2009 H1N1 flu virus continues circulating globally
Influenza activity increased in several areas of the Southern Hemisphere and was dominated by the 2009 pandemic H1N1 strain over the 2-week period from Jul 7 through Jul 20, according to World Health Organization (WHO) updates.
Data were reported from 73 countries. The Global Influenza Surveillance and Response System (GISRS) tested 24,825 specimens. Of the 1,884 specimens positive for influenza, 1,590 (84.4%) were influenza A and 294 (15.6%) were influenza B. Of the 1,310 type A specimens that were subtyped, 719 (54.9%) were 2009 H1N1 and 590 (45%) were H3N2.
Increased cases of H3N2 were seen in Australia and increased influenza B in New Zealand, although the numbers are lower than in previous years. Flu activity decreased in much of tropical Asia, although several countries in Southeast Asia reported higher levels of H3N2. Much of Central America and the Caribbean region reported increased activity, and tropical South America reported increased 2009 H1N1 and H3N2 activity.
Two more deaths tied to steroid-linked fungal infections
Two more patients have died in the outbreak of infections linked with contaminated steroid injections that emerged last fall, raising the toll to 63, though the overall case count stayed steady at 749, according to numbers reported yesterday by the Centers for Disease Control and Prevention (CDC).
The state with the most cases is Michigan with 264, followed by Tennessee with 153. The 749 cases include 233 of meningitis only, 333 of paraspinal or spinal infection only, 151 of meningitis plus paraspinal or spinal infection, 33 with peripheral joint infection only, 2 with paraspinal or spinal plus peripheral joint infection, and 7 of stroke without lumbar puncture only.
The steroid injections implicated contain preservative-free methylprednisolone acetate produced by the New England Compounding Center of Framingham, Mass.
Aug 5 CDC update
Study: Mortality pattern in 1918 flu pandemic related to 1889 pandemic
A team of Canadian and US scientists says that 28-year-olds had the highest mortality during the 1918 flu pandemic, and they suggest that the high death rate in young people was related to childhood exposure to flu during the pandemic of 1889-90.
Writing in PLoS One, the authors say they used historical records from Canada and the United States to determine that 28-year-olds had the highest risk of death during the 1918 pandemic. The team was headed by Joaquin Madrenas of McGill University as senor author.
The scientists suggest that the vulnerability of young adults in 1918 was shaped by their exposure to the "Russian flu," which spread from Russia to Western Europe in the fall of 1889 and reached North America in the winter of 1889-90.
They speculate that the 1889 pandemic was caused by an influenza A/H3 virus, and argue that "commitment very early in life to this subtype would have led to an immune profile offering little or no humoral protection to the antigenically dissimilar H1N1 subtype that emerged in 1918," resulting in an increased risk of death.
The scientists also suggest that exposure to a virus in utero or infancy may permanently affect later health and mortality by causing changes in the T cell repertoire, impairing lung maturation, or affecting metabolism.
"Yet, despite compelling evidence, these explanations remain incomplete," they add. "At a minimum, more detailed analyses using exact ages derived from historical birth and death records for 1889-90 and 1918 are needed."
Aug 5 PLoS One report