Veterinary researchers discover first U.S. strains of hepatitis E virus from rabbits | ScienceBlog.com

Researchers in the Virginia-Maryland Regional College of Veterinary Medicine at Virginia Tech have identified the first strains of hepatitis E virus from farmed rabbits in the United States.

It is unknown whether the virus can spread from rabbits to humans.

Caitlin Cossaboom of Salisbury, Md., a second-year student in the combined Doctor of Veterinary Medicine and Ph.D. program in the Department of Biomedical Sciences and Pathobiology, is the first author of a publication entitled “Hepatitis E Virus in Rabbits, Virginia, USA” in the November issue of Emerging Infectious Diseases, published by the U.S. Centers for Disease Control and Prevention.

“Although researchers found hepatitis E virus in rabbits in China in 2009, this is the first time the virus has been identified in rabbits in the United States or anywhere outside of China,” Cossaboom said.

Dr. X.J. Meng, professor of biomedical sciences and pathobiology in the veterinary college, Cossaboom’s graduate advisor, and senior author of the study, identified the first animal strains of hepatitis E virus — swine hepatitis E virus from pigs — in 1997.

Following the landmark study on swine hepatitis E virus by Meng and his colleagues at the National Institutes of Health’s National Institute of Allergy and Infectious Diseases, researchers began to consider hepatitis E virus a zoonotic virus.

“Since 1997, researchers have found hepatitis E virus in pigs essentially in every swine-producing country and shown that the virus from pigs can infect humans,” said Meng.

He added that his lab also identified avian hepatitis E virus from chickens in the United States and that other researchers later discovered strains of the virus in other animal species, including rats, mongoose, deer, and wild boars.

Hepatitis E is an acute hepatic disease caused by infection with an RNA virus that has a fecal-oral transmission route.

The disease is mainly prevalent in developing countries, though sporadic cases have been reported in industrialized countries such as the United States.

The mortality rate associated with hepatitis E virus infection in humans is generally less than 1 percent, but it can reach up to 28 percent in infected pregnant women.

The virus has at least four distinct genotypes. Genotypes 1 and 2 infect only humans and typically occur in developing countries with poor sanitation conditions.

Meanwhile, genotypes 3 and 4 are zoonotic, can spread from animals to humans, and are found in both industrialised and developing countries.

“It is worth noting that the strains of the virus found in rabbits in the U.S. and China closely relate to genotype 3, a genotype that has been shown to transfer from animals to humans,” Meng said.

“The question is, ‘Do the strains of hepatitis E virus in rabbits infect humans?’ We don’t know, but the possibility is there and more research is needed to address this potential concern.”

She added that pigs can serve as “animal reservoirs” for genotypes 3 and 4 hepatitis E virus. In other words, the pigs can carry and shed the virus, and occasionally the virus may transmit to humans.

“However, it is unknown if the virus from rabbits can infect across species or serve as a reservoir,” Cossaboom said.

There are five known types of viral hepatitis: Hepatitis A transmits from person to person from ingesting contaminated food and water. Hepatitis B and C spread by blood-to-blood contact; the hepatitis C virus can also cause chronic infection and, in some cases, liver cancer.

Hepatitis D occurs in individuals who already have hepatitis B. Although all of these viruses, including hepatitis E virus, target the liver, none of them are genetically related.

Giant Rabbit Skeleton (Nuralagus rex) found on the Spanish island of Minorca

Unfrotunately, Nuralagus rex, also known as the Menorcan King of the Rabbits was too big to hop.

Due to his short stiff spine he would have been forced to clumsily haul himself along like a beaver getting out of water, researchers have said.

A creature initially mistaken for an extinct tortoise has turned out to be a giant bunny that had tiny ears and couldn't hop.

The 5-million-year-old remains of Nuralagus rex were found on the Spanish island of Minorca by independent researcher Josep Quintana. 

At an estimated 12 kilograms, it was around 10 times the weight of wild Spanish rabbits today.

Quintana came across the first fossil in the early 1990s when he was 19. He initially thought it was part of an extinct Minorcan tortoise. Later, Meike Köhler and Salvador Moya-Sola of the Autonomous University of Barcelona's Catalan Institute of Paleontology identified it as a giant rabbit.

Now the three have uncovered enough fossils to reconstruct the entire animal and name it. They say its closest relative was Alilepus, a now-extinct genus whose members were about a tenth the size of N. rex and lived in Eurasia and North America at the time.

Land bridge

Quintana says the ancestors of N. rex colonised Minorca 5.3 million years ago when sea levels in the Mediterranean dropped by about 1.5 kilometres, connecting the Balearic Islands to the mainland.

As sea levels rose again and cut Minorca off, N. rex evolved separately from Alilepus. It shared the island with tortoises, bats and a large dormouse species, and in the absence of predators chose life in the slow lane. 

"If you don't have natural enemies, why run?" asks Quintana. Gradually, its legs grew shorter, its ears shrank and its spine lost the curvature that helps rabbits hop.

Journal reference: Journal of Vertebrate Paleontology, vol 31, p 231

Nuclear Clean up: Going through the motions

WASHINGTON — Anything that hops, burrows, buzzes, crawls or grazes near a nuclear weapons plant may be capable of setting off a Geiger counter and at the Hanford nuclear reservation, one of the dirtiest of them all, its droppings alone might be enough to trigger alarms.

A government contractor at Hanford, in south-central Washington State, just spent a week mapping radioactive rabbit feces with detectors mounted on a helicopter flying 50 feet over the desert scrub. An onboard computer used GPS technology to record each location so workers could return later to scoop up the droppings for disposal as low-level radioactive waste.

The Hanford site, overseen by the federal Department of Energy, produced roughly two-thirds of the plutonium used in the nation’s nuclear weapons arsenal, beginning in World War II and ending in the 1980s. Today it is the focus of the nation’s largest environmental cleanup, an effort that has cost tens of billions of dollars and is expected to continue for decades.

Yet the helicopter flights, which covered 13.7 square miles and were paid for with $300,000 in federal stimulus money, took place in an area that had never been used by the bomb makers.

The area had, however, been used by rabbits that had also burrowed into other areas that were contaminated. Many of the contaminants were in the form of salts, which attract wildlife. The rabbits carried strontium and cesium, which emit gamma rays, back out of the area in their digestive tracts.