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The borna virus is at once obscure and grotesque. It can infect mammals and birds, but scientists know little about its effects on its victims. In some species it seems to be harmless, but it can drive horses into wild fits. The horses sometimes kill themselves by smashing in their skulls. In other cases, they starve themselves to death. Some scientists have even claimed that borna viruses alter human behavior, playing a role in schizophrenia and bipolar disorder, although others say there is no solid evidence of a link.
EVOLVED Fossil viruses are helping to shed light on the deep history of viruses like HIV, shown above with red triangular cores of RNA material.
The virus now turns out to have an intimate bond with every person on Earth. In the latest issue of Nature, a team of Japanese and American scientists report that the human genome contains borna virus genes. The virus infected our monkey-like ancestors 40 million years ago, and its genes have been passed down ever since.
Borna viruses are not the only viruses lurking in our genome. Scientists have found about 100,000 elements of human DNA that probably came from viruses. But the borna virus belongs to a kind of virus that has never been found in the human genome before. Its discovery raises the possibility that many more viruses are left to be found.
Scientists who hunt for these viruses think of themselves as paleontologists searching for fossils. Just as animals get buried in rock, these viruses become trapped in the genomes of their hosts. While their free-living relatives continue to evolve, fossil viruses are effectively frozen in time.
“We can really dig fossils out of the genome and literally put them back together,” said Cédric Feschotte, a genome biologist at the University of Texas, Arlington. “It’s like putting a hominid back together and asking it if it can walk upright.”
When scientists sequenced the human genome in 2001, they noticed many segments that bore a striking resemblance to genes in retroviruses, a class of viruses that includes H.I.V.
Retroviruses carry their genetic material in a single-stranded version of DNA, called RNA. To make new viruses, they make DNA versions of their genes, which are inserted into a host cell’s genome. The cell then reads the retrovirus’s genes as if they were its own, and manufactures new retroviruses.
Scientists speculated that every now and then a retrovirus inserted itself into a host cell and then failed to turn it into a virus factory. If the trapped retrovirus happened to be in sperm or egg cells, its DNA might be passed down to the host’s descendants. From generation to generation, the virus’s DNA would mutate. It would lose its ability to produce normal viruses. For a while it might be able to make new viruses that could re-infect the same cell, but over enough time, the viruses would become disabled.
In recent years, scientists have found several lines of evidence to support this idea. . Koala retroviruses, for example, appear to be in the middle of the journey. The viruses can move from one koala to another. But in some populations of koalas, the virus’s DNA is permanently lodged in their genomes.
Thierry Heidmann of the Gustave Roussy Institute in France and his colleagues put the fossil virus hypothesis to a spectacular test: they tried to resurrect a dead retrovirus. They first identified a number of copies of the same virus-like stretch of DNA in the human genome. Each version had its own set of mutations that it acquired after the virus had invaded our ancestors.Hunting Fossil Viruses in Human DNA Hunting Fossil Viruses in Human DNA
By comparing the copies, Dr. Heidmann and his colleagues were able to figure out what the original sequence of the virus’s genes had been. When they synthesized the genes from scratch and injected the genetic material into cells, the cells produced new viruses.Hunting Fossil Viruses in Human DNA
“It was a tour-de-force of an experiment,” said John Coffin, an expert on fossil viruses at Tufts University.
Now fossil virus hunters are moving beyond the human genome. They’re taking advantage of the growing number of mammal genomes piling up in online databases and helping to flesh out the evolutionary history of viruses, reaching back tens of millions of years. Aris Katzourakis, an evolutionary biologist at the University of Oxford, and his colleagues recently went on a hunt for fossils of foamy viruses in mammals. Foamy viruses infect some mammals, including monkeys and apes. Primate foamy viruses can infect humans harmlessly, but researchers fear they may evolve to become dangerous. Dr. Katzourakis and his colleagues discovered hundreds of foamy virus copies in the DNA of the two-toed sloth. They then found the same virus lurking in the genome of the three-toed sloth. Before Dr. Katzourakis’s fossil hunt, scientists had never found a foamy virus infecting any sloths, or any of their relatives like armadillos and anteaters.
Sloths and their relatives branched off from all other placental mammals about 100 million years ago. Dr. Katzourakis’s discovery thus reveals the great antiquity of foamy viruses. They were already infecting the common ancestor of all placental mammals back when dinosaurs ruled the Earth.Hunting Fossil Viruses in Human DNA
These fossils are also offering clues to how viruses evolved. Dr. Katzourakis and his colleagues have found fossil viruses that are helping shed light on the deep history of H.I.V., for example.
H.I.V. evolved about a century ago from a chimpanzee virus known as simian immunodeficiency virus, or S.I.V. Many apes and monkeys carry their own strain of S.I.V, but it’s not clear how long the viruses have been infecting primates.
In 2008, Dr. Katzourakis and his colleagues discovered fossil S.I.V. in the genome of the gray lemur, a primate that lives in Madagascar. Last May, Dr. Feschotte and his colleagues reported that they had found the same fossil virus in the fat-tailed lemur.
Scientists had never before found S.I.V. in lemurs, which branched off from all other living primates some 50 million years ago. The fossil virus is also missing one of the genes found in all other forms of S.I.V. and H.I.V. It may be a transitional form of the virus, akin to the fossils paleontologists have found of feathered dinosaurs that couldn’t fly.
Fossil viruses are also illuminating human evolution. Scientists estimate that 8.3 percent of the human genome can be traced back to retrovirus infections. To put that in perspective, that’s seven times more DNA than is found in all the 20,000 protein-coding genes in the human genome.
But that figure may be too low, according to Dr. Katzourakis. “The measurable diversity of viruses may go up, and the true diversity may be much higher,” he said.
(Reuters) - Hackers have flooded the Internet with virus-tainted spam that targets Facebook's estimated 400 million users in an effort to steal banking passwords and gather other sensitive information.
The emails tell recipients that the passwords on their Facebook accounts have been reset, urging them to click on an attachment to obtain new login credentials, according to anti-virus software maker McAfee Inc.New password-stealing virus targets Facebook
If the attachment is opened, it downloads several types of malicious software, including a program that steals passwords, McAfee said on Wednesday.
Hackers have long targeted Facebook users, sending them tainted messages via the social networking company's own internal email system. With this new attack, they are using regular Internet email to spread their malicious software.
A Facebook spokesman said the company could not comment on the specific case, but pointed to a status update the company posted on its web site earlier on Wednesday warning users about the spoofed email and advising users to delete the email and to warn their friends.
McAfee estimates that hackers sent out tens of millions of spam across Europe, the United States and Asia since the campaign began on Tuesday.New password-stealing virus targets Facebook
Dave Marcus, McAfee's director of malware research and communications, said that he expects the hackers will succeed in infecting millions of computers.New password-stealing virus targets Facebook
"With Facebook as your lure, you potentially have 400 million people that can click on the attachment. If you get 10 percent success, that's 40 million," he said.
The email's subject line says "Facebook password reset confirmation customer support," according to Marcus.New password-stealing virus targets Facebook
(Additional reporting by Alexei Oreskovic; Editing by Bernard Orr)New password-stealing virus targets Facebook
Cyber criminals have raided the accounts of thousands of British internet bank customers in one of the most sophisticated attacks of its kind.
The fraudsters used a malicious computer programme that hides on home computers to steal confidential passwords and account details from at least 3,000 people.
The internet security experts M86, who uncovered the scam, estimate that at least £675,000 has been illegally transferred from the UK in the last month - and that the attacks are still continuing.
Out of action: The new trojan virus can empty bank accounts without their owners knowing about the theft as it shows them fake statements
All the victims were customers with the same unnamed online bank, the company said.
Last night online banking customers were urged to make sure their anti-virus software was up to date - and to check for any missing sums from their accounts.
The attack has been traced to a 'control and command' centre in Eastern Europe. However, the nationality of the cybercriminals is unknown.
The attacks were carried out when hundreds of thousands of home computers were infected with a type of harmful computer code called a Trojan. Trojan virus
Trojans hide in websites, emails or downloads. Once installed on a computer they can record every type of the keyboard, steal confidential information or even open up a PC's security so that it can be controlled remotely from another country.Trojan virus
The latest attack involved a Trojan called Zeus v3 which hides inside adverts on legitimate websites.Trojan virus
Once installed on a home computer, the programme waits until the user visits their online bank and then secretly records their account details and passwords - using the information to transfer between £1,000 and £5,000 to other bank accounts.
The attacks began on July 5 and are still progressing, according to Ed Rowley, product manager at M86.
'In the vast majority of cases, if people had kept their computer's operating systems and software such as Internet Explorer up to date they would not have been attacked,' he said.
'More often than not Trojans exploit known vulnerabilities that can be simply patched and fixed by downloading updates.'
McAfee, the security software maker, said production of software code known as malware, which can harm computers and steal user passwords, reached a new high in the first six months of 2010.Trojan virus
It said total malware production continued to soar and 10 million new pieces of malicious code were catalogued.Trojan virus
It also warned users of Apple's Mac computers, considered relatively safe from virus attacks, that they may also be subjected to malware attacks in the future.
'For a variety of reasons, malware has rarely been a problem for Mac users. But those days might end soon,' a spokesman said.
Attacks by ‘Trojan viruses’ are on the rise in Britain.
Although up-to-date anti-virus software should prevent an attack, experts say an alarming number of people leave their computers vulnerable to cybertheft.
Trojans are malicious programmes that hide inside apparently harmless computer files.
They can lurk on websites, online adverts or hitch a lift in emails.
The Zeus v3 Trojan involved in the latest attacks hides in adverts that appear on legitimate websites. Trojan virus
Each time someone clicks on the advert, the code is downloaded to their home computer where it lies dormant.
The code only becomes active when the computer connects to a bank website when it starts to record account details, passwords and other confidential information.
It checks to see if the account holds enough cash and then transfers up to £5,000 to a ‘mule’ account - a legitimate bank account held by a real customer.
Owners of these mule accounts operate on the edge of the law and agree to transfer sums they receive to someone else, after taking a cut.
By the time the police have investigated a Trojan attack, the recipient of the money has usually vanished without trace.
Security experts say it is relatively easy to protect against Trojan attacks by installing anti-virus software and keeping it up to date.
Computer owners should also make sure they have downloaded any updates of their operating software - usually Windows - and other programmes such as Internet Explorer, Firefox and Adobe.Trojan virus
People should also be alert to junk emails that pretend to be from banks, the Inland Revenue or online shops like Amazon and Ebay.
The emails invite the unwary to click on a link to a webpage containing a Trojan.
'Our latest threat report depicts that malware has been on a steady incline in the first half of 2010,' Mike Gallagher, chief technology officer of Global Threat Intelligence for McAfee, said in the report that was obtained by Reuters.
The internet security company has passed on details of the attacks to the UK Police Central E-Crime Unit in London.
Britain's high street banks declined to comment on the attacks, but urged customers to protect themselves from virus attacks.
A spokesman for HSBC said: 'There are millions of viruses and other malicious software.
'We urge people to take basic measure to protect themselves from virus attacks.
'Any customer who is a victim of fraud will be reimbursed by HSBC.'
Last year £59.7 million was stolen in online banking fraud, while another £440 million was lost to credit card fraud.
A Financial Fraud Action UK spokeswoman said: ‘The idea that criminals are targeting people by using malicious software or Trojans is nothing new.Trojan virus
‘Bank systems are hard to attack so they’re having to go through the easier link in the chain, which is the customers.
‘They’re hoping customers aren’t taking security precautions. We’ve been seeing this for the last few years and we’re constantly urging people to protect their computers to try to mitigate the risk of becoming a victim.”
Online banking customers can take measures to protect themselves by keeping their anti-virus software up to date and keeping their firewalls set to the highest level, she added.
Victims of online banking fraud usually get their money back.
Earlier this month, an internet security company Trusteer, warned that 100,000 British computers were infected with an earlier version of Zeus.
