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Three-dimensional visualization of cultural clusters in the 1878 yellow fever epidemic of New Orleans.

Curtis AJ - Int J Health Geogr (2008)

Bottom Line: These generally mirror the results of other global cluster and density surfaces created for the entire epidemic in New Orleans.A final examination of mortalities for one of the nativity clusters reveals that further sub-division is present, and that this pattern would only be revealed at this scale (street level) of investigation.Disease spread in an epidemic is complex resulting from a combination of geographic distance, geographic distance with specific connection to the built environment, disease-specific time frame between deaths, impediments such as herd immunity, and social or cultural connection.

View Article: PubMed Central - HTML - PubMed

Affiliation: GIS Research Laboratory, Department of Geography, University of Southern California, Kaprielian Hall (KAP), Room 416, 3620 South Vermont Avenue, Los Angeles, CA 90089-0255, USA. ajcurtis@usc.edu

ABSTRACT

Background: An epidemic may exhibit different spatial patterns with a change in geographic scale, with each scale having different conduits and impediments to disease spread. Mapping disease at each of these scales often reveals different cluster patterns. This paper will consider this change of geographic scale in an analysis of yellow fever deaths for New Orleans in 1878. Global clustering for the whole city, will be followed by a focus on the French Quarter, then clusters of that area, and finally street-level patterns of a single cluster. The three-dimensional visualization capabilities of a GIS will be used as part of a cluster creation process that incorporates physical buildings in calculating mortality-to-mortality distance. Including nativity of the deceased will also capture cultural connection.

Results: Twenty-two yellow fever clusters were identified for the French Quarter. These generally mirror the results of other global cluster and density surfaces created for the entire epidemic in New Orleans. However, the addition of building-distance, and disease specific time frame between deaths reveal that disease spread contains a cultural component. Same nativity mortality clusters emerge in a similar time frame irrespective of proximity. Italian nativity mortalities were far more densely grouped than any of the other cohorts. A final examination of mortalities for one of the nativity clusters reveals that further sub-division is present, and that this pattern would only be revealed at this scale (street level) of investigation.

Conclusion: Disease spread in an epidemic is complex resulting from a combination of geographic distance, geographic distance with specific connection to the built environment, disease-specific time frame between deaths, impediments such as herd immunity, and social or cultural connection. This research has shown that the importance of cultural connection may be more important than simple proximity, which in turn might mean traditional quarantine measures should be re-evaluated.

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Related in: MedlinePlus

Kernel density surfaces of US, French, Italian born and children under the age of 5. The four kernel density surfaces display different geographic patterns of mortality concentration, though the tightest and densest of these occur with Italian deaths. Each of these contoured surfaces has been classified into ten equal categories (allowing for the interpretation that each accounts for approximately 10% of the total disease density), which in turn allows for comparison between the maps (the darker the areas, the more disease), especially in conjunction with Table 1.
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Figure 3: Kernel density surfaces of US, French, Italian born and children under the age of 5. The four kernel density surfaces display different geographic patterns of mortality concentration, though the tightest and densest of these occur with Italian deaths. Each of these contoured surfaces has been classified into ten equal categories (allowing for the interpretation that each accounts for approximately 10% of the total disease density), which in turn allows for comparison between the maps (the darker the areas, the more disease), especially in conjunction with Table 1.

Mentions: Figure 3 displays the KD surfaces for US born, French, Italians and children under the age of 5. Both the KD surfaces for US born and French occupy the area "B" (in Figure 1) which also corresponds to the first NNHC clusters in the French Quarter. The French KD surface also coincides with area "C", and NNHC clusters for September. The Italian KD surface presents the tightest concentration, again coinciding with area "A". The KD surface for children under the age of 5, although having its highest concentration in a similar area as "A", is generally more dispersed across the French Quarter compared to the other three surfaces. From these initial surfaces, it is apparent that the highest concentration of disease across the entire New Orleans epidemic was disproportionately suffered by Italians living in area "A" of the French Quarter. This is supported in Table 1 which compares actual numbers of mortalities and density values for each of the four subgroups.


Three-dimensional visualization of cultural clusters in the 1878 yellow fever epidemic of New Orleans.

Curtis AJ - Int J Health Geogr (2008)

Kernel density surfaces of US, French, Italian born and children under the age of 5. The four kernel density surfaces display different geographic patterns of mortality concentration, though the tightest and densest of these occur with Italian deaths. Each of these contoured surfaces has been classified into ten equal categories (allowing for the interpretation that each accounts for approximately 10% of the total disease density), which in turn allows for comparison between the maps (the darker the areas, the more disease), especially in conjunction with Table 1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2538514&req=5

Figure 3: Kernel density surfaces of US, French, Italian born and children under the age of 5. The four kernel density surfaces display different geographic patterns of mortality concentration, though the tightest and densest of these occur with Italian deaths. Each of these contoured surfaces has been classified into ten equal categories (allowing for the interpretation that each accounts for approximately 10% of the total disease density), which in turn allows for comparison between the maps (the darker the areas, the more disease), especially in conjunction with Table 1.
Mentions: Figure 3 displays the KD surfaces for US born, French, Italians and children under the age of 5. Both the KD surfaces for US born and French occupy the area "B" (in Figure 1) which also corresponds to the first NNHC clusters in the French Quarter. The French KD surface also coincides with area "C", and NNHC clusters for September. The Italian KD surface presents the tightest concentration, again coinciding with area "A". The KD surface for children under the age of 5, although having its highest concentration in a similar area as "A", is generally more dispersed across the French Quarter compared to the other three surfaces. From these initial surfaces, it is apparent that the highest concentration of disease across the entire New Orleans epidemic was disproportionately suffered by Italians living in area "A" of the French Quarter. This is supported in Table 1 which compares actual numbers of mortalities and density values for each of the four subgroups.

Bottom Line: These generally mirror the results of other global cluster and density surfaces created for the entire epidemic in New Orleans.A final examination of mortalities for one of the nativity clusters reveals that further sub-division is present, and that this pattern would only be revealed at this scale (street level) of investigation.Disease spread in an epidemic is complex resulting from a combination of geographic distance, geographic distance with specific connection to the built environment, disease-specific time frame between deaths, impediments such as herd immunity, and social or cultural connection.

View Article: PubMed Central - HTML - PubMed

Affiliation: GIS Research Laboratory, Department of Geography, University of Southern California, Kaprielian Hall (KAP), Room 416, 3620 South Vermont Avenue, Los Angeles, CA 90089-0255, USA. ajcurtis@usc.edu

ABSTRACT

Background: An epidemic may exhibit different spatial patterns with a change in geographic scale, with each scale having different conduits and impediments to disease spread. Mapping disease at each of these scales often reveals different cluster patterns. This paper will consider this change of geographic scale in an analysis of yellow fever deaths for New Orleans in 1878. Global clustering for the whole city, will be followed by a focus on the French Quarter, then clusters of that area, and finally street-level patterns of a single cluster. The three-dimensional visualization capabilities of a GIS will be used as part of a cluster creation process that incorporates physical buildings in calculating mortality-to-mortality distance. Including nativity of the deceased will also capture cultural connection.

Results: Twenty-two yellow fever clusters were identified for the French Quarter. These generally mirror the results of other global cluster and density surfaces created for the entire epidemic in New Orleans. However, the addition of building-distance, and disease specific time frame between deaths reveal that disease spread contains a cultural component. Same nativity mortality clusters emerge in a similar time frame irrespective of proximity. Italian nativity mortalities were far more densely grouped than any of the other cohorts. A final examination of mortalities for one of the nativity clusters reveals that further sub-division is present, and that this pattern would only be revealed at this scale (street level) of investigation.

Conclusion: Disease spread in an epidemic is complex resulting from a combination of geographic distance, geographic distance with specific connection to the built environment, disease-specific time frame between deaths, impediments such as herd immunity, and social or cultural connection. This research has shown that the importance of cultural connection may be more important than simple proximity, which in turn might mean traditional quarantine measures should be re-evaluated.

Show MeSH
Related in: MedlinePlus