The Spanish flu 1918 pandemic beginning with an index case, the first individual to show overt symptoms of the disease, led to 20-40 million deaths worldwide (Sawchuk & Tripp, 2012). However, there are three major points to be noted regarding this pandemic; the cause of death, sex-related mortality differences and age-related mortality patterns. Research indicates that most deaths attributed to the flu were not directly caused by flu but by other flu related respiratory complications such as pneumonia . In addition, the pandemic disproportionately led to male mortality where females were found to be at a relative advantage . The most distinguishing feature of this pandemic was the mortality age profile where typically for epidemics a U-shaped curve is observed with most deaths occurring among the infants and the elderly . This U-shape curve is consistent with the healthy worker effect where typically least deaths are expected of young active employed individuals . Spanish influenza mortality patterns, in contrast to a typical epidemic, yield a W-shaped curve with a disproportionate number of deaths occurring among individuals between the ages of 20-40. In addition, the pandemic led to fewer deaths of elderly perhaps because of the immunity they may have conferred from exposure to a similar strain during the 1847 pandemic . In this paper, I will discuss the nature of 1918 epidemic in the town of Silverton located in Southwest Colorado, based on a 170 deaths that occurred from September 1918 to March 1919. The population of Silverton primarily consisted of young male immigrant miners who had little resistance to influenza due to the respiratory disorders they had acquired through continuous exposure to mine cave-ins and powder explosions (Peterson, 2004).
In my analysis of the 170 cases in Silverton, through temporally sorting the deaths, the index case was found to be a 55 year old male miner named John Thomas Guanella who died on September 26th, 2011. Figure 1 shows the weekly distribution of deaths during 22nd September, 1918 to 29th March, 1919, with most deaths occurring during the week of 20th October to 26th October and 27th October to 2nd November 1918 (See Appendix A). Figure 2 shows the weekly distribution of flu and flu-related deaths, where flu-related deaths were found to be more than those caused by flu (See Appendix A). Figure 3 shows that males consistently had higher mortality rates than females with most deaths occurring between ages 30-33 (See Appendix A).
My analysis of the 170 reported cases revealed that the epidemic in Silverton began from John Thomas Guanella. Details of this case revealed that his death was initially attributed to pneumonia, but later suggested that it may have been an unrecognized flu death. This may have happened because flu virus induces pneumonia in the victim. However, attributing this individual as an index may be problematic because his diagnosis was not confirmed. Further, the gap between his death and the next recorded influenza-related death was of 19 days, a significant time period given the short incubation period of influenza virus . In addition, since the US Public Health Service did not require the states to report influenza cases before September 27th, many influenza cases before John Guanella may have gone unreported. Further, contrary to my findings, the Silverton PDF reported the first county death due to flu to be a 34 old male named James Joseph Ruane. However, my analysis revealed 3 other flu related deaths…