Disease and Antarctic Wildlife
Concern in Antarctica | Recent developments | Monitoring for early detection | Prevention | Response | Research priorities | View components
Why is wildlife disease in Antarctica a concern?
Antarctica is the only continent where disease resulting from human activities has not been documented among native wildlife. However, unexplained mass mortalities of seals and penguins have been observed in the past. Recently antibodies to Infectious Bursal Disease Virus (a disease of domestic poultry), have been found in Antarctic penguins, and antibodies to Bruccella (a disease causing abortion in cattle), have also been reported from both Antarctic fur seals and Weddell seals. None of these events have been conclusively attributed to human activity, but the risk of accidentally introducing and spreading wildlife disease grows as the number of visitors to Antarctica increases.
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In 1964, the Antarctic Treaty System accepted The Agreed Measures for the Conservation of Antarctic Fauna and Flora. These Measures prohibited the introduction of any plant or animal species that was not indigenous to the Treaty Area, except in accordance with a permit. The Agreed Measures also included precautions to prevent accidental introduction of parasites and diseases into the Treaty Area. All dogs (imported for working) were to be inoculated against distemper, contagious canine hepatitis, rabies and leptospirosis, and the transport of live poultry into the Treaty Area was prohibited.
When the Protocol on Environmental Protection to the Antarctic Treaty (Madrid Protocol) came into force in 1998 the Agreed Measures were superseded by new regulations. Signatories to the protocol are no longer permitted to take dogs to Antarctica, and those that were already present within the Treaty Area were removed. Precautions were introduced to prevent the introduction of alien micro-organisms into native Antarctic fauna including: a ban on the import of live poultry (and other birds); routine inspection of dressed poultry for signs of Newcastle's disease, tuberculosis and yeast infection; and to avoid the import to Antarctica of non-sterile soil to the maximum extent possible.
Although many countries, including Australia, impose strict quarantine control on the importation of materials from Antarctica there is little in international law to ensure quarantine control in the reverse direction. This is probably because there is no Antarctic equivalent to the national self-interest (i.e. protection of domestic livestock markets) that drives the establishment of quarantine restrictions elsewhere.
Recent developments
In 1997, Australia presented an information paper to Antarctic Treaty Consultative Meeting XXI reporting serological evidence that Adélie penguins and emperor penguins at some locations had been exposed to Infectious Bursal Disease Virus (IBDV). The observation was based on antibody reactions and the virus causing the reaction has not been positively isolated. However, the discovery focused attention on the increasing risk of disease introduction due to the greater number of people travelling to Antarctica. Australia offered to host a workshop to discuss the issues of disease and to report the outcomes of the workshop at a later Antarctic Treaty Consultative Meeting.
Disease workshop
The workshop, convened in 1998 by the Australian Antarctic Division in Hobart, was the first international meeting to consider disease in Antarctic wildlife. The meeting was open to all interested parties and was attended by 52 participants from 8 different countries. Participants included Antarctic biologists, legal and policy specialists, scientists with experience of wildlife disease in other regions and quarantine procedures, members of non-government environmental organisations and an Antarctic tourist operator. The objectives of the workshop were to identify the potential for disease incursion into Antarctic wildlife and to develop a series of recommendations to reduce the risk of disease introduction, and to limit the chance of disease establishment and spread.
Major findings of the workshop
Risks of disease introduction and spread
There are a number of direct and indirect mechanisms for human activity in Antarctica to be the cause of disease outbreaks. People could act as vectors for infectious agents, either by bringing non-indigenous pathogens into the region or by translocating indigenous pathogens. In addition, stress caused by human activity could reduce immunity, increase pathogenicity and could cause the expression of an indigenous disease that might otherwise not have revealed itself. Stress may be the result of direct human disturbance, food shortage (perhaps caused by fisheries competing for the same food stocks), exposure to pollutants and possibly, in the longer term, as a result of climate change.
The nature of activities in Antarctica is changing in ways that could increase the risk of disease introduction or spread. Access to the continent is becoming easier with the introduction of new intercontinental air transport facilities and rapid movement around the continent is possible using both helicopters and fixed wing aircraft. Tourism interest in the Antarctic is increasing and aggregations of wildlife are a major attraction for tourists, with many itineraries including visits to several colonies around the Antarctic coast. Sequential visits to a number of colonies could facilitate the transfer of disease from one colony to another if precautions are not taken.
The remoteness of the Antarctic continent may have isoloated its wildlife from many diseases that are common elsewhere. A possible consequence of this isolation could be that Antarctic species have limited immunity and are more susceptible to disease once they are exposed to infectious agents. The highly contagious viral diseases (such as morbillivirus, Newcastle disease and influenza), the immunosuppressant diseases (such as infectious bursal disease, morbillivirus and retrovirus) and agricultural and zoonotic diseases (such as brucellosis, tuberculosis and leptospirosis) are considered to be the greatest potential risk to the health of Antarctic wildlife. Non-infectious agents such as pollutants and toxins discharged from stations and ships might be the direct cause of unusual mortality events or they might be just one contributing factor leading to the expression of disease that might otherwise remain dormant.
Monitoring to ensure early detection
Monitoring should be designed to detect unusual mortalities in Antarctic wildlife, to identify the causal agent or agents, and to determine whether the causal agent is indigenous or exotic. Routine monitoring should be based upon standardised protocols for selection of species and sites, for collection, storage and transport of samples, for post-mortem techniques and reporting procedures. Serum and specimen banks will be required to house samples and these need to be established. Priorities for monitoring should be those sites that are most frequently visited. Appropriate control sites, away from human activity, will be essential for reliable interpretation of monitoring results. Monitoring should be reported regularly and coordinated by a central clearing-house responsible for receiving all results and for making the collated information available to assist in an emergency response.
Preventing introduction and spread by people
The isolation of Antarctica can be used to reduce the chance of introductions if appropriate quarantine procedures are implemented. The good-will that exists among both Governmental and non-Governmental operators towards the Antarctic environment and its wildlife is probably the most important factor for establishing measures which will reduce the probability of disease introduction. It also provides the foundation on which to establish a variety of measures to limit the spread by people of naturally occurring disease.
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Quarantine practices should be applied to both inter- and intra-continental travel. Gateway states could be used as an effective mechanism for applying disease prevention measures but the use of gateway states cannot be enforced. However, in the absence of such controls, uniform practices based on existing and familiar standards and procedures should be applied at point of departure, point of landing, point of dispersal to field sites and in the marine environment. A code of behaviour should be developed and adopted by all operators to ensure that all visitors to Antarctica understand the risk. The free exchange of information should also increase understanding of the risks and may help prevent the transmission of disease agents.
Response to a suspected disease incident
If unusual mortality of wildlife is observed some response is required even if it is no more than to note the incident. A generic response plan should be designed to minimise anthropogenic amplification of the event and should include procedures to help identification of the species involved, the extent of affected animals and the possible causative agents. The response plan should also assist with decisions on whether control actions are appropriate.
The response plan should include elements that assist with readiness for a disease event, administration and coordination, communication, identification of resources and should provide access to information from any precedents. Response should be graduated and tailored to the circumstances of the event. The initial response should be containment by temporary restriction of access to the area and communication to all Antarctic Treaty Consultative Parties, the International Association of Antarctic Tourist Operators, international and national agencies and Antarctic operators. Each event should be carefully documented and reported through a central coordinating body so that the Antarctic community can learn from the event.
Research priorities
So little is known about the natural status of disease in Antarctic wildlife that at the moment it would be impossible to determine whether a disease event in Antarctica was caused by human activity or whether it occurred naturally. The first priority for research is to build an understanding of the types of disease that are naturally present in Antarctic wildlife populations. This information will be used as the basis for monitoring for diseases that could have been introduced by human activity and as baseline data to help explain unusual mass mortality events in future.
Antibodies to some diseases, such as IBDV and Brucella that are known to infect domestic animals, have been identified in Antarctic wildlife. However, it is not known whether these are naturally occurring or whether people have brought them to Antarctica. It is important to find out because if they are naturally occurring and there is no other evidence that human activity has introduced disease then the minimal precautions to prevent disease introduction used in the past may be adequate. However, if there is evidence that these diseases, or others, were bought into Antarctica by people this would be a compelling argument for more stringent precautions. The disease status of animals close to stations is being compared with that of animals remote from human activity to determine whether proximity to stations increases the incidence of disease or antibodies. An increased incidence of disease adjacent to stations would not conclusively prove that stations are the source, however, this could never be proven without baseline information on the diseases present before human activity in Antarctica.
For more information, email: hi@aad.gov.au
See more information on the Australian Antarctic Division's Human Impacts program
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