Chronic disease in the Mojave desert tortoise: Host physiology and recrudescence obscure patterns of pathogen transmission
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Authors
Sandmeier, Franziska C.
Maloney, Nichole K.
Tracy, C. Richard
Hyde, David
Mohammadpour, Hamid A.
Marlow, Ron
DuPré, Sally A.
Hunter, Kenneth W.
Issue Date
2017
Type
Article
Language
Keywords
ectotherm , immune function , reptile , subclinical disease , wildlife disease
Alternative Title
Abstract
A seminatural, factorial-design experiment was used to quantify dynamics of the pathogen Mycoplasma agassizii and upper respiratory tract disease in the Mojave desert tortoise (Gopherus agassizii) over 2years. Groups of initially healthy animals were separated into serologically positive (seropositive), seronegative, and artificially infected groups and paired into 23 pens. We found no evidence of long-term immune protection to M.agassizii or of immunological memory. Initially seronegative, healthy tortoises experienced an equal amount of disease when paired with other seronegative groups as when paired with seropositive and artificially infected groupssuggesting that recrudescence is as significant as transmission in introducing disease in individuals in this host-pathogen system. Artificially infected groups of tortoises showed reduced levels of morbidity when paired with initially seronegative animalssuggesting either a dilution effect or a strong effect of pathogen load in this system. Physiological dynamics within the host appear to be instrumental in producing morbidity, recrudescence, and infectiousness, and thus of population-level dynamics. We suggest new avenues for studying diseases in long-lived ectothermic vertebrates and a shift in modeling such diseases.
Description
Citation
Sandmeier, F. C., Maloney, K. N., Tracy, C. R., Hyde, D., Mohammadpour, H., Marlow, R., … Hunter, K. (2017). Chronic disease in the Mojave desert tortoise: Host physiology and recrudescence obscure patterns of pathogen transmission. Ecology and Evolution, 7(24), 10616–10629. doi:10.1002/ece3.3480
Publisher
Journal
Volume
Issue
PubMed ID
ISSN
2045-7758