Hidden costs of disease to greater Yellowstone elk

Brucellosis reduces pregnancy say USU ecologists

Date:  October 29, 2018

Source:  S.J. & Jessie E. Quinney College of Natural Resources, Utah State University

For decades researchers have known that a bacterial disease in elk, bison and cattle in the Greater Yellowstone Ecosystem causes periodic abortions in these animals and chronic illness in humans drinking infected cow's milk. The disease, called brucellosis, poses a financial concern for dairy producers and cattle ranchers, but its effects on the wild elk population have generally been considered minor.

In recent years, however, elk pregnancy rates have become the subject of controversy. Various researchers claim that stress caused by fear of wolves and nutritional deficiencies caused by drought can explain low pregnancy rates in specific elk herds, but until now the effects of brucellosis on elk pregnancy have not been scrutinized.

Utah State University researchers Gavin Cotterill and Johan du Toit report that by mid-winter, elk that test positive for brucellosis are less likely to be pregnant than healthy elk, independent from the abortions caused by that disease later in the year. Cotterill and du Toit, along with colleagues from the Wyoming Game and Fish Department, US Geological Survey Northern Rocky Mountain Science Center, and University of California Berkeley, discuss their findings in Ecology and Evolution published 28 October 2018.

"Mid-winter elk pregnancy rates are often seen as an indicator of an elk herd's health and viability," says Cotterill, a PhD candidate at USU and lead author of the paper. "If we're interested in figuring out the effect that predators or climate are having on elk we need to also account for disease."

Read more 

Oldest evidence of dairying on the East Asian Steppe

Dairying of cattle, sheep, and goats was established in northern Mongolia by 1300 BC

Date:  November 5, 2018

Source:  Max Planck Institute for the Science of Human History

Although dairy pastoralism once made Mongolian steppe herders successful enough to conquer most of Asia and Europe, the origins of this way of life on the East Asian steppe are still unclear. Now an international team of researchers led by the Max Planck Institute for the Science of Human History has uncovered evidence that dairying arrived in Mongolia as early as 1300 BC through a process of cultural transmission rather than population replacement or migration.

Two thousand years before the armies of Ghengis Khan, populations in Mongolia were already living a pastoralist, dairying lifestyle -- similar to that which would enable future populations to conquer most of Asia and Europe. Although pastoralism has long been the primary means of subsistence on the East Asian steppe, the origins of this tradition have been unclear. Now, an international team of researchers has uncovered the earliest direct evidence to date of dairying in Mongolia -- around 1300 BC -- by tracking milk proteins preserved in tooth tartar. The livestock that were milked -- cattle, sheep and goats -- are not native to the region and were likely introduced by Western Steppe herders. However, ancient DNA evidence from Bronze Age Mongolians indicates minimal genetic contributions from Western Steppe herders, suggesting that the livestock and dairying technologies were transferred by cultural processes rather than a major population migration, in contrast to the pattern seen in Europe. The findings are published in PNAS.

Read on  

'Antelope perfume' keeps flies away from cows

Researchers involved in research that shows how the tsetse fly can be tricked in Africa

Date:  October 20, 2017

Source:  University of Bonn

Summary:

In Africa, tsetse flies transfer the sleeping sickness also to cattle. The damage is estimated to be about 4.6 billion US dollars each year. Experts have developed an innovative way of preventing the disease. Tsetse flies avoid waterbucks, a widespread antelope species in Africa. The scientists imitated the smell of these antelopes.

Continued  

Researchers discover new cattle disease and prevent it from spreading

Date:  September 21, 2017

Source:  University of Copenhagen The Faculty of Health and Medical Sciences

Summary:

Following genetic studies of deformed calves, research is able to uncover a previously unknown disease found among Holstein cattle. The breeding bull from which the mutation and thus the deformation originate has now been put down to prevent the disease from spreading further.

Read on  

'Tuberculosis-resistant' cattle developed in China

By Helen Briggs BBC News


1 February 2017
 
Scientists in China say they have produced cloned cattle with increased resistance to bovine tuberculosis.

Twenty calves were born, of which 11 survived for more than three months.

Bovine TB is a risk to cattle in many countries, including parts of the UK, Africa and Asia.

Researchers in China used a genome editing tool to change the genetic code of cattle. They say the technology could have widespread uses in agriculture.

A team from the College of Veterinary Medicine, Northwest A&F University in Shaanxi, China, altered a gene involved in fighting infection.

"The resulting transgenic cattle exhibited increased resistance to M. bovis (bovine TB) infection," they said.

"Our study provides an avenue to develop the CRISPR/Cas9 system for agricultural applications."

The latest research, published in the journal, Genome Biology, used the new genome editing tool, which is more precise.

Tests on resistance to TB were carried out on blood samples taken from the cloned animals.

It is not clear what would happen if the transgenic cattle were exposed to tuberculosis in normal conditions.

Prof Ian McConnell, emeritus professor of veterinary science at the University of Cambridge, said TB in cattle is a complex disease.

Read on 

Big data analysis shows weak link between badgers and cattle for TB transmission

Date: September 26, 2016

Source: University of Queen Mary London

The largest simulation to date of the numbers of cattle and badgers infected with tuberculosis (TB) casts serious doubts about the extent to which badgers cause TB in cattle, according to research from Queen Mary University of London (QMUL).

Using a mathematical model that combines a huge number of cattle and badgers that have TB, the researchers were able to quantify the relationship between the two animals and use a big data approach to show that the route of infection for cattle is from other cattle rather than from other species. Reciprocally, badgers are mainly infected by other infected badgers.

"If badgers are causing TB in cattle, we would see a similar pattern of infection in both species, however our analysis reveals that this isn't the case and could have implications for a strategy to vaccinate badgers, as an efficient control strategy if policymakers were to pursue this option," said lead author Dr Aristides Moustakas from QMUL's School of Biological and Chemical Sciences.

Bovine TB poses serious issues for the farming industry in particular, as cattle found to be TB positive need to be killed and their products may not be sold, which has financial implications.

The modelling exercise in this new research paper follows over a million cattle and 50,000 badgers over different scenarios to understand how the movement of one species affects the transmission of TB in the other.

Dr Moustakas adds: "There is little geographical overlap between farms with infected cattle and setts with infected badgers, and cycles of infections between the two species are not synchronised. Also, the spatial aggregation pattern of TB in cattle and badgers is different -- in badgers, we find that the disease is found in clusters whereas in cattle the disease is much more random and dispersed."

Read on

Change way we test and house cattle to control bovine TB, says new research

Cattle testing, not badger culling will beat TB say researchers

According to new research, the culling of badgers will potentially reduce the number of Bovine TB infected cattle by just 12 out of a herd of 15,000.

However, reducing the interval between TB tests on cattle by one month could reduce the number of sick cattle by 193.

The Queen Mary University of London (QMUL) research found that regular and frequent testing of cattle could eventually lead to the eradication of the disease, whether or not badgers were culled, and despite the current test being at most 80 per cent accurate.

Badger culling alone, however, did not lead to TB eradication in the study and is therefore thought unlikely to be a successful control strategy.

The model also suggested that housing cattle in large sheds over winter could potentially double the number of infected animals in a herd, because under such conditions there is a much greater chance of TB being passed between cows.

Read more ...

Four indicted in Feb. recall of 8.7 million pounds of contaminated beef

Published time: August 19, 2014 17:36

Four people from the slaughterhouse at the center of a massive beef recall in February have been indicted for purposely allowing diseased cattle into its processed meat and misleading health inspectors.

Federal prosecutors on Monday this week claimed the owners of Rancho Feeding Corp., a Northern California beef processing plant, schemed with employees to butcher about 79 cows with skin cancer of the eye rather than stopping plant operations during inspector lunch breaks. The government also said that plant workers swapped the heads of diseased cattle with heads of healthy cows to hide them from inspectors.

The company’s co-owners, Jesse Amaral, Jr. and Robert Singleton, were indicted, along with yardman Eugene Corda and foreman Felix Cabrera. Amaral and the two employees were charged with 11 felony counts, including distribution of adulterated and misbranded meat, mail fraud and conspiracy. Singleton was charged with only one count of distributing adulterated, misbranded and uninspected meat.

Amaral pleaded not guilty during a Monday morning hearing and was released on $50,000 bail; the status of Cabrera and Corda is still pending. Singleton is expected to plead guilty and cooperate with the US Attorney’s Office in the prosecution of the other three defendants, KQED reported.

Continued ...

Here’s a new way to keep cattle burps from toasting the planet

By John Upton

Telling cows to eat more slowly and avoid cola won’t do much to curb their incessant belching. But the Dutch company DSM has developed a more bovine-appropriate solution for the climate-wrecking problem of cattle gassiness.

Staff scientists and academic researchers funded by the company have developed a powder that can be mixed in with cattle feed, interfering with the microorganisms that produce methane. Newsweek reports:

“In trials we’ve managed to reduce methane emissions by up to 60 percent,” says Petra Simic, a biochemist who directs DSM’s cow-methane efforts. “We have solid proof of concept that our compound does what it’s supposed to do. What we’re working on now is figuring out the best way of mixing it into the cow’s feed.”

Continued

Genetic find might lead to cattle that are more resistant to TB

Date:

February 12, 2014

Source:

University of Edinburgh

Summary:

Scientists have identified genetic traits in cattle that might allow farmers to breed livestock with increased resistance to bovine tuberculosis.

Read on

The Case for Low Methane-Emitting Cattle

Jan. 10, 2014 — A new research project looks into the possibilities of adapting every aspect of cattle husbandry and selection processes to lower their greenhouse gas emissions.

You may think that climate change is being caused by burning oil, coal and gas. But not so fast! The emission of methane from cattle is a surprisingly important factor. Methane from cows -- a greenhouse gas 25 times more powerful than carbon dioxide -- makes up 20% of greenhouse emissions from agriculture, or about 1% of all anthropogenic greenhouse gases. That's according to Phil Garnsworthy, professor of dairy science at the University of Nottingham in the UK. He is also one of the project scientists of an EU-funded research project, called Ruminomics, which is using cutting-edge science to reduce greenhouse gas emissions from cattle.

Continued

African Breed of Cattle Harbours Potential Defense Against Life-Threatening Parasite

Sep. 27, 2013 — Every year, millions of cattle die of trypanosomosis. The UN and the International Livestock Research Institute list trypanosomosis among the ten diseases of cattle with the greatest impact on the poor. In Africa the disease is known as "Nagana," which translates literally as "being in low or depressed spirits." The disease is caused by a parasite that enters the animals' blood as a result of the bite of the Tsetse fly.

Surprisingly, one West-African dwarf cattle breed, the Baoulé, seems less affected by trypanosomosis than others. When they are infected, Baoulé cattle develop fever and lose weight but do not necessarily die. Their immune system is thus better able to fight the parasite than that of other breeds. In other words, the cattle seem to have a natural tolerance against the parasite.

A method to detect different trypanosomes

Katja Silbermayr from the Institute of Parasitology of the University of Veterinary Medicine, Vienna (Vetmeduni), together with an international research team, collected blood samples from three cattle types. The scientists have developed a method that can identify the parasites responsible for trypanosomosis, the trypanosomes, and can even detect three different forms of the parasite in a single step. The information is extremely valuable to veterinarians and farmers as each type of trypanosome causes a slightly different disease progression and requires a different type of treatment.

Read on

Defra statistics show bTB soared after cattle imports

A case of foot in mouth for Defra as their own evidence reveals true cause of bTB outbreak

May 2013. Statistics released by Defra in a bid to explain why the badger cull must go ahead have, in fact, revealed the true cause of the bTB outbreak that they are trying to stop, say Care for the Wild.

bTB soared after Foot and Mouth controls relaxed

Figures show that incidences of bTB soared in 2000/2001, in certain areas. This correlates almost exactly with the relaxation of movement controls after the Foot and Mouth epidemic, which saw large numbers of herds restocked from the UK and across Europe.

Influx of untested cattle

Philip Mansbridge, Care for the Wild CEO, said: "It's not been a good day for advocates of the badger cull. First, Lord Krebs, the leading expert on bTB, repeated his belief that a cull is ‘crazy'. Then Defra themselves give detailed evidence as to why they are culling - but close examination shows that badgers clearly are not to blame for this outbreak - it was the influx of untested cattle after the Foot and Mouth outbreak.

"There's an increasing air of Emperor's New Clothes about this badger cull. Defra desperately want people to believe that it will work, and that it is scientifically valid - but it won't and it isn't. The science says that at best it'll reduce bTB by 16% after nine years - that simply is not enough to justify slaughtering 8 out of 10 badgers in this country.

Read on

Werner Bock Blames Death Rays, Aliens For Cows' Deaths; Faces Charges In Canada

A Canadian farmer has lost at least 250 cows in the past 10 years. While the government has charged him and says he failed to feed them, the farmer claims the alien defense.

Werner Bock has posted plenty of YouTube videos in recent years detailing his cattle's malnourished appearance, sunken features and hair loss. He declares that his cows were the victims of "death rays," some form of alien weapon that's been covered up by the Royal Canadian Mounted Police.

"At least 250 head of cattle have died from what we call a death beam," Bock said on camera in May of last year. "Where the atmospheric air is manipulated into a death beam, focused on the noses of the animals."

The animals breath in the death beam and slowly die, the eastern New Brunswick farmer claims.

 


Continued: http://www.huffingtonpost.com/2012/06/12/werner-bock-blames-death-rays-aliens-for-cow-deaths_n_1589706.html?utm_hp_ref=weird-news

DNA Traces Cattle Back to a Small Herd Domesticated Around 10,500 Years Ago

ScienceDaily (Mar. 27, 2012) — All cattle are descended from as few as 80 animals that were domesticated from wild ox in the Near East some 10,500 years ago, according to a new genetic study.

An international team of scientists from the CNRS and National Museum of Natural History in France, the University of Mainz in Germany, and UCL in the UK were able to conduct the study by first extracting DNA from the bones of domestic cattle excavated in Iranian archaeological sites. These sites date to not long after the invention of farming and are in the region where cattle were first domesticated.

The team examined how small differences in the DNA sequences of those ancient cattle, as well as cattle living today, could have arisen given different population histories. Using computer simulations they found that the DNA differences could only have arisen if a small number of animals, approximately 80, were domesticated from wild ox (aurochs).

The study is published in the current issue of the journalMolecular Biology and Evolution.

Read on:  http://www.sciencedaily.com/releases/2012/03/120327124243.htm

Grazing Zebras Versus Cattle: Not So Black and White

ScienceDaily (Sep. 22, 2011) — African ranchers often prefer to keep wild grazers like zebra off the grass that fattens their cattle. But a new study by UC Davis and Kenyan researchers shows that grazing by wild animals doesn't always harm -- and can sometimes benefit -- cattle. The results are published Sept. 23 in the journal Science.

"Although savanna rangelands worldwide are managed on the premise that cattle and wildlife compete for food, there is little scientific information to support this assumption," said Wilfred Odadi, a researcher at the Mpala Research Centre in Kenya.

"Our findings provide further evidence that biodiversity conservation and economic development can be simultaneously achieved in human-occupied savanna landscapes," he said.

Truman Young, a professor of plant sciences at UC Davis and senior author of the study, said the interaction between cattle and wildlife is more complicated than has been appreciated.

"When we look at the effect of wildlife on cattle, we find that they sometimes do suppress weight gain by cattle, but also sometimes enhance it," Young said.

"Generally the decision has been to exclude wild animals, but we're saying that things are not that simple," he said.

The researchers enclosed 10-acre plots of savanna rangeland inside fences to exclude wild animals (principally zebra). Then they weighed the cattle grazing inside and outside the fences to measure how much weight they put on at different times of the year.

The research team found that during the dry season, cattle that grazed with wild animals had reduced weight gain -- the bottom line for ranchers. But in the wet season, cattle actually put on more weight when they grazed alongside wildlife.

The explanation is that during the wet season, grass can grow long and become rank, inaccessible and poor in nutritional value.

"When the grass grows very fast and is at risk of becoming rank, having zebras is beneficial," Young said. "They are more than willing to knock back the rank grass."

That means higher-quality, fresher grass for the cattle.

It's not yet clear whether there is a net benefit over a whole year or series of years, Young said, because conditions can vary considerably from year to year. Ranchers are beginning to explore additional ways to control rank grass, such as controlled burns.

The other coauthors of the study are Moses Karachi, Egerton University, Kenya and Shaukat Abdulrazak, National Council for Science and Technology, Nairobi, Kenya. The work was funded by the Smithsonian Institution, the National Geographic Society, the National Science Foundation, the African Elephant Program of the U.S. Fish and Wildlife Service, and the International Foundation for Science.

http://www.sciencedaily.com/releases/2011/09/110922141900.htm

Cows Clock-In for Monitored Mealtimes

ScienceDaily (Aug. 1, 2011) — Electronic ear tags are being used to provide an early warning system that will help farmers identify sick animals within a herd.

Cattle fitted with "RFID" ear tags to monitor changes in feeding behavior which may indicate the early signs of disease. Part of a research project by the School of Agriculture, Food and Rural Development at Newcastle University's Cockle Park Farm in Northumberland, UK. (Credit: Newcastle University)

The new system, being trialled by scientists at Newcastle University, tracks the feeding behaviour of each individual animal, alerting farmers to any change that might indicate the cow is unwell.


Using RFID (radio frequency identification) technology -- similar to that used in the Transport for London Oyster card -- each calf is 'clocked' in and out every time they approach the trough, with the time spent feeding being logged by a computer.

Ollie Szyszka, a PhD student in Newcastle University's School of Agriculture, Food and Rural Development, who is leading the project with Professor Ilias Kyriazakis, said the aim was to help farmers spot any illness in the herd much earlier on and treat the animals more effectively.

"Just as we know when we are sickening for something because we perhaps lose our appetite or feel more lethargic, animals also demonstrate subtle changes in behaviour when unwell," explains Ollie.

"Like any animal, the earlier you can spot and start treating an infection or disease the better chance there is of it making a full recovery. You also reduce the risk of the infection spreading if you can identify and isolate a sick animal but for a farmer with a herd of maybe 500 cattle it is easy to miss any early signs of disease.

"By giving each calf a unique code and tracking its feeding pattern our system is able to alert farmers to small -- but significant -- changes in behaviour which might indicate the animal is unwell."

The project is part of Newcastle University's drive to improve animal welfare on farms and research ways in which agriculture can become more sustainable. Published in the Annual Proceedings of the British Society for Animal Science Conference 2011, the work is being trialled at the University's Cockle Park farm, in Northumberland.

The tracking system -- developed by Newcastle University computing technician Steven Hall -- uses RFID chips fitted into the ear tag of each animal and short-range antennae mounted to their feeding troughs. The antennae pick up a signal every time the animal approaches to feed. The signal is blocked when the animal moves away.

The animals have also been fitted with pedometers which allow the Newcastle team to measure posture, relaying information about how active the calf is and how much time they spend lying down.

The results so far have shown that cattle suffering from an underlying health 'challenge' or infection do show significant changes in their behaviour.

Professor Kyriazakis adds: "Modern farming systems have minimised the contact between the animal and its keeper so we need to constantly look for ways to re-address the balance.

"What we are trying to do here at Newcastle is find ways to detect early infection or deterioration of an individual -- regardless of the size of the herd -- so the farmer can intervene at an early stage.

"In the light of recent outbreaks of diseases such as Foot and Mouth and TB, finding ways of detecting changes in behaviour before there are any obvious signs of disease, is becoming increasingly more important."


http://www.sciencedaily.com/releases/2011/07/110727204407.htm

China Genetically Modifying Cows To Produce Human Breast Milk

Updated: Friday, 10 Jun 2011, 8:06 AM EDT
Published : Wednesday, 08 Jun 2011, 7:54 AM EDT

BY NEWSCORE

BEIJING - Chinese scientists have genetically modified dairy cows to produce human breast milk, and hope to be selling it in supermarkets within three years.

The milk produced by the transgenic cows is identical to the human variety, with the same immune-boosting and antibacterial qualities as breast milk, scientists at China's Agricultural University in Beijing said.

The transgenic herd of 300 was bred by inserting human genes into cloned cow embryos which were then implanted into surrogate cows. The technology used was similar to that used to produce Dolly the sheep, the first mammal to be cloned by scientists, in Scotland.

The milk is still undergoing safety tests, but with government permission it will be sold to consumers as a more nutritious dairy drink than cow's milk.

Workers at the university's dairy farm have already tasted the milk -- and said it is sweeter and stronger than the bovine variety, according to Sky News .

"It's good," said worker Jiang Yao. "It's better for you because it's genetically modified."

The scientists have also produced animals that are resistant to mad cow disease, as well as beef cattle that are genetically modified to produce more nutritious meat.

The director of the research project, Professor Li Ning, said Western concerns about the ethics of genetic modification are misplaced.

"There are 1.5 billion people in the world who don't get enough to eat," he said. "It's our duty to develop science and technology, not to hold it back. We need to feed people first, before we consider ideals and convictions."

UPDATE:  Argentine Scientists Claim To Have Created Herd To Produce Breast Milk

http://www.myfoxny.com/dpp/news/china-genetically-modifying-cows-to-produce-human-breast-milk-20110608-ncx

New strain of MRSA superbug found in cows

3 June 2011
By Pallab Ghosh
Science correspondent, BBC News

A new strain of the MRSA "superbug" has been found in British cows and is believed to be infecting humans.

Environmental campaigners say the new strain has emerged because of the over-use of antibiotics by dairy farmers.

Dr Mark Holmes of Cambridge University, who led the research, said this was a "credible hypothesis".

The researchers, writing in the Lancet Infectious Diseases Journal, say there is no additional health risk from eating milk and dairy products.

'Financial pressure'

MRSA, or methicillin-resistant Staphylococcus aureus, is a drug-resistant form of a usually harmless bacterium which can be deadly when it infects wounds.

The 35 or so strains of antibiotic-resistant superbugs are genetically fairly similar. However, this new variety is very different and it is thought that it might have first emerged from cows.

Its discoverers have dubbed it "New MRSA"

Antibiotics are widely used by dairy farmers to treat cows with mastitis. However over-use means some bacteria become resistant and difficult to treat if humans become infected.

Dr Holmes said the problem might be exacerbated by financial pressures on diary farmers.

"If you drive your cows harder to produce more milk you get more mastitis," he told reporters at a news conference.

The Soil Association has called for a complete ban on routine use of antibiotics in farming.

Soil Association director Helen Browning said: "Dairy systems are becoming ever more antibiotic-dependent. We need to get farmers off this treadmill, even if that means that milk has to cost a few pennies more".

National Farmers' Union chief dairy adviser Rob Newberry said the health and welfare of cows were of "paramount importance" to British dairy farmers.

"In the interests of human and animal health, and animal welfare, it is important that veterinary medicines are administered as little as possible but as much as necessary," he said.

"Any antibiotic or veterinary medicine being administered to a food producing animal has strict conditions of use, including milk and meat withdrawal times, and in general, under European law, would only be available under prescription."

Dr Holmes and his colleague Dr Laura Garcia-Alvarez discovered the new strain while studying a bacterium known to cause mastitis in cows.

They found that, like other MRSA strains, it was resistant to the most commonly used antibiotics. However, the bug was found to be genetically very different.

Subsequent research showed that the strain was also present in humans.

Dr Garcia-Alvarez says that finding a new strain in both in humans and cows is "very worrying".

"Workers on dairy farms are at higher risk of carrying MRSA but we don't yet know if this translates to a higher risk [of them becoming ill]," she said.

'Very low risk'

Dr Holmes said very few people had been infected with the new strain, probably fewer than 100 a year in the UK. "But it does appear that the numbers are rising," he says.

The Health Protection Agency said the risk of becoming infected with the new strain was "very low".

Dr Holmes and Dr Garcia-Alvarez will now investigate the prevalence of the new strain and whether it is more or less harmful than current strains.

They also plan to conduct studies on farms to look for more MRSA strains of this type and explore any potential risks to farm workers.

MRSA is often found in hospitals and was linked to 1,593 deaths in 2007.

Since then the number of suspected fatal cases has fallen dramatically. There were 1,290 in 2008 and 781 in 2009.

A Department of Health spokesman said: "From the available evidence, we understand this new form of MRSA is rare in the UK and is not causing infections in humans.

"However, our expert committee, ARHAI, will be reviewing this issue at their next meeting and will consider potential medical, veterinary and food safety issues."

A Food Standards Agency spokesman said the study did not provide direct evidence that humans were being infected with MRSA from cattle.

"The risk of contracting this new strain of MRSA through drinking milk is extremely low because the vast majority of cows' milk is pasteurised and the pasteurisation process destroys all types of MRSA," he added.

http://www.bbc.co.uk/news/health-13632369

Mass culling for foot-and-mouth 'may be unnecessary'

6 May 2011
By Pallab Ghosh
Science correspondent, BBC News

The mass cull of farm animals to control the spread of foot-and-mouth disease may be unnecessary if there is a new outbreak, scientists suggest.

A new analysis of disease transmission suggests that future outbreaks might be controlled by early detection and killing only affected animals.

The scientists said their findings did not suggest the mass slaughter policy during the 2001 UK outbreak was wrong.

The research, by a UK team, is reported in the journal Science.

Until now, vets had assumed animals could be infectious while they carried the virus that causes foot-and-mouth, which may be for between four and eight days.

However, by exposing calves to infected cattle and closely monitoring them, researchers from the Institute for Animal Health in Surrey and Edinburgh University discovered that the period of infection was less than two days.

Perhaps more importantly, the researchers also discovered that animals were not infectious until they showed symptoms of the disease.

Scientists had previously thought animals were infectious for hours or even days before manifesting any symptoms.

These results suggest that any future outbreak could be brought under control by closely monitoring animals and slaughtering them as soon as they become ill.

This approach is in contrast to the policy adopted to bring the 2001 epidemic under control.

Too drastic

Ten years ago, the UK Government slaughtered not only all the animals on infected farms but also all animals on adjacent farms, regardless of whether infection had been reported there.

The policy of "contiguous culling" was adopted following scientific advice that this was the only way of controlling the epidemic.

It led to the slaughter of 6.5 million cattle, sheep and pigs, some of which were burned on open air pyres.

Many vets and farmers felt at the time - and still argue - that the policy was far too drastic, and that a more targeted approach would have been sufficient to bring the outbreak under control.

Dr Bryan Charleston, of the Institute for Animal Health, was among those asked to undertake the new study in response to public concern about the use of contiguous culling.

The research, he says, "doesn't say that this policy was wrong" - but it does suggest that mass culling could be avoided in the future.

Writing in Science, his team says: "These results imply that controversial pre-emptive control measures may be unnecessary.

"Instead, efforts should be directed at early identification of infection and rapid intervention."

Dr Charleston also told BBC News it would be worth developing simple test kits to detect herds that are infected before the onset of clinical signs, and also to detect herds that are not infected "so they would not need to be culled".

Targeted approach

So if mass culling could be avoided in the future, why was it not "wrong" in 2001, as Dr Charleston argues?

Professor Neil Ferguson, of Imperial College London, was among those advising government on how to control the epidemic a decade ago.

He said the more targeted approach suggested by the new research would have been impossible by the time government had realised that there was a major outbreak.

"The biggest problem in 2001 was that by the time we realised what was happening, there were something between 30 and 50 infected farms," he said.

"It took a huge amount of effort to deal with that, and so very intensive surveillance of infected areas proved impossible from the outset."

But government agencies are now much better placed to detect new infections much earlier.

That being the case, the implications of this paper are that in future, vets will be able to nip foot-and-mouth outbreaks in the bud.

Indeed, this is what happened in 2007 when there was a small outbreak as a result of a leak of foot-and-mouth virus from a laboratory in Surrey.

That outbreak was confined to a small area, and so vets were able to monitor closely and test herds that were in close proximity to infected animals.

Those that were found to have the virus were culled; those that tested negative were not.

This approach was sufficient to bring the 2007 outbreak under control. But such a scheme could not be applied to a larger outbreak, according to Professor Ferguson.

He said: "When the outbreak is very small, it becomes more feasible to pick up any signs of infection on a farm as soon as possible; and this research suggests that might be very effective at stopping onward transmission.

"But in 2001, really rapid diagnosis proved to be challenging.

"If you have a lot of animals on a lot of farms, it's hard to inspect them all every day. So although the general conclusion is that rapid diagnosis might have a big effect in practice, it might be hard to achieve (once the outbreak exceeds a certain size)."

The research also suggests that vets should not be wary of using vaccination to control any future outbreak, as they were in 2001.

Then, there was concern that vaccination would lead to animals becoming infected at a very low level without displaying symptoms, and that these animals could in turn have infected animals in other farms.

The new research, however, suggests that this kind of subclinical infection is not a worry.

It indicates that if an animal does not show symptoms, it is not infectious; so vaccinating in the face of an outbreak might be more effective than scientists previously thought.

http://www.bbc.co.uk/news/science-environment-13299666