Pearls of wisdom before swine panic

Posted May 20, 2009, at 8:51 p.m.

An assortment of media sources has been ramping up flu hysteria. Pandemics are guaranteed to draw eyeballs and increase readership. Some Internet alarmists are even claiming that this “weaponized” virus was engineered in a lab and that authorities are hiding the huge number of deaths. Drumbeats like these help keep flu panic in play.

The real story of the origin and transmission of H1N1 is much less dramatic. In Newsweek’s May 18 cover story — Laurie Garrett, author of the comprehensive “The Coming Plague and Betrayal of Trust: The Collapse of Global Public Health” —traces the first appearance of this virus not to a Mexico City outbreak, but to a boy in Wisconsin in the fall of 2005. This mild infection seems to have been an earlier stage of the evolving virus. Unlike any previously seen, it “appeared to be a mosaic of a wild bird form of flu, a human type and a strain found in pigs.” Some researchers trace genetic elements of the virus to an Indiana pig farm in 1987. Centers for Disease Control and Prevention blood analysis of the 2005 Wisconsin case found pieces of RNA that matched a human flu first seen in New Caledonia in 1999, two swine flu types common in Asia and Wisconsin for several years, and an unknown avian virus. The ability of virologists to follow this evolving flu strain effectively puts an end to rumors of sinister plots.

How is it that these viruses are constantly evolving and changing, thus confounding our attempts to develop a vaccine? When a virus invades a cell, it uses the host to copy its own RNA. Often it picks up bits of its host’s genetic elements in the process. Pigs, like birds, may carry several flu strains at once. If a human flu strain also shows up in an animal cell, a new virus can emerge through a process called “reassortment” — the exchange of chromosomes among multiple viral strains. The current H1N1 is an example of a triple reassortment.

While viral strains can pass bidirectionally between pigs and humans, the resulting flu is rarely serious. The Wisconsin teenager and others infected with this strain recovered quickly after a brief illness. The concern is that the mutating virus will evolve more dangerous attributes that can be transmitted human-to-human. Air travel can spread disease overnight from one or two infected people to points all over the globe, and the flu can be contagious before symptoms such as fever develop. Some foresee a possible return of swine flu in the fall, in a more dangerous incarnation.

Such a scenario is possible, but any comparison to the 1918 Spanish flu outbreak is unrealistic. A great deal has changed since 1918, including the level of hygiene — both personal and environmental. Rapid communication enhances preparedness worldwide. Mexico City brilliantly role-modeled prompt action in closing down schools, businesses and scheduled events to curtail the spread of illness. Further, medical advances in the intervening years have lessened the likelihood of dying from flu-related causes such as pneumonia and other respiratory conditions. Keith Klugman of Emory University attributes the majority of 1918 flu deaths to bacterial superinfection by Streptococcus pneumoniae. “Neither antimicrobial drugs nor serum therapy was available for treatment in 1918,” Klugman’s team wrote.

The oft-repeated figure of 36,000 annual flu deaths is an exaggerated estimate. First, it includes complications from flu, not merely the flu itself. Further, the 36,000 figure is based on statistical modeling, meaning that it is little more than guesswork or approximation. The CDC’s mortality table for pneumonia and influenza, sepa-rated out, from 1979 to 2001, shows the highest number of flu deaths for all ages was in 1981 with 3,006. The lowest was 257, in 2001, and 152 — well over half — of those were ages 75 and up. Clearly influenza itself is rarely a killer, but can lead to serious secondary infections in those with compromised immune systems. Unfor-tunately, the wildly inaccurate 36,000 figure continues to go unchallenged, maintaining our anxiety level.

Flu pandemics occur periodically. Will there be another? Undoubtedly. Will it be a repeat of 1918? Not at all. Too much progress has occurred in the intervening years. Should swine flu return this fall, meet it with a strong immune system, clean hands, and plenty of Vitamin D.

Peggy Gannon, a health researcher, mental health professional and former Unity College faculty member, resides in Palmyra.

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