Replies

UW study of swine flu virus finds it more virulent than regular flu

By Mark Johnson of the Journal Sentinel
Posted: July 13, 2009
http://www.jsonline.com/features/health/50634332.html

An international team of scientists led by a University of Wisconsin-Madison virologist has produced a highly detailed portrait of the new swine flu virus that has killed 211 people in the U.S., suggesting it is more virulent than previously thought and contradicting assertions that the virus appears similar to seasonal flu.

What makes the new H1N1 virus different and more deadly than common seasonal influenza is its ability to infect cells deep in the lungs where it can cause scarring and pneumonia, according to a fast-tracked report Monday in the journal Nature.

The new study sends “a very clear message” that doctors and patients in the U.S. must adopt a new approach to influenza, said UW virologist Yoshihiro Kawaoka, who led the group of more than 50 scientists in Madison and Japan who are studying the H1N1 virus.

“Seeing physicians early and getting anti-viral drugs is not common practice,” Kawaoka said. “That has to be changed.”

The study also found that people exposed to the deadly 1918 influenza appear to have antibodies that neutralize swine flu. This may explain why relatively few elderly people have died in the recent H1N1 outbreak. So far, the virus has killed four people in Wisconsin, including two children.

Kawaoka and his colleagues infected mice, ferrets, pigs and nonhuman primates with the H1N1 virus, using samples of the virus obtained from patients in California, Wisconsin, the Netherlands and Japan. They found that while seasonal flu usually infects only cells in the upper respiratory system - the nose, throat and larynx - swine flu was able to take root and grow in the lungs.

In mice with swine flu, the lungs essentially filled with fluid until they could not take in oxygen and the animals died. Other animals in the study did not die from the swine flu.

“There is a misunderstanding about this virus,” Kawaoka said. “People think this pathogen may be similar to seasonal influenza. This study shows that is not the case.”

“This swine influenza,” he added, “is more (virulent) than seasonal influenza. That is for sure.”

Some skepticism

However, some experts remain unconvinced that the H1N1 virus is substantially more deadly than seasonal flu.

Fall awaited

He said the number of new swine flu cases in Milwaukee has dropped off rapidly in recent weeks, but health officials are concerned about what will happen in the fall, when children return to school.

“It’s either going to start coming back two weeks into school or it won’t, and if it doesn’t, all bets are off,” he said.

Henrickson and others have been studying the flu outbreak in Milwaukee, where more cases have been reported than in many entire states. He said H1N1 is more concentrated than the seasonal influenza.

Many researchers are now studying the genetic evolution of the H1N1 strain. The hope is that learning how the virus evolves will help health care officials plan for it better and produce a more effective vaccine.

Scientists studying the virus in animals are likely to continue searching for specific markers of virulence.

“The 1918 virus had several virulence factors,” Siegel said, “including the ability to destroy the mitochondria of cells,” an ability that H1N1 has yet to demonstrate. The mitochondria generate energy for cells; when they’re destroyed, the cells die.

UK:

Telegraph: Swine flu alert for pregnant women and babies

19 July 2009 | 03:54
FOCUS News Agency
http://www.focus-fen.net/?id=n188057

London. Urgent swine flu advice is to be issued to pregnant women and new parents in an attempt to limit the spread of the virus among the most vulnerable. Expectant mothers will be urged to avoid unnecessary journeys and crowds, with experts suggesting that they do not travel on trains and the London Underground at peak times. Parents will be advised to keep babies away from crowds, while pregnant women will also be encouraged to limit the movements of their other children, so they do not bring the virus home. The warnings come amid increasing concern that pregnant women and young children are among the groups most at risk from swine flu.

So far, more than 650 people have been taken to hospital with the virus in England, including more than 200 children. Under-fives have been three times more likely than older patients to be taken to hospital. In Scotland, 44 people have been taken to hospital, while 11 have been treated in Welsh hospitals. At least 146 cases have been recorded in Ireland. Officially, there have been 29 British deaths involving swine flu, including four children and two mothers who died shortly after giving birth. All except one – six-year-old Chloe Buckley, who died 10 days ago in west London — were known to have been suffering from underlying health problems.

Pregnant women are at increased risk of contracting any infection because their immunity is suppressed to ensure that their body does not reject their baby. Experts believe that most cases of swine flu would not harm the mother or foetus, but rare cases could lead to premature labour or miscarriage or cause birth defects. In Australia, where 11 expectant women with swine flu are in intensive care, pregnant women have been urged to stay at home when possible, and to wear face masks when they do go out. Mask-wearing is not part of Britain’s strategy because it is thought to do little to reduce the spread of disease and encourages complacency against more useful measures, such as regular hand-washing.

The new guidance, to be published on the National Health Service website, www.nhs.uk, and circulated via parenting forums, will alert parents and pregnant women to recommendations that have been drawn up by the Royal College of Midwives and the Royal College of Obstetricians and Gynaecologists. Senior figures from both organisations said that while significant changes in lifestyle, to avoid crowds and public transport, might not be realistic for all pregnant women and parents with babies, individuals should be made aware of the risks.

Sue Macdonald, from the Royal College of Midwives, said: “Pregnant women have got a strong instinct to protect their baby, but we have to be realistic about the kinds of adjustments people can make. If they normally have to travel on the Tube or on crowded trains in rush hour they might be better to come in later or earlier, but of course it is difficult to avoid crowds entirely. This is about being sensible and being aware of the risks.”

The advice states that the simplest way to reduce the risk of contracting swine flu is regular hand-washing, especially after journeys. In separate guidance, pregnant GPs and community nurses have been told that they should not see patients with suspected swine flu. The Government has decided against advising women to delay pregnancy until the swine flu pandemic has passed, even though such a recommendation was contained in previous plans.

The number of people off work with symptoms of flu more than doubled last week, according to figures compiled for The Sunday Telegraph. On Friday , about 177,000 people were absent with flu-like symptoms, compared with 80,000 the week before. Aaron Ross, the chief executive of FirstCare, an absence management company that carried out the survey of 1,000 companies, said businesses should offer home working to staff who are most vulnerable to swine flu.