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that the arboreal nature of
P. olfersii
was reflected by the occurrence of a sampling of
bites while the victim was “off of the ground” (presumably, in an elevated dwelling/
domicile or low-lying tree), while all of the bites from
P. patagoniensis
occurred with
the victim on level ground.
Similarly, Ribeiro et al. (1999) reported that
P. olfersii
bites occurred in Brazil
most frequently during the hottest months, with a peak incidence in January (23.3% of
diagnosed
P. olfersii
bites recorded at Instituto Butantan, 1982-1990). Of 43 patients
reviewed in their retrospective study, 74.4% were male, and most victims were bitten
between 2400 and 0600 h (58.1%) and between 0600 and 1200 h (27.9%). Forty-one
snakes involved in these cases were measured, and the overwhelming majority (90.2%)
were
50 cm in length (Ribeiro et al., 1999). The measured lengths of 21 specimens
were recorded with a mean length of 87.7 cm. Twelve snakes were sexed; 10 were
female, two male (Ribeiro et al., 1999). Twelve of the victims were handling the snake
when bitten, while 12 reported being bitten while working, and eight children were bit-
ten while playing. The authors indicated that it was unclear if any of the children were
handling or trying to capture the snake when bitten. Of the remaining victims, only two
reported being bitten while sleeping. This is in contrast with many reported bites from
brown tree snakes (
B. irregularis
) on Guam (see later, and in Section 4.4). Not sur-
prisingly, victims were most commonly bitten on the hands (72.1%) or feet (20.9%).
Twenty-seven victims (62.8%) exhibited symptoms that may have resulted from the
bite, while 16 (37.2%) were asymptomatic and showed no evidence of envenoming
(Ribeiro et al., 1999).
Between 1959 and 2008, 297 cases of bites by
P. patagoniensis
, proven by quali-
fied examination of the dead snake, were admitted to Instituto Butantan's Hospital in
São Paulo, Brazil (de Medeiros et al., 2010). It is relatively uncommon and noteworthy
that the identity of the offending snakes was formally verified in all cases included in
their study. Snakes' lengths (snout-cloaca [vent]) ranged 160-1080 mm, and 61.3% of
the snakes were female. Most (89.1%) had empty stomachs. As reported by Fowler
and Salomão (1994) and Ribeiro et al. (1999) in regard to bites from
P. olfersii
and/
or
P. patagoniensis
in Brazil, most of the bites (66%) occurred during spring and sum-
mer (October-March) during warmer periods of the day (likely reflecting the diur-
nality and periods of heightened activity of these taxa; 1000-1600 h); 34% occurred
during autumn and winter (April-September; de Medeiros et al., 2010). The mean age
of bite victims was 24.1
15.1 years and, as noted in previous studies, the majority
of the victims were male (69.4%). There were no significant differences per distribu-
tion of bites by age group according to gender (de Medeiros et al., 2010). Most of the
victims (92%) sought medical attention within 6 h of being bitten, and the majority of
bites were inflicted on the feet and hands (69%). Symptoms included pain (50.8%),
transient bleeding (36%), erythema (16%), and edema in the absence of a tourniquet
(13%). None of the victims exhibited ecchymoses. Seven patients reported mild diz-
ziness, and the authors commented on the likely anxiety-driven etiology for this com-
plaint (de Medeiros et al., 2010). None had incoagulable blood, but eight (2.7%) were
given
Bothrops
antivenom before referral to Butantan. The minor nature of most of
these bites is demonstrated by the minimal number of patients (13.4%) who received
any treatment, limited to antihistamines and/or analgesics. Eighty-eight (29.6%) of
