Scientists find similarities between H1N1, 1918 flu strain

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MELVILLE, N.Y. — Fatal cases of swine flu result from a
devastating form of lung damage virtually identical to the pulmonary
devastation caused in the 1918 and 1957 global flu outbreaks, confirming that
H1N1 is more like its pandemic cousins than seasonal strains of influenza,
scientists reported Tuesday.

But while autopsy data of 34 people who died of H1N1 earlier
this year adds yet another chapter to medicine’s knowledge of pandemic
influenza, another study suggests that by the time the current flu season is
over, H1N1 will not have been a potent threat to most people.

The autopsy studies involved people who died between May 15
and July 9, and revealed a consistent pattern of deeply penetrating damage
throughout the lungs’ lower airways, said Dr. James Gill of the New York City
medical examiner’s office, which conducted the study along with the National
Institute of Allergy and Infectious Diseases.

“Pathologically, it’s very similar to (autopsy
findings) in the 1957 and 1918 pandemics,” Gill said, noting as previous
studies have also revealed, a preponderance of flu deaths in younger people —
infants to adults up to age 49. Seasonal influenza, by contrast, is most
devastating among the elderly, he said, and primarily causes upper respiratory
infections.

Dr. Jeffrey Taubenberger, a pioneering flu scientist at
NIAID in Maryland, added that the autopsy cases also revealed evidence of
secondary bacterial infections, mostly pneumococcal pneumonia and
methicillin-resistant staphylococcus aureus — MRSA. These bacterial culprits
took advantage of the lungs’ weakened state and were able to penetrate into the
tissue and exacerbate the victims’ respiratory distress.

“Over 90 percent of the cases had an underlying medical
issue, primarily cardiac disease, respiratory disease or
immunodeficiency,” Taubenberger said, adding that 72 percent of the 34
people were morbidly obese, a condition that may have also caused respiratory
insufficiency.

Gill said death was swift for all who succumbed to swine
flu, a course that proceeded rapidly downhill within a matter of days. Some
people died before hospitalization, he said.

But despite the bad news, a U.S. and British team of
scientists in mathematical studies of the swine flu pandemic say that by the
time it’s over it will have produced a fatality rate of only 0.1 percent, or
one death for every 1,000 symptomatic cases.

Via McClatchy-Tribune News Service.

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