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The Duvernoy's secretion exhibited proteolytic activity, while this was absent in the
mixed buccal salivary secretions (Glenn et al., 1992).
In another comparison of
H. gigas
buccal secretions and Duvernoy's secretion, Hill
and Mackessy (2000) used pilocarpine (see previous sections for details) in order to boost
secretion yields. These investigators reported mean Duvernoy's secretion liquid and
solid yields of 423 μL and 7.31 mg, respectively. Duvernoy's secretion contained a mean
67.1% protein, and the buccal secretions contained 30.9% protein (Hill and Mackessy,
2000). The total carbohydrate concentration of the Duvernoy's secretion ranged from
0.1% to 4.7%, and azocaseinase and caseinase, also present in the mixed buccal secre-
tions, were the only enzymatic activities detected (Hill and Mackessy, 2000). Of the 12
non-front-fanged colubroid species studied, the
H. gigas
Duvernoy's secretion proteo-
lytic activity was one of the two highest detected (Hill and Mackessy, 2000).
4.4.3.4 Analysis and Conclusions
Hydrodynastes gigas
is a large, heavy-bodied, xenodontine colubroid popular in pri-
vate collections. Although many are maintained in captivity, only four well-docu-
mented bites have been reported. Of these, only the single case described previously
(Manning et al., 1999) featured symptoms suggestive of systemic effects such as
PACs, “muscle paralysis,” dysarthria, and “muscle weakness.” The incident resulted
in an extended convalescence, and “muscle weakness” that purportedly lasted almost
2 months (Manning et al., 1999). The major clinical features (particularly immobil-
ity, perceived muscular weakness, tachycardia, etc.) of this case, previously reviewed
(Warrell, 2004), are most parsimoniously attributed to somatosensory amplification
due to anxiety (see Section 4.5). As the snake reportedly inflicted a protracted bite, the
mild-to-moderate edema may be due to the effects of a larger volume of Duvernoy's
secretion introduced into the wound and/or hypersensitivity to the secretion, as well as
other oral gland products (see Section 4.6). The patient indicated that he had received
several insignificant bites previously, and these may have sensitized him. Thus, the
protracted bite conceivably stimulated a notable anaphylactic response that resulted
from acquired hypersensitivity.
Although the medical history of the patient is not available, there is no mention of
any preexisting comorbidities or other factors predisposing to some of the reported
effects (e.g., alcohol, prescription medications). However, a detailed analysis of this
case may illustrate how consideration of alternative (and more likely) causes may
clarify the origin of the observed effects. Therefore, the reported PACs are worthy of
further consideration, as this was an objective finding. PACs are caused by generation
of a premature impulse by the sinoatrial node (SA node). This impulse is conducted
normally and results in a contraction; it is often asymptomatic, or experienced by the
patient as a palpitation/“skipped beat.” These arrhythmias are common and are most
often benign in those without underlying cardiac disease. However, under pathologi-
cal circumstances, some PACs may initiate atrial fibrillation (Narayan et al., 2008;
Sra et al., 2001). Similarly, palpitations may also be caused by premature ventricular
contractions (PVCs) that are caused by an ectopic cardiac pacemaker located in the
ventricle, below the SA node. There are many causes of PACs and PVCs, including
