DOI: 10.5061/dryad.73f23
title: Data from: Frequent and seasonally variable sublethal anthrax infections are accompanied by short-lived immunity in an endemic system

description: 1. Few studies have examined host-pathogen interactions in wildlife from
 an immunological perspective, particularly in the context of seasonal and
 longitudinal dynamics. In addition, though most ecological immunology
 studies employ serological antibody assays, endpoint titer determination
 is usually based on subjective criteria and needs to be made more
 objective. 2. Despite the fact that anthrax is an ancient and emerging
 zoonotic infectious disease found worldwide, its natural ecology is not
 well understood. In particular, little is known about the adaptive immune
 responses of wild herbivore hosts against Bacillus anthracis. 3. Working
 in the natural anthrax system of Etosha National Park, Namibia, we
 collected 154 serum samples from plains zebra (Equus quagga), 21 from
 springbok (Antidorcas marsupialis), and 45 from African elephants
 (Loxodonta africana) over 2-3 years, resampling individuals when possible
 for seasonal and longitudinal comparisons. We used enzyme-linked
 immunosorbent assays to measure anti-anthrax antibody titers and developed
 three increasingly conservative models to determine endpoint titers with
 more rigorous, objective mensuration. 4. Between 52-87% of zebra, 0-15% of
 springbok, and 3-52% of elephants had measurable anti-anthrax antibody
 titers, depending on the model used. While the ability of elephants and
 springbok to mount anti-anthrax adaptive immune responses is still
 equivocal, our results indicate that zebra in ENP often survive sublethal
 anthrax infections, encounter most B. anthracis in the wet season, and can
 partially booster their immunity to B. anthracis. 5. Thus, rather than
 being solely a lethal disease, anthrax often occurs as a sublethal
 infection in some susceptible hosts. Though we found that adaptive
 immunity to anthrax wanes rapidly, subsequent and frequent sublethal B.
 anthracis infections cause maturation of anti-anthrax immunity. By
 triggering host immune responses, these common sublethal infections may
 act as immunomodulators and affect population dynamics through indirect
 immunological and co-infection effects. 6. In addition, with our three
 endpoint titer models, we introduce more mensuration rigor into
 serological antibody assays, even under the often-restrictive conditions
 that come with adapting laboratory immunology methods to wild systems.
 With these methods we identified significantly more zebras responding
 immunologically to anthrax than have previous studies using less
 comprehensive titer analyses.
description: Anti-PA Titers for Equus
 quaggaAnti-anthrax
 (anti-protective antigen toxin) antibody titers for wild plains zebra
 immobilized and sampled over 1-5 seasons in Etosha National Park, Namibia.
 id=animal capture ID. titer=anti-PA titer; the titer is the highest
 dilution in the titration series for which the mean sample optical density
 (OD) for that dilution is greater than the mean negative control OD
 titration curve from all plates (dilution is as 1:dilution; e.g. 1024 is a
 1:1024 dilution). titerDUP=anti-PA titer for which the titer is the last
 dilution at which the mean sample OD is greater than the mean negative
 control OD buffered by a 95% confidence interval determined by the
 inter-duplicate error at that dilution, across all samples.
 titerNCONT=anti-PA titer for which the titer is the last dilution at which
 the mean sample OD is greater than the mean negative control OD buffered
 by a 95% confidence interval determined by the inter-negative control
 error at that dilution, across all samples. plate=plate identifier (date
 and plate number on that day). ncont=identifier of the negative control
 sample used.EQtitersPA.csvAnti-PA Titers for Antidorcas marsupialisAnti-anthrax (anti-protective antigen toxin) antibody titers for wild springbok immobilized and sampled over 1-2 seasons in Etosha National Park, Namibia. id=animal capture ID. titer=anti-PA titer; the titer is the highest dilution in the titration series for which the mean sample optical density (OD) for that dilution is greater than the mean negative control OD titration curve from all plates (dilution is as 1:dilution; e.g. 1024 is a 1:1024 dilution). titerDUP=anti-PA titer for which the titer is the last dilution at which the mean sample OD is greater than the mean negative control OD buffered by a 95% confidence interval determined by the inter-duplicate error at that dilution, across all samples. titerNCONT=anti-PA titer for which the titer is the last dilution at which the mean sample OD is greater than the mean negative control OD buffered by a 95% confidence interval determined by the inter-negative control error at that dilution, across all samples. plate=plate identifier (date and plate number on that day). ncont=identifier of the negative control sample used.AMtitersPA.csvAnti-PA Titers for Loxodonta africanaAnti-anthrax (anti-protective antigen toxin) antibody titers for wild African elephants immobilized and sampled over 1-2 seasons in Etosha National Park, Namibia. id=animal capture ID. titer=anti-PA titer; the titer is the highest dilution in the titration series for which the mean sample optical density (OD) for that dilution is greater than the mean negative control OD titration curve from all plates (dilution is as 1:dilution; e.g. 1024 is a 1:1024 dilution). titerDUP=anti-PA titer for which the titer is the last dilution at which the mean sample OD is greater than the mean negative control OD buffered by a 95% confidence interval determined by the inter-duplicate error at that dilution, across all samples. titerNCONT=anti-PA titer for which the titer is the last dilution at which the mean sample OD is greater than the mean negative control OD buffered by a 95% confidence interval determined by the inter-negative control error at that dilution, across all samples. plate=plate identifier (date and plate number on that day). ncont=identifier of the negative control sample used.LAtitersPA.csv