More good news and bad news about H1N1
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Let’s take the bad news first.
A new report released today by the journal Nature finds that the new H1N1 flu has quite a talent for making its way deep into the lungs. Once there, the so-called swine flu churns out copies of itself, producing symptoms such as bronchitis, alveolitis and pneumonia.
The researchers, led by Yoshihiro Kawaoka of the University of Wisconsin-Madison and University of Tokyo, infected mice, ferrets, monkeys and pigs with four variants of H1N1, along with a version of the seasonal flu for comparison. Unlike the pandemic strains, the seasonal flu did most of its damage in the upper respiratory tract.
Two other research teams reported very similar findings in the July 3 edition of Science.
Kawaoka’s group also noted that the H1N1 flu particles were shaped like rods instead of the usual spheres. “The biological significance,” the team wrote, “remains unknown.”
When pigs were infected with the new H1N1, the virus went gangbusters in the animals’ respiratory organs, but the pigs showed no outward signs of illness. The pandemic strains could have been spreading far and wide in pigs long before people had any reason to suspect trouble.
So what’s the good news? In lab dishes, all four of the pandemic strains that were studied were vulnerable to Tamiflu and Relenza, along with an experimental neuraminidase inhibitor known as R-125489 and a new compound called T-705 that is still under development. (However, the World Health Organization said last week that three cases of Tamiflu-resistant H1N1 have emerged in Denmark, Japan and Hong Kong.)
And depending on your age, this is either good news or bad news: Many people who were born before 1920 already have antibodies against the new H1N1. (The report didn’t specify how many people had immunity, but the Centers for Disease Control and Prevention recently estimated that about one-third of people over age 60 were immune.) By contrast, “no appreciable neutralizing antibodies” were found in people under age 89, according to the report.
For those who have been reassured by H1N1’s low mortality rate, it may be time to start worrying again. “People think this pathogen may be similar to seasonal influenza,” Kawaoka said in a statement. “This study shows that is not the case.”
Meanwhile, the WHO says the first licensed vaccine for H1N1 probably won’t be ready until the end of the year.
-- Karen Kaplan
