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from two specimens ranged between 75% and 100%. Intraperitoneal murine LD 50 of
B. blandingi secretion ranged between 2.85 and 4.88 mg/kg (Levinson et al., 1976;
Weinstein and Smith, 1993). Standardization for protein content resulted in a lower
LD 50 (Weinstein and Smith, 1993).
Similarly, B. d. melanota yielded 127.5 μL, but with 8 mg solids, while B. d. multi-
cincta yielded 87.5 μL with only 1 mg solids (Weinstein and Smith, 1993). The murine
i.p. LD 50 of B. d. melanota and B. d. multicincta secretions (protein standardized and
weight/volume) were: 3.26-4.04 mg/kg and 3.91-7.17 mg/kg, respectively (Weinstein
and Smith, 1993). An earlier study reported a murine i.v. LD 50 of 4.85 mg/kg for
B. dendrophila secretion (Sakai et al., 1984).
Proteolytic and/or hemorrhagic activity was detected in Duvernoy's secretions
from B. blandingi , B. d. melanota , and B. d. multicincta (Hill and Mackessy, 2000;
Sakai et al., 1984; Weinstein and Smith, 1993). Pulmonary and/or subendocardial
hemorrhage has been noted in mice injected i.v. or i.p. with Boiga dendrophila , B. d.
melanota , and B. d. multicincta secretions (Sakai et al., 1984; Weinstein and Smith,
1993). Boiga dendrophila secretion contained moderate levels of phospholipases A 2
(PLA 2 ; Hill and Mackessy, 2000). Phosphodiesterase was detected in B. dendrophila
saliva, but not in Duvernoy's secretion (Hill and Mackessy, 2000).
Although postsynaptically active neurotoxins have been detected in Duvernoy's
secretions from B. blandingi , B. irregularis , and B. dendrophila , as noted previously,
these toxins [“denmotoxin,” a monomeric 77 amino acid polypeptide containing five
disulfide bridges from B. dendrophila Duvernoy's secretion, and “irditoxin,” a het-
erodimeric polypeptide from B. irregularis Duvernoy's secretion (see Section 4.4)]
have marked specificity for saurian or avian subjects (Pawlak et al., 2006, 2009).
To date, there is no evidence of any clinical significance of these toxins. Similarly,
although Sakai et al. (1984) reported in vitro coagulant activities of B. dendrophila
Duvernoy's secretion, there are no documented cases of systemic effects in humans,
including coagulopathy, resulting from bites inflicted by this species.
4.2.1.3 Conclusion and Assessment of Boiga spp.
The mild effects reported in the few documented cases of bites from these species,
as well as the limited data regarding Duvernoy's secretion toxicity and yield from
these snakes, suggest a very low medical risk to humans. However, a protracted bite
inflicted by a large specimen might cause significant local effects.
Assessment of Boiga spp. (excluding B. irregularis ) based on available evi-
dence: Hazard Level 3/4 (typically only mild local effects such as puncture
wounds/lacerations, erythema, edema, and insignificant bleeding, with potential for
more pronounced local effects such as more extensive edema and pain).
4.2.2 Genus Philodryas spp.: Background and General Features of
Documented Bites
Of the 18 species of South American racers, Philodryas , five (and one subspe-
cies) have been reported to inflict medically significant bites ( Table 4.1 ). These
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