Biology Reference
In-Depth Information
life-threatening hazard. Although there is only a single well-documented neurotoxic
envenomation by
M. monspessulanus
, it does provide evidence of the neurotoxic
effects that may result from a bite from this species. However, the presumed neuro-
toxicity ascribed to bites by
B. irregularis
does not have such unambiguous support-
ing evidence. Therefore, although it may be prudent on occasion to “err on the side
of caution,” risk assignment must be founded on sound, verifiable evidence.
Similarly, incorrect identification may result in assignment of medical importance
to the wrong species. In a case documenting the mild local effects that resulted from
a bite inflicted by
Stenorrhina freminvillei
, the author published a photo of the snake
involved (Cook, 1984). Several years later, Johnson (1988) published a commentary
on the case correcting the identification to
Conophis lineatus
(
Table 4.1
).
Incorrect identification carries the potential for other serious consequences.
Nonvenomous species or those of unknown medical importance may be mistaken for
venomous species. This can lead to inappropriate provision of antivenom, thereby sub-
jecting the patient to unnecessary and even life-threatening adverse effects (Ariaratnam
et al., 2009; Viravan et al., 1992). For example, in their review of 91 cases of non-
venomous snakebite that were recorded in a teaching hospital in Brazil, Silveira and
Nishioka (1992) reported several cases of provision of antivenom for nonvenom-
ous bites. In one example, these authors documented life-threatening anaphylaxis in
a patient given anti-
Bothrops
spp. antivenom after being bitten by a nonvenomous
colubrine,
Drymarchon corais
ssp. (cribo; subspecies was not indicated). A bite from
a
Sibynomorphus mikanii
(South American slug-eating snake or Mikan's tree snake)
that reportedly caused a prolonged clotting time was treated with anti-
Bothrops
spp.
antivenom (Silveira and Nishioka, 1992;
Table 4.1
). Similarly, a child bitten by a
Boiruna maculata
(mussurana; culebra de sangra; others; the name “mussurana” is
also commonly used for
Clelia
spp.; see Table 4.1) presented with mild-to-moderate
local effects and “discrete cyanosis” was also treated with anti-
Bothrops
spp. anti-
venom (Santos-Costa et al., 2000;
Table 4.1
). As this child also had a tourniquet
applied to the affected limb, the described “cyanosis” may be a result of inappropri-
ate and incorrectly applied first aid. It is noteworthy that of 43 patients reviewed in
a Brazilian retrospective study of
P. olfersii
bites (see Section 4.1), six (14%) pre-
sented with a tourniquet that had been previously applied proximal to the bite (Ribeiro
et al., 1999). Similarly, approximately 29 of 297 patients bitten by
P. patagoniensis
in
São Paulo, Brazil, had received a tourniquet prior to presentation at the hospital, and
this was significantly associated with the presence of local edema (de Medeiros et al.,
2010). Misidentification of a
Chrysopelea pelias
(twin-barred tree or flying snake) for
a
Bungarus
spp. (krait) resulted in unnecessary administration of antivenom. In addi-
tion, the antivenom did not even have efficacy for any of the medically important spe-
cies of the region (Malaysia; Ismail et al., 2010;
Table 4.1
). Similarly, a herpetologist
with mild local effects from a bite by a
Pliocercus elapoides
(false-coral snake) was
treated with polyvalent antivenom incorrectly and uselessly administered intramuscu-
larly in aliquots (Seib, 1980;
Table 4.1
). There are several reports of patients with mild-
to-moderate local effects after receiving bites from
Philodryas
spp. that were treated
with anti-
Bothrops
spp. antivenom (
Table 4.1
).
It is also conceivable that a venomous species might be misidentified as a non-
