Temporal patterns of anthrax outbreaks among livestock in Lesotho, 2005-2016.

Relebohile Juliet Lepheana,Daniel Nenene Qekwana,James Wabwire Oguttu,N.S Duesbery

doi:10.1371/journal.pone.0204758

Relebohile Juliet Lepheana, Daniel Nenene Qekwana + Show 2 more

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https://doi.org/10.1371/journal.pone.0204758

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Journal: PloS one	Publication Date: Oct 24, 2018
Citations: 8	License type: CC BY 4.0

Affiliation: University of Pretoria, University of South Africa

Abstract

BackgroundAlthough anthrax is endemic in Lesotho, limited information is available on the patterns of the disease among livestock animals. This study investigated temporal patterns of anthrax outbreaks and cases among livestock animals in Lesotho.MethodsSecondary data of anthrax outbreaks reported to the Department of Livestock Services between January 2005 and December 2016 was used for this study. Proportions of anthrax outbreaks and cases, and their corresponding 95% confidence interval were calculated and compared across year, season, month and region using the Chi-square or Fisher’s exact test. The autoregression model was used to evaluate annual trends of anthrax outbreaks and cases.ResultsA total of 38 outbreaks were reported in the Lowlands districts of Lesotho. District was significantly (p<0.0001) associated with outbreaks and cases, with the highest proportions of outbreaks (52.6%) and cases (70.2%) reported in Maseru. Significantly (p = 0.0004) higher proportions of anthrax outbreaks (78.9%) and cases (95.1%) were reported in the rainy-hot season compared to the dry-cold season. Five hundred and twenty-six (n = 526) anthrax cases were reported with significantly (p<0.0001) higher proportion of cases (70.3%) in cattle compared to other species. Higher proportion of anthrax cases (35.9%) were reported in 2008 and during the months of February (30.8%) and April (30.2%). There was no significant annual trend in anthrax outbreaks (r = 0.0282; p = 0.6213) and cases (r = 0.0873; p = 0.3512) over the study period.ConclusionThe burden of anthrax in Lesotho is significantly higher in cattle. Anthrax outbreaks occur only in the lowland districts and follow a seasonal pattern. Therefore, more effort should be targeted at curbing the disease in cattle and the lowlands districts. Furthermore, there should be heightened monitoring of cases in the rainy season to ensure that resultant carcasses are disposed of appropriately to minimise future outbreaks.

Highlights

Anthrax disease is caused by Bacillus anthracis, a gram-positive, aerobic, endospore-forming, and rod shaped bacterium [1]
Secondary data of anthrax outbreaks reported to the Department of Livestock Services between January 2005 and December 2016 was used for this study
(p = 0.0004) higher proportions of anthrax outbreaks (78.9%) and cases (95.1%) were reported in the rainy-hot season compared to the dry-cold season

Summary

Introduction

Anthrax disease is caused by Bacillus anthracis, a gram-positive, aerobic, endospore-forming, and rod shaped bacterium [1]. It is primarily a disease of herbivores, with cattle and sheep being the most affected [2,3]. The disease is endemic in South Africa [6], Zimbabwe [7], Namibia [8], and Tanzania [9], it is still under-diagnosed and under-reported [10,11]. Anthrax is endemic in Lesotho, limited information is available on the patterns of the disease among livestock animals. This study investigated temporal patterns of anthrax outbreaks and cases among livestock animals in Lesotho.

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Results

Conclusion