Spanish Influenza is the common name for the flu virus that caused the 1918-1919 pandemic that Centers for Disease Control and Prevention (CDC) researchers dub "the mother of all pandemics." The Spanish Influenza pandemic is credited for up to 100 million deaths around the globe, making it one of the most lethal outbreaks of infectious disease in human history. Spanish Influenza re-emerged as a topic of interest in 2009 because of shared genetic material with the novel H1N1 influenza strain commonly referred to as "swine flu."
Sickness and Death
In a 2006 report in the journal "Emerging Infectious Diseases," Drs. Jeffery Taubenberger and David Morens of the CDC estimate that one third of the world's population at the time--about 500 million people--were infected with the Spanish Influenza during the 1918-1919 pandemic. Approximately 2.5 percent of infected people died, compared with death rates of less than 0.1 percent for other influenza pandemics. In absolute numbers, this translates to 50 million to 100 million deaths.
Symptoms
Symptoms of the Spanish flu were no different from those caused by other strains of influenza. According to the authors of a 2006 report in the scientific journal "Nature," symptoms included fever, fatigue, cough, headache, muscle pain and poor appetite.
Pathology
The authors of the "Nature" study found that modern pathological analysis of autopsy samples from Spanish flu cases demonstrated significant damage to the lungs, with acute focal inflammation of the airways and soft tissue of the lungs. These changes were associated with massive swelling, bleeding and near-complete destruction of the surface cell layer of the lungs. The first two would have made it difficult for patients to get enough oxygen, while the latter would have provided the ideal breeding ground for bacteria.
Cause of Death
In a 2008 report in the "Journal of Infectious Diseases," National Institutes of Health researchers confirmed that most patients died from secondary bacterial pneumonia following Spanish Influenza, rather that the disease itself. The authors note that, while bacterial pneumonia remains the most common complication of influenza, the lung damage wrought by Spanish Influenza was remarkably severe, and antibiotic treatment as we now know it did not exist in 1918.
Legacy
Genes from the Spanish Influenza virus persist in flu viruses circulating today, including the 2009 H1N1 virus, or "swine flu." One reason why subsequent epidemics have been less severe, according to a 2010 report in the "New England Journal of Medicine," is that none of the descendant viruses has included more than one of the Spanish Influenza virus's eight key genes.
References
- Nature (journal); "Genomic analysis of increased host immune and cell death responses induced by 1918 influenza virus"; J.C. Kash et al; Oct. 5. 2006
- Journal of Infectious Disease; "Predominant role of bacterial pneumonia as a cause of death in pandemic influenza and implications for pandemic influenza preparedness"; D.M. Morens, J.K. Taubenberger, A.S. Fauci; Oct. 1 2008
- New England Journal of Medicine; "The persistent legacy of the 1918 influenza virus"; D.M. Morens, J.K. Taubenberger, A.S. Fauci; Jan. 16 2010
