Distinctive virus behind mystery horse disease

Nature News ^ | 18 March 2013 | Ed Yong

[neverdem]

Origin of Theiler hepatitis was a century-old puzzle.

For almost 100 years, veterinarians have puzzled over the cause of Theiler disease, a mysterious type of equine hepatitis that is linked to blood products and causes liver failure in up to 90% of afflicted animals.

A team of US scientists has now discovered that the disease is caused by a virus that shares just 35% of its amino acid sequences with its closest-known relative. The team named it Theiler disease-associated virus (TDAV), and published the discovery in the Proceedings of the National Academy of Sciences1.

Led by Amy Kistler at the Novartis Institutes for BioMedical Research in Emeryville, California, the team responded to an outbreak of Theiler disease at a farm in which eight horses had suddenly developed hepatitis after being injected with an antitoxin to prevent them from developing botulism. The researchers used next-generation sequencing to analyse RNA samples from the antitoxin and from two of the horses, and assembled the complete genome of the new virus. The virus was found in every one of the eight horses, as well as in the animal (from a different farm) that was the source of the contaminated antitoxin.

“In the span of a few months, we were able to sequence and validate a virus that had gone undetected for almost a century,” says Kistler. She thinks that traditional virus-hunting techniques failed to find TDAV because they rely on strong similarities to known viruses, or on the ability to culture the mystery culprit. By contrast, her team sequenced everything in their samples — an approach “that meant we didn’t have to know what we were looking for”, she says...

[Born to Conserve]

-—an approach “that meant we didn’t have to know what we were looking for”-—

I think we just crossed the line — computer intelligence is now more useful than human intelligence.

[neverdem]

Deadly mushroom chemistry

FReepmail me if you want on or off my combined microbiology/immunology ping list.

[Amberdawn]

Interesting. I’ve worked with horses for 35+ years and have never even heard of one with hepatitis.

[Smokin' Joe]

Ping... (Thanks, neverdem!) The really neat part to me is the idea of sequencing everything present and not prejudicing the analysis by only looking for known pathogens. (If you only find what you look for, looking for every/anything just might find the answer).

[vetvetdoug]

I have worked with horses for almost 40 years and hepatitis is a real concern. In retrospect, I have seen hepatitis post vaccine administration several times. Some of the cases have been serious but luckily none ended up with death. I had one case where I had to watch the liver enzymes because intermittently the hepatitis would reoccur.

[Alamo-Girl]

Thanks for the ping!

[null and void]

You can see a lot just by looking ~ Yogi Berra

[Smokin' Joe]

You’re Welcome, Alamo-Girl!

[Amberdawn]

I worked with racehorses, mostly Standardbreds, Trakhaners, Arabians, 1/4 horses, many others. In all my days, I never had, or heard of a horse with Hep. Lucky, I’m sure.

[exDemMom]

Very interesting.

I wonder what kinds of previously unidentified pathogens will show up as “next generation” sequencing tools are applied more often to research problems.