Distinguishing viruses responsible for influenza-like illness
OIE Declares The World Free Of Rinderpest, One Of The Deadliest Cattle Diseases
Friday, May 27th 2011 - 02:00 UTCFull article
Dr Bernard Vallat, Director General of the OIE made the official announcement The World Organization for Animal Health (OIE) declared rinderpest, one of the deadliest diseases of cattle and of several other animal species, eradicated from the surface of the earth.
At the OIE 79th annual General Session in Paris the national delegates unanimously adopted Resolution 18/2011 which officially recognized, following thorough control by the OIE with the support of FAO, that all 198 countries and territories with rinderpest-susceptible animals in the world are free of the disease.
A three-stage "OIE Rinderpest Pathway" for countries to be officially recognized as free from the disease by the OIE was initially launched in 1989 and in 1994, implemented in parallel with the Global Rinderpest Eradication Program (GREP) managed by the FAO in collaboration with the United Nations International Atomic Energy Agency (IAEA).
In February 2011, OIE experts in charge of recommending free status recognition in the framework of the OIE Pathway gave the green light for recognizing the free status of the last eight countries not yet recognized.
Using considerable support to eligible countries from donors such as the European Union, these international cooperation and coordination mechanisms have been a key to move towards global eradication particularly in poorest countries.
"Today we witness a historical event as rinderpest is the first animal disease ever to be eradicated by humankind" declared Dr Bernard Vallat, Director General of the OIE. "It's a major breakthrough, not only for science, but also for the cooperation policies amongst international organizations and with the international community as a whole. Above all, it is a success for veterinary services and the entire veterinary profession, since the scarcity of resources available to veterinary services in many countries that were previously infected constituted a major obstacle to the progressive control of rinderpest" he added.
"Rinderpest has been one of the top priorities of FAO in its quest to defeat hunger and improve lives through agriculture" said Ann Tutwiler, FAO Deputy Director-General (Knowledge). "With the eradication of the disease in live animals livestock production around the globe has become safer and the livelihoods of millions of livestock farmers are less at risk. There are important lessons to be learnt when it comes to defeating other animal diseases."
However post-eradication phase constitutes a great challenge too. Although the rinderpest virus no longer circulates amongst live animals it is still present in a number of laboratories, e.G. For the production of vaccines, should the disease reappear as a result of an accidental release or deliberate act.
FAO and OIE are working on the preparation and implementation of recommendations on confining the virus for research or vaccine production purposes, in full compliance with international biosecurity measures.
The term Rinderpest means bovine plague and rightly reflects the devastation the disease brings to hit domestic and wild animal populations, people's livelihoods and consequently, on entire local or national economies.
Rinderpest, also known as cattle plague, is a contagious viral disease affecting several species of wild and domestic cloven-hoofed animals (animals with a hoof split into two toes) notably cattle and buffalo. Rinderpest is caused by a virus of the family Paramyxoviridae, genus Morbillivirus. Many species of wild and domestic cloven-hoofed animals including sheep and goats can show milder clinical signs of the disease when infected, but the mortality rate can reach up to 100% in highly susceptible cattle or buffalo herds.
Rinderpest was known before the Roman era. Plagues of rinderpest killed hundreds of millions of cattle in Europe, Asia and Africa.
An outbreak of rinderpest in imported animals in Belgium in 1920 was the impetus for international cooperation in controlling animal diseases, and was one of the key factors leading to the establishment of the OIE in 1924.
The announcement of the eradication of rinderpest coincides with the 250th anniversary of the creation of the veterinary profession in Lyon, France, and this victory marks a historical day for the profession.
The Rinderpest Campaigns
'In her innovative, engaging, and deeply-researched book, Amanda Kay McVety brilliantly recounts the history of Rinderpest and the international struggle to contain it. Putting biology and the environment at the center of postwar history, her book makes a valuable contribution to the study of twentieth-century internationalism(s) and global development.'
Julia F. Irwin - University of South Florida, author of Making the World Safe: The American Red Cross and a Nation's Humanitarian Awakening
'A compelling, surprising, and elegantly written account of the disease that drew the world together. You'll never feel safe around cows again.'
Daniel Immerwahr - Northwestern University, Illinois,author of Thinking Small: The United States and the Lure of Community Development
'The book incorporates a broad array of primary sources, including archives from multiple countries and interviews with family and colleagues of scientific protagonists … compellingly written …'
Susan D. Jones Source: The Journal of American History
'McVety has a lively style, and her evident enthusiasm for 'the idea of an international community united by shared hopes and fears' is engaging …'
John Landers Source: American Historical Review
'The main strength of the book is the way in which McVety integrates the history of vaccine research with a broader and perceptive critique of the role of non-human actors in this story. In particular, the book provides a valuable insight into the interrelated issues of the development of scientific internationalism and national security …'
John Martin Source: Agricultural History Review
'This is a very timely book, told in a masterful way.'
Alain Touwaide Source: Doody's Reviews
End Of The Big Beasts
Who or what snuffed out the mammoths and other megafauna 13,000 years ago?
It takes a certain kind of person to take on this question as his or her life's work. You have to be itching to know the answer yet patient as a Buddha, for the answer is frustratingly elusive. I know I'm not the type. I'm intrigued by the question but far too anxious to calmly accept, as some experts suggest, that it might be years or decades, if ever, that a definitive, widely accepted solution will come.
The three people I spoke to about the so-called megafaunal extinctions possess this sort of edgy sangfroid. They also stand in three decidedly different camps regarding why America's rich complement of big animals went extinct quite suddenly at the end of the Ice Age. The three camps are known tongue in cheek as "overkill," "overchill," and "overill":
Archeologist Gary Haynes of the University of Nevada Reno thinks that the continent's first human hunters, fresh from Siberia, killed the big beasts off as they colonized the newly discovered land.
Donald Grayson, an archeologist at the University of Washington, Seattle, believes that climate changes at the end of the Pleistocene epoch triggered the collapse.
And mammalogist Ross MacPhee of the American Museum of Natural History has advanced the idea, with virologist Preston Marx, that a virulent "hyperdisease" brought with the first people might have raced through species with no natural immunity, bringing about their demise.
Despite their differing views, these researchers sound remarkably similar over the phone. Each is convincing about the merits of his chosen hypothesis, even as he acknowledges its limitations. Each is adamant as to the flaws that he thinks dooms one or both of the other theories, even as he is gracious toward those who side with that theory. Finally, each reveals that spark of deep passion for the subject, and the choke needed to rein it for the long haul.
So why is the answer so elusive? As often happens in paleontology, it all comes down to lack of empirical evidence, something all three hypotheses arguably suffer from. (There's a fourth hypothesis, actually—that a combination of overkill and overchill did it.)
Overkill 
In the early 1960s ecologist Paul Martin of the University of Arizona advanced the idea that the first Americans, who as every schoolchild knows are thought to have crossed from Siberia to America across the Bering Land Bridge, hunted the megafauna to extinction. For many years, "overkill" became the leading contender. The timing seemed more than coincidental: humans were thought to have arrived no earlier than about 14,000 years ago, and by roughly 13,000 years ago, most of the megafaunal species abruptly vanish from the fossil record. (See a list of all 35 vanished genera of North American Ice Age mammals.)
But some skeptics, Grayson among them, have asked where's the evidence? Grayson and archeologist David Melzer of Southern Methodist University have noted that late-Ice Age sites bearing megafaunal remains that show unequivocal evidence of slaughter by humans number just 14. Moreover, they stress, only two types of giants were killed at those 14 sites, mammoth and mastodon. No signs have turned up that early hunters preyed on giant ground sloths, short-faced bears, camels, or any of the other large mammals that went extinct. That's hardly enough evidence, they argue, to lay blame for a continent's worth of lost megafauna at the foot of the first Americans.
Gary Haynes begs to differ. "I don't care what anybody else says, 14 kill sites of mammoth and mastodon in a very short time period is extraordinary," he told me. It's one thing to find a campsite with some animal bones in it, he says, quite another to find the actual spot where an animal was downed and butchered—where, say, a spearpoint turns up still sticking in bone. "It's very, very rare to find a kill site anywhere in the world," he says. And absence of other megafauna in kill sites doesn't mean they weren't hunted. "There is no doubt Native Americans were eating deer and bear and elk," Haynes says, citing several megafauna that pulled through. "But you cannot find a single kill site of them across 10,000 years."
Could what scholars agree must have been a relatively modest initial population of hunters have emptied an entire continent of its megafauna virtually overnight, geologically speaking? (In fact, it's three continents: South America and, to a lesser extent, Northern Eurasia also lost many large creatures at the end of the Ice Age.)
MacPhee, for his part, finds it hard to swallow. "I just don't think it's plausible, especially if we're also talking about collapses for megafauna that didn't actually go extinct." (Researchers have found evidence that certain populations of surviving megafauna, including musk oxen in Asia, fell precipitously at the end of the Ice Age.) "It gets a little bit beyond probability in my view that people could have been so active as to hunt every animal of any body size, in every context, in every possible environment, over three continents."
Overchill Could climate change have done it? Scholars generally agree that North America witnessed some rapid climate adjustments as it shook off the Ice Age beginning about 17,000 years ago. The most significant swing was a cold snap between about 12,900 and 11,500 years ago. Known as the Younger Dryas, this partial return to ice-age conditions may have stressed the megafauna and their habitats sufficiently to cause widespread die-offs, Grayson and others believe.
Detractors, again, point to the lack of evidence. "There aren't any deposits of starved or frozen or somehow naturally killed animals that are clearly non-cultural in origin that you would expect if there was an unusual climate swing," says Haynes. "I don't think that evidence exists." Another question anti-overchillers have is how the megafauna survived numerous glaciations and deglaciations during the past two million years only to succumb to the one that closed the Pleistocene.
The dearth of evidence doesn't deter researchers working in this area. In fact, it's a spur.
MacPhee points to yet another problem: the geography of the extinctions. For one thing, both North and South America suffered them. "This is to me practically the most decisive evidence there is that it could not have been what we conventionally think of as climate change," he says. "If the entire continental part of the Western Hemisphere was affected at roughly the same time, as good as we can tell with the carbon-14 record, then what force of nature are we talking about? The guys who support climate change are silent on that point." And why was Africa spared? (Elephants, giraffes, and many other African megafauna made it through just fine.) "There's nothing that we know of in nature, climatically speaking, that works in that fashion, as to affect one half of the world and not the other," MacPhee says.
Grayson admits that overchill advocates have failed to develop the kind of records that are needed to test climate hypotheses in detail. But he focuses on climate change, he says, because he sees absolutely no evidence that people were involved. "You can't look at climate and say climate didn't do it for the simple reason that we don't really know what to look for," Grayson told me. "But what you can do fairly easily is look at the evidence that exists for the overkill position. That position would seem to make fairly straightforward predictions about what the past should have been like, and when you look to see if it was that way, you don't find it."
Overill Not finding supportive evidence has particularly plagued the "overill" hypothesis. This is the notion that diseases brought unwittingly by newly arriving people, either in their own bodies or in those of their dogs or perhaps rats, could have killed off native species that had no natural immunity. MacPhee devised this hypothesis after realizing that the link between initial human arrival and subsequent large-animal extinctions was strong not just in North America but in many other parts of the world (see map at right), but that in his opinion, convincing evidence for hunting as the trigger simply did not exist.
Despite what he calls "prodigious effort" using DNA techniques and immunological probes, however, MacPhee and his colleagues have failed to detect clues to any pathogens in megafaunal bones, much less nail down a specific disease, like rabies or rinderpest, that could have jumped species boundaries and wiped out all the big beasts. "[MacPhee's hyphothesis] doesn't even have circumstantial evidence," says Haynes, "because we can't prove there was hyperdisease. We can prove people were here, and we can prove climates were changing." Fair enough, says MacPhee, though he points out that the burgeoning ability of Asian bird flu to infect across species boundaries seems to suggest that some diseases are ecologically and genetically preordained to, as he puts it, "go hyper."
Soldiering on The dearth of evidence—seemingly significant in all three camps—doesn't deter researchers working in this area. In fact, it's a spur. MacPhee may be speaking for all scholars involved in this famously contentious debate when he says: "What's of interest here for me personally is that these Pleistocene extinctions have occupied the minds of some very able thinkers over the last half century or so, and nobody's come up with anything that's drop-dead decisive. So it's attractive as an intellectual problem."
Granted. But hey, aren't you just dying to know what happened? 
Comments
Post a Comment