoming, a shorter interval between the bite and the detection of incoagulable blood, and more extensive local swelling with a greater percentage circumference increase of the bitten limb; but their bites were not associated with higher initial venom antigenaemia or a greater risk of developing acute renal failure INTRODUCTION Snakebite is a major medical problem in Myanmar, resulting in more than a thousand deaths per year (Myint-Lwin et al., 1985). Especially in the rice-growing area, the majority of bites are attributed to Russell’s viper (Daboia russelii siamensis), the venom of which causes local swelling, haemostatic disturbances, shock and acute renal failure (Myint-Lwin et al., 1985). A similar clinical syndrome can result from envenoming by green pit vipers (Trimeresurus spp.) and by the Malayan pit viper (Calloselasma rhodostoma), which may 41
Management of Snakebite and Research 42 occur in the south of the country. When a snakebite victim fails to identify or bring to hospital the snake responsible, the choice of antivenom will depend on the clinical history and symptoms, which may not be specific. An enzyme immunoassay (EIA) was used to measure Russell’s viper venom antigen in serum for retrospective assessment of the clinical diagnosis and exploration of the pathophysiology and treatment of envenoming. The notion that smaller snakes and those that have eaten recently might be less venomous has been tested in a large number of cases. MATERIALS AND METHODS We studied 413 patients with proved or suspected bites by Russell’s vipers admitted to Tharrawaddy township hospital, 80 km north of Yangon, Myanmar, during 5 rice-harvesting seasons (November-January) in 1984-1988; 155 patients (38%) brought the dead snake. The total lengths of the dead snakes were measured. The stomach was opened through a ventral incision to see if the snake had fed recently. In the patients, severity of envenoming was graded clinically as none, local or systemic according to criteria established in a previous study (Myint-Lwin et al., 1985). The 20-minute whole blood clotting test, a simple bedside test, was used to monitor coagulopathy (Warrell et al., 1977). Quantitation of venom antigen in serum was done by EIA technique already described. (Tun-Pe et al, 1991a). RESULTS Detection of venom antigen by Enzyme Immunoassay Out of 311 snakebite victims studied by EIA, Russell’s viper venom was detected in the sera of 175 (56.3%). Among those 311 studied, 136 brought the dead snakes and the remaining 175 had failed to bring the dead snake. Out of 175, EIA achieved a species diagnosis of Russell’s viper bite in 101 (57.7%). Lengths of snakes responsible for bites and correlation with severity of envenoming The distribution of the total lengths (tip of snout to tip of tail) of 155 snakes responsible for bites was bimodal, indicating the presence of 2 distinct populations (< 375 mm and > 550 mm long)(Fig.1). Bites by 112 snakes 550 mm long caused 26 cases of systemic envenoming (Fig. 1). Systemic envenoming was significantly correlated with bites by longer snakes (χ 2 = 27.60, p 550 mm long (68.66± 20.51 [1 standard deviation] and 59.53 ± 23.04 ng/ml respectively) (t= 0.98, 0.20
Page 1 and 2: World Health Organization Regional
Page 3 and 4: ii WHO Library Cataloguing in Publi
Page 5 and 6: iv 10. Recent Advances in the Exper
Page 7 and 8: The seminar, convened at the Depart
Page 9 and 10: Early use of antivenom by health wo
Page 11 and 12: � Raising awareness of endotrache
Page 13 and 14: Part 2 Working Papers 7
Page 15 and 16: Management of Snakebite and Researc
Page 47: Management of Snakebite and Researc
Page 99 and 100:
Management of Snakebite and Researc
Page 101 and 102:
Page 103 and 104:
Page 105 and 106:
Page 107 and 108:
Page 109 and 110:
Page 111 and 112:
Page 113 and 114:
Page 115 and 116:
show all

Management of Snakebite and Research Management of Snakebite ...

Create successful ePaper yourself

Delete template?

Save as template?