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Vlaams Diergeneeskundig Tijdschrift, 2011, 80 Case report 351
INTRODUCTION
Tetanus is a life-threatening toxico-infection caused
by the neurotoxin of C. tetani. Typical symptoms are
increased general muscular rigidity evolving to a com-
plete tetanic state, frequently with a fatal outcome
(Linnenbrink et al., 2006). Although tetanus is descri-
bed in all domestic animals, small ruminants and horses
are known to be the most susceptible species (Aslani
et al., 1998; Driemeier et al., 2006; Wernery et al.,
2004). Tetanus usually affects a single animal, but out-
breaks have been sporadically described in farm ani-
mals, especially in association with serial injections
(Barbosa et al., 2009; Driemeier et al., 2007). Infection
occurs as a result of contamination of wounds with spo-
res of C. tetani, which desporulate to the vegetative
form and produce tetanus toxin when anaerobic con-
ditions are present. The most frequently described in-
fection sites in farm animals are castration, shearing
and injection wounds (Aslani et al., 1998). As less
frequent infection sources surgical contamination,
snake bites, umbilical infections and ear tagging have
also been described in animals (Aslani et al., 1998; Lin-
nenbrink et al., 2006; Poudel et al., 2009). This case re-
port describes two tetanus cases with an atypical por-
tal of entry, the first being an outbreak of tetanus in
dairy calves, shortly after thermal dehorning and the se-
cond in a three-year old goat, after ear tagging.
Thermic dehorning and ear tagging as atypical portals of entry of
Clostridium tetani in ruminants
Thermische onthoorning en oormerken als atypische intredeplaatsen van
Clostridium tetani bij herkauwers
1B. Valgaeren, 1P. De Schutter, 1B. Pardon, 2V. Eeckhaut, 2F. Boyen, 2F. Van Immerseel, 1P. Deprez
1Department of Internal Medicine and Clinical Biology of Large Animals
2Department of Pathology, Bacteriology and Avian Diseases,
Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium
bonnie.valgaeren@ugent.be
ABSTRACT
This paper describes two infections with Clostridium tetani (C. tetani). One outbreak occurred after de-
horning of calves, the second infection happened after ear tagging of a goat. In the first case 3 young Holstein
Friesian calves showed generalized stiffness, severe lock-jaw and bloat two weeks after dehorning. The ther-
mal dehorning wounds were identified as the infection sites of C. tetani by bacterial culture and PCR. The se-
cond case was a three-year old male castrated goat, with generalized stiffness. The animal had been ear tag-
ged one week prior to the onset of the symptoms. C. tetani could be cultured from pus on the ear tag.
Treatment was attempted in two calves and the goat. Wounds were debrided and disinfected, penicillin and
anti-tetanus serum were administered and polyionic perfusions provided. In addition, the goat was vaccina-
ted against tetanus. The goat and one calf fully recovered after 36 and 8 days respectively. To the authors’ know-
ledge a tetanus outbreak in association with thermal dehorning has not been described previously. Also ear
tagging as a possible cause for C. tetani infection has not been described in goats.
SAMENVATTING
In dit artikel worden twee infecties met Clostridium tetani beschreven. Een eerste uitbraak ontstond na het ont-
hoornen van kalveren, de tweede infectie na het oormerken van een geit. In de eerste casus vertoonden drie jonge
holstein-friesiankalveren veralgemeende stijfheid, een trismus en tympanie twee weken na het onthoornen. De won-
den na de thermische onthoorning werden geïdentificeerd als de infectieplaatsen van Clostridium tetani door mid-
del van bacteriële cultuur en PCR. De tweede casus betrof een mannelijke gecastreerde geit van drie jaar oud met
veralgemeende stijfheid. Een week vóór het begin van de symptomen werden oormerken geplaatst. C. tetani kon
geïsoleerd worden uit de etter verkleefd aan het oormerk. Twee van de drie kalveren en de geit werden behandeld.
De wonden werden schoongemaakt en gedesinfecteerd en penicilline, antitetanus-serum en polyionisch infuus wer-
den toegediend. De geit werd bijkomend gevaccineerd tegen tetanus. De geit en één kalf herstelden volledig na res-
pectievelijk 36 en acht dagen.
Voor zover bekend werd er nog nooit een tetanusuitbraak geassocieerd met thermisch onthoornen, beschreven.
Ook het oormerken werd nog niet beschreven als een mogelijke oorzaak van een C. Tetani-infectie bij geiten.
352 Vlaams Diergeneeskundig Tijdschrift, 2011, 80
CASE 1
Case history
In May 2011 three Holstein Friesian calves, be-
tween 3 and 5 months of age, were referred to the Ve-
terinary Clinic in Merelbeke with complaints of stiff-
ness, recumbency, ruminal bloat and lock-jaw. The
symptoms had started 2 to 7 days before presentation.
At the farm, all animals were housed in the same pen
together with thirteen other calves. Fourteen days be-
fore admission, eight of these calves were thermally de-
horned. Seven days before admission, one of the re-
cently dehorned calves was found dead. No previous
symptoms were noted by the owner, and no necropsy
was performed. The animals were vaccinated against
IBR, but not against clostridial diseases.
Clinical examination and ancillary diagnostics
All calves showed stiffness in all four limbs, mar-
kedly increased muscle tone, pricked ears, lifted tail
and bloat. One calf was still able to lie down and get
up without assistance and to ingest small amounts of
feed and water, whereas the other two calves could not
bend their legs, had severe lock-jaw and were unable
to eat or drink. The dehorning wounds had a thick
crust with pus underneath. No other wounds were de-
tected. Temperature, respiration and heart rate were
normal in all calves.
Standard hematology, biochemistry and blood gas
analysis only showed a mild to severe dehydration in
all calves. The crust was removed from the dehorning
wounds and cultured for Clostridium tetani. The crust
was suspended in sterile phosphate buffer solution
(PBS) and heated at 80°C for 20 minutes. Of this su-
spension, 100µl was cultivated at 37°C for 24 hours on
a blood plate in an anaerobic chamber (Ruskinn Tech-
nology) with 84% N2, 8% CO2and 8% H2. A pure cul-
ture of a hemolytic gram-positive rod with terminal
spores was obtained (Figure 1a). The final identifica-
tion of C. tetani was done by PCR (Akbulut et al.,
2005).
Treatment and further evolution
One calf was euthanized immediately at arrival due
to the graveness of the symptoms and the bad progno-
sis. The dehorning wounds of the remaining calves
were thoroughly cleaned with H2O2.The calves recei-
ved IV 10 ml of anti-tetanus serum®(Intervet), daily in-
jections with procaine benzylpenicillin (10 mg/kg, IM,
Duphapen, Pfizer A.H.) and thiamine (10mg/kg, IV,
tid) for 6 days and polyionic perfusion with 10% glu-
cose. A second calf was euthanized 2 days after arrival
in the clinic due to worsening of the symptoms. In the
third calf, which showed the best clinical condition at
arrival, the symptoms gradually improved and the pa-
tient could leave the clinic 7 days after presentation
with minimal signs of stiffness.
CASE 2
Case history
In June 2011, a castrated male goat of 3 years of age
was presented at the clinic with symptoms of apathy,
generalized stiffness, dysphagia and reduced ruminal
sounds. At home, the veterinarian suspected indigestion
or ruminal acidosis and treated the animal with bu-
tylscopolamine (Buscopan®, Boehringer Ingelheim
BV), flunixine meglumine (Bedozane®, Eurovet), a bi-
carbonate perfusion and supplementation with vita-
mins and minerals. The animal was kept in a hobby set-
ting on pasture together with 5 apparently healthy
other goats. Although all animals were officially re-
gistered since birth, their ear tags had only been placed
a week before presentation at the clinic. The animal had
been vaccinated once against C. tetani before castration
at 6 months of age, but without continuation of the vac-
cination program.
Figure 1b. Spores and bacteria of Clostridium tetani with
a typical drum-stick shape isolated from the ear tags in
case 2 (Malachite Green – 1000x).
Figure 1a. Spores and bacteria of Clostridium tetani with
a typical drum-stick shape isolated from the crust of the
dehorning wounds in case 1 (gram-staining-1000x).
Vlaams Diergeneeskundig Tijdschrift, 2011, 80 353
Clinical examination and ancillary diagnostics
Upon admission, the goat showed obvious stiff-
ness of the limbs and was alert. Rectal temperature,
pulse and respiration rates were normal. Elevated ab-
dominal tension, pricked ears, elevated tail and subtle
ruminal bloat were present. The uptake of food and wa-
ter was impossible due to severe lock-jaw. The animal
could still defecate and urinate in a normal way.
The goat was slightly dehydrated. No other deviati-
ons were found on standard blood examination. The ru-
minal fluid had a normal macroscopic aspect and a pH
of 7.3 (normal values 6-7). Multiple living protozoa
were detected on microscopic examination (10x mag-
nification). Standard parasitological examination resul-
ted in a strongyle count of 8100 eggs per gram feces and
an Eimeria spp. count of 450 oöcysts per gram faeces.
Of the detected oöcysts roughly 10% belonged to the vi-
rulent species Eimeria ninakohlyakimovae. The ear tags
were removed after permission of the official authority
responsible for food animal identification. From pus
sticking to the ear tags, an anaerobic culture was per-
formed as described in case 1 and Clostridium tetani
could be cultured. Further identification was done as
described in case 1. A smear of the purified colonies was
stained with Malachite Green and safranin and the ty-
pical drum-stick shaped rods were visible, as demon-
strated in Figure 1b.
Treatment and further evolution
The crusts were removed and the wounds were dis-
infected with H2O2. The goat received 4 ml of anti-te-
tanus serum® (Intervet), and daily injections with pro-
caine benzylpenicillin (10 mg/kg, IM, Duphapen,
Pfizer A.H.) and thiamine (10mg/kg, IV, tid) for 6 days
and a polyionic perfusion with 10% glucose. Additio-
nally the goat was vaccinated with Covexin 10®(Pfi-
zer AH) containing a minimum of 4.9 IE C. tetani
toxoid. A mixture of beet pulp and moistened concen-
trates was offered by syringe in the animal’s mouth.
Three days after referral to the clinic, the animal was
found in lateral recumbency with severe ruminal bloat,
worsened jaw-lock and stiffness of the limbs. Most pro-
bably the animal had fallen during the night and had
been unable to stand up by itself, resulting in ruminal
bloat. Because of the degree of excitation, the animal
was mildly sedated (midazolam, 0.25 mg/kg, Dormi-
cum, Roche). The bloat was relieved by rumen punc-
ture with a 16G catheter after surgical preparation.
The ear wounds were debrided again and 2 ml of pe-
nicillin was locally administered. The symptoms sta-
bilized over the next days and the animal gradually re-
covered. Eight days after admission, when the animal
was able to eat unaided, it was discharged. The remai-
ning symptoms (stiffness of the limbs) continued to
decrease and 5 weeks after submission in the clinic, the
animal had fully recovered. New ear tags were placed
after recovery.
DISCUSSION
Tetanus is a fatal toxico-infection, caused by toxins
of Clostridium tetani (Poudel et al., 2009). This bac-
terium is able to produce two important toxins, namely
tetanolysin and tetanospasmin. The first has the ability
to lyse cell membranes, causing tissue damage and
stimulating the development of an anaerobic environ-
ment. The latter is responsible for the neurological
symptoms by inhibiting the release of inhibitory neu-
rotransmitters, causing generalized muscle spasm and
alterations of autonomic control. Because the toxin is
slowly transported retrograde from the peripheral ner-
ves to the central nervous system, incubation periods
of 3 to 18 days are described (Driemeier et al., 2006;
Linnenbrink et al., 2006). C. tetani produces very re-
sistant spores that can survive boiling temperatures
for several minutes (Dixit et al., 2005; Linnenbrink et
al., 2006). In order to desporulate to a vegetative form,
the spores need an environment with low oxygen ten-
sion, typically generated under the crust of penetrating
wounds (Linnenbrink et al., 2006). Although the ad-
vanced symptoms might resemble those seen in trau-
matic reticuloperitonitis, white muscle disease, grass
tetany, meningitis, cerebrocortical necrosis, lead in-
toxication, strychnine-intoxication and to a lesser ex-
tent laminitis, poly-arthritis, esophageal obstruction
and other causes of ruminal tympany (Stöber, 2002).
However, in the case of tetanus the symptoms quickly
evolve to the pathognomonic tonic-clonic cramps of
the antigravitational muscles, protrusion of the third
eye lid, stiff ears and a raised tail base. Although teta-
nus typically is an individual problem, outbreaks have
been described in several animal species and humans,
due to very different entry routes. Most famous are hu-
man outbreaks in intravenous drug users due to the use
of contaminated needles (Sun K., 1994; Gormley et al.,
2004). Also in ruminants multiple outbreaks have been
described following injections with contaminated need-
les, for example after injection with anthelmintics in
sheep and cattle or after rabies vaccination in buffalo’s
(Driemeier et al., 2006; Barbosa et al., 2009). Al-
though goats and sheep are more sensitive than cattle,
(Aslani et al., 1998) outbreaks have more frequently
been described in young cattle, possibly due to the
more frequent application of mass injections in calves
(Driemeier et al., 2006).
The present case report describes an outbreak of te-
tanus in three animals of the same herd, following
thermal dehorning. Since the ban on chemical dehor-
ning in 2008, thermal dehorning is the standard de-
horning method for calves of 4 to 8 weeks of age
(Nantier, 2009). The dehorning iron is heated to 600-
700 degrees Celsius and is then placed upon the horn
stumps, burning the epithelium and surrounding tissue
and resulting in permanent removal of the horn stumps.
After 1 to 2 days a thick impermeable crust is formed
which encloses the dehorning wounds (Nantier, 2009).
The temperature reached on the iron is kept for several
minutes and is probably lethal to spores. Therefore, it
is unlikely that the iron itself serves as a vector for C.
354 Vlaams Diergeneeskundig Tijdschrift, 2011, 80
tetani (Dixit et al., 2005). Environmental contamina-
tion of the dehorning wound with faecal material and
dirt from the stable environment seems a more likely
infection route (Driemeier et al., 2006; Linnenbrink et
al., 2006). Additionally, the thermal treatment also
causes the perfect circumstances for the creation of an
anaerobic environment by destroying the blood vessels
and creating a thick impermeable crust. These factors
predispose to the growth and toxin production of C. te-
tani (Nitzschke et al., 2008). Burning wounds are a
well known risk for tetanus in humans whereas no re-
ports in animals were found (Cassel et al., 2002). This
is the first time thermal dehorning is described as a
cause of a tetanus infection. As this method is nowa-
days the standard dehorning procedure in Belgium and
since most calves are not vaccinated against C. tetani
for economical reasons, a higher incidence of tetanus
outbreaks in future years might be possible.
Although the insertion of ear tags is routinely done
in young ruminants, including goats, only one out-
break of tetanus in lambs following ear tag insertion at
7 to 8 days of age has been described (Aslani et al.,
1998). It is not clear whether the older age of the ani-
mal was a risk factor for the occurrence of tetanus.
However, permethrin-impregnated ear tags are relati-
vely frequently administered in cattle and small rumi-
nants at older age and no cases of tetanus have been re-
ported. Therefore, the occurrence of tetanus associated
with ear tagging in this adult goat is likely an unfortu-
nate incident.
A solid vaccination scheme for tetanus is the most
effective preventive measure, both for adults as through
maternal immunity in newborns (Gall et al., 2011).
Vaccination is advisable in highly susceptible species
such as small ruminants and in animals with high eco-
nomical or emotional value. Double primo-vaccination
at minimally 8 and 12 weeks of age followed by yearly
boosters provide a lasting protection later in life. Per-
forming dehorning and ear tagging as clean as possi-
ble and local administration of antimicrobial sprays
might decrease the risk. Inspection of the wounds a few
days later and disinfection when necessary are advisa-
ble. The preventive application of antitetanus serum
might be an option when ear tagging or dehorning va-
luable unvaccinated animals.
These cases illustrate the importance of a continued
alertness when executing routine invasive interventions
as ear tagging and dehorning. Although small rumi-
nants are more sensitive than cattle and although extra
attention should be given to tetanus prophylaxis when
working with goats or sheep, tetanus may also occur in
young cattle.
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