Christine Dell'Amore, National Geographic News 7 Oct 08;
A spike in deadly infectious diseases in wildlife and people may be the "most immediate consequence" of global warming, according to a new report released today.
Dubbed the "deadly dozen," sicknesses such as Lyme disease, yellow fever, plague, and avian influenza, or bird flu, may skyrocket as global shifts in temperature and precipitation transform ecosystems.
Babesia, cholera, ebola, intestinal and external parasites, red tides, Rift Valley fever, sleeping sickness and tuberculosis round out the list.
An "early warning system" based on an international wildlife-monitoring network may be the only effective defense, said William Karesh, a report co-author and vice president of Global Health Programs at the New York-based Wildlife Conservation Society.
Observing wildlife could yield crucial signals of potential outbreaks.
"Without the presence of wildlife, we would be clueless about what's going on in the environment," Karesh told a briefing at the International Union for Conservation of Nature (IUCN) World Conservation Congress in Barcelona.
"Why wait until people are sick and dying?"
Out of Sync
Of 14,000 known infectious organisms, 600 are shared between animals and humans.
The deadly dozen were chosen by the conservation society's health experts as some of the most ominous health threats.
"The reason we want to draw attention to [microbes] is they're difficult to see, they have devastating effects, and we also don't think about them until it's too late," Karesh said.
Since microbes and wildlife have evolved together over time, animal species have developed adaptations to cope with the organisms. So disease spikes usually point to something "out of sync with nature," Karesh said.
Climate change has already thrown ecosystems off balance, experts say.
For example, bird flu—which can "jump" to humans, as it did to cause the Spanish flu of 1918—may be worsened by drought. Wild birds that carry the disease have been seen drinking alongside domesticated birds at scarce water sources.
Such behavior has created a "loss of natural boundaries [that] natural hosts have evolved," said Kristine Smith, assistant director of Global Health Programs for the society.
And as certain regions warm, disease-carrying parasites such as ticks and mosquitoes will expand into new territories that are unprepared for the parasites' arrival, the authors added.
Jeff McNeely, IUCN's chief scientist, said that the "ecology of climate change is receiving inadequate attention.
"To me, the most important part of climate change is that it's changing the distribution of ecosystems, and diseases tend to be specific to ecosystems," he added.
Warning Systems
On-the-ground monitoring has already been shown to work, said the Wildlife Conservation Society's Karesh.
In Brazil forest communities that spot primates sick with yellow fever report back to their health agencies, which in turn start vaccinating for the mosquito-borne illness.
In the Republic of the Congo a group of local hunters has been trained to pinpoint symptoms of Ebola hemorrhagic fever in animals. The strategy has led to three years without a single human case in that region, said Karesh.
The Global Avian Influenza Network for Surveillance also draws on indigenous knowledge through a system of people in 34 countries, who monitor wild bird populations for signs of sickness.
Of course, other unnatural forces are contributing to the spread of disease, experts added.
For instance, the illegal wildlife trade, especially robust in Asia, is bringing people and animals into closer quarters, said the Wildlife Conservation Society's Smith.
The 2002 outbreak of severe acute respiratory syndrome (SARS) was traced to civets. The cat-size mammal, prized for its meat, had ended up in wildlife markets in China, she said.
Wildlife, already struggling, faces fresh threat in disease
Marlowe Hood Yahoo News 7 Oct 08;
From tiny tree frogs to gorillas, wild animals already facing extinction due to habitat loss, pollution and hunting must now cope with the added threat of virulent disease, conservation scientists said Tuesday.
Many pathogens are being spread among wildlife by global warming, and some could have dire consequences for humans as well, the researchers told participants at the World Conservation Congress in Barcelona.
"Climate change conjures up images of rising sea levels and stranded polar bears," said Steven Sanderson, president of New York-based Conservation Society.
"But perhaps the greatest threat will come from emerging infectious diseases as a result of changing temperatures and rainfall levels."
Outbreaks, for example, of Ebola and its close cousin the Marburg virus -- lethal to gorillas, chimpanzee and humans -- have been closely linked to unusual patterns in rainfall and dry seasons.
There is no known cure for either disease, which cause painful internal hemorrhaging and high fevers.
Increasingly frequent algae blooms known as "red tides", triggered by higher sea surface temperatures, create toxins that have killed massive numbers of fish, caused sea mammal to flounder, and increased mortality among penguins and sea birds.
They can also provoke serious illness and death in humans that consume contaminated shellfish.
Some diseases spread further afield by shifting climate patterns do not harm the animals that host them but are dangerous to people, including lyme disease, transmitted by ticks bloated with deer blood, or mosquito-borne sicknesses such as malaria and yellow fever.
Other bacteria and viruses, however, affect only animals -- at least for now.
"We are seeing novel, emerging threats in the form of disease coming out of nowhere and having devastating impacts on animal populations," said Michael Hoffman, a scientist at the International Union for the Conservation of Nature (IUCN) and co-author of a comprehensive study of the survival status of mammals, published this week in the journal Science.
The survey found that one in four mammals are threatened with extinction, and half are in decline.
"Disease has always had a role to play in affecting populations, but now we are seeing diseases that are highly pathogenic," he told AFP.
Amphibians, in particular, have suffered more species loss more than any other animal group, due to a fungus called chytridiomycosis.
The disease has already wiped out hundreds of frog, toad and salamander species, and is spreading across the globe, in part due to climate change but also through the international trade -- much of it illegal -- in wildlife.
Scientists are scrambling to find a cure that will work in the wild even as more species disappear.
The Tasmanian devil, a carnivorous marsupial found only on the Australian island for which it is named, has declined by 60 percent in only 10 years, ravaged by a terrible face cancer that spreads through contact.
Listed as "endangered" on the IUCN's "Red List" -- an inventory of the survival status of more than 44,000 animals and plants -- its prospects as a species "are extremely bleak," said Simon Stuart, in charge of biodiversity assessment for the IUCN.
Monitoring the health status of wildlife can serve as an "early warning system" for humans, said William Karesh, director of global health programs at the Conservation Society.
"Any disturbance in the environment shows up in wildlife because they don't adapt very quickly or easily," he said.
Disease warning on climate change
Richard Black, BBC News website 7 Oct 08;
Climate change may hasten the spread of diseases that can move from wild animals to humans, warns the Wildlife Conservation Society (WCS) in a report.
The Deadly Dozen highlights 12 zoonoses - animal-borne diseases - that may spread as the climate warms.
The US-based organisation advocates establishing a global early warning network making use of Western and indigenous people's knowledge.
The report was launched here at the World Conservation Congress.
"We've seen Lyme disease work its way up from the US into Canada, and West Nile fever as well," said William Karesh, director of WCS's global health programmes.
"Basically what you have now are fewer frozen nights in this region, and that allows the ticks and mosquitoes that carry these diseases to survive further north."
In its landmark assessment of climate impacts, released last year, the Intergovernmental Panel on Climate Change (IPCC) noted that elevated temperatures would change the distribution of animals that carry diseases affecting humans, and that improved disease surveillance was a "climate adaptation" measure that some countries were already taking.
Long-term gains
Among the other zoonoses likely to be affected by climatic shifts are avian influenza, Rift Valley fever, and Ebola, the WCS report says.
Prevalence of Vibrio cholerae , the bacterium that causes cholera, rises with water temperature, and can be incubated in shellfish.
Some shifts might not be triggered by rising temperatures. Water scarcity, for example, could induce more sharing of drinking pools by wild and domesticated animals, making the emergence of new viral strains more likely.
WCS acknowledges that climatic shifts could also lessen the prospects for some zoonotic diseases.
Without observations, it suggests, we cannot really know; and wild animals can act as early indicators of disease.
"The health of wild animals is closely linked to the ecosystems in which they live, and even minor disturbances can have far-reaching consequences on what diseases they might encounter and transmit as climate changes," said the organisation's chief executive Steven Sanderson.
"Monitoring wildlife health will help us predict where trouble spots will occur and plan how to prepare."
For some time, it has been urging the strengthening of monitoring systems at a national and global level so that early signs of outbreak are detected and dealt with.
It operates the Global Avian Influenza Network for Surveillance (Gains) project, which is funded by US government agencies.
But, said Dr Karesh, indigenous knowledge and skills should also be brought into play.
In northern Republic of Congo, he said, hunters used to bring dead animals they found in the forest back to the villages, which in the case of animals that had died from Ebola would immediately produce a human outbreak.
"Now the local people look out for these animals, they don't bring them back but report what they have found.
"So they are doing disease surveillance, and there hasn't been an outbreak of Ebola in this region for several years."
Climate change seen aiding spread of deadly diseases
Yahoo News 7 Oct 08;
A "deadly dozen" diseases ranging from avian flu to yellow fever are likely to spread more because of climate change, the Wildlife Conservation Society said on Tuesday.
The society, based in the Bronx Zoo in the United States and which works in 60 nations, urged better monitoring of wildlife health to help give an early warning of how pathogens might spread with global warming.
It listed the "deadly dozen" as avian flu, tick-borne babesia, cholera, ebola, parasites, plague, lyme disease, red tides of algal blooms, Rift Valley fever, sleeping sickness, tuberculosis and yellow fever.
"Even minor disturbances can have far reaching consequences on what diseases (wild animals) might encounter and transmit as climate changes," said Steven Sanderson, head of the society.
"The term 'climate change' conjures images of melting ice caps and rising sea levels that threaten coastal cities and nations, but just as important is how increasing temperatures and fluctuating precipitation levels will change the distribution of dangerous pathogens," he said.
"Monitoring wildlife health will help us predict where those trouble spots will occur and plan how to prepare," he said in a statement.
The U.N. Climate Panel says that greenhouse gas emissions, mainly from human use of fossil fuels, are raising temperatures and will disrupt rainfall patterns and have impacts ranging from heatwaves to melting glaciers.
"For thousands of years people have known of a relationship between health and climate," William Karesh of the society told a news conference in Barcelona to launch the report at an International Union for Conservation of Nature congress.
Among phrases, people said they were "under the weather" when ill, he noted.
He said that the report was not an exhaustive list but an illustration of the range of infectious diseases that may threaten humans and animals.
(Editing by Giles Elgood)
Climate change will allow tropical disease to spread to Europe
Paul Eccleston, The Telegraph 7 Oct 08;
Climate change will allow wildlife diseases to spread more easily, a new report warns.
The Wildlife Conservation Society (WCS) lists the "deadly dozen" diseases which could threaten human health and global economies.
The study shows the impact climate change could have on the health of wild animals and how it can cascade onto human populations.
Avian flu, TB and Ebola are just some of the broad range of infectious diseases that threaten both humans and animals.
Pathogens that originate in or move through wildlife populations can also inflict massive economic damage. Since the mid 1990s avian inluenza is estimated to have caused $100bn in losses to the global economy.
The report, The Deadly Dozen: Wildlife Diseases in the Age of Climate Change, says better monitoring of wildlife is needed to detect how diseases are moving so health professionals can restrict their impact.
Dr Steven E Sanderson, president and CEO of the WCS, said: "The term 'climate change' conjures images of melting ice caps and rising sea levels that threaten coastal cities and nations, but just as important is how increasing temperatures and fluctuating precipitation levels will change the distribution of dangerous pathogens.
"The health of wild animals is tightly linked to the ecosystems in which they live and influenced by the environment surrounding them, and even minor disturbances can have far reaching consequences on what diseases they might encounter and transmit as climate changes.
"Monitoring wildlife health will help us predict where those trouble spots will occur and plan how to prepare."
WCS leads an international consortium that helps to monitor the movements of avian influenza through wild bird populations around the world.
The Global Avian Influenza Network for Surveillance (GAINS) was created in 2006 and now involves dozens of private and public partners that monitor global wild bird populations for avian flu.
Congresswoman Rosa L DeLauro, who supports GAINS, said: "Emerging infectious diseases are a major threat to the health and economic stability of the world.
"What we've learned from WCS and the GAINS program is that monitoring wildlife populations for potential health threats is essential in our preparedness and prevention strategy and expanding monitoring beyond bird flu to other deadly diseases must be our immediate next step."
The disease list includes some of the pathogens that may spread as a result of climate change:
•Avian influenza: Like human influenza, avian influenza viruses occur naturally in wild birds, though often with no dire consequences. The virus is shed by infected birds via secretions and faeces. Poultry may contract the virus from other domestic birds or wild birds. A highly pathogenic strain of the disease-H5N1-is currently a major concern for the world's governments and health organisations.
•Babesiosis: Babesia species are examples of tick-borne diseases that affect domestic animals and wildlife, and Babesiosis is an emerging disease in humans. In some instances, Babesia may not always cause severe problems by themselves but when infections are severe due to large numbers of ticks, the host becomes more susceptible to other infectious diseases.
•Cholera: Cholera is a water-borne diarrhoeal disease affecting humans mainly in the developing world. It is caused by a bacterium, Vibrio cholerae, which survives in small organisms in contaminated water sources and may also be present in raw shellfish such as oysters. Once contracted, cholera quickly becomes deadly.
•Ebola: Ebola hemorrhagic fever virus and its closely related cousin - the Marburg fever virus - easily kill humans, gorillas, and chimpanzees, and there is currently no known cure. As climate change disrupts and exaggerates seasonal patterns, we may expect to see outbreaks of these deadly diseases occurring in new locations and with more frequency.
•Intestinal and external parasites: Parasites are widespread throughout terrestrial and aquatic environments. As temperatures and precipitation levels shift, survival of parasites in the environment will increase in many places, infecting an increasing number of humans and animals.
•Lyme disease: This disease is caused by a bacterium and is transmitted to humans through tick bites. Tick distributions will shift as a result of climate change, bringing Lyme disease into new regions to infect more animals and people.
•Plague: Plague, Yersinia pestis - one of the oldest infectious diseases known - still causes significant death rates in wildlife, domestic animals, and humans in certain locations. Plague is spread by rodents and their fleas and alterations in temperatures and rainfall are expected to change the distribution of rodent populations.
•"Red tides": Harmful algal blooms off global coasts create toxins that are deadly to both humans and wildlife. These occurrences - commonly called "red tides"- cause mass fish deaths, marine mammal strandings, penguin and seabird mortality, and human illness and death from brevetoxins, domoic acid, and saxitoxins (the cause of "paralytic shellfish poisoning").
•Rift Valley Fever: Rift Valley fever virus (RVFV) is an emerging zoonotic disease of significant public health, food security, and overall economic importance, particularly in Africa and the Middle East. In infected livestock such as cattle, sheep, goats and camels, abortions and high death rates are common. In people (who can get the virus from butchering infected animals), the disease can be fatal.
•Sleeping sickness: Also known as trypanosomiasis, this disease affects people and animals. It is caused by the protozoan, Trypanosoma brucei, and transmitted by the tsetse fly. The disease is endemic in certain regions of Sub-Saharan Africa, affecting 36 countries, with estimates of 300,000 new cases every year and more than 40,000 human deaths each year in eastern Africa. Effects of climate change on tsetse fly distributions could play a role in the distribution of the disease.
•Tuberculosis: As humans have moved cattle around the world, bovine tuberculosis has also spread. It now has a global distribution and is especially problematic in Africa, where it was introduced by European livestock in the 1800s. Climate change impacts on water availability due to drought are likely to increase the contact of wildlife and livestock at limited water sources, resulting in increased transmission of the disease between livestock and wildlife and livestock and humans.
•Yellow fever: Found in the tropical regions of Africa and parts of Central and South America, this virus is carried by mosquitoes, which will spread into new areas as changes in temperatures and precipitation levels permit. One type of the virus-jungle yellow fever-can be spread from primates to humans and vice-versa via mosquitoes that feed on both hosts.
