Equine herpes virus killed polar bear, researchers show
Scientists accept established that a 2 polars bears that became sick at a High German zoo had contracted a form of equine herpes virus.
In 2010 at the Wuppertal Zoo inward Germany, a woman mortal polar bear, Jerka, died of encephalon swelling despite the best efforts of the zoo veterinarians to salvage her. Her manful mortal companion, Lars, showed similar symptoms merely survived every bit a termination of intervention too long-term veterinary care.
The researchers who established the drive of the bears’ sickness said their illness was an unforseen effect of bringing together different fauna species that would never run across each other inward the wild.
Their study proved that the bears were infected alongside a recombinant zebra-derived virus that had jumped into other species.
The finding were reported this calendar week past times an international squad of researchers inward the journal, “Current Biology”.
They warned that such species-jumping viruses, if non detected, may threaten the conservation utilisation of zoos.
To date, it has rarely been considered that such a species mix may accept unpredictable consequences inward damage of transfer of pathogens amidst zoo animals.
Generally, pathogens conform to a specific host, merely to a greater extent than or less are opportunistic too tin spread to novel hosts upon encounter.
The study past times researchers from the Leibniz Institute for Zoo too Wildlife Research Berlin, the Freie Universität Berlin, the University of Sydney too the Zoological Gardens at Wuppertal investigated the worrying polar deport illness.
Dr Arne Lawrenz, zoo veterinary inward Wuppertal, described the situation: “The symptoms were quite shocking, too it was completely unclear at the fourth dimension what was causing them.
“We tried to stabilize both animals for days. In the illustration of Jerka, nosotros were sadly unsuccessful. Fortunately, however, Lars recovered later several weeks too is silent live today.”
Encephalitis tin live caused past times a large number of viruses too bacteria, too identifying novel pathogens inward wild animals is a huge, oftentimes insurmountable, challenge.
However, the intensive investigation of Jerka, Lars too nine additional polar bears yielded a zebra-derived herpes virus every bit the solely candidate pathogen.
A surprising reveal was that polar deport Struppo, who died years before from renal failure inward a different zoo alongside no contact to Jerka or Lars, was besides positive for the virus. This indicates that this virus has jumped independently before too may piece of occupation on to create so.
Interestingly, the virus turned out to live a recombinant – a combination of the genetic cloth of 2 different viruses both found inward zebras.
It originated when the equine herpesvirus EHV9 transferred a share of its deoxyribonucleic acid into the related EHV1.
While recombination is non uncommon for herpesviruses, the factor part transferred inward this illustration is notable for its utilisation inward causing neurological diseases fifty-fifty inward horses.
Whether this novel virus emerged late inward the zoo zebra population or a long fourth dimension agone inward Africa, too whether the recombination lawsuit is responsible for the powerfulness of the virus to boundary to novel hosts too drive deadly disease, are opened upwards questions.
The study’s atomic number 82 author, Professor Alex Greenwood, of the Berlin-based Leibniz Institute for Zoo too Wildlife Research, said: “When nosotros started, at that topographic point was an overwhelming number of potential pathogens that mightiness accept caused Jerka’s death.
“At starting fourth dimension it seemed easy, because nosotros rapidly got a signal for EHV. But when nosotros looked at the viral deoxyribonucleic acid sequence, it could accept been either EHV1 or EHV9. With to a greater extent than sequence information it became clear that at that topographic point was i factor that was partly similar i virus too partly similar the other.”
Another opened upwards inquiry is how the bears were infected.
Polar bears inward Wuppertal are non cared for past times the same zookeepers every bit zebras. In addition, the zebras are housed 68 metres away, hence straight contact is unlikely to live the road of transmission.
However, bears too zebras are non the solely hosts, every bit the raise viruses were associated alongside fatal encephalitis inward other zoo species such every bit gazelles too guinea pigs.
Professor Klaus Osterrieder, from the Freie Universität Berlin, explains: “These viruses create non seem to abide by species boundaries too inward fact, nosotros don’t actually know whether they accept any.
“One conundrum is that these viruses are non especially stable inward the environment, too so it is of import to figure out how they motion betwixt species.”
The authors of the study are currently exploring the possibility that transmission could fifty-fifty move on through wild mice or rats.
Being warning to the possibility of pathogen species jumps too their potentially fatal consequences, zoos tin serve every bit sentinels for affliction outbreaks too protect their animals.
However, this of import chore volition live complex, every bit pathogens may drive no symptoms inward to a greater extent than or less species or individuals too unexplained decease inward others.
For most of the many pathogens that tin drive encephalitis or death, non much is known almost their powerfulness to piece of occupation inward novel host species.
Further wild animals affliction research, ameliorate communication betwixt institutions too careful monitoring volition live required to ensure the success of the conservation mission of zoos, the researchers said.
At to the lowest degree i illustration has been successfully resolved though, Wuppertal Zoo’s Lawrenz said.
“With our colleagues nosotros accept screened our polar bears inward Wuppertal to brand certain they are EHV-free, too nosotros volition create too so on a regular basis. Now that nosotros are aware of this issue, nosotros are ameliorate prepared too tin live proactive.”
Greenwood AD, Tsangaras K, Ho SYW, Szentiks CA, Nikolin VM, Ma G, Damiani A, East ML, Lawrenz A, Hofer H, Osterrieder N, Influenza A virus subtype H5N1 potentially fatal mix of herpes inward zoos. Current Biology, (2012), http://dx.doi.org/10.1016/j.cub.2012.07.035
Belum ada Komentar untuk "Equine herpes virus killed polar bear, researchers show"
Posting Komentar