Jun 29, 2012
Scientists discover influenza A virus's 13th gene
An international group of scientists has discovered a new gene in the influenza A virus that may play a role in controlling the body's response to infection, according to a study in Science yesterday. Previously, scientists believed the flu virus contained only 12 genes. The protein of the new gene, called PA-X, found in the third of the virus's eight RNA strands, is produced when the ribosome (the part of the virus that translates RNA into amino acids) skips ahead while reading messenger RNA (mRNA) nucleotide chains. The ribosome reads the nucleotides in groups of three, so if it skips forward one nucleotide, it will read the nucleotides in different combinations and produce PA-X. The researchers—from the Universities of Cambridge, Cork, Edinburgh and Utah, the Institute of Systems Biology in Seattle, and the US National Institutes of Health—then studied how the newfound gene affects the behavior of the 1918 pandemic H1N1 flu virus. They found that when PA-X was active, mice infected with the virus subsequently recovered, but when it did not work properly, the immune system overreacted and made the infection worse. They report that PA-X inhibits the expression of RNA polymerase II, which is responsible for translating DNA into mRNA. Paul Digard, PhD, of The Roslin Institute at the University of Edinburgh, said in a university press release, "Just finding this gene in the first place is important, but the find is even more significant because of the role it seems to play in the body's response to flu." Digard doesn't appear to be done discovering new flu genes. "I'm working on a manuscript today that describes another one," he told Discover magazine.
Jun 28 Science abstract
Jun 28 University of Edinburgh press release
Jun 28 Discover story
More South African ostrich farms hit by H5N2 outbreaks
Two more ostrich farms in South Africa have been hit by highly pathogenic H5N2 influenza outbreaks, continuing a series of outbreaks that began last year, according a report that South African agriculture offices filed with the World Organization for Animal Health (OIE). The two farms are in the Hessequa area of Western Cape province. In an outbreak that began a month ago, one farm had 38 cases in a flock of 450 ostriches, and the other had 1,447 cases among 5,427, for a combined total of 1,485 cases among 5,877 ostriches. No deaths were reported, but the ostriches on the two farms were to be destroyed to stop further transmission, the report said. The source of the infection was listed as unknown. South Africa has filed 13 reports of H5N2 on ostrich farms since April 2011.
Jun 28 OIE report
EU: Malaria, dengue, TB among rising travel-related infections
A study of travel-related illness patterns in Europe found increases in malaria, dengue, Campylobacter, and pulmonary tuberculosis (TB) infections, according to a report yesterday in Eurosurveillance. Researchers looked at diagnoses from 7,408 returning international travelers who sought care at 16 EuroTravNet sites in 2010 and compared the numbers with levels seen in 2008 and 2009. The number of Plasmodium falciparum malaria was responsible for 6% of all travel-related illnesses (up from 4% in 2008), with Plasmodium vivax malaria rising to 1% of cases. Dengue fever infections rose from 2% in 2008 and 2009 to 5% in 2010. Diarrhea related to Campylobacter infections rose from 7% in 2008 to 12% in 2010. The researchers identified 121 pulmonary TB cases, a threefold increase from 2008. The team found that disease patterns varied by duration of travel stay, with malaria, dengue, and chikungunya infections more common in short-term visits, and illnesses such as TB and Chagas disease more often seen in long-term travelers. They noted that malaria remains the most common cause of fever in travelers to tropical countries, with dengue as an increasingly frequent cause. Another trend they noted was more hospitalizations and fewer pretravel consultations.
Jun 28 Eurosurveillance study