Roles of host and environment in shift of primary anthrax host species in Kruger National Park

dc.contributor.authorOchai, Sunday Ochonu
dc.contributor.authorSnyman, Lourens F.
dc.contributor.authorDolfi, Amelie C.
dc.contributor.authorRamoelo, Abel
dc.contributor.authorReilly, Brian K.
dc.contributor.authorBotha, Judith M.
dc.contributor.authorDekker, Edgar H.
dc.contributor.authorVan Schalkwyk, Ockert Louis
dc.contributor.authorKamath, Pauline L.
dc.contributor.authorArcher, Emma Rosa Mary
dc.contributor.authorTurner, Wendy C.
dc.contributor.authorVan Heerden, Henriette
dc.date.accessioned2025-05-26T11:03:28Z
dc.date.available2025-05-26T11:03:28Z
dc.date.issued2024-12-06
dc.descriptionDATA AVAILABILTY STATEMENT : All data used to generate the results of this study are provided in the supplementary data, ensuring transparency and reproducibility. However, the opportunistic passive mortality surveillance data for kudu, impala, and elephant were obtained from the Skukuza State Veterinary Services under the South African National Parks (SANParks), South Africa (Ref: BMTA 006/22). Due to the restrictions imposed by SANParks, we do not have the permission to share these specific data publicly.
dc.descriptionSUPPORTING INFORMATION : DATA S1. TABLE S1. Binomial generalized linear model table for the presence/absence of anthrax mortality for only kudu (Tragelaphus strepsiceros) with the presence/absence as the response variable and season, Normalized difference vegetation index (NDVI), standardised. TABLE S2. Negative binomial model table for the anthrax mortality count for only kudu (Tragelaphus strepsiceros) with the count data as the response variable and season, Normalized difference vegetation index (NDVI), standardised precipitation index (SPI), and precipitation as predictor variables. TABLE S3. Binomial generalized linear model table for the presence/absence of anthrax mortality for only impala (Aepyceros melampus) with the presence/absence as the response variable and season, Normalized difference vegetation index (NDVI), standardised precipitation index (SPI) 3 and 12, year of mortality and kudu (Tragelaphus strepsiceros) density (TS_density) as predictor variables. TABLE S4. Negative binomial model table for the anthrax mortality count for only impala (Aepyceros melampus) with the count data as the response variable and season, Normalized difference vegetation index (NDVI), standardised precipitation index (SPI), maximal temperature, elephant (Loxodonta africana) density (LA_density), year and kudu (Tragelaphus strepsiceros) density (TS_density) as predictor variables.
dc.description.abstractEnvironmental and climatic factors, as well as host demographics and behaviour, significantly influence the exposure of herbivorous mammalian hosts to pathogens such as Bacillus anthracis, the causative agent of anthrax. Until the early 1990s in Kruger National Park (KNP), kudu (Tragelaphus strepsiceros) was the host species most affected by anthrax, with outbreaks occurring predominantly in the dry season, particularly during drought cycles. However, the most affected host species has shifted to impala (Aepyceros melampus), with more frequent anthrax outbreaks during the wet season. This study investigates the roles of environmental variation and other host species in this shift. Temporal trends in environmental variables such as precipitation, soil moisture, temperature, and normalised difference vegetation index (NDVI) were analyzed in relation to anthrax occurrence (presence/ absence and counts). Additionally, correlations between host species' densities and anthrax mortalities over time were examined. Anthrax cases in 1990 were concentrated in the central and northern regions of KNP (excluding Pafuri), primarily affected kudus; while subsequent mortalities affected mostly impala and were restricted to the far north, in Pafuri. Significant correlations were found between kudu anthrax mortality and a decrease in NDVI, average temperature, SPI-6 and SPI-12 (Standardised Precipitation Index in various time intervals. Conversely, anthrax occurrence in impalas was associated with a decline in SPI-3, and temperature rise, with increased mortality during the rainy season. Elephant density correlated negatively with kudu mortality, but a positive correlation with both impala mortality and impala density. The study concludes that environmental variables and species' densities may alter the diversity and frequency of hosts exposed to B. anthracis. Climate extremes and alterations therein may exacerbate anthrax severity by modifying species susceptibility and their probability of exposure over time.
dc.description.departmentVeterinary Tropical Diseases
dc.description.departmentGeography, Geoinformatics and Meteorology
dc.description.librarianam2025
dc.description.sdgSDG-03: Good health and well-being
dc.description.sdgSDG-13: Climate action
dc.description.sdgSDG-15: Life on land
dc.description.sponsorshipNational Science Foundation (NSF) through the NSF- National Institutes of Health (NIH)- U.S. Department of Agriculture (USDA) Ecology and Evolution of Infectious Diseases program.
dc.description.urihttps://journals.plos.org/plosone/
dc.identifier.citationOchai, S.O., Snyman, L., Dolfi, A.C., Ramoelo, A., Reilly, B.K., Botha, J.M., et al. (2024) Roles of host and environment in shift of primary anthrax host species in Kruger National Park. PLoS ONE 19(12): e0314103. https://doi.org/10.1371/journal.pone.0314103.
dc.identifier.issn1932-6203 (online)
dc.identifier.other10.1371/journal.pone.0314103
dc.identifier.urihttp://hdl.handle.net/2263/102513
dc.language.isoen
dc.publisherPublic Library of Science
dc.rightsThe work is made available under the Creative Commons CC0 public domain dedication.
dc.subjectKruger National Park (KNP)
dc.subjectKruger National Park (South Africa)
dc.subjectBacillus anthracis
dc.subjectKudu (Tragelaphus strepsiceros)
dc.subjectAnthrax
dc.subjectImpala (Aepyceros melampus)
dc.subjectEnvironmental factors
dc.subjectClimatic factors
dc.titleRoles of host and environment in shift of primary anthrax host species in Kruger National Park
dc.typeArticle

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