Megadrought and Megadeath in 16th Century Mexico

The native population collapse in 16th century Mexico was a demographic catastrophe with one of the highest death rates in history. Recently developed tree-ring evidence has allowed the levels of precipitation to be reconstructed for north central Mexico, adding to the growing body of epidemiologic evidence and indicating that the 1545 and 1576 epidemics of cocoliztli (Nahuatl for "pest”) were indigenous hemorrhagic fevers transmitted by rodent hosts and aggravated by extreme drought conditions

Latitude and longitude coordinates, population size, and mean baseline pneumonia and influenza death rates for 66 large US reporting cities (1910–1920) with 100, 000 or more inhabitants [10].

<p>Latitude and longitude coordinates, population size, and mean baseline pneumonia and influenza death rates for 66 large US reporting cities (1910–1920) with 100, 000 or more inhabitants <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0023467#pone.0023467-Bureau1" target="_blank">[10]</a>.</p

Relationship between the number of influenza deaths and population size for 66 US cities.

<p>Relationship between the total number of influenza deaths and population size for the 66 US cities. The dashed blue line represents the best linear fit to the data in log-log scale. A solid black line representing a slope of one is shown as a reference to illustrate the expected relationship if influenza mortality rates did not vary with population size. The slope of the observed data is ‘linear’ for all years (invariant death rates across cities) except for a slope less than one for year 1918 suggesting that less populous cities were more heavily affected during the 1918 influenza pandemic.</p

Correlation between pneumonia death rate before pandemic influenza and pneumonia death rate during pandemic influenza in 66 large US cities.

<p>The correlation between the mean baseline pneumonia death rate during 1910–1917 and the pneumonia death rate in 1918, 1919 and 1920 across the 66 US cities.</p

Spearman correlation coefficient (and corresponding P value) between pneumonia and influenza mortality rates in baseline years (1910–17) and pandemic years (1918–20) in 66 US cities.

<p>Spearman correlation coefficient (and corresponding P value) between pneumonia and influenza mortality rates in baseline years (1910–17) and pandemic years (1918–20) in 66 US cities.</p

2005 Drought, epidemic disease, and the fall of classic period cultures in Mesoamerica (AD 750–950). Hemorrhagic fevers as a cause of massive population

Summary The classical period in Mexico (AD 250-750) was an era of splendor. The city of Teotihuacan was one of the largest and most sophisticated human conglomerates of the pre-industrial world. The Mayan civilization in southeastern Mexico and the Yucatan peninsula reached an impressive degree of development at the same time. This time of prosperity came to an end during the Terminal Classic Period (AD 750-950) a time of massive population loss throughout Mesoamerica. A second episode of massive depopulation in the same area was experienced during the sixteenth century when, in less than one century, between 80% and 90% of the entire indigenous population was lost. The 16th century depopulation of Mexico constitutes one of the worst demographic catastrophes in human history. Although newly imported European and African diseases caused high mortality among the native population, the major 16th century population losses were caused by a series of epidemics of a hemorrhagic fever called Cocoliztli, a highly lethal disease unknown to both Aztec and European physicians during the colonial era. The cocoliztli epidemics occurred during the 16th century megadrought, when severe drought extended at times from central Mexico to the boreal forest of Canada, and from the Pacific to the Atlantic coast. The collapse of the cultures of the Classic Period seems also to have occurred during a time of severe drought. Tree ring and lake sediment records indicate that some of the most severe and prolonged droughts to impact North America-Mesoamerica in the past 1000-4000 years occurred between AD 650 and 1000, particularly during the 8th and 9th centuries, a period of time that coincides with the Terminal Classic Period. Based on the similarities of the climatic (severe drought) and demographic (massiv

The 1918–19 Influenza Pandemic in Boyacá, Colombia

To quantify age-specific excess-mortality rates and transmissibility patterns for the 1918–20 influenza pandemic in Boyacá, Colombia, we reviewed archival mortality records. We identified a severe pandemic wave during October 1918–January1919 associated with 40 excess deaths per 10,000 population. The age profile for excess deaths was W shaped; highest mortality rates were among infants (age), followed by elderly persons (\u3e60 y) and young adults (25–29 y). Mean reproduction number was estimated at 1.4–1.7, assuming 3- or 4-day generation intervals. Boyacá, unlike cities in Europe, the United States, or Mexico, experienced neither a herald pandemic wave of deaths early in 1918 nor a recrudescent wave in 1920. In agreement with reports from Mexico, our study found no death-sparing effect for elderly persons in Colombia. We found regional disparities in prior immunity and timing of introduction of the 1918 pandemic virus across populations