Experts look for clues in 1918 pandemic virus family tree

first_imgJun 29, 2009 (CIDRAP News) – To outside observers, the novel H1N1 virus spreading quickly to every corner of the globe must seem like it came out of nowhere, but the organism is a fourth generation of the 1918 pandemic virus and comes from an H1N1 family tree that is colorful and complex, according to two historical reviews that appear today in the New England Journal of Medicine (NEJM).Understanding the history of swine influenza viruses, particularly their contribution to the 1918 pandemic virus, underscores the need to better comprehend zoonotic viruses as well as the dynamics of human pandemic viruses that can arise from them, the authors report in an early online NEJM edition.The world is still in a “pandemic era” that began in 1918, wrote three experts from the National Institute of Allergy and Infectious Diseases (NIAID), senior investigator David Morens, MD, medical epidemiologist Jeffery Taubenberger, MD, PhD, and NIAID director Anthony Fauci, MD.The 1918 virus has used a “bag of evolutionary tricks” to survive in humans and pigs and to launch other novel viruses, they wrote. “The 2009 H1N1 pandemic virus represents yet another genetic product in the still-growing family tree of this remarkable 1918 virus.”The novel H1N1 virus’ complex evolutionary history involved genetic mixing within human viruses and between avian- and swine-adapted viruses, gene segment evolution in multiple species, and evolution from the selection pressure of herd immunity in populations at different times, the group wrote, adding. “The fact that this novel H1N1 influenza A virus has become a pandemic virus expands the previous definition of the term,”Though any new virus is unpredictable, Fauci and his colleagues wrote that in this pandemic era, severity appears to be decreasing over time, with an evolutionary pattern that appears to favor transmissibility over pathogenicity.Two researchers from the University of Pittsburgh, in a review article on the emergence of H1N1 viruses, wrote that viral adaptation to a new host species is complex, but the 1918 influenza A H1N1 virus was unusual because it emerged from a bird source in pigs and humans at the same time. In contrast, researchers have said the new H1N1 virus probably emerged from swine to humans. The authors are Shanta Zimmer, MD, from the medical school, and Donald Burke, MD, from the graduate school of public health.Previous research suggests that antibody specificity against the 1918 human influenza virus diverged quickly from swine influenza viruses, and genetic differences in hemagglutinin (HA) continue to show the same type of rapid divergence between human and swine viruses, they wrote.Researchers still don’t know why H1N1 retreated in 1957 for the next 20 years, though likely factors include high levels of existing homologous immunity plus the sudden appearance of heterologous immunity from a new H2N2 strain, Zimmer and Burke wrote.Cross-species transfers of swine influenza H1N1 cropped up a few times over the next two decades, and human H1N1 didn’t surface again until 1977, presumably because of a laboratory accident in the former Soviet Union. This event marked a first in interpandemic history: the cocirculation of two influenza A viruses.The authors wrote that it’s difficult to predict how well the pandemic strain will compete against the seasonal H1N1 virus. Both viruses share three gene segments with their remote 1918 descendant: nucleocapsid, nonstructural, and HA. They pointed out that studies of B-cell memory response in 1918 pandemic survivors showed that the neutralizing body against HA was specific and long-lasting.Cell-mediated immunity may also affect competition between the two viruses, the authors wrote. Though it’s not clear if cytotoxic T lymphocytes clinically protect humans, they have been shown to reduce viral shedding, even in the absence of antibodies against HA and neuraminidase.”Cytotoxic T lymphocytes that are generated by seasonal influenza viruses against conserved epitopes might provide heterotypic immune responses that could dampen transmission, even in the absence of measurable antibody protection,” Zimmer and Burke wrote.Morens DM, Taubenberger JK, Fauci AS. The persistent legacy of the 1918 influenza virus. N Engl J Med 2009 Jul 16;361(3):225-29 [Full text]Zimmer SM, Burke DS. Historical perspective—emergence of influenza A (H1N1) viruses. N Engl J Med 2009 Jul 16;361(3):279-85 [Full text]last_img read more

Madrid see off Bayern in controversial thriller to reach semis

first_imgBy Rik SharmaMADRID, Spain (Reuters) – Cristiano Ronaldo scored a hat-trick to send Real Madrid through to the Champions League semi-finals with a 4-2 extra-time win against 10-man Bayern Munich to seal a 6-3 aggregate victory in controversial circumstances.A bizarre Sergio Ramos own goal forced the extra period after Robert Lewandowski opened the scoring for Bayern from the penalty spot and Ronaldo equalised.Marcelo twice cleared off the line for Madrid and Jerome Boateng did the same for Bayern in a thrilling game, which was tilted in Madrid’s favour by Arturo Vidal’s dismissal for two yellow cards, the second of which was harsh.Ronaldo put Madrid level at 2-2 on the night in the first period of extra time when he scored his 100th Champions League goal, from a clearly offside position, before he wrapped up his treble and Marco Asensio added a fourth.Carlo Ancelotti’s Bayern began well, with Thiago Alcantara’s close-range shot brilliantly blocked on the goal line by Marcelo. Arjen Robben lashed the rebound into the side-netting.Vidal crashed a strike inches over the crossbar and Real goalkeeper Keylor Navas had to be quick off his line to beat Ribery to a through-ball.Madrid began to find their feet and were soon dominating, with the effervescent Marcelo crossing for Karim Benzema, who headed wide, and Dani Carvajal also firing an effort just off target.Ramos nearly put the hosts ahead after the otherwise superb Manuel Neuer spilled a shot, but Jerome Boateng somehow blocked his effort on the line to keep his side in the tie.Toni Kroos fired over and Ronaldo shot when he should have passed to Benzema as Madrid ended the first half looking far more dangerous than their opponents.However, it was Bayern who took the lead when Casemiro fouled Robben in the area and Lewandowski sent Navas the wrong way from the spot.Ronaldo levelled the score, heading beyond Neuer in the 76th minute from a fine cross by Casemiro, but Bayern restored overall parity within a minute.Ramos so used to being Madrid’s hero turned villain when he shinned the ball into his own net after a scramble in the area.With the game heading towards extra-time Vidal was sent off for a second booking after appearing to win the ball cleanly from Asensio.It gave Madrid the upper hand going into the added 30 minutes and they took advantage when Ronaldo scored the crucial second from Ramos’s cross, despite being in an offside position.Madrid added two more late on, leaving Bayern exhausted and angry.last_img read more

Palumbo and Walczak Named MVC Doubles Team of the Week for Second Time

first_imgST. LOUIS – Carmen Palumbo (McLean, Va.) and Daria Walczak (Lodz, Poland) of the Drake University women’s tennis team are the Missouri Valley Conference Doubles Team of the Week, the MVC office announced Tuesday, April 9. This is the second time this season the pair are the MVC’s top doubles team after previously winning it on Feb. 19. Drake hosts its final home match Saturday against Valparaiso. First serve at the Roger Knapp Tennis Center is scheduled for 11 a.m. Print Friendly Version Last week, Palumbo and Walczak went 2-0 and helped Drake split its first two MVC matches. They claimed a 7-5 win over Reghan Lynch/Claudia Toledo of UNI in the No. 1 match in a 6-1 victory over the Panthers. They followed that with a 6-3 win over Alye Darter/Mara Presot of Missouri State in the No. 2 match in a close 4-3 defeat to the Bears. The perfect week improved the pair’s record to 11-7 together.last_img read more