HR: 0800h
AN: B41C-03    [Abstracts]
TI: Association of Drought with Typhus Epidemics in Central Mexico
AU: * Acuna-Soto, R
EM: yvonne@ibt.unam.mx
AF: Facultad de Medicina Universidad Nacional Autonoma de Mexico, Ciudad Universitaria Delegacion Coyoacan, Ciudad de Mexico, DF 04510, Mexico
AU: Stahle, D
EM: dstahle@uark.edu
AF: Tree-ring Laboratory Department of Geosciences, Ozark Hall 113 University of Arkansas, Fayetteville, ARK 72701, United States
AU: Villanueva Diaz, J
EM: villanueva.jose@inifap.gob.mx
AF: INIFAP Cenid-Raspa, Km. 6.5 Margen Derecha Canal de Sacramento, Gomez Palacio, DUR 35140, Mexico
AU: Therrell, M
EM: therrell@virginia.edu
AF: University of Virginia, Center for Regional Environmental Studies, VA , United States
AB: Typhus is an acute infectious disease caused by the bacteria Rickettsia prowazekii, which is transmitted among humans by the body lice (Pediculus humanus corporis). The disease is highly contagious and transmission is favored in populations living in crowded conditions. Under these circumstances, typhus transmission is facilitated by factors that favor the colonization and proliferation of body lice such as absence of personal hygiene and wearing the same clothes for long periods of time. Historically, periods of war and famine were associated with devastating epidemics with high mortality rates in many parts of the world. Central Mexico has a long record of typhus epidemics. In this region, at > 2000 meters above sea level, the disease was endemic and occurred with a seasonal pattern in winter, with occasional large epidemics. Recently, we completed a chronology of epidemics in Mexico. A total of 22 well-defined major typhus epidemics were identified between 1650 and 1920. All of them caused periods of increased mortality that lasted 2 - 4 years (more than one standard deviation from the previous ten year period). The record of typhus epidemics was evaluated against the tree-ring record of Cuauhtmoc La Fragua, Puebla. This chronology, based on Douglas fir, has demonstrated to be a faithful record of precipitation in central Mexico. The results indicate that a statistically significant drought (t test, p < .05) prevailed during the first year of all 22 large outbreaks of typhus in recent Mexican history. No distinction is made between times of peace and war. This indicates that drought alone was capable of inducing the social conditions for increased transmission of typhus in pre-industrial central Mexico.
DE: 1807 Climate impacts
DE: 1812 Drought
DE: 1817 Extreme events
DE: 1833 Hydroclimatology
DE: 1834 Human impacts
SC: Biogeosciences [B]
MN: 2007 Joint Assembly