A case of anthrax in wild elephant from the Western Ghats region
of Kerala, India
P.M.Priya 1, M. Mini 2, P. Rameshkumar3 &
V.Jayesh 4
1 Assistant
Professor, 2 Associate Professor, Department of Veterinary Microbiology,
College of Veterinary and Animal Sciences, Pookot, Wayanad District, Kerala 673576, India
3 Teaching
Assistant, Department of Veterinary Pathology, College of Veterinary and Animal Sciences, Pookot, Wayanad Distirct, Kerala 673576, India
4 Veterinary
Surgeon, Clinical lab, District Veterinary Centre, Kalpetta,Wayanad District, Kerala, India
Email: 1 priyamelepat@rediffmail.com
Date
of publication 26 March 2009
ISSN 0974-7907
(online) | 0974-7893 (print)
Editor: Jacob V. Cheeran
Manuscript
details:
Ms # o1756
Received on 07
April 2007
Final revised
received 27 November 2007
Finally accepted
21 July 2008
Citation: Priya, P.M., M. Mini, P. Rameshkumar& V. Jayesh (2009). A case of
anthrax in wild elephant from the Western Ghats region of Kerala, India. Journal of Threatened Taxa 1(3): 192-193.
Copyright: © P.M. Priya, M. Mini, P. Rameshkumar& V. Jayesh 2009. Commons Attribution 3.0 Unported License. JoTT allows
unrestricted use of this article in any medium for non-profit purposes,
reproduction and distribution by providing adequate credit to the authors and
the source of publication.
Acknowledgements: The authors
thank the Associate Dean, College of Veterinary and Animal Sciences, Pookot, for providing facilities to carry out the work.
Anthrax is a
highly contagious zoonotic disease which affects
virtually all mammalian species (Quinn et al. 1994), caused by Bacillus anthracis, a Gram-positive, non-motile sporulating rod bacterium. It is a list B disease of the OIE (World Animal Health Organisation). The
disease was one of the foremost causes of uncontrolled mortality in livestock
worldwide during the late 19th and early 20th century. The development of effective livestock
vaccine by Sterne, successful application of penicillin therapy and the
implementation of quarantine regulations have drastically decreased livestock
cases, but anthrax remains unchecked in wildlife due to the practical
difficulties in vaccination (Hugh-Jones & De Vos2002). Though the disease occurrence was
reported in various species from different parts of our country, isolation and
identification of Bacillus anthracisfrom wild elephants has not been well documented in India and has not been
reported in Kerala.
On 29 September
2006, the death of a wild elephant was reported by a forest guard to the local
veterinary surgeon. The animal belonged
to the Chedleth forest range, Pulpallyof Wayanad district of Kerala, which is a border area
between the two states, Kerala and Karnataka. A detailed examination of the carcass revealed discharge of blood from
the eyes, trunk and also from a deep cut wound in the middle part of the
trunk. On suspicion of anthrax, the
veterinary surgeon examined peripheral blood smears prepared from the cut wound
as well as from the eyes. The duplicate
smears were sent to District Veterinary Centre, Kalpetta. No pathogenic organisms could be detected on
any of the stained smears by Leishman’stechnique. Hence, a post-mortem was
conducted; no abnormality could be detected except for the unclottedblood from the internal organs. For
detailed laboratory examination, heart blood was brought to the Department of
Veterinary Microbiology. Thin blood
smears were prepared and stained by Leishman’s stain
and examined microscopically. Heart
blood was cultured on nutrient agar and the plate was incubated aerobically at
370C for 24 hours. The pure culture
obtained was characterized and the isolate was confirmed as Bacillus anthracis by mice inoculation test as per the method
described by Lennette (1980).
Blood smear
stained with Leishman’s stain revealed numerous blue
rods with typical truncated ends in short chains. (Image 1). For the demonstration of capsule, polychrome methylene blue staining was done. It revealed blue colored bacilli with pink
colored capsular material, the ‘Mac Fadyeanreaction’, which is considered as pathognomonic for
anthrax (Quinn et al. 1994).
On nutrient
agar, irregularly round colonies of about 4mm in diameter, flat, dull, opaque, greyish-white and a frosted glass appearance were
noticed. Under low magnification, the
edges of the colonies resembled locks of matted hairs, the typical ‘medusa head
appearance’. The colonies were weakly haemolytic on blood agar. Gram’s stained culture smear revealed Gram positive bacilli arranged end
to end in long chains and presented a ‘bamboo stick’ appearance.
An inoculum for animal pathogenicitytesting was prepared by scraping some growth from an 18-24 hr incubated agar
plate with a loop and emulsifying into 10ml of sterile saline in a test tube by
holding the tube in a 450 angle and rubbing some growth into the area of
meniscus so that the upper 0.5ml of saline became slightly turbid. Tube contents were mixed and the resulting
suspension did not show any turbidity (contained
approximately 105 to 106 organisms/ml). Two mice were each inoculated with 0.1-0.2ml subcutaneously and one
mouse kept as control. The animals were
observed at 6-hourly intervals and the test mouse was found to be dead 30 hr of
post inoculation. The post mortem
conducted on the dead mouse revealed hemorrhagic lungs, liver and splenomegaly. Impression smears from liver, lungs, spleen and heart blood smear
readily revealed the bacilli by Leishman’sstaining. The inoculated organism was
re-isolated from all the organs with lesions, thus proving the Koch postulates.
Control measures
like precautionary disposal of carcass, public awareness programs and
vaccination of animals were successfully done by the veterinary officials, and
the forest officials were also informed.
According to
Hugh-Jones & De Vos (2002), variation in the
number of bacilli in a peripheral smear could be expected not only within the
animal species, but also between species. Some animals show consistently high terminal bacteraemiccounts, while in others few or no Bacillus anthracisorganisms could be detected terminally. Low numbers could also be expected in animals treated with antibiotics
or in those possessing some immunity. In
the present case, the animal did not have enough organisms to be detected in
peripheral blood smears. This forms an
interesting and informative case of anthrax in a wild elephant in Kerala.
References
Hugh-Jones,M.E & V. De Vos (2002). Anthrax and
wildlife. Review of scientific technical in office
international des epizooties 21(2): 359-382.
Quinn,
P.J., M.E. Carter, B.K. Markey & G.R. Carter (1994). Clinical Veterinary Microbiology. 1st edition. Wolfe Publishing
Company, Morby Year Book Europe Ltd, 179pp.
Lennette, E.H. (1980). Manual of Clinical Microbiology. American
Society for Microbiology, Michigan, 146pp.