The Venom Of A
Terciopelo In the
Caribbean Is Quite
Different Than That of
The Snake In The Pacific
Coast
At simple sight a
terciopelo in Limón is
the same as the that of
the Puntarenas.
The Bothrops asper, also
known as fer-de-lance,
is a venomous pitviper
species, sometimes
referred to as the
"ultimate pitviper,"
these snakes are found
in a wide range of
lowland habitats, often
near human habitations.
Large and nervous, this
species is the main
cause of snakebite
incidents within its
range.
It is considered the
most dangerous snake in
Costa Rica, responsible
for almost half of all
snake bites and one
third of all
hospitalized cases.
These are among the most
sexually dimorphic
snakes.
The two sexes are born
the same size, but at
the age of 7 to 12
months, females begin to
grow faster than males.
Males never reach 1.95 m
long, while females
average perhaps 1.85 m,
and the greatest
confirmed length is 2.5
m. Females have thick
bodies, and big females
may weigh 6 kg; heavier
ones have been reported.
Thus female terciopelos
are among the heaviest
venomous snakes. They
also have heads two or
three times as big as
males in proportion to
their size, and
proportionally bigger
fangs (typically 2.5 cm)
as well.
This species is
irritable, fast-moving
and agile. It is also
regarded as being more
excitable and
unpredictable than B.
atrox, and has a
reputation for being
aggressive. Its large
size and habit of
raising its head high
off the ground can
result in bites above
the knee. It has also
been observed to eject
venom over a distance of
at least 6 feet (1.8 m)
in fine jets from the
tips of its fangs.
Bite symptoms include
pain, oozing from the
puncture wounds, local
swelling that may
increase for up to 36
hours, bruising that
spreads from the bite
site, blisters,
numbness, mild fever,
headache, bleeding from
the nose and gums,
hemoptysis,
gastrointestinal
bleeding, hematuria,
hypotension, nausea,
vomiting, impaired
consciousness and
tenderness of the
spleen.
Although the terciopelo
of Caribbean and the
Pacific look much alike,
their venom is
different.
The venom produced by
the snake in the
Caribbean coast has more
toxins that affect blood
coagulation, while the
Pacific coast snake
produces a toxin with
destroys more muscular
tissue.
The difference was
identified by a study of
the Universidad de Costa
Rica (UCR), the
Instituto Clodomiro
Picado and the nstituto
de Biomedicina de
Valencia, Spain.
According to the report
"Snake Venomics of the
Lancehead Pitviper
Bothrops asper:
Geographic, Individual,
and Ontogenetic
Variations" using a
similarity coefficient,
it was estimated that
the similarity of venom
proteins between the two
B. asper populations may
be around 52%.
Compositional
differences between
venoms among different
geographic regions may
be due to evolutionary
environmental pressure
acting on isolated
populations.
To investigate venom
variability among
specimens from the two
B. asper populations,
the reverse-phase HPLC
protein profiles of 15
venoms from Caribbean
specimens and 11 venoms
from snakes from Pacific
regions were compared.
Within each B. asper
geographic populations,
all major venom protein
families appeared to be
subjected to individual
variations.
Analysis of pooled venoms of neonate specimens from Caribbean and Pacific
regions with those of
adult snakes from the
same geographical
habitat revealed
prominent ontogenetic
changes in both
geographical
populations.
Major ontogenetic
changes appear to be a
shift from a
PIII-SVMP-rich to a PI-SVMP-rich
venom and the secretion
in adults of a distinct
set of PLA2 molecules
than in the neonates.
In addition, the
ontogenetic venom
composition shift
results in increasing
venom complexity,
indicating that the
requirement for the
venom to immobilize prey
and initiate digestion
may change with the size
(age) of the snake.
Besides ecological and
taxonomical
implications, the
geographical venom
variability reported
there may have an impact
in the treatment of bite
victims and in the
selection of specimens
for antivenom
production.
The occurrence of intraspecies variability in the biochemical composition
and symptomatology after
envenomation by snakes
from different
gegraphical location and
age has long been
appreciated by
herpetologist and
toxinologists, though
detailed comparative
proteomic analysis are
scarce.
The study represents the
first detailed
characterization of
individual and
ontogenetic venom
protein profile
variations in two
geographical isolated B.
asper populations, and
highlights the necessity
of using pooled venoms
as a statistically
representative venom for
antivenom production.
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