Livestock, Not Mongolian Gazelles, Drive Foot-And-Mouth Disease Outbreaks

ScienceDaily (Jan. 30, 2012) — Wildlife health experts from the Wildlife Conservation Society have published evidence which supports the conclusion that Mongolian gazelles -- one of the most populous large land mammals Outbreaks of FMD in Mongolia affect domestic sheep, goats, camels, and cattle as well as Mongolian gazelles. In a country where roughly one-third of the human population relies directly on livestock production for their subsistence, outbreaks of FMD cause severe disruption of the rural economy.

The study, titled "Serosurveillance for Foot-and-Mouth Disease in Mongolian Gazelles (Procapra gutturosa) and Livestock on the Eastern Steppe of Mongolia," appears in the January edition of theJournal of Wildlife Diseases. The authors include: Sanjaa Bolortsetseg, Shiilegdamba Enkhtuvshin, Wendy Weisman, Amanda Fine, Angela Yang, and Damien Joly of the Wildlife Conservation Society; and D. Nyamsuren of the Dornod Aimag Veterinary Laboratory, Choibalsan, Dornod Province, Mongolia.

The Mongolian gazelle is a medium-sized antelope with a heart-shaped patch of white fur on its rump. The species gathers in vast migratory herds across Mongolia's Eastern Steppe, considered the largest intact temperate grassland in the world. The gazelle is under pressure from a variety of threats, particularly exploration for oil, gas, and minerals.

The research culminates a decade-long effort to examine the potential role of the gazelles in FMD ecology. In the recently published study (undertaken between 2005-2008), the research team collected blood samples from 36 gazelle calves and 57 adult gazelles in order to determine the prevalence of antibodies to the foot-and-mouth virus (FMDV). The team also collected samples from domestic animals kept in areas frequented by gazelles, including 138 sheep, 140 goats, 139 Bactrian camels, and 138 cattle for comparison.

The authors found that the patterns of FMDV antibody prevalence in gazelle populations reflect the dynamics of FMD in livestock across the Eastern Steppe of Mongolia. During 1998-99 (outbreak free years in livestock), researchers detected no antibodies in gazelles; conversely, during a FMD outbreak in livestock in 2001, researchers detected a 67 percent prevalence rate in gazelles. The recently published study examines the following outbreak free periods, during which the team noted a declining prevalence in FMDV antibodies in the gazelle population. Based on these observations, the authors conclude that the Mongolian gazelle population is not a reservoir for FMDV on the Eastern Steppe of Mongolia, but rather, the virus enters the gazelle population after spillover from livestock during sporadic outbreaks.

"The successful control of foot-and-mouth disease on the Eastern Steppe will require a program that focuses on livestock populations and entails health monitoring and vaccinations of domestic animals when needed," said WCS veterinary epidemiologist and co-author Shiilegdamba Enkhtuvshin.

http://www.sciencedaily.com/releases/2012/01/120130172408.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

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