̽��ֱ�� of Cambridge - veterinary school

Massive projected increase in use of antimicrobials in animals could lead to widespread antimicrobial resistance in humans

sc604 — Thu, 28 Sep 2017 18:00:00 +0000

̽��ֱ��researchers, from ETH Zürich, Princeton, and the ̽��ֱ�� of Cambridge, conducted the first global assessment of different intervention policies that could help limit the projected increase of antimicrobial use in food production. Their results, reported in the journal Science, represent an alarming revision from already pessimistic estimates made in 2010, pushed up mostly by recent reports of high antimicrobial use in animals in China.

In modern animal farming, large quantities of antimicrobials are used for disease prevention and for growth promotion. “Worldwide, animals receive almost triple the amount of antibiotics that people do, although much of this use is not medically necessary, and many new strains of antibiotic-resistant infections are now common in people after originating in our livestock,” said co-author Emma Glennon, a Gates Scholar and PhD student at Cambridge’s Department of Veterinary Medicine. “As global demand for meat grows and agriculture continues to transition from extensive farming and smallholdings to more intensive practices, the use of antimicrobials in food production will increasingly threaten the efficacy of these life-saving drugs.”

Global policies based on a user fee and stricter regulation could help mitigate those ominous projections. “Under a user fee policy, the billions of dollars raised in revenues could be invested in the development of new antimicrobial compounds, or put towards improving farm hygiene around the world to reduce the need for antibiotics, in particular in low- and middle-income countries,” said Dr Thomas Van Boeckel from ETH Zurich, the study’s first author.

Compared to a business as usual scenario, a global regulation putting a cap of 50 mg of antimicrobials per kilogram of animal per year in OECD countries could reduce global consumption by 60% without affecting livestock-related economic development in low-income countries.

However, such a policy may be challenging to enforce in resource-limited settings. An alternative solution could be to impose a user fee of 50% of the current price on veterinary antimicrobials: this could reduce global consumption by 31% and generate yearly revenues of between US$ 1.7 and 4.6 billion.

An important limiting factor in performing this global assessment was accessing sufficient data on veterinary antimicrobial sales volumes and prices. ̽��ֱ��present study is based on publicly available data, limited to 37 countries. Representatives from the animal health industry were approach for this study but all declined to share information on antimicrobial sales or prices.

̽��ֱ��research was funded by the program for Adaptation to a Changing Environment, the ETH postdoctoral fellowship program and the European Research Council.

Reference:
Thomas P. Van Boeckel et al. ‘Reducing global antimicrobial use in food animals.’ Science (2017). DOI: 10.1126/science.aao1495

Adapted from at ETH Zurich press release.

̽��ֱ��amount of antimicrobials given to animals destined for human consumption is expected to rise by a staggering 52% and reach 200,000 tonnes by 2030 unless policies are implemented to limit their use, according to new research.

Worldwide, animals receive almost triple the amount of antibiotics that people do.

Emma Glennon

Marcelo Braga

Expresso Porco

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No simple way of predicting breathing difficulties in pugs, French bulldogs and bulldogs from external features

sjr81 — Tue, 01 Aug 2017 18:00:17 +0000

̽��ֱ��findings have implications for attempts to ‘breed out’ this potentially life-threatening condition.

Pugs and bulldogs have become popular breeds in recent years – the French bulldog is set to become the UK's most popular canine, according to the Kennel Club. However, a significant proportion are affected by a condition known as Brachycephalic Obstructive Airway Syndrome (BOAS) related to their head structure.

Studies suggest that for over half of such dogs, BOAS may lead to health problems, causing not just snoring but also difficulty exercising and potentially overheating. It can even prove life-threating. But as symptoms often do not arise until after the dog has begun breeding, veterinary scientists have been searching for markers that can predict whether a dog is likely to develop breathing difficulties – and hence potentially help breed out the condition.

A study in 2015 led by researchers at the Royal Veterinary College, ̽��ֱ�� of London, working across many breeds suggested that dogs whose muzzles comprised less than half their cranial lengths and dogs with thicker neck girths were at increased risk of BOAS. However, a new study carried out by researchers at the Department of Veterinary Medicine, ̽��ֱ�� of Cambridge, and published today in the journal PLOS ONE, suggests that these measures applied to individual breeds are not dependable for this purpose.

̽��ֱ��Cambridge researchers took external measurements of features of head and neck shape, and of the external appearance of nostrils, together with measurements of body size and body condition score (an approximation to the degree of fatness/obesity) in just over 600 pugs, bulldogs and French bulldogs, the most numerous breeds that show this problem. Each of the dogs had also been graded objectively for respiratory function.

̽��ֱ��team found that while the external head measurements did have some predictive value for respiratory function, the relationship was not strong, and the measurements that showed the best predictive relationship to BOAS differed between breeds. They were unable to reproduce conclusively the findings from the previous study by the Royal Veterinary College in any breed.

“It can be incredibly difficult to take measurements such as distance between eyes or length of nose accurately, even for experienced vets, as the dogs don’t keep still,” says Dr Jane Ladlow, joint lead author. “This may explain why it is so difficult to replicate the findings of the previous study or find any conclusive markers in our own.”

Neck girth was a slightly more reproducible measurement, and larger neck girth in comparison to chest girth or neck length was associated with disease in the bulldogs and French bulldogs. In male bulldogs, neck girth showed a close enough association with disease to give moderately good predictive accuracy for the presence of clinically significant BOAS.

̽��ֱ��best measure identified by the Cambridge team was the degree of nostril opening, which proved a moderately good predictor of the presence and severity of BOAS in pugs and French bulldogs, and was also a useful marker for disease in bulldogs.

Altogether the variables measured, when combined, gave an 80% accuracy in predicting whether or not dogs will have BOAS, the difficulty of taking some of the measurements accurately, and the need to make multiple measurements and combine them in order to produce a prediction means that the researchers would not recommend using them as a guide to breeding.

Dr Nai-Chieh Liu, first author of the study, says: “Breeding for open nostrils is probably the best simple way to improve these breeds. Dog breeders should also avoid using dogs with extremely short muzzles, wide faces, and thick necks. These traits are all associated with increased risk of having BOAS.”

Joint lead author Dr David Sargan adds “At this moment there is no conclusive way of predicting whether any individual pug or bulldog will develop breathing difficulties, so we are now looking for genetic tests that may help breeders get rid of BOAS more rapidly.

“ ̽��ֱ��best advice we can give to owners of short-nosed dogs is to make sure you get your dog checked annually for any potential difficulties in breathing, even if you have not yourself observed any in your dog, and to keep your dog fit and not let it get fat.”

As many as a half of all short-nosed dogs such as pugs, French bulldogs and bulldogs experience breathing difficulties related to their facial structure. However, research published today by the ̽��ֱ�� of Cambridge suggests that there is no way to accurately predict from visible features whether an apparently healthy pug or French bulldog will go on to develop breathing difficulties.

Dog breeders should also avoid using dogs with extremely short muzzles, wide faces, and thick necks.

Nai-Chieh Liu

LW Yang

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First randomised controlled trial to show spinal cord regeneration in dogs

fpjl2 — Mon, 19 Nov 2012 14:54:25 +0000

In a collaboration between the ̽��ֱ��’s Veterinary School and MRC’s Regenerative Medicine Centre, scientists used a unique type of cell to regenerate the damaged part of the dogs’ spines. ̽��ֱ��researchers are cautiously optimistic that the work could have a future role in the treatment of human patients with similar injuries if used alongside other treatments.

Scientists have been aware for over a decade that olfactory ensheathing cells (OEC) might be useful in treating the damaged spinal cord because of their unique properties. ̽��ֱ��cells have the ability to support nerve fibre growth that maintains a pathway between the nose and the brain.

Previous research using laboratory animals has already revealed that OECs can aid regeneration of the parts of nerve cells that transmit signals (axons) so as to form a ‘bridge’ between damaged and undamaged spinal cord tissue. A Phase 1 trial in human patients with SCI established that the procedure is safe.

̽��ֱ��study, published in the latest issue of the neurology journal Brain, is the first double-blinded randomised controlled trial to test the effectiveness of these transplants to improve function in ‘real-life’ spinal cord injury. ̽��ֱ��trial was performed on animals that had spontaneous and accidental injury rather than in the controlled environment of a laboratory, and some time after the injury occurred. This far more closely resembles the way in which the procedure might be used in human patients.

̽��ֱ��34 pet dogs had all suffered severe spinal cord injury. Twelve months or more after the injury, they were unable to use their back legs to walk and unable to feel pain in their hindquarters. Many of the dogs were dachshunds which are particularly prone to this type of injury. Dogs are also more likely to suffer from SCIs because the spinal cord may be damaged as a result of what in humans is the relatively minor condition of a slipped disc.

In the study, funded by the MRC, one group of dogs had olfactory ensheathing cells from the lining of their own nose injected into the injury site. ̽��ֱ��other group of dogs was injected with just the liquid in which the cells were transplanted. Neither the researchers nor the owners (nor the dogs!) knew which injection they were receiving.

̽��ֱ��dogs were observed for adverse reactions for 24 hours before being returned to their owners. From then on, they were tested at one month intervals for neurological function and to have their gait analysed on a treadmill while being supported in a harness. In particular, the researchers analysed the dogs’ ability to co-ordinate movement of their front and back limbs.

̽��ֱ��group of dogs that had received the OEC injection showed considerable improvement that was not seen in the other group. These animals moved previously paralysed hind limbs and co-ordinated the movement with their front legs. This means that in these dogs neuronal messages were being conducted across the previously damaged part of the spinal cord. However, the researchers established that the new nerve connections accounting for this recovery were occurring over short distances within the spinal cord and not over the longer distances required to connect the brain with the spinal cord.

Professor Robin Franklin, a co-author of the study from the Wellcome Trust-MRC Cambridge Stem Cell Institute, ̽��ֱ�� of Cambridge, said: “Our findings are extremely exciting because they show for the first time that transplanting these types of cell into a severely damaged spinal cord can bring about significant improvement. We’re confident that the technique might be able to restore at least a small amount of movement in human patients with spinal cord injuries but that’s a long way from saying they might be able to regain all lost function. It’s more likely that this procedure might one day be used as part of a combination of treatments, alongside drug and physical therapies, for example.”

Dr Rob Buckle, Head of Regenerative Medicine at the MRC, commented: “This proof of concept study on pet dogs with the type of injury sustained by human spinal patients is tremendously important and an excellent basis for further research in an area where options for treatment are extremely limited. It’s a great example of collaboration between veterinary and regenerative medicine researchers that has had an excellent outcome for the pet participants and potentially for human patients.”

̽��ֱ��researchers stress that human patients with a spinal injury rate a return in sexual function and continence far higher than improved mobility. Some of the dogs in the study did regain bowel and bladder control but the number of these was not statistically significant.

Mrs May Hay, owner of Jasper who took part in the trail (and can be seen in the video), said: “Before the trial, Jasper was unable to walk at all. When we took him out we used a sling for his back legs so that he could exercise the front ones. It was heartbreaking. But now we can’t stop him whizzing round the house and he can even keep up with the two other dogs we own. It’s utterly magic.”

Text courtesy of the Medical Research Council

Researchers have shown it is possible to restore co-ordinated limb movement in dogs with severe spinal cord injury (SCI).

Our findings are extremely exciting because they show for the first time that transplanting these types of cell into a severely damaged spinal cord can bring about significant improvement.

Robin Franklin

Cambridge Veterinary School

A dog called Jasper during the trial

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