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Study reveals likely cause of mystery epidemic
Icelandic horses are highly susceptible to any new bacteria or viruses that find their way into the country.

DNA sequencing reveals endemic strain of bacteria 

The likely cause of a mystery epidemic which affected Iceland’s native horse population has been identified in a new study.

In 2010, a respiratory disease spread rapidly through Iceland’s population of 77,000 Icelandic horses, leading to a self-imposed ban on their export and significant cost to the country.

Due to the speed at which the disease spread, researchers thought the cause was viral. However, a study by the University of Iceland showed that only Streptococcus zooepidemicus, was consistently recovered from coughing horses and rare fatal cases of infection.  However, this bacteria can also be found in healthy horses.

To investigate further, researchers at the AHT and the Wellcome Trust Sanger Institute sequenced the DNA from 257 samples of bacteria from diseased animals and people. This revealed one specific strain of S. zooepidemicus, called ST209, was the likely culprit. Researchers also found the strain in a human case of blood poisoning.

“This study highlights, for the first time, how DNA sequencing can be used to identify endemic strains of bacteria and distinguish them from the cause of an epidemic infection,” said Dr Simon Harris form the Wellcome Trust Sanger Institute.

Thanks to a ban on the importation of horses in 1882, Iceland is free of major equine infectious diseases. As such, Icelandic horses are highly susceptible to any new bacteria or viruses that find their way into the country, so strict biosecurity regulations are in place to protect them.

When the disease entered Iceland in 2010, it spread through the horse population in weeks and even managed to infect dogs, cats and humans.

Dr Sigríður Björnsdóttir of the MAST Icelandic Food and Veterinary Authority used information from owners and vets to build an epidemiological network. This enabled her to trace the virus back to an equine rehabilitation centre where the horses exercised on a water treadmill.

It is thought that the water treadmill provided the perfect breeding ground for the disease, allowing it to be transmitted to another animal as water was splashed up and ingested. Horses would then complete their rehabilitation and return home, whilst incubating the disease, taking the infection with them.

There are a couple of theories as to how the ST209 entered Iceland. The AHT believes the most likely route was via imported equipment or clothing. However, researchers say this particular strain could have infected a human who travelled to Iceland.

“We are delighted to have helped uncover the likely identity of the cause of this epidemic. Our investigation highlights the ability of S. zooepidemicus strains to cause disease in animals and people,” commented Dr Andrew Waller, head of bacteriology at the AHT.

“We found evidence that even endemic strains of S. zooepidemicus were likely causing cases of respiratory disease in Icelandic horses, illustrating that this group of bacteria causes more clinical problems in horses than was previously thought.”

He added: “We hope that raising awareness of the cause of this epidemic, and the likely involvement of a water treadmill as a key factor in disease transmission, will encourage veterinarians around the world to improve disease control precautions preventing future epidemics.”

Image (C) Andreas Tille.

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Birmingham Dogs Home makes urgent appeal

News Story 1
 Birmingham Dogs Home has issued an urgent winter appeal as it faces more challenges over the Christmas period.

The rescue centre has seen a dramatic increase in dogs coming into its care, and is currently caring for over 200 dogs. With rising costs and dropping temperatures, the charity is calling for urgent support.

It costs the charity £6,000 per day to continue its work.

Fi Harrison, head of fundraising and communications, said: "It's heart-breaking for our team to see the conditions some dogs arrive in. We really are their last chance and hope of survival."

More information about the appeal can be found here

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Avian flu confirmed at premises in Cornwall

A case of highly pathogenic avian influenza H5N1 has been detected in commercial poultry at a premises near Rosudgeon, Cornwall.

All poultry on the infected site will be humanely culled, and a 3km protection zone and 10km surveillance zone have been put in place. Poultry and other captive birds in the 3km protection zone must be housed.

The case is the second avian flu case confirmed in commercial poultry this month. The H5N5 strain was detected in a premises near Hornsea, East Riding of Yorkshire, in early November. Before then, the disease had not been confirmed in captive birds in England since February.

The UK chief veterinary officer has urged bird keepers to remain alert and practise robust biosecurity.

A map of the disease control zones can be found here.