A case series of envenoming by Sawscaled viper Echis carinatus in Sri Lanka

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A case series of envenoming by Saw-scaled viper
(Echis carinatus) in Sri Lanka

• Gnanathasan CA1, Rodrigo PC1, Peranantharajah S2,
  Anitha Coonghe3, Pieris P 4
• 1Faculty of Medicine, University of Colombo, No
  25, Kynsey Road, Colombo 08, Sri Lanka
• 2Teaching Hospital, Jaffna, Sri Lanka
• 3District Hospital, Mannar, Sri Lanka
• 4Zoological garden, Dehiwela, Colombo, Sri Lanka.

Global issues in Clinical Toxinology 2008,
Melbourne
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Saw -Scaled viper
Echis carinatus sinhaleyas Vali polonga
(Sinhala), Surutai pambu (Tamil)
Global issues in Clinical Toxinology 2008,
Melbourne
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Saw-scaled viper (echis carinatus)

• Geographical distribution Northern Africa,
  Middle East,
• Iran, Afghanistan,
• India and Sri Lanka.
• Found in dry and semi-arid,
• desert habitats with rocky, sandy surface or
  grassy undergrowth

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Melbourne
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Distribution of Saw-Scaled Viper in Sri Lanka

• Saw-scaled vipers have been observed in the
  coastal areas of Sri Lanka from Mannar to Yala
• This includes the coastal areas of Northern,
  North western and Eastern provinces.
• They are commonly found in Mannar, Jaffna
  peninsula,
• Mullaitivu and Yala

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Biology

• Length 20 to 30cm
• Arrow shaped or Birds foot mark on head
• Short head, slender stout body, short tail
• Top side is chestnut brown or tan, underside is
  whitish or yellowish white
• Dark edged whitish spots along backbone
• Wavy white line on sides

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Biology

• Mainly nocturnal in habit
• Moves rapidly, attacks aggressively
• Easily excitable
• Viviparous
• Feeds on rodents,lizards a variety of
  arthropods eg. scorpions, centipedes

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Echis carinatus VENOM

• First described scientifically by Patrick Russell
  (1796) in India
• Wall (1921) comments This is the most venomous
  snake I know 1
• Venom of Sri Lankan species is seldom or never
  fatal to man, causing only grave discomfort for
  2-3 days 2

• 1 Wall F. Ophida Taprobanica or the snakes of
  Ceylon.Cottle H R, Government printer ,
  Colombo.1921
• 2 Deraniyagala P.E.P, A Coloured Atlas of some
  vertebrates from Ceylon,19553Serpentoid
  reptilia. Government press, Ceylon, Colombo.

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Envenoming by saw-scaled viper

• Haemotoxicity with local effects are frequently
  reported by other studies in India and Africa
• Clotting factors II, V, VIII and XIII are
  depleted
• Levels of X and VII are normal
• Venom has procoagulant activity and haemorrhagic
  properties

Warrell DA, Davidson N.McD, Greenwood BM, et al.
Poisoning by bites of the saw-scaled or carpet
viper (Echis carinatus) in Nigeria. Q J Med.
1977463362.
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Melbourne
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A case report from 1959

• Mr. G.P.B.K. was bitten on the left index
  finger. The surrounding flesh turned blue
  immediately. He arrived at Jaffna hospital 20
  minutes after being bitten. The swelling spread
  up to his elbow by next day. He was treated with
  2 bulbs of mixed antivenom and analgesics. The
  patient did not show any overt bleeding
  manifestations but complained of a severe
  headache. He developed an urticarial rash to
  antivenom but recovered completely in 22 days

Deraniyagala PEP. 1960. The effects of the venom
of Echis carinatus sinhaleya the Saw scaled viper
of Ceylon, Spolia Zeylanica, 29(1)33-34.
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The study

• Background
• Saw-scaled viper bites in Sri Lanka are
  considered as rare. Only a few case reports are
  available.
• Clinical features of such bites is not well
  established.
• Due to ongoing war situation in Northern areas of
  island, data on saw-scaled viper bites are
  under-reported.
• This study is aimed to define the clinical
  profile of Saw-scaled viper bites.

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Prospective study

• Conducted in
• Jaffna Teaching hospital
• Mannar District hospital
• All snakes brought by snake-bitten patients were
  saved for expert identification
• Data of patients recorded
• Demography
• Clinical pattern
• Treatment
• outcome

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Results
Number of victims Jaffna 15, Mannar
30 Male Female 31 Saw scaled viper bites
as a percentage of total venomous snake
bites Jaffna 22 , Mannar 56 Most bitten
while working or walking in the dark (outdoor
bites) Site of bites lower limbs in 80
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Results Demographic data
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Results envenoming
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Envenoming by Saw-scaled viper

• Local envenoming
• A significant number (64) had bleeding,
  swelling etc.
• Systemic envenoming
• Incoagulable blood detected by 20 Minutes Whole
  Blood Clotting Test (75)
• 24 had spontaneous bleeding
• Neurotoxicity and renal dysfunction were not seen

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Treatment with antivenom

• 32 patients were treated with antivenom
• Evidence of systemic envenoming or a positive
  20WBCT alone were indications for antivenom
• Antivenom
• Indian polyspecific antivenom against Saw -
  scaled Viper, Cobra, Russells viper Indian
  Krait
• 60 had reactions to antivenom
• 10 20 vials were used per patient
• There were no deaths

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Conclusions

• Clinical syndrome of Saw-scaled viper bite mainly
  haemotoxicity and local envenoming
• Neurotoxicity and nephrotoxicity were not seen
• It causes significant morbidity in the semi-arid,
  northern and north western parts of
• Sri Lanka
• The case fatality rate is very low when
  compared to other countries such as Africa

Global issues in Clinical Toxinology 2008,
Melbourne
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Acknowledgements

• Staff of Teaching Hospital Jaffna and District
  Hospital Mannar
• All our patients

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Thank you