By Jack Woodall
Saving Bison, Losing Tigers
Wildlife conservation approaches to anthrax and poaching have divergent results.
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One country's conservation effort exposes the paltry efforts of others.
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As every reader of this magazine knows since the anthrax-by-mail episode in October 2001, anthrax is caused by a bacterium, Bacillus anthracis, which can infect the skin, gut, or lungs and produce a toxin that is rapidly fatal; vaccination or antibiotics can prevent this infection. Scientists also know that B. anthracis is an ubiquitous soil organism that affects livestock all over the world, with the exception of small island countries, those on the east coast of Arabia, and for some reason, Sweden. It causes sporadic deaths in cattle, sheep, horses, and goats, which ingest a certain amount of soil with the grass they pull up to eat.
Anthrax also kills wild herbivores, such as bison (also known as wood buffalo) in Canada's last remaining wild herd. During the past summer, in Canada's remote Wood Buffalo National Park, a number of bison died of the infection. Their carcasses were spotted in twice daily helicopter sweeps using military-type infrared sensors that can pinpoint the heat of a recently dead two-and-a-half ton bison against the cooler background of the earth.
In a previous year, the carcasses were left to rot, but the result was patches of land contaminated with anthrax spores that led to many more bison deaths the following year. So the current practice is to cremate the bodies. (I am indebted to my veterinary colleague Martin Hugh-Jones, and Brett Elkins of the Canadian Wildlife & Fisheries Division for the details).
When they are first spotted, dead bison are doused with formalin to keep away predators that would carry off pieces and spread the infection further. Then helicopters are used to fly in firewood and coal. Napalm has been tried but does not work as well; neither does diesel fuel, which was used successfully on the thousands of cattle culled during the foot and mouth disaster in Britain. Cattle have plenty of fat to aid in combustion, but bull bison are solid muscle.
To incinerate the bison, a base is made of a half-dozen green logs and 12 to15 22-kg bags of coal. The carcass is rolled onto the base using rope and a portable winch, and a couple of cords of timber are stacked on top. This gives a long, hot burn that reduces the carcass to ash, and kills all spores that have leaked onto the surrounding ground from hemorrhages during the bison's death throes.
So to deal with the 28 dead bison whose bodies were located in July, more than eight tons of coal and 600 cubic meters of timber were flown in - think of the cost! - a striking testimony to the priority that Canada gives to its natural heritage.
This year in South Africa's world-famous Kruger National Park, kudu, nyala, buffalo, and giraffe died of anthrax; in previous years zebra, elephant, lion, cheetah, and rhino have also died. Years ago, I came across the bizarre sight in Uganda of a hippo, dead from anthrax, floating in a lake, legs rigidly pointing skyward, with a bare-headed marabou stork standing on its bloated stomach, preparing to pick at the entrails.
The game parks of India report some deaths of deer and elephants from anthrax, but suffer badly from an equally deadly disease, poaching. The Bandhavgar tiger reserve in India had 44 tigers in 2005; by the time we visited there in April this year, only 28 were left, thanks to poachers and a shortage of park guards to combat them. We counted ourselves quite lucky to get close-up photos of the dominant male as he strolled past our open vehicle - and even luckier to escape unscathed when the fuel pump broke and stranded us after dark in his territory. I might have been killed and eaten and never have lived to write this.
The 28 Canadian bison that died were incinerated at enormous expense to protect their 10,000 herd-mates. Only 28 tigers were left alive out of the handful in one Indian national park, for lack of a fraction of the amount spent on burning those bison, to pay for more antipoaching guards. Other tiger reserves are suffering the same attrition. Canada will see its herds of bison increase, but by the time India gets around to beefing up its park security, there may be no tigers left.
Jack Woodall is director of the Nucleus for the Investigation of Emerging Infectious Diseases in the Institute of Medical Biochemistry at Brazil's Federal University of Rio de Janeiro.
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Responding to anthrax in northern bison by John Nishi
[Comment posted 2006-11-14 03:09:52]
Jack Woodall uses anthrax outbreaks in northern wood bison to emphasize the expenditure of resources in Canada for wildlife conservation, and contrasts this situation against the lack of funding that is available to combat poaching of tigers in India. Although I cannot comment on the accuracy of his description of the tiger situation in India, and I think his comparison based on financial resources may be overly simplistic, I would like to outline several points that should be clarified on his description of anthrax in wood bison, and the response of wildlife management agencies to these disease epizootics.
- In Canada, wood bison are listed as a ￂﾓthreatenedￂﾔ subspecies of the American bison. Wood bison are currently listed as ￂﾓendangeredￂﾔ under the U.S. Endangered Species Act.
- In summer 2006, a small outbreak of anthrax occurred in free-ranging wood bison in the eastern Slave River Lowlands (SRL) in the Northwest Territories (1). A total of 28 carcasses were found, including 2 calves that likely died from starvation after their mothers succumbed to the disease.
- Anthrax is endemic in the SRL, with 6 documented outbreaks between 1963 and 2001 killing at least 925 bison (2,3). In northern Canada, anthrax outbreaks in bison tend to occur, usually in mid-July to mid-August, after there has been a wet spring followed by hot dry weather (3).
- The SRL are located northeast and outside of Wood Buffalo National Park and are therefore under jurisdiction of the Department of Environment and Natural Resources, Government of the Northwest Territories (GNWT), The SRL bison represent a subpopulation of WBNP population and comprise approximately 700 ￂﾖ 800 bison. The most recent population estimate for bison within WBNP was approximately 5000 animals.
- The GNWT has developed an Anthrax Emergency Response Plan to guide activities during the summer season (2). This plan is consistent with the World Health Organizationￂﾒs guidelines on anthrax surveillance and control (4), and includes media communications and area closures to reduce disease risk to humans, increased aerial surveillance, sampling, and diagnostic confirmation, followed by carcass treatment and disposal (2). The response plan also facilitates research and monitoring activities, which in turn provide information for continued technical improvement and cost-savings in field activities (2,3).
- Biweekly surveillance flights during the summer anthrax season are conducted using fixed-wing aircraft. Because of cost considerations, helicopters are used primarily during an active response to an actual anthrax outbreak. A helicopter-mounted infrared monitor was not used in the 2006 outbreak. To ensure cost-efficiency, surveillance and field activities during an active anthrax outbreak are coordinated with existing forestry personnel and forest management activities where and when possible.
- The cost of helicopter time represents the largest expenditure when responding to an anthrax outbreak and incinerating bison carcasses. Costs will often influence the type of response to an outbreak and whether carcasses are incinerated. For example, in 2000 and 2001, although 100 and 92 bison died of anthrax in Wood Buffalo National Park respectively, park managers did not incinerate the carcasses. Lack of carcass disposal resulted in environmental contamination (5)
- A critically important aspect of managing anthrax in wildlife and livestock, is timely and proper carcass disposal to reduce environmental contamination with anthrax spores and, thereby, reduce the severity or frequency, or both, of future outbreaks (2,6). In northern Canada, we have found that carcass treatment is best achieved through disinfection with formaldehyde (7) followed by complete carcass incineration (8). Application of formaldehyde reduces carcass scavenging over the short term, and thereby lengthens the time available for ground crews to incinerate carcasses. Proper incineration removes contaminated tissues (1) and kills the resistant spores at a carcass site (8).
Literature Cited
1. Nishi, J.S., B.T. Elkin, T.R. Ellsworth, N. Lee, D. Dewar, and D.C. Dragon. In press. An outbreak of anthrax (Bacillus anthracis) in free-roaming bison in the Northwest Territories, June ￂﾖ July 2006. Canadian Veterinary Journal.
2. Nishi, J.S., D.C. Dragon, B.T. Elkin, J. Mitchell, T.R. Ellsworth, and M.E. Hugh-Jones. 2002. Emergency response planning for anthrax outbreaks in bison herds of Northern Canada: A balance between policy and science. Annals of the New York Academy of Sciences. 969:245ￂﾖ250.
3. Dragon, D.C., B.T. Elkin, J.S. Nishi, and T.R. Ellsworth. 1999. A review of anthrax in Canada and implications for research on the disease in northern bison. Journal of Applied Microbiology. 87: 208-213.
4. Turnbull, P.C.B., Boￂﾨhm, R., Doganay, M., Hugh-Jones, M., Lalitha, M.K. and De Vos, V. 1999. Guidelines on Anthrax Surveillance and Control. Geneva: World Health Organisation. Who/EMC/ZDI/98ￂﾷ6.
5. Dragon, D.C., D.E. Bader, J. Mitchell, and N. Woollen. 2005. Natural dissemination of Bacillus anthracis spores in northern Canada. Applied and Environmental Microbiology. 71: 1610-1615.
6. Hugh-Jones, M.E. and V. de Vos. 2002. Anthrax and wildlife. Revue scientifique et technique de l'Office international des Epizooties. 21:359ￂﾖ383.
7. Miles, J., P.M. Latter, I.R. Smith, and O.W. Heal. 1988. Ecological effects of killing Bacillus anthracis on Gruinard Island with formaldehyde. Reclamation and Revegetation Research. 6: 271-283.
8. Dragon, D.C., J.S. Nishi, B.T. Elkin and T.R. Ellsworth. 2004. Evaluation of carcass disposal techniques after an anthrax outbreak in free-ranging bison in northern Canada. Paper presented at 1st International Conference on Fate of Biological Agents, Williamsburg, Virginia, 7-10 June 2004.
A Complex problem by Abhik Gupta
[Comment posted 2006-11-10 15:18:40]
Jack Woodall has raised some very important and contentious issues in wildlife conservation. It is true that improved funding such as that available in countries like Canada could help achieving conservation goals in developing countries like India, where poaching poses a threat to many wild species, including the tiger. Interestingly, Bandhavgarh Tiger Reserve, where he had an unpleasant and life-threatening experience is supposed to be among the better-managed ones, having been ranked the fifth-best in an IUCN study1. It is also one of the few reserves that have recorded an increase in forest cover2. Conditions are far worse in many other reserves, especially those in remote areas. Dampa in Mizoram, for instance, is reported to have only eight personnel to guard its 500 km2 area! The poaching problem is accentuated by the presence of human settlements within the protected areas and one just cannot push them out because tribals and other ecosystem people have been living in the forest since ages. It is therefore an uphill task now to sequester areas untrod by humans where the tiger can roam and hunt free. Tribals evicted from their lands in other areas as well as illegal non-tribal migrants are also entering the reserves, thereby further complicating the scenario. It is no wonder that as many as eleven tiger reserves of the existing twenty nine have recorded decrease in their forest cover2. The Tiger Task Force (TTF) appointed by the Prime Minister has noted that ￂﾓthe biggest threat to the tiger today is not poaching per se, but a deadly combination of the poachersￂﾒ guns and the growing anger of the people who live in and around tiger habitatsￂﾔ3. The point seems to be well-made, because the tiger has vanished from the Sariska Tiger Reserve in Rajasthan, which ironically is guarded by the formidable Rajasthan Armed Constabulary1. The TTF report further states that while ￂﾓnot every tiger reserve in India is facing a Sariska-type crisis, (a similar) crisis haunts every protected area in India. The tiger is under attack from poachers, miners and other exploitative activity. Worse, it is also under siege from the people who co-inhabited its land, who have never benefited from conservation and continue to face daily harassmentￂﾔ3. Thus a mere increase in funds is unlikely to solve the multi-faceted problems of Indiaￂﾒs tiger reserves, where the greatest challenge is to find an economic-ethical mechanism that would perhaps enable people and tigers to co-exist. Unless these issues are addressed with an innovative, humane and balanced policy, the tiger in India would eventually find a place only in the annals of wildlife historians.
1. Protected Area Update (Ed. P. Sekhsaria) vol XII (5); 13 (2006)
2. Protected Area Update (Ed. P. Sekhsaria) vol XII (4), 16-17 (2006)
3. Protected Area Update (Ed. P. Sekhsaria) vol XI (5); 22-24 (2005)
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