Biogeography of human infectious diseases: a global historical analysis.

<h4>Objectives</h4>Human pathogen richness and prevalence vary widely across the globe, yet we know little about whether global patterns found in other taxa also predict diversity in this important group of organisms. This study (a) assesses the relative importance of temperature, precip...

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Main Author: Elizabeth Cashdan
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2014-01-01
Series:PLoS ONE
Online Access:https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0106752&type=printable
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author Elizabeth Cashdan
author_facet Elizabeth Cashdan
author_sort Elizabeth Cashdan
collection DOAJ
description <h4>Objectives</h4>Human pathogen richness and prevalence vary widely across the globe, yet we know little about whether global patterns found in other taxa also predict diversity in this important group of organisms. This study (a) assesses the relative importance of temperature, precipitation, habitat diversity, and population density on the global distributions of human pathogens and (b) evaluates the species-area predictions of island biogeography for human pathogen distributions on oceanic islands.<h4>Methods</h4>Historical data were used in order to minimize the influence of differential access to modern health care on pathogen prevalence. The database includes coded data (pathogen, environmental and cultural) for a worldwide sample of 186 non-industrial cultures, including 37 on islands. Prevalence levels for 10 pathogens were combined into a pathogen prevalence index, and OLS regression was used to model the environmental determinants of the prevalence index and number of pathogens.<h4>Results</h4>Pathogens (number and prevalence index) showed the expected latitudinal gradient, but predictors varied by latitude. Pathogens increased with temperature in high-latitude zones, while mean annual precipitation was a more important predictor in low-latitude zones. Other environmental factors associated with more pathogens included seasonal dry extremes, frost-free climates, and human population density outside the tropics. Islands showed the expected species-area relationship for all but the smallest islands, and the relationship was not mediated by habitat diversity. Although geographic distributions of free-living and parasitic taxa typically have different determinants, these data show that variables that influence the distribution of free-living organisms also shape the global distribution of human pathogens. Understanding the cause of these distributions is potentially important, since geographical variation in human pathogens has an important influence on global disparities in human welfare.
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spelling doaj.art-de6644465c7e4aa7ab8dedd0c6f988b02025-02-22T05:32:32ZengPublic Library of Science (PLoS)PLoS ONE1932-62032014-01-01910e10675210.1371/journal.pone.0106752Biogeography of human infectious diseases: a global historical analysis.Elizabeth Cashdan<h4>Objectives</h4>Human pathogen richness and prevalence vary widely across the globe, yet we know little about whether global patterns found in other taxa also predict diversity in this important group of organisms. This study (a) assesses the relative importance of temperature, precipitation, habitat diversity, and population density on the global distributions of human pathogens and (b) evaluates the species-area predictions of island biogeography for human pathogen distributions on oceanic islands.<h4>Methods</h4>Historical data were used in order to minimize the influence of differential access to modern health care on pathogen prevalence. The database includes coded data (pathogen, environmental and cultural) for a worldwide sample of 186 non-industrial cultures, including 37 on islands. Prevalence levels for 10 pathogens were combined into a pathogen prevalence index, and OLS regression was used to model the environmental determinants of the prevalence index and number of pathogens.<h4>Results</h4>Pathogens (number and prevalence index) showed the expected latitudinal gradient, but predictors varied by latitude. Pathogens increased with temperature in high-latitude zones, while mean annual precipitation was a more important predictor in low-latitude zones. Other environmental factors associated with more pathogens included seasonal dry extremes, frost-free climates, and human population density outside the tropics. Islands showed the expected species-area relationship for all but the smallest islands, and the relationship was not mediated by habitat diversity. Although geographic distributions of free-living and parasitic taxa typically have different determinants, these data show that variables that influence the distribution of free-living organisms also shape the global distribution of human pathogens. Understanding the cause of these distributions is potentially important, since geographical variation in human pathogens has an important influence on global disparities in human welfare.https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0106752&type=printable
spellingShingle Elizabeth Cashdan
Biogeography of human infectious diseases: a global historical analysis.
PLoS ONE
title Biogeography of human infectious diseases: a global historical analysis.
title_full Biogeography of human infectious diseases: a global historical analysis.
title_fullStr Biogeography of human infectious diseases: a global historical analysis.
title_full_unstemmed Biogeography of human infectious diseases: a global historical analysis.
title_short Biogeography of human infectious diseases: a global historical analysis.
title_sort biogeography of human infectious diseases a global historical analysis
url https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0106752&type=printable
work_keys_str_mv AT elizabethcashdan biogeographyofhumaninfectiousdiseasesaglobalhistoricalanalysis