A CAJM article on  cases of snake bites admitted to a hospital in Harare, Zimbabwe (formerly Salisbury, Rhodesia)The relative abundance of snake species varies geographically. The commonest venomous snakes in Salisbury are probably the Rhombic Nightadder  (Causus rhombeatus) (Fig. 1), Egyptian Cobra (Naja Haje) (Fig. 4) and Boomslang (Dispholi- dus typus). In the majority of cases identification of the type of venous bite  cannot be obtained as the patient fails to bring  the snake to hospital. The purpose of this paper will be to review the main features noted in a  retrospective series of 186 cases of snake bite seen at Harare Hospital, Salisbury, between January, 1967, and December, 1971, and to provide a brief account of the main features of the common snakes seen in the Salisbury area

Broadley, D.G.

Levin, L.

Wapnick, S.

Central African Journal of Medicine

English

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The Centra] African Journal of Medicine
Editor: i:
! ,
MICHAEL GELFAND, C.B.E., M.D., F.R.C.P.
Assistant Editor: i
JOSEPH RITCHKEN, M.Dil
Volume Eighteen 
JANUARY- DECEMBER 
1972
Salisbury Rhodesia
T h e  Central African
J ournal of M edicine
A Study of Snake Bites 
Admitted to a Hospital in 
Rhodesia
BY
S. WAPNICK,* M.D., F.R.C.S. (Eng.)
L. LEVIN, M.B. Ch .B.,
AND
D. G. BROADLEY,f PhD., F.Z.S.
Department of Surgery, Godfrey Huggins School of 
Medicine and Harare Hospital, Salisbury, Rhodesia.
The relative abundance of snake species varies 
geographically. The commonest venomous snakes 
in Salisbury are probably the Rhombic Nightadder 
0Causus rhombeatus) (Fig. 1), Egyptian Cobra 
(Naja Haje) (Fig. 4) and Boomslang (Dispholi- 
dus typus). In the majority,of cases identification 
of the type of venous bite'cannot be obtained as 
the patient fails to bring ,the snake to hospital. 
The purpose of this paperjwill be to review the 
main features noted in a ^retrospective series of 
186 cases of snake bite seen at Harare Hospital, 
Salisbury, between January, |;1967, and December, 
1971, and to provide a briefaccount of the main 
features of the common snakes seen in the Salis­
bury area.
*Present address: Ichilov Hospital, Tel Aviv, Israel. 
f Curator, Umtali Museum, Umtali.
X&tg f  j
RHOMBIC NIGHT ADDER 
Causus rhombeatus 
Mount Hampden, Salisbury, Rhodesia.
July, 1972. SNAKE BITES IN RHODESIA T h e  Central African
J ournal of Medicine
Table 1
Tachycardia and Cytotoxic R eaction in  D ifferent Age Groups
- (In patients with tachycardia) j
^  Age group Total No. of Extensive cytotoxic reaction 1
' (years) Patients Pulse>90/min.* Present Absent
Less than 26 124 33 (26,6%) 20 13
26 and above 60 11 (18,3%) 3 8
Overall 184 44 (23,9%) 23 ■21
f Figures in brackets refer to the percentage of all cases who had a tachycardia.
Method and Materials 
The case notes of 186 patients admitted follow­
ing a snake bite were examined. In each case the 
age, sex, site and-main morphological features of 
the bite, and prognosis of the patient were noted. 
The month of the year was also noted to ascertain 
whether or not a seasonal incidence of snake' bites 
occurs. The main features of seven common 
snakes seen in the Salisbury area will be pre­
sented.
Results
(a) Age and Sex:
One hundred and ten patients were less than 
20 years of age; 57 were 20-39 years, and 19 
were more than 39 years of age (Fig. 2). The 
overall male : female ratio was 1,3 ; 1.
(b) Extent of local reaction to Snake Bite: 
Twenty-three patients had severe cytotoxic
reactions, characterised by oedema of the entire 
affected limb (with or without necrosis). Patients 
below 26 years of age had more extensive local 
cytotoxic reactions (13 per cent.) than older 
patients (5 per cent.). (Table 1.)
(c) Systemic effects:
Thirty-three patients who were less than 25 
years of age (26 per cent.) had a pulse rate above 
90 per minute (Table 1). Blood pressure measure­
ments were not available in those less than eight 
years of age, and in the remainder, none had a 
systolic pressure recorded below 100 mm Hg. 
Eleven of the patients over 25 years (18,3. per
cent.) had a pulse rate above 90 per minute anc 
one was hypotensive.
Of the patients who presented with tachycardia, 
20 (60 per cent.) of those less than 26 years of 
age and three (27,3 per cent.) of the older 
patients and evidence of local cytotoxic changes. 
The patient mentioned above who had a blood 
pressure of 90/60 mm Hg., a.pulse of 125/minute, 
also showed extensive necrosis with blistering. It 
should be emphasised that: these observations are 
based upon a retrospective survey and that the 
true incidence of severe |local cytotoxic reaction 
may be much higher. ;
There were two patients in this series who 
were known to have developed a bleeding dis­
order. One female patient developed a severe 
coagulopathy with thrombocytopaenia, a pro­
longed prothrombin time, hypofibrinogenaemia 
and severe bleeding following a boomslang bite. 
The bleeding disorder was reversed following 
heparin and specific antivenene -administration. 
Details of this case have been reported elsewhere 
(Riley, 1971), and the subject has been reviewed 
by De Vries and Cohen (1969). The second 
patient developed a severe cytotoxic reaction, 
thrombocytopaenia and temporary prolongation 
of the prothrombin time after a bit& probably due 
to a puff adder (Levin and Wapnick, 1972).
(d) Seasonal incidence:
The peak seasonal incidence of snake bites 
occurs from October to April (Fig. 3). There
No. of cases
Fig. 3.—Monthly frequency in series.
138
Ju ly , 1972. SNAKE BITES IN RHODESIA T h e  Cen t r a l  A fr ic a n
J ou rn al  of M e d ic in e
were 26 cases seen in the month of February, 
whereas the figure for July was two.
(e) Mortality:
There were no cases in this series who died. 
This does not exclude the possibility that some 
patients may have died before reaching hospital.
Venomous Snakes of Salisbury D istrict
Seven venomous snakes found in the Salisbury 
district are potential sources of serious snake bite 
cases.
The Boomslang (Dispholidus typhus) is a 
back-fanged species which secretes a particularly 
potent venom. It is a rather slender tree snake 
averaging about 1,5 metres in length, readily 
identified by its short head and very large eyes, 
combined with oblique keeled body scales. 
Juveniles are brown or blackish above with blue 
spots on some scales, the belly is finely stippled 
with red-brown and the eye is bright green. 
Adults are green, often with black-edged scales 
(usually males) or olive-brown (usually females). 
Although a common snake throughout Rhodesia, 
the boomslang rarely bites anybody because its 
good eyesight enables it to keep out of man’s 
way most of the time.
The Egyptian Cobra (Naja haje) (Fig. 4) is a 
common snake around Salisbury. It is a heavily- 
built snake, averaging 1,5. to 2 metres in length. 
Colouring varies from yellowish (especially 
juveniles) through shades of brown to black, 
while some specimens are strikingly banded in 
black and yellow. When this cobra rears up and 
spreads its “hood”, there is a broad dark band 
across the front; of it. This species can be dis-
(Fig. 4)
EGYPTIAN COBRA 
Naja haje anriulijera (Banded phase) 
Umtali, S. Rhodesia.
(Fig. 5)
' BLACK MAMBA 
Dendroaspis polylepis 
‘ Kapami, Wankie, Rhodesia."
tinguished from i other cobras by a series of small 
scales below the' eye; in other cobras these are ■ 
absent and the shields that border the lip also 
enter the eye. j .
i 1
The Mozambique Spitting Cobra (Naja
mossambica) is hot common in the Salisbury 
district as it prefers lower altitudes. It has been 
collected in the Borrowdale area and on the 
Golden Stairs Road. This cobra rarely exceeds 
1,5 metres in length and is light grey or olive 
above, salmon pink below. The “hood” is narrow 
when spread and has a series of irregular black 
bands and blotches on its anterior face. It is the 
only snake in this area which can project its 
venom into the eyes of an adversary.
The Black Mamba (Dendroaspis polylepis\ 
(Fig. 5) is scarce around Salisbury, but is known 
from the Golden Stairs Road, Borrowdale and 
Arcturus. Averaging nearly 2,5 metres in length, 
it has a long, coffin-shaped head, slender body 
and long tail. The colour is usually olive-brown or 
greyish, lighter below, with the inside of the mouth 
blackish.
The Burrowing Adder (Atractaspis bibrotiii) 
is a small burrowing snake which is most fre­
quently encountered after rain. Averaging .less 
than half a metre in length, it is purple-brown to 
black above; brown, white or mottled below. It 
does not open its mouth to bite, the long fangs 
being brought down on each side of the com­
pressed lower jaw. Many amateur snake-catchers 
are bitten by this vicious little snake, often 
suffering permanent damage to fingers.
Ju l y , 1972. SNAKE BITES IN RHODESIA T h e  Central African
JounNAL of Medicine
The Rhombic Night-adder {Causus rhom- 
beatus) is one of the commonest snakes around 
Salisbury. Averaging a little over half a metre in 
length, the ground colour is usually olive or 
pinkish brown, with a darker V-marking pointing 
forward on the head and a series of large blotches 
on the back (some specimens completely lack 
these markings). Most night-adder bites merely 
cause local pain and swelling and leave no after 
effects.
The Puff-adder {Bitis arietans) is not found in 
central Salisbury, but has been recorded from the 
Golden Stairs Road, Borrowdale and Hatfield. 
Averaging about 0,75 metre in length, it is heavy­
bodied with a broad flat head and a slender 
neck. It is usually brown or yellowish with a 
series of backward pointing black and yellow 
chevrons on the back. This snake is responsible 
for most of the serious snake-bites in Africa.
D iscussion
The majority of patients bitten by a venomous 
snake and seen at Harare Hospital, Salisbury, 
recover completely within 3-6 days. The fact 
that there were no deaths recorded in this series 
lends support to the impression that the Rhombic 
Night-adder is responsible for most of these bites. 
The rapid onset of symptoms and the early 
appearance of lymphangitis is the hallmark of the 
majority. A few patients, however, develop 
systemic toxicity with tachycardia, my cocarditis 
and in severe cases, hypotension (Levin and 
Wapnick, 1972). It is our policy to admit all 
patients bitten by venomous snakes, elevate the 
affected limb and administer tetanus toxoid. 
Although we administer penicillin and phenergan 
to these patients, we have no proof of their exact 
value. We have not used calcium gluconate 
(Strover, 1955), or steroids in the management 
of these cases (Strover, 1964).
If the snake has been captured and fangs 
are shown to be absent, antivenom is contra­
indicated. We cannot support the widely recom­
mended viewpoint that antivenom . should be 
administered to all people, bitten by a venomous 
snake as serious untoward reactions may occur. 
In the minority of cases where severe local or 
systemic reaction is evident during the first few 
hours following a bite (usually following a puff- 
adder or cobra bite), specific antivenom is indi­
cated. These patients may require intensive 
supportive therapy with intravenous fluid 
administration, with electrolyte, acid-base, urinary 
output and central venous pressure monitoring.
Antivenom should only be administered after 
subcutaneous and intravenous test doses have 
been given. Even if there is no anaphylaxis with
the test dose, the antivenom should be adminis­
tered by controlled drip infusion and the rate of 
flow monitored carefully against the patient’s 
pulse and blood pressure. Furthermore, if the 
antivenom is to be given, it is pointless giving 
less than 70-100 ml. (Reid, 1968). The adminis­
tration of 10 ml. antivenom as a routine pro­
cedure in cases of snake bite is not only ineffec­
tive, but could be highly dangerous.
The application of a tight tourniquet on a limb 
for a long period may seriously impair the 
circulation of the affected part. Tourniquets 
should probably be used in elapid bites until 
specific antivenom can be administered. Mason 
(1963) recommends that the tourniquet should 
be removed for half-minute intervals 30, 50 and 
90 minutes after a bite, and must be discarded 
two hours after its initial application.
The presence of a severe, -local cytotoxic 
reaction with extensive gangrene of the skin 
suggests that the bite is due to; that of a puff- 
adder. One should, however, refrain from ex­
tensive excision or amputation pf the limb unless 
it is obvious that its circulation is inadequate. 
Where possible, excision shouldj.be delayed until 
a clear line of demarcation is I evident. In one 
patient we considered that an aboVe-knee amputa­
tion would be necessary. The leg was elevated, 
the hypotension corrected and three weeks later 
an excision of the superficial necrotic skin per­
formed. The greater part of the gastrocnemius 
and soleus tendons were destroyed, but she was 
able to walk and did not require a prosthesis.
An interesting finding in this study is the high 
percentage of young patients who showed severe 
local reactions. The more severe reaction in the 
younger age group could be accounted for bn 
the basis that venom concentration is greater 
where the confined area of the bite is smaller 
(Reid, 1968). For the same reason a bite on the 
toe, for example, will produce a more severe 
cytotoxic reaction than one of the skin overlying 
the posterior tibial compartment.
It is useful to remember that systemic poisoning 
caused by venomous snakes is only evident after 
the first 30-60 minutes following the bite. If the 
patient shows immediate systemic features with 
clouding of consciousness, tachycardia, sweating 
and tachyphoea, it can most likely be attributed 
to the patient’s response to fear at having been 
bitten. The presence of local oedema and lymph­
angitis are helpful signs in the diagnosis of bites 
due to venomous snakes. As a rule, a severe 
clinical response to snake bites can be anticipated 
if marked symptoms are evident one or two hours 
following the bite.
140
Iuly, 1972. SNAKE BITES IN  RHODESIA T h e  Central African
J ournal of Medicine
Table 2
M ain F eatures of Snake Bites Occurring in  the Salisbury Area
Viperidae Elapidae Colubridae
Examples 1. Rhombic Night-Adder
2. Puff Adder
3. Burrowing Adder
1. Egyptian Cobra
2. Mozambique Spitting 
Cobra
3. Black Mamba
Boomslang
Fangs Anterior Anterior Posterior
(grooved)
Attachment of fangs to 
jaw
Mobile
Fangs erected during the 
act of biting
Fixed
Permanently erect
Permanently erect
Toxin (main effect) Cytotoxic Neurotoxic Haemorhagic
Bite marks (fangs) pair
(more severe local 
reaction)
pair
(minimal local reaction)
Often multiple and 
ragged
Antivenom None except for severe 
cases of puff adder bites
Cobra Antivenom 
(for Cobra) 
Polyvalent Mamba 
■ antivenom 
(for mamba)
Specific Monovalent 
(Obtained from S.A. 
Med. Res. Inst., 
Johannesburg)
Patients bitten by a colubrid snake (e.g., 
boomslang) (see Table 2) require specific anti­
venom in addition to supportive therapy. For­
tunately bites by a boomslang are rare. If 
severe fibrinogen depletion with haemorrhage 
occur in a patient recently bitten by a'venomous 
snake in Rhodesia, specific , boomslang antivenom 
should be obtained by urgent air-freight from the 
South African Institute of Medical Research, 
Johannesburg. Further treatment, other than 
blood transfusion, includes small amounts of 
intravenous heparin if an associated coagulopathy 
is present, or Trasylol if excessive fibrinolysis is 
evident.
Although the main toxic effects of the indi­
vidual snakes in Rhodesia correspond in general 
with that in Table 3, it should be noted that the 
venom of certain snakes of the same family order 
in other parts of the globe have different toxic 
properties. The Malayan pit viper (Reid, et ai., 
1963) and Echis coloratus in Israel (Fainau, et al., 
1970) causes severe haemorrhagic reaction. 
Montgomery (1959) reported the occurrence of 
ophthalmoplegia, due to the neurotoxic effect of a 
Berg-adder bite.
Although no death was recorded in this series 
of cases admitted to a hospital in Salisbury, there 
have been 21 deaths caused by snake bites in 
Rhodesia during a five-year period (Castle, 1971). 
These findings indicate that the majority of severe 
snake bites fail,to reach hospital, or alternatively 
the cases of snake bites in other parts of Rho­
desia have more serious sequelae.
.‘'Summary
The main features noted in a review of 186 
cases of snake bities admitted to Harare Hospital 
have been reviewed. Several local systemic 
reactions were more frequent in the younger 
patients. The maximum 'number of snake bites 
occur between October and February. The 
review shows that the majority of patients bitten 
by a venomous snake in the Salisbury area make 
a rapid recovery and do not require antivenom 
administration. We find that high elevation of the 
affected limb is the single most useful factor in 
securing rapid recovery.
BIBLIOGRAPHY
Castle, W. M. (1971). C. Afr. J. Med., 17, 165.
De  Vreis, A. and Cohen , I. (1969) in: Poller, L. (Ed.)
"'Recent advances in blood coagulation”.
F ainau, M., Manny; N., H erschke, C. and E isenberg, 
S. (1970). Is. J. med. Sci., 6, 720.
Levin, L and Wapnick, S. (1972). Clinical and electro­
cardiographic changes following snake bite. (In  pre­
paration.)
M ason, J. H. (1963). C. Afr. J. Med., 9, 219. 
M ontgomery, J. (1959). C. Afr. J. Med., 5, 173.
Riley, M. J. (1970). Paper read to 48th South African 
Medical Congress.
Reid, H. A., T hean, P . C., Chan, K . E . and Baharom, 
A. R. (1963). Lancet, 1, 617.
Reid, H. A. (1968). Brit. Med. J., 11, 359.
Strover, H. M. (1955). Trap, Dis. Bull., 52, 421. 
Stkover, A. E. (1964). C. Afr. J. Med., 10, 283.
ACKNOWLEDGMENTS
The authors thank Mr. G. Davies, Mr. D. R. Barley 
and Miss S. Fleming for their assistance, and the 
Director of Medical Services for access to die hospital 
records.
141
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A Study of Snake Bites Admitted to a Hospital in Rhodesia

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A Study of Snake Bites Admitted to a Hospital in Rhodesia

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