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

Environmental 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 strepsic...

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Main Authors: Sunday O Ochai, Lourens Snyman, Amelie C Dolfi, Abel Ramoelo, Brian K Reilly, Judith M Botha, Edgar H Dekker, O Louis van Schalkwyk, Pauline L Kamath, Emma Archer, Wendy C Turner, Henriette van Heerden
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2024-01-01
Series:PLoS ONE
Online Access:https://doi.org/10.1371/journal.pone.0314103
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author Sunday O Ochai
Lourens Snyman
Amelie C Dolfi
Abel Ramoelo
Brian K Reilly
Judith M Botha
Edgar H Dekker
O Louis van Schalkwyk
Pauline L Kamath
Emma Archer
Wendy C Turner
Henriette van Heerden
author_facet Sunday O Ochai
Lourens Snyman
Amelie C Dolfi
Abel Ramoelo
Brian K Reilly
Judith M Botha
Edgar H Dekker
O Louis van Schalkwyk
Pauline L Kamath
Emma Archer
Wendy C Turner
Henriette van Heerden
author_sort Sunday O Ochai
collection DOAJ
description Environmental 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.
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spelling doaj-art-1735f8645c3842909cab2e211b8c61b72024-12-10T05:32:04ZengPublic Library of Science (PLoS)PLoS ONE1932-62032024-01-011912e031410310.1371/journal.pone.0314103Roles of host and environment in shift of primary anthrax host species in Kruger National Park.Sunday O OchaiLourens SnymanAmelie C DolfiAbel RamoeloBrian K ReillyJudith M BothaEdgar H DekkerO Louis van SchalkwykPauline L KamathEmma ArcherWendy C TurnerHenriette van HeerdenEnvironmental 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.https://doi.org/10.1371/journal.pone.0314103
spellingShingle Sunday O Ochai
Lourens Snyman
Amelie C Dolfi
Abel Ramoelo
Brian K Reilly
Judith M Botha
Edgar H Dekker
O Louis van Schalkwyk
Pauline L Kamath
Emma Archer
Wendy C Turner
Henriette van Heerden
Roles of host and environment in shift of primary anthrax host species in Kruger National Park.
PLoS ONE
title Roles of host and environment in shift of primary anthrax host species in Kruger National Park.
title_full Roles of host and environment in shift of primary anthrax host species in Kruger National Park.
title_fullStr Roles of host and environment in shift of primary anthrax host species in Kruger National Park.
title_full_unstemmed Roles of host and environment in shift of primary anthrax host species in Kruger National Park.
title_short Roles of host and environment in shift of primary anthrax host species in Kruger National Park.
title_sort roles of host and environment in shift of primary anthrax host species in kruger national park
url https://doi.org/10.1371/journal.pone.0314103
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