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Title
Declines in large wildlife increase landscape-level prevalence of rodent-borne disease in Africa. |
Full text
https://escholarship.org/uc/item/1mr6m07r |
Date
2014 |
Author(s)
Young, Hillary S; Dirzo, Rodolfo; Helgen, Kristofer M; McCauley, Douglas J; Billeter, Sarah A; Kosoy, Michael Y; Osikowicz, Lynn M; Salkeld, Daniel J; Young, Truman P; Dittmar, Katharina |
Abstract
Populations of large wildlife are declining on local and global scales. The impacts of this pulse of size-selective defaunation include cascading changes to smaller animals, particularly rodents, and alteration of many ecosystem processes and services, potentially involving changes to prevalence and transmission of zoonotic disease. Understanding linkages between biodiversity loss and zoonotic disease is important for both public health and nature conservation programs, and has been a source of much recent scientific debate. In the case of rodent-borne zoonoses, there is strong conceptual support, but limited empirical evidence, for the hypothesis that defaunation, the loss of large wildlife, increases zoonotic disease risk by directly or indirectly releasing controls on rodent density. We tested this hypothesis by experimentally excluding large wildlife from a savanna ecosystem in East Africa, and examining changes in prevalence and abundance of Bartonella spp. infection in rodents and their flea vectors. We found no effect of wildlife removal on per capita prevalence of Bartonella infection in either rodents or fleas. However, because rodent and, consequently, flea abundance doubled following experimental defaunation, the density of infected hosts and infected fleas was roughly twofold higher in sites where large wildlife was absent. Thus, defaunation represents an elevated risk in Bartonella transmission to humans (bartonellosis). Our results (i) provide experimental evidence of large wildlife defaunation increasing landscape-level disease prevalence, (ii) highlight the importance of susceptible host regulation pathways and host/vector density responses in biodiversity-disease relationships, and (iii) suggest that rodent-borne disease responses to large wildlife loss may represent an important context where this relationship is largely negative. |
Subject(s)
Animals; Animals; Wild; Humans; Rodentia; Bartonella Infections; Zoonoses; Lice Infestations; Rodent Diseases; Prevalence; Risk Factors; Ecosystem; Biodiversity; Africa; Eastern; Kenya; Xenopsylla; Flea Infestations; dilution effect; Emerging Infectious Diseases; Vector-Borne Diseases; Infectious Diseases; 2.2 Factors relating to physical environment; Infection; Wild; Africa; Eastern |
Coverage
7036 - 7041 |
Publisher
eScholarship, University of California |
Type of publication
article |
Format
application/pdf |
Source
Proceedings of the National Academy of Sciences of the United States of America, vol 111, iss 19 |
Rights
public |
Identifier
qt1mr6m07r |
Repository
Berkeley - University of California
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Added to C-A: 2020-02-13;10:35:45 |
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