Livestock infection
March 20, 2012
Belgian scientists have detected the transmission vector of the Schmallenberg virus, which has affected livestock across an estimated 1,000 farms in Germany, and more in neighboring countries, including Denmark, Belgium, the Netherlands, France, Spain and Britain. It’s an important step in slowing this viral outbreak in northwestern Europe.
"We were able to demonstrate the virus in the heads of three species of biting midges," said Redgi De Deken, a researcher at the Institute of Tropical Medicine in Antwerp, Belgium, in an interview with DW.
Midges, some of which are blood-sucking, are very small insects that are commonly known as "no-see-ums" in North American English. Various species exist in other parts of the world.
The virus affects cattle, goats, and sheep, and the symptoms are animal diarrhea and fever. While this can be treated in livestock, the main concern is if animals, particularly sheep, are infected in an early stage of pregnancy. If this happens, the fetus can be infected directly while its neural cells are forming. The animal is then sometimes born with physical problems, particularly in the brain and limbs.
Not harmful to humans
The virus is under-researched, but studies are underway.
"A mass-test for the detection of antibodies will probably be available soon," said Thomas Mettenleiter, a virologist and head of the German Federal Research Institute for Animal Health (FLI), in an interview with the German news agency, DPA, on Monday.
Also on Monday, the FLI announced that 160 cattle, 799 sheep and 41 goats had been infected across all states in Germany, except Bremen.
On Tuesday, Russia said it would stop importing live pigs, cattle, goats and sheep from the European Union as a precautionary measure.
But the virus is not known to be harmful to humans.
"Previously, genetically-similar orthobunyaviruses have not caused disease in humans," wrote the European Centre for Disease Prevention and Control, in a December 2011 statement posted on its website. "It is therefore unlikely that this virus will cause disease in humans, but it cannot be excluded at this stage."
Spreading 'incredibly fast'
The virus was first identified late last year by German researchers when a sample arrived from the town of Schmallenberg, about 124 kilometers northeast of Cologne.
De Deken says it tends to infect its host for between four and five days before the animal's immune system is able to fight it off and create a natural immunity.
But the virus is spreading "incredibly fast," De Deken said.
Germany's Cattle Breeders association says it has suffered "high" economic losses due to the outbreak, but has yet to release specific figures.
Back in January 2012, the FLI's Thomas Mettenleiter told the journal Science that infections had likely occurred in Germany at the end of last year.
"Now, in some herds 20 to 50 percent of lambs are showing these malformations," Mettenleiter said. "And most of the animals are born dead."
A team from the FLI was able to visually isolate the virus earlier this month, and has continued to work on a vaccine, which it says may be available by next year - a target which Mettenleiter describes as "very ambitious."
Author: Cyrus Farivar
Editor: Zulfikar Abbany