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Chanda MM, Purse BV, Sedda L, Benz D, Prasad M, Reddy YN, Yarabolu KR, Byregowda SM, Carpenter S, Prasad G, Rogers DJ. Bluetongue Risk Map for Vaccination and Surveillance Strategies in India. Pathogens 2024; 13:590. [PMID: 39057817 PMCID: PMC11280473 DOI: 10.3390/pathogens13070590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2024] [Revised: 07/07/2024] [Accepted: 07/13/2024] [Indexed: 07/28/2024] Open
Abstract
Bluetongue virus (BTV, Sedoreoviridae: Orbivirus) causes an economically important disease, namely, bluetongue (BT), in domestic and wild ruminants worldwide. BTV is endemic to South India and has occurred with varying severity every year since the virus was first reported in 1963. BT can cause high morbidity and mortality to sheep flocks in this region, resulting in serious economic losses to subsistence farmers, with impacts on food security. The epidemiology of BTV in South India is complex, characterized by an unusually wide diversity of susceptible ruminant hosts, multiple vector species biting midges (Culicoides spp., Diptera: Ceratopogonidae), which have been implicated in the transmission of BTV and numerous co-circulating virus serotypes and strains. BT presence data (1997-2011) for South India were obtained from multiple sources to develop a presence/absence model for the disease. A non-linear discriminant analysis (NLDA) was carried out using temporal Fourier transformed variables that were remotely sensed as potential predictors of BT distribution. Predictive performance was then characterized using a range of different accuracy statistics (sensitivity, specificity, and Kappa). The top ten variables selected to explain BT distribution were primarily thermal metrics (land surface temperature, i.e., LST, and middle infrared, i.e., MIR) and a measure of plant photosynthetic activity (the Normalized Difference Vegetation Index, i.e., NDVI). A model that used pseudo-absence points, with three presence and absence clusters each, outperformed the model that used only the recorded absence points and showed high correspondence with past BTV outbreaks. The resulting risk maps may be suitable for informing disease managers concerned with vaccination, prevention, and control of BT in high-risk areas and for planning future state-wide vector and virus surveillance activities.
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Affiliation(s)
- Mohammed Mudassar Chanda
- ICAR-National Institute of Veterinary Epidemiology and Disease Informatics (NIVEDI), Ramagondanahalli, Yelahanka, Bengaluru 560064, India
| | - Bethan V. Purse
- UK Centre for Ecology & Hydrology, Maclean Building, Crowmarsh Gifford, Wallingford OX10 8BB, UK;
| | - Luigi Sedda
- Lancaster Ecology and Epidemiology Group, Lancaster Medical School, Lancaster University, Furness Building, Lancaster LA1 4YG, UK;
| | - David Benz
- Department of Biology, University of Oxford, 11A Mansfield Road, Oxford OX1 3SZ, UK; (D.B.); (D.J.R.)
| | - Minakshi Prasad
- National Research Centre on Equines, Sirsa Road, Hisar 125001, India;
| | - Yella Narasimha Reddy
- Department of Animal Biotechnology, P.V. Narsimha Rao Telangana University, Hyderabad 500030, India;
| | - Krishnamohan Reddy Yarabolu
- Vaccine Research Centre-Viral Vaccines, Centre for Animal Health Studies Tamil Nadu Veterinary and Animal Sciences University, Chennai 600051, India;
| | - S. M. Byregowda
- Institute of Animal Health and Veterinary Biological, Bengaluru 560024, India;
| | - Simon Carpenter
- School of the Biological Sciences, 17 Mill Lane, Cambridge CB2 1RX, UK;
| | - Gaya Prasad
- International Institute of Veterinary Education & Research, Rohtak 124001, India;
| | - David John Rogers
- Department of Biology, University of Oxford, 11A Mansfield Road, Oxford OX1 3SZ, UK; (D.B.); (D.J.R.)
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Joka FR. Mapping high probability area for the Bacillus anthracis occurrence in wildlife protected area, South Omo, Ethiopia. Spat Spatiotemporal Epidemiol 2024; 49:100657. [PMID: 38876568 DOI: 10.1016/j.sste.2024.100657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 05/02/2024] [Accepted: 05/03/2024] [Indexed: 06/16/2024]
Abstract
Anthrax is a zoonotic disease caused by a spore-forming gram-positive bacterium, Bacillus anthracis. Increased anthropogenic factors inside wildlife-protected areas may worsen the spillover of the disease at the interface. Consequently, environmental suitability prediction for B. anthracis spore survival to locate a high-risk area is urgent. Here, we identified a potentially suitable habitat and a high-risk area for appropriate control measures. Our result revealed that a relatively largest segment of Omo National Park, about 23.7% (1,218 square kilometers) of the total area; 36.6% (711 square kilometers) of Mago National Park, and 29.4% (489 square kilometers) of Tama wildlife Reserve predicted as a high-risk area for the anthrax occurrence in the current situation. Therefore, the findings of this study provide the priority area to focus on and allocate resources for effective surveillance, prevention, and control of anthrax before it causes devastating effects on wildlife.
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Affiliation(s)
- Fekede Regassa Joka
- Ethiopian Wildlife Conservation Authority, Wildlife Research and Development Lead Executive officer, Po Box 386, Addis Ababa, Ethiopia.
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Oduoye MO, Scott GY, Dave T, Bolanle AHH, Mwinbong AD, Modupeoluwa OO. One health approach to mitigate anthrax in Ghana. Health Sci Rep 2024; 7:e1807. [PMID: 38196565 PMCID: PMC10775134 DOI: 10.1002/hsr2.1807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 09/21/2023] [Accepted: 12/22/2023] [Indexed: 01/11/2024] Open
Abstract
Anthrax outbreaks in Ghana have become a pressing public health concern, posing threats to human health, the agricultural sector, and social well-being. This letter to the editor highlights the gravity of the anthrax situation in Ghana and advocates for comprehensive interventions using a One Health approach. The epidemiology of anthrax, including its historical roots and modes of transmission, is discussed. The consequences of anthrax outbreaks, such as severe illness, economic losses, and social distress, are outlined. To combat this complex issue, the letter emphasizes the importance of enhanced awareness, prevention, accurate diagnosis, and timely treatment. Recommendations include vaccination of animals and humans, education campaigns, proper disposal of infected carcasses, strengthening healthcare systems, surveillance, and early detection. Collaboration and coordination among professionals in the human, animal, and environmental sectors are crucial. By adopting a One Health approach and implementing these measures, Ghana can effectively mitigate the impact of anthrax outbreaks and safeguard the health and well-being of its population and livestock.
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Affiliation(s)
- Malik O Oduoye
- Department of Research Medical Research Circle (MedReC) Bukavu Democratic Republic of the Congo
| | - Godfred Y Scott
- Department of Medical Diagnostics Kwame Nkrumah University of Science and Technology Kumasi Ghana
| | - Tirth Dave
- Bukovinian State Medical University Chernivtsi Ukraine
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Amenu K, McIntyre KM, Moje N, Knight-Jones T, Rushton J, Grace D. Approaches for disease prioritization and decision-making in animal health, 2000-2021: a structured scoping review. Front Vet Sci 2023; 10:1231711. [PMID: 37876628 PMCID: PMC10593474 DOI: 10.3389/fvets.2023.1231711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 09/06/2023] [Indexed: 10/26/2023] Open
Abstract
This scoping review identifies and describes the methods used to prioritize diseases for resource allocation across disease control, surveillance, and research and the methods used generally in decision-making on animal health policy. Three electronic databases (Medline/PubMed, Embase, and CAB Abstracts) were searched for articles from 2000 to 2021. Searches identified 6, 395 articles after de-duplication, with an additional 64 articles added manually. A total of 6, 460 articles were imported to online document review management software (sysrev.com) for screening. Based on inclusion and exclusion criteria, 532 articles passed the first screening, and after a second round of screening, 336 articles were recommended for full review. A total of 40 articles were removed after data extraction. Another 11 articles were added, having been obtained from cross-citations of already identified articles, providing a total of 307 articles to be considered in the scoping review. The results show that the main methods used for disease prioritization were based on economic analysis, multi-criteria evaluation, risk assessment, simple ranking, spatial risk mapping, and simulation modeling. Disease prioritization was performed to aid in decision-making related to various categories: (1) disease control, prevention, or eradication strategies, (2) general organizational strategy, (3) identification of high-risk areas or populations, (4) assessment of risk of disease introduction or occurrence, (5) disease surveillance, and (6) research priority setting. Of the articles included in data extraction, 50.5% had a national focus, 12.3% were local, 11.9% were regional, 6.5% were sub-national, and 3.9% were global. In 15.2% of the articles, the geographic focus was not specified. The scoping review revealed the lack of comprehensive, integrated, and mutually compatible approaches to disease prioritization and decision support tools for animal health. We recommend that future studies should focus on creating comprehensive and harmonized frameworks describing methods for disease prioritization and decision-making tools in animal health.
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Affiliation(s)
- Kebede Amenu
- Global Burden of Animal Diseases (GBADs) Programme, University of Liverpool, Liverpool, United Kingdom
- Department of Microbiology, Immunology and Veterinary, Public Health, College of Veterinary Medicine and Agriculture, Addis Ababa University, Bishoftu, Ethiopia
- Animal and Human Health Program, International Livestock Research Institute (ILRI), Addis Ababa, Ethiopia
| | - K. Marie McIntyre
- Global Burden of Animal Diseases (GBADs) Programme, University of Liverpool, Liverpool, United Kingdom
- Department of Livestock and One Health, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
- Modelling, Evidence and Policy Group, School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Nebyou Moje
- Department of Biomedical Sciences, College of Veterinary Medicine and Agriculture, Addis Ababa University, Bishoftu, Ethiopia
| | - Theodore Knight-Jones
- Global Burden of Animal Diseases (GBADs) Programme, University of Liverpool, Liverpool, United Kingdom
- Animal and Human Health Program, International Livestock Research Institute (ILRI), Addis Ababa, Ethiopia
| | - Jonathan Rushton
- Global Burden of Animal Diseases (GBADs) Programme, University of Liverpool, Liverpool, United Kingdom
- Department of Livestock and One Health, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Delia Grace
- Global Burden of Animal Diseases (GBADs) Programme, University of Liverpool, Liverpool, United Kingdom
- Food and Markets Department, Natural Resources Institute, University of Greenwich, London, United Kingdom
- Animal and Human Health Program, International Livestock Research Institute (ILRI), Nairobi, Kenya
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Metrailer MC, Hoang TTH, Jiranantasak T, Luong T, Hoa LM, Ngoc DB, Pham QT, Pham VK, Hung TTM, Huong VTL, Pham TL, Ponciano JM, Hamerlinck G, Dang DA, Norris MH, Blackburn JK. Spatial and phylogenetic patterns reveal hidden infection sources of Bacillus anthracis in an anthrax outbreak in Son La province, Vietnam. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2023; 114:105496. [PMID: 37678701 DOI: 10.1016/j.meegid.2023.105496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 08/07/2023] [Accepted: 08/29/2023] [Indexed: 09/09/2023]
Abstract
Bacillus anthracis, the bacterial cause of anthrax, is a zoonosis affecting livestock and wildlife often spilling over into humans. In Vietnam, anthrax has been nationally reportable since 2015 with cases occurring annually, mostly in the northern provinces. In April 2022, an outbreak was reported in Son La province following the butchering of a water buffalo, Bubalus bubalis. A total of 137 humans from three villages were likely exposed to contaminated meat from the animal. Early epidemiological investigations suggested a single animal was involved in all exposures. Five B. anthracis isolates were recovered from human clinical cases along with one from the buffalo hide, another from associated maggots, and one from soil at the carcass site. The isolates were whole genome sequenced, allowing global, regional, and local molecular epidemiological analyses of the outbreak strains. All recovered B. anthracis belong to the A.Br.001/002 lineage based on canonical single nucleotide polymorphism analysis (canSNP). Although not previously identified in Vietnam, this lineage has been identified in the nearby countries of China, India, Indonesia, Thailand, as well as Australia. A twenty-five marker multi-locus variable number tandem repeat analysis (MLVA-25) was used to investigate the relationship between human, soil, and buffalo strains. Locally, four MLVA-25 genotypes were identified from the eight isolates. This level of genetic diversity is unusual for the limited geography and timing of cases and differs from past literature using MLVA-25. The coupled spatial and phylogenetic data suggest this outbreak originated from multiple, likely undetected, animal sources. These findings were further supported by local news reports that identified at least two additional buffalo deaths beyond the initial animal sampled in response to the human cases. Future outbreak response should include intensive surveillance for additional animal cases and additional molecular epidemiological traceback to identify pathogen sources.
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Affiliation(s)
- Morgan C Metrailer
- Spatial Epidemiology and Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, FL, USA; Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | | | - Treenate Jiranantasak
- Spatial Epidemiology and Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, FL, USA; Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Tan Luong
- Spatial Epidemiology and Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, FL, USA; Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA; National Institute of Hygiene and Epidemiology, Hanoi, Viet Nam
| | - Luong Minh Hoa
- National Institute of Hygiene and Epidemiology, Hanoi, Viet Nam
| | - Do Bich Ngoc
- National Institute of Hygiene and Epidemiology, Hanoi, Viet Nam
| | - Quang Thai Pham
- National Institute of Hygiene and Epidemiology, Hanoi, Viet Nam
| | - Van Khang Pham
- National Institute of Hygiene and Epidemiology, Hanoi, Viet Nam
| | | | | | | | | | | | - Duc Anh Dang
- National Institute of Hygiene and Epidemiology, Hanoi, Viet Nam
| | - Michael H Norris
- Spatial Epidemiology and Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, FL, USA; Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Jason K Blackburn
- Spatial Epidemiology and Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, FL, USA; Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA.
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Ndolo VA, Redding DW, Lekolool I, Mwangangi DM, Odhiambo DO, Deka MA, Conlan AJK, Wood JLN. Drivers and potential distribution of anthrax occurrence and incidence at national and sub-county levels across Kenya from 2006 to 2020 using INLA. Sci Rep 2022; 12:20083. [PMID: 36418897 PMCID: PMC9684160 DOI: 10.1038/s41598-022-24589-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 11/17/2022] [Indexed: 11/24/2022] Open
Abstract
Anthrax is caused by, Bacillus anthracis, a soil-borne bacterium that infects grazing animals. Kenya reported a sharp increase in livestock anthrax cases from 2005, with only 12% of the sub-counties (decentralised administrative units used by Kenyan county governments to facilitate service provision) accounting for almost a third of the livestock cases. Recent studies of the spatial extent of B. anthracis suitability across Kenya have used approaches that cannot capture the underlying spatial and temporal dependencies in the surveillance data. To address these limitations, we apply the first Bayesian approach using R-INLA to analyse a long-term dataset of livestock anthrax case data, collected from 2006 to 2020 in Kenya. We develop a spatial and a spatiotemporal model to investigate the distribution and socio-economic drivers of anthrax occurrence and incidence at the national and sub-county level. The spatial model was robust to geographically based cross validation and had a sensitivity of 75% (95% CI 65-75) against withheld data. Alarmingly, the spatial model predicted high intensity of anthrax across the Northern counties (Turkana, Samburu, and Marsabit) comprising pastoralists who are often economically and politically marginalized, and highly predisposed to a greater risk of anthrax. The spatiotemporal model showed a positive link between livestock anthrax risk and the total human population and the number of exotic dairy cattle, and a negative association with the human population density, livestock producing households, and agricultural land area. Public health programs aimed at reducing human-animal contact, improving access to healthcare, and increasing anthrax awareness, should prioritize these endemic regions.
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Affiliation(s)
- Valentina A. Ndolo
- grid.5335.00000000121885934Disease Dynamics Unit, Department of Veterinary Medicine, University of Cambridge, Madingley Rd, Cambridge, Cambridgeshire UK
| | - David William Redding
- grid.83440.3b0000000121901201Department of Genetics, Evolution and Environment, Centre for Biodiversity and Environment Research, University College London, London, UK
| | - Isaac Lekolool
- grid.452592.d0000 0001 1318 3051Department of Veterinary Services, Kenya Wildlife Service, Nairobi, Kenya
| | - David Mumo Mwangangi
- State Department for Livestock (Kenya), Directorate of Veterinary Services, Kabete, Kenya
| | - David Onyango Odhiambo
- grid.10604.330000 0001 2019 0495Department of Biochemistry, University of Nairobi, Nairobi, Kenya
| | - Mark A. Deka
- grid.416738.f0000 0001 2163 0069US Centers for Disease Control and Prevention, 1600 Clifton Rd. NE, Atlanta, GA USA
| | - Andrew J. K. Conlan
- grid.5335.00000000121885934Disease Dynamics Unit, Department of Veterinary Medicine, University of Cambridge, Madingley Rd, Cambridge, Cambridgeshire UK
| | - James L. N. Wood
- grid.5335.00000000121885934Disease Dynamics Unit, Department of Veterinary Medicine, University of Cambridge, Madingley Rd, Cambridge, Cambridgeshire UK
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7
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Ndolo VA, Redding D, Deka MA, Salzer JS, Vieira AR, Onyuth H, Ocaido M, Tweyongyere R, Azuba R, Monje F, Ario AR, Kabwama S, Kisaakye E, Bulage L, Kwesiga B, Ntono V, Harris J, Wood JLN, Conlan AJK. The potential distribution of Bacillus anthracis suitability across Uganda using INLA. Sci Rep 2022; 12:19967. [PMID: 36402889 PMCID: PMC9675733 DOI: 10.1038/s41598-022-24281-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Accepted: 11/14/2022] [Indexed: 11/21/2022] Open
Abstract
To reduce the veterinary, public health, environmental, and economic burden associated with anthrax outbreaks, it is vital to identify the spatial distribution of areas suitable for Bacillus anthracis, the causative agent of the disease. Bayesian approaches have previously been applied to estimate uncertainty around detected areas of B. anthracis suitability. However, conventional simulation-based techniques are often computationally demanding. To solve this computational problem, we use Integrated Nested Laplace Approximation (INLA) which can adjust for spatially structured random effects, to predict the suitability of B. anthracis across Uganda. We apply a Generalized Additive Model (GAM) within the INLA Bayesian framework to quantify the relationships between B. anthracis occurrence and the environment. We consolidate a national database of wildlife, livestock, and human anthrax case records across Uganda built across multiple sectors bridging human and animal partners using a One Health approach. The INLA framework successfully identified known areas of species suitability in Uganda, as well as suggested unknown hotspots across Northern, Eastern, and Central Uganda, which have not been previously identified by other niche models. The major risk factors for B. anthracis suitability were proximity to water bodies (0-0.3 km), increasing soil calcium (between 10 and 25 cmolc/kg), and elevation of 140-190 m. The sensitivity of the final model against the withheld evaluation dataset was 90% (181 out of 202 = 89.6%; rounded up to 90%). The prediction maps generated using this model can guide future anthrax prevention and surveillance plans by the relevant stakeholders in Uganda.
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Affiliation(s)
- V. A. Ndolo
- grid.5335.00000000121885934Disease Dynamics Unit, Department of Veterinary Medicine, University of Cambridge, Madingley Rd, Cambridge, Cambridgeshire UK
| | - D. Redding
- grid.83440.3b0000000121901201Centre for Biodiversity and Environment Research, Department of Genetics, Evolution and Environment, University College London, London, UK
| | - M. A. Deka
- grid.416738.f0000 0001 2163 0069US Centers for Disease Control and Prevention, 1600 Clifton Rd. NE, Atlanta, GA USA
| | - J. S. Salzer
- grid.416738.f0000 0001 2163 0069US Centers for Disease Control and Prevention, 1600 Clifton Rd. NE, Atlanta, GA USA
| | - A. R. Vieira
- grid.416738.f0000 0001 2163 0069US Centers for Disease Control and Prevention, 1600 Clifton Rd. NE, Atlanta, GA USA
| | - H. Onyuth
- grid.11194.3c0000 0004 0620 0548College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - M. Ocaido
- grid.11194.3c0000 0004 0620 0548College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - R. Tweyongyere
- grid.11194.3c0000 0004 0620 0548College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - R. Azuba
- grid.11194.3c0000 0004 0620 0548College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - F. Monje
- grid.415705.2Uganda National Institute of Public Health, Ministry of Health, Kampala, Uganda
| | - A. R. Ario
- grid.415705.2Uganda National Institute of Public Health, Ministry of Health, Kampala, Uganda
| | - S. Kabwama
- grid.415705.2Uganda National Institute of Public Health, Ministry of Health, Kampala, Uganda
| | - E. Kisaakye
- grid.415705.2Uganda National Institute of Public Health, Ministry of Health, Kampala, Uganda
| | - L. Bulage
- grid.415705.2Uganda National Institute of Public Health, Ministry of Health, Kampala, Uganda
| | - B. Kwesiga
- grid.415705.2Uganda National Institute of Public Health, Ministry of Health, Kampala, Uganda
| | - V. Ntono
- grid.415705.2Uganda National Institute of Public Health, Ministry of Health, Kampala, Uganda
| | - J. Harris
- grid.416738.f0000 0001 2163 0069US Centers for Disease Control and Prevention, 1600 Clifton Rd. NE, Atlanta, GA USA
| | - J. L. N. Wood
- grid.5335.00000000121885934Disease Dynamics Unit, Department of Veterinary Medicine, University of Cambridge, Madingley Rd, Cambridge, Cambridgeshire UK
| | - A. J. K. Conlan
- grid.5335.00000000121885934Disease Dynamics Unit, Department of Veterinary Medicine, University of Cambridge, Madingley Rd, Cambridge, Cambridgeshire UK
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Walker MA, Tan LM, Dang LH, Van Khang P, Ha HTT, Hung TTM, Dung HH, Anh DD, Duong TN, Hadfield T, Thai PQ, Blackburn JK. Spatiotemporal Patterns of Anthrax, Vietnam, 1990–2015. Emerg Infect Dis 2022; 28:2206-2213. [PMID: 36285873 PMCID: PMC9622238 DOI: 10.3201/eid2811.212584] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Anthrax is a priority zoonosis for control in Vietnam. The geographic distribution of anthrax remains to be defined, challenging our ability to target areas for control. We analyzed human anthrax cases in Vietnam to obtain anthrax incidence at the national and provincial level. Nationally, the trendline for cases remained at ≈61 cases/year throughout the 26 years of available data, indicating control efforts are not effectively reducing disease burden over time. Most anthrax cases occurred in the Northern Midlands and Mountainous regions, and the provinces of Lai Chau, Dien Bien, Lao Cai, Ha Giang, Cao Bang, and Son La experienced some of the highest incidence rates. Based on spatial Bayes smoothed maps, every region of Vietnam experienced human anthrax cases during the study period. Clarifying the distribution of anthrax in Vietnam will enable us to better identify risk areas for improved surveillance, rapid clinical care, and livestock vaccination campaigns.
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Deka MA, Vieira AR, Bower WA. Modelling the ecological niche of naturally occurring anthrax at global and circumpolar extents using an ensemble modelling framework. Transbound Emerg Dis 2022; 69:e2563-e2577. [PMID: 35590480 PMCID: PMC10961590 DOI: 10.1111/tbed.14602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 04/25/2022] [Accepted: 05/16/2022] [Indexed: 11/30/2022]
Abstract
Bacillus anthracis, the causative agent of anthrax, is a spore-forming bacterium that primarily affects herbivorous livestock, wildlife and humans exposed to direct contact with infected animal carcasses or products. To date, there are a limited number of studies that have delineated the potential global distribution of anthrax, despite the importance of the disease from both an economic and public health standpoint. This study compiled occurrence data (n = 874) of confirmed human and animal cases from 1954 to 2021 in 94 countries. Using an ensemble ecological niche model framework, we developed updated maps of the global predicted ecological suitability of anthrax to measure relative risk at multiple scales of analysis, including a model for circumpolar regions. Additionally, we produced maps quantifying the disease transmission risk associated with anthrax to cattle, sheep and goat populations. Environmental suitability for B. anthracis globally is concentred throughout Eurasia, sub-Saharan Africa, the Americas, Southeast Asia, Australia and Oceania. Suitable environments for B. anthracis at the circumpolar scale extend above the Arctic Circle into portions of Russia, Canada, Alaska and northern Scandinavia. Environmental factors driving B. anthracis suitability globally include vegetation, land surface temperature, soil characteristics, primary climate conditions and topography. At the circumpolar scale, suitability is influenced by soil factors, topography and the derived climate characteristics. The greatest risk to livestock is concentrated within the Indian subcontinent, Australia, Anatolia, the Caucasus region, Central Asia, the European Union, Argentina, Uruguay, China, the United States, Canada and East Africa. This study expands on previous work by providing enhanced knowledge of the potential spatial distribution of anthrax in the Southern Hemisphere, sub-Saharan Africa, Asia and circumpolar regions of the Northern Hemisphere. We conclude that these updated maps will provide pertinent information to guide disease control programs, inform policymakers and raise awareness at the global level to lessen morbidity and mortality among animals and humans located in environmentally suitable areas.
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Affiliation(s)
- Mark A Deka
- Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Antonio R Vieira
- Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - William A Bower
- Centers for Disease Control and Prevention, Atlanta, Georgia, USA
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Leveraging Machine Learning and Geo-Tagged Citizen Science Data to Disentangle the Factors of Avian Mortality Events at the Species Level. REMOTE SENSING 2022. [DOI: 10.3390/rs14102369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Abrupt environmental changes can affect the population structures of living species and cause habitat loss and fragmentations in the ecosystem. During August–October 2020, remarkably high mortality events of avian species were reported across the western and central United States, likely resulting from winter storms and wildfires. However, the differences of mortality events among various species responding to the abrupt environmental changes remain poorly understood. In this study, we focused on three species, Wilson’s Warbler, Barn Owl, and Common Murre, with the highest mortality events that had been recorded by citizen scientists. We leveraged the citizen science data and multiple remotely sensed earth observations and employed the ensemble random forest models to disentangle the species responses to winter storm and wildfire. We found that the mortality events of Wilson’s Warbler were primarily impacted by early winter storms, with more deaths identified in areas with a higher average daily snow cover. The Barn Owl’s mortalities were more identified in places with severe wildfire-induced air pollution. Both winter storms and wildfire had relatively mild effects on the mortality of Common Murre, which might be more related to anomalously warm water. Our findings highlight the species-specific responses to environmental changes, which can provide significant insights into the resilience of ecosystems to environmental change and avian conservations. Additionally, the study emphasized the efficiency and effectiveness of monitoring large-scale abrupt environmental changes and conservation using remotely sensed and citizen science data.
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Pittiglio C, Shadomy S, El Idrissi A, Soumare B, Lubroth J, Makonnen Y. Seasonality and Ecological Suitability Modelling for Anthrax (Bacillus anthracis) in Western Africa. Animals (Basel) 2022; 12:ani12091146. [PMID: 35565571 PMCID: PMC9105891 DOI: 10.3390/ani12091146] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 04/23/2022] [Accepted: 04/24/2022] [Indexed: 02/04/2023] Open
Abstract
Simple Summary Anthrax is a globally distributed, neglected, underreported, soil-borne zoonotic disease. In West Africa, the disease is hyper-endemic, severely affecting the livestock sector. Many challenges exist to control the disease in this region, particularly constraints on financial and human resources. Therefore, methods that can be utilized to improve reporting, guide and prioritize surveillance and control activities and rationalize the allocation of limited resources are crucial. In this study, we showed how to optimize the use of fragmented, heterogeneous and limited precise reporting data of anthrax in Burkina Faso, Ghana, Togo, Benin and Niger to understand risk periods as well as identify and predict risk areas. To achieve this, we used anthrax data from different databases in combination with environmental and climate variables and geospatial remote sensing techniques. Our study demonstrated that the number of anthrax outbreaks by month increase with the increasing monthly rates of change in precipitation and normalized difference vegetation index (NDVI) during the transition period from the dry to the wet season. Livestock density, precipitation, NDVI and alkaline soils were the main predictors of anthrax suitability in the region. Our findings on anthrax seasonality and ecological suitability can inform surveillance, prevention and control programs undertaken by animal and public health authorities and enhance collaborative One Health strategies. Abstract Anthrax is hyper-endemic in West Africa affecting wildlife, livestock and humans. Prediction is difficult due to the lack of accurate outbreak data. However, predicting the risk of infection is important for public health, wildlife conservation and livestock economies. In this study, the seasonality of anthrax outbreaks in West Africa was investigated using climate time series and ecological niche modeling to identify environmental factors related to anthrax occurrence, develop geospatial risk maps and identify seasonal patterns. Outbreak data in livestock, wildlife and humans between 2010 and 2018 were compiled from different sources and analyzed against monthly rates of change in precipitation, normalized difference vegetation index (NDVI) and land surface temperature. Maximum Entropy was used to predict and map the environmental suitability of anthrax occurrence. The findings showed that: (i) Anthrax outbreaks significantly (99%) increased with incremental changes in monthly precipitation and vegetation growth and decremental changes in monthly temperature during January–June. This explains the occurrence of the anthrax peak during the early wet season in West Africa. (ii) Livestock density, precipitation seasonality, NDVI and alkaline soils were the main predictors of anthrax suitability. (iii) Our approach optimized the use of limited and heterogeneous datasets and ecological niche modeling, demonstrating the value of integrated disease notification data and outbreak reports to generate risk maps. Our findings can inform public, animal and environmental health and enhance national and regional One Health disease control strategies.
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Affiliation(s)
- Claudia Pittiglio
- Food and Agriculture Organization of the United Nations, Animal Production and Health Division, Viale delle Terme di Caracalla, 00153 Rome, Italy;
- Correspondence:
| | - Sean Shadomy
- Food and Agriculture Organization of the United Nations, Joint FAO/WHO Centre (CODEX Food Standards and Zoonotic Diseases), Viale delle Terme di Caracalla, 00153 Rome, Italy; (S.S.); (A.E.I.)
- U.S. Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases, 1600 Clifton Rd NE, Mailstop H16-5, Atlanta, GA 30333, USA
| | - Ahmed El Idrissi
- Food and Agriculture Organization of the United Nations, Joint FAO/WHO Centre (CODEX Food Standards and Zoonotic Diseases), Viale delle Terme di Caracalla, 00153 Rome, Italy; (S.S.); (A.E.I.)
| | - Baba Soumare
- Food and Agriculture Organization of the United Nations, Animal Production and Health Division, Viale delle Terme di Caracalla, 00153 Rome, Italy;
| | - Juan Lubroth
- One Health Consultancies, 00153 Rome, Lazio, Italy;
| | - Yilma Makonnen
- Food and Agriculture Organization of the United Nations, Sub-Regional Office for Eastern Africa (SFE), CMC Road, Bole Sub City, Kebele 12/13, Addis Ababa P.O. Box 5536, Ethiopia;
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Obanda V, Otieno VA, Kingori EM, Ndeereh D, Lwande OW, Chiyo PI. Identifying Edaphic Factors and Normalized Difference Vegetation Index Metrics Driving Wildlife Mortality From Anthrax in Kenya’s Wildlife Areas. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.643334] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Anthrax, an acute disease of homeotherms caused by soil-borne Bacillus anthracis is implicated in dramatic declines in wildlife mainly in sub-Saharan Africa. Anthrax outbreaks are often localized in space and time. Therefore, understanding predictors of the spatial and temporal occurrence of anthrax in wildlife areas is useful in supporting early warning and improved response and targeting measures to reduce the impact of epizootic risk on populations. Spatial localization of anthrax is hypothesized to be driven by edaphic factors, while the temporal outbreaks are thought to be driven by extreme weather events including temperature, humidity, rainfall, and drought. Here, we test the role of select edaphic factors and normalized difference vegetation index (NDVI) metrics driven by vegetation structure and climate variability on the spatial and temporal patterns of wildlife mortality from anthrax in key wildlife areas in Kenya over a 20-year period, from 2000 to 2019. There was a positive association between the number of anthrax outbreaks and the total number of months anthrax was reported during the study period and the nitrogen and organic carbon content of the soil in each wildlife area. The monthly occurrence (timing) of anthrax in Lake Nakuru (with the most intense outbreaks) was positively related to the previous month’s spatial heterogeneity in NDVI and monthly NDVI deviation from 20-year monthly means. Generalized linear models revealed that the number of months anthrax was reported in a year (intensity) was positively related to spatial heterogeneity in NDVI, total organic carbon and cation exchange capacity of the soil. These results, examined in the light of experimental studies on anthrax persistence and amplification in the soil enlighten on mechanisms by which these factors are driving anthrax outbreaks and spatial localization.
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Blackburn JK, Kenu E, Asiedu-Bekoe F, Sarkodie B, Kracalik IT, Bower WA, Stoddard RA, Traxler RM. High Case-Fatality Rate for Human Anthrax, Northern Ghana, 2005-2016. Emerg Infect Dis 2021; 27:1216-1219. [PMID: 33754993 PMCID: PMC8007318 DOI: 10.3201/eid2704.204496] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The human cutaneous anthrax case-fatality rate is ≈1% when treated, 5%-20% when untreated. We report high case-fatality rates (median 35.0%; 95% CI 21.1%-66.7%) during 2005-2016 linked to livestock handling in northern Ghana, where veterinary resources are limited. Livestock vaccination and access to human treatment should be evaluated.
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Sushma B, Shedole S, Suresh KP, Leena G, Patil SS, Srikantha G. An Estimate of Global Anthrax Prevalence in Livestock: A Meta-analysis. Vet World 2021; 14:1263-1271. [PMID: 34220129 PMCID: PMC8243666 DOI: 10.14202/vetworld.2021.1263-1271] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 04/06/2021] [Indexed: 11/30/2022] Open
Abstract
Background and Aim: Anthrax, caused by the soil-borne spore-forming bacteria called Bacillus anthracis, is a zoonotic disease that persists worldwide in livestock and wildlife and infects humans. It is a great hazard to livestock; henceforth, evaluating the global concerns about the disease occurrence in livestock is essential. This study was conducted to estimate the global prevalence of anthrax and predict high-risk regions, which could be an input to veterinarians to take necessary steps to control and avoid the disease. Materials and Methods: A literature review was performed using online databases, namely, PubMed, Google Scholar, Scopus, Biomed Central, and Science Direct, to extract relevant publications worldwide between 1992 and 2020.</AQ9> Initially, 174 articles were selected, and after scrutinizing, 24 articles reporting the prevalence of anthrax were found to be adequate for the final meta-analysis. The statistical study was accompanied by employing fixed effects and random effects models using R. Results: The pooled prevalence of anthrax globally was 28% (95% confidence interval, 26-30%) from 2452 samples through the fixed effects model. Continent-wise subgroup analysis through the random effects model revealed that the pooled prevalence of anthrax was highest in Africa (29%) and least in North America (21%). Conclusion: In these publications, anthrax causes economic loss to farmers and, thus, to the world. Hence, controlling anthrax infections in high-risk regions are essential by implementing appropriate control measures to decrease the effect of the disease, thereby reducing economic loss.
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Affiliation(s)
- Bylaiah Sushma
- Department of Computer Science and Engineering, M S Ramaiah Institute of Technology, Matthikere, Bengaluru, Karnataka, India
| | - Seema Shedole
- Department of Computer Science and Engineering, M S Ramaiah Institute of Technology, Matthikere, Bengaluru, Karnataka, India
| | - Kuralayanapalya Puttahonnappa Suresh
- Spatial Epidemiology Laboratory, Indian Council of Agricultural Research (ICAR) National Institute of Veterinary Epidemiology and Disease Informatics (NIVEDI), Yelahanka, Bengaluru, Karnataka, India
| | - Gowda Leena
- Department of Veterinary Public Health and Epidemiology, Veterinary College, Hebbal, Bengaluru, Karnataka, India
| | - Sharanagouda S Patil
- Virology Laboratory, Indian Council of Agricultural Research (ICAR) - National Institute of Veterinary Epidemiology and Disease Informatics (NIVEDI), Yelahanka, Bengaluru, Karnataka, India
| | - Gowda Srikantha
- Spatial Epidemiology Laboratory, Indian Council of Agricultural Research (ICAR) National Institute of Veterinary Epidemiology and Disease Informatics (NIVEDI), Yelahanka, Bengaluru, Karnataka, India
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Otieno FT, Gachohi J, Gikuma-Njuru P, Kariuki P, Oyas H, Canfield SA, Bett B, Njenga MK, Blackburn JK. Modeling the Potential Future Distribution of Anthrax Outbreaks under Multiple Climate Change Scenarios for Kenya. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:4176. [PMID: 33920863 PMCID: PMC8103515 DOI: 10.3390/ijerph18084176] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 03/17/2021] [Accepted: 03/23/2021] [Indexed: 11/16/2022]
Abstract
The climate is changing, and such changes are projected to cause global increase in the prevalence and geographic ranges of infectious diseases such as anthrax. There is limited knowledge in the tropics with regards to expected impacts of climate change on anthrax outbreaks. We determined the future distribution of anthrax in Kenya with representative concentration pathways (RCP) 4.5 and 8.5 for year 2055. Ecological niche modelling (ENM) of boosted regression trees (BRT) was applied in predicting the potential geographic distribution of anthrax for current and future climatic conditions. The models were fitted with presence-only anthrax occurrences (n = 178) from historical archives (2011-2017), sporadic outbreak surveys (2017-2018), and active surveillance (2019-2020). The selected environmental variables in order of importance included rainfall of wettest month, mean precipitation (February, October, December, July), annual temperature range, temperature seasonality, length of longest dry season, potential evapotranspiration and slope. We found a general anthrax risk areal expansion i.e., current, 36,131 km2, RCP 4.5, 40,012 km2, and RCP 8.5, 39,835 km2. The distribution exhibited a northward shift from current to future. This prediction of the potential anthrax distribution under changing climates can inform anticipatory measures to mitigate future anthrax risk.
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Affiliation(s)
- Fredrick Tom Otieno
- Animal Health Program, International Livestock Research Institute, P.O. Box 30709 Nairobi 00100, Kenya;
- School of Environment, Water and Natural Resources, South Eastern Kenya University, P.O. Box 17, Kitui 90200, Kenya; (P.G.-N.); (P.K.)
| | - John Gachohi
- Paul Allen School for Global Health, Washington State University-Global Health Kenya, One Padmore Place, George Padmore Lane, P.O. Box 19676 Nairobi 00100, Kenya; (J.G.); (M.K.N.)
- School of Public Health, Jomo Kenyatta University of Agriculture and Technology, P.O. Box 62000, Nairobi 00200, Kenya
| | - Peter Gikuma-Njuru
- School of Environment, Water and Natural Resources, South Eastern Kenya University, P.O. Box 17, Kitui 90200, Kenya; (P.G.-N.); (P.K.)
| | - Patrick Kariuki
- School of Environment, Water and Natural Resources, South Eastern Kenya University, P.O. Box 17, Kitui 90200, Kenya; (P.G.-N.); (P.K.)
| | - Harry Oyas
- Veterinary Epidemiology and Economics Unit, Kenya Ministry of Agriculture, Livestock and Fisheries, P.O. Box 30028 Nairobi 00100, Kenya;
| | - Samuel A. Canfield
- Spatial Epidemiology and Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, FL 32611, USA; (S.A.C.); (J.K.B.)
- Emerging Pathogens Institute, University of Florida, 2055 Mowry Road, Gainesville, FL 32611, USA
| | - Bernard Bett
- Animal Health Program, International Livestock Research Institute, P.O. Box 30709 Nairobi 00100, Kenya;
| | - Moses Kariuki Njenga
- Paul Allen School for Global Health, Washington State University-Global Health Kenya, One Padmore Place, George Padmore Lane, P.O. Box 19676 Nairobi 00100, Kenya; (J.G.); (M.K.N.)
| | - Jason K. Blackburn
- Spatial Epidemiology and Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, FL 32611, USA; (S.A.C.); (J.K.B.)
- Emerging Pathogens Institute, University of Florida, 2055 Mowry Road, Gainesville, FL 32611, USA
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Campbell Z, Coleman P, Guest A, Kushwaha P, Ramuthivheli T, Osebe T, Perry B, Salt J. Prioritizing smallholder animal health needs in East Africa, West Africa, and South Asia using three approaches: Literature review, expert workshops, and practitioner surveys. Prev Vet Med 2021; 189:105279. [PMID: 33581421 PMCID: PMC8024747 DOI: 10.1016/j.prevetmed.2021.105279] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 12/18/2020] [Accepted: 01/18/2021] [Indexed: 12/15/2022]
Abstract
Managing the health needs of livestock contributes to reducing poverty and improving the livelihoods of smallholder and pastoralist livestock keepers globally. Animal health practitioners, producers, policymakers, and researchers all must prioritize how to mobilize limited resources. This study employed three approaches to prioritize animal health needs in East and West Africa and South Asia to identify diseases and syndromes that impact livestock keepers. The approaches were a) systematic literature review, b) a series of expert workshops, and c) a practitioner survey of veterinarians and para-veterinary professionals. The top constraints that emerged from all three approaches include endo/ ectoparasites, foot and mouth disease, brucellosis, peste des petits ruminants, Newcastle disease, and avian influenza. Expert workshops additionally identified contagious caprine pleuropneumonia, contagious bovine pleuropneumonia, mastitis, and reproductive disorders as constraints not emphasized in the literature review. Practitioner survey results additionally identified nutrition as a constraint for smallholder dairy and pastoralist small ruminant production. Experts attending the workshops agreed most constraints can be managed using existing veterinary technologies and best husbandry practices, which supports a shift away from focusing on individual diseases and new technologies towards addressing systemic challenges that limit access to veterinary services and inputs. Few research studies focused on incidence/ prevalence of disease and impact, suggesting better incorporation of socio-economic impact measures in future research would better represent the interests of livestock keepers.
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Affiliation(s)
- Zoë Campbell
- International Livestock Research Institute (ILRI), P.O. Box 30709, Nairobi, 00100, Kenya.
| | - Paul Coleman
- H20 Venture Partners, 33-35 George Street, Oxford, OX1 2AY, United Kingdom
| | - Andrea Guest
- H20 Venture Partners, 33-35 George Street, Oxford, OX1 2AY, United Kingdom
| | - Peetambar Kushwaha
- GALVmed Asia Office, Unit 118 & 120 B, Splendor Forum, Plot No 3, Jasola District Centre, Jasola, New Delhi, 110025, India
| | - Thembinkosi Ramuthivheli
- GALVmed Africa Office, International Livestock Research Institute (ILRI), Swing One, Naivasha Road, Nairobi, Kenya
| | - Tom Osebe
- GALVmed Africa Office, International Livestock Research Institute (ILRI), Swing One, Naivasha Road, Nairobi, Kenya
| | - Brian Perry
- Nuffield College of Clinical Medicine, University of Oxford, United Kingdom; College of Medicine and Veterinary Medicine, University of Edinburgh, Arthurstone House, Meigle, Blairgowrie, PH12 8QW, Scotland, United Kingdom
| | - Jeremy Salt
- GALVmed UK Office, Doherty Building, Pentlands Science Park, Bush Loan, Penicuik Edinburgh, EH26 0PZ, Scotland, United Kingdom
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Otieno FT, Gachohi J, Gikuma-Njuru P, Kariuki P, Oyas H, Canfield SA, Blackburn JK, Njenga MK, Bett B. Modeling the spatial distribution of anthrax in southern Kenya. PLoS Negl Trop Dis 2021; 15:e0009301. [PMID: 33780459 PMCID: PMC8032196 DOI: 10.1371/journal.pntd.0009301] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 04/08/2021] [Accepted: 03/08/2021] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Anthrax is an important zoonotic disease in Kenya associated with high animal and public health burden and widespread socio-economic impacts. The disease occurs in sporadic outbreaks that involve livestock, wildlife, and humans, but knowledge on factors that affect the geographic distribution of these outbreaks is limited, challenging public health intervention planning. METHODS Anthrax surveillance data reported in southern Kenya from 2011 to 2017 were modeled using a boosted regression trees (BRT) framework. An ensemble of 100 BRT experiments was developed using a variable set of 18 environmental covariates and 69 unique anthrax locations. Model performance was evaluated using AUC (area under the curve) ROC (receiver operating characteristics) curves. RESULTS Cattle density, rainfall of wettest month, soil clay content, soil pH, soil organic carbon, length of longest dry season, vegetation index, temperature seasonality, in order, were identified as key variables for predicting environmental suitability for anthrax in the region. BRTs performed well with a mean AUC of 0.8. Areas highly suitable for anthrax were predicted predominantly in the southwestern region around the shared Kenya-Tanzania border and a belt through the regions and highlands in central Kenya. These suitable regions extend westwards to cover large areas in western highlands and the western regions around Lake Victoria and bordering Uganda. The entire eastern and lower-eastern regions towards the coastal region were predicted to have lower suitability for anthrax. CONCLUSION These modeling efforts identified areas of anthrax suitability across southern Kenya, including high and medium agricultural potential regions and wildlife parks, important for tourism and foreign exchange. These predictions are useful for policy makers in designing targeted surveillance and/or control interventions in Kenya. We thank the staff of Directorate of Veterinary Services under the Ministry of Agriculture, Livestock and Fisheries, for collecting and providing the anthrax historical occurrence data.
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Affiliation(s)
- Fredrick Tom Otieno
- Animal Health Program, International Livestock Research Institute, Nairobi, Kenya
- Department of Environmental Science and Land Resources Management, School of Environment, Water and Natural Resources, South Eastern Kenya University, Kitui, Kenya
| | - John Gachohi
- Washington State University, Global Health Kenya, Nairobi, Kenya
- School of Public Health, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
| | - Peter Gikuma-Njuru
- Department of Environmental Science and Land Resources Management, School of Environment, Water and Natural Resources, South Eastern Kenya University, Kitui, Kenya
| | - Patrick Kariuki
- Department of Environmental Science and Land Resources Management, School of Environment, Water and Natural Resources, South Eastern Kenya University, Kitui, Kenya
| | - Harry Oyas
- Veterinary Epidemiology and Economics Unit, Kenya Ministry of Agriculture, livestock and Fisheries, Nairobi, Kenya
| | - Samuel A. Canfield
- Spatial Epidemiology and Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - Jason K. Blackburn
- Spatial Epidemiology and Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | | | - Bernard Bett
- Animal Health Program, International Livestock Research Institute, Nairobi, Kenya
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TaqMan Assays for Simultaneous Detection of Bacillus anthracis and Bacillus cereus biovar anthracis. Pathogens 2020; 9:pathogens9121074. [PMID: 33371332 PMCID: PMC7767396 DOI: 10.3390/pathogens9121074] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 12/12/2020] [Accepted: 12/16/2020] [Indexed: 11/22/2022] Open
Abstract
Anthrax is a worldwide zoonotic disease caused by the spore-forming bacterium Bacillus anthracis. Primarily a disease of herbivores, human infections often result from direct contact with contaminated animal products (cutaneous and inhalational anthrax) or through consumption of infected meat (gastrointestinal anthrax). The genetic near neighbor, Bacillus cereus biovar anthracis (Bcbva), causes an anthrax-like illness in the wildlife and livestock of west and central Africa due to the presence and expression of B. anthracis-specific virulence factors in this background. While Bcbva infections have not been reported in humans, a recent seroprevalence study detected Bcbva antibodies in the rural population around Taï National Park. This work describes the development of new TaqMan multiplex PCRs for the simultaneous detection of B. anthracis and Bcbva. The assays are designed to amplify Ba-1, capB, and lef markers in B. anthracis and genomic island IV (GI4), capB, and lef in Bcbva. Our assays allow for the rapid discrimination of B. anthracis and Bcbva and will provide insights into the molecular epidemiology of these two important pathogens that share an overlapping geographical range in west and central Africa.
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Norris MH, Kirpich A, Bluhm AP, Zincke D, Hadfield T, Ponciano JM, Blackburn JK. Convergent evolution of diverse Bacillus anthracis outbreak strains toward altered surface oligosaccharides that modulate anthrax pathogenesis. PLoS Biol 2020; 18:e3001052. [PMID: 33370274 PMCID: PMC7793302 DOI: 10.1371/journal.pbio.3001052] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 01/08/2021] [Accepted: 12/14/2020] [Indexed: 11/19/2022] Open
Abstract
Bacillus anthracis, a spore-forming gram-positive bacterium, causes anthrax. The external surface of the exosporium is coated with glycosylated proteins. The sugar additions are capped with the unique monosaccharide anthrose. The West African Group (WAG) B. anthracis have mutations rendering them anthrose deficient. Through genome sequencing, we identified 2 different large chromosomal deletions within the anthrose biosynthetic operon of B. anthracis strains from Chile and Poland. In silico analysis identified an anthrose-deficient strain in the anthrax outbreak among European heroin users. Anthrose-deficient strains are no longer restricted to West Africa so the role of anthrose in physiology and pathogenesis was investigated in B. anthracis Sterne. Loss of anthrose delayed spore germination and enhanced sporulation. Spores without anthrose were phagocytized at higher rates than spores with anthrose, indicating that anthrose may serve an antiphagocytic function on the spore surface. The anthrose mutant had half the LD50 and decreased time to death (TTD) of wild type and complement B. anthracis Sterne in the A/J mouse model. Following infection, anthrose mutant bacteria were more abundant in the spleen, indicating enhanced dissemination of Sterne anthrose mutant. At low sample sizes in the A/J mouse model, the mortality of ΔantC-infected mice challenged by intranasal or subcutaneous routes was 20% greater than wild type. Competitive index (CI) studies indicated that spores without anthrose disseminated to organs more extensively than a complemented mutant. Death process modeling using mouse mortality dynamics suggested that larger sample sizes would lead to significantly higher deaths in anthrose-negative infected animals. The model was tested by infecting Galleria mellonella with spores and confirmed the anthrose mutant was significantly more lethal. Vaccination studies in the A/J mouse model showed that the human vaccine protected against high-dose challenges of the nonencapsulated Sterne-based anthrose mutant. This work begins to identify the physiologic and pathogenic consequences of convergent anthrose mutations in B. anthracis.
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Affiliation(s)
- Michael H. Norris
- Spatial Epidemiology & Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - Alexander Kirpich
- Department of Population Health Services, Georgia State University, Atlanta, Georgia, United States of America
| | - Andrew P. Bluhm
- Spatial Epidemiology & Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - Diansy Zincke
- Spatial Epidemiology & Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - Ted Hadfield
- Spatial Epidemiology & Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - Jose Miguel Ponciano
- Department of Biology, University of Florida, Gainesville, Florida, United States of America
| | - Jason K. Blackburn
- Spatial Epidemiology & Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
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Walker MA, Uribasterra M, Asher V, Ponciano JM, Getz WM, Ryan SJ, Blackburn JK. Ungulate use of locally infectious zones in a re-emerging anthrax risk area. ROYAL SOCIETY OPEN SCIENCE 2020; 7:200246. [PMID: 33204443 PMCID: PMC7657905 DOI: 10.1098/rsos.200246] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 09/18/2020] [Indexed: 05/05/2023]
Abstract
Environmentally mediated indirect pathogen transmission is linked to host movement and foraging in areas where pathogens are maintained in the environment. In the case of anthrax, spores of the causative bacterium Bacillus anthracis are released into the environment following host death and create locally infectious zones (LIZs) around carcass sites; by grazing at LIZs, herbivores are potentially exposed to spores. Here, we used camera traps to assess how ungulate species use carcass sites in southwestern Montana and evaluated how these behaviours may promote indirect anthrax transmission, thus providing, to our knowledge, the first detailed documentation and study of the fine-scale mechanisms underlying foraging-based disease transmission in this ecosystem. We found that carcasses at LIZs significantly increased aboveground biomass of vegetation and concentrations of sodium and phosphorus, potentially making these sites more appealing to grazers. Host behavioural responses to LIZs varied depending on species, sex, season and carcass age; but, overall, our results demonstrated that carcasses or carcass sites serve as an attractant to herbivores in this system. Attraction to LIZs probably represents an increased risk of exposure to B. anthracis and, consequently, increased anthrax transmission rates. Accordingly, continued anthrax surveillance and control strategies are critical in this system.
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Affiliation(s)
- Morgan A. Walker
- Spatial Epidemiology and Ecology Research Laboratory, University of Florida, Gainesville, FL, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Maria Uribasterra
- Spatial Epidemiology and Ecology Research Laboratory, University of Florida, Gainesville, FL, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Valpa Asher
- Turner Enterprises Inc., 1123 Research Drive, Bozeman, MT, USA
| | | | - Wayne M. Getz
- Department of Environmental Sciences, Policy, and Management, University of California, Berkeley, 130 Mulford Hall, Berkeley, CA, USA
- School of Mathematical Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Sadie J. Ryan
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
- Quantitative Disease Ecology and Conservation Laboratory, Department of Geography, University of Florida, Gainesville, FL, USA
| | - Jason K. Blackburn
- Spatial Epidemiology and Ecology Research Laboratory, University of Florida, Gainesville, FL, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
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Assefa A, Bihon A, Tibebu A. Anthrax in the Amhara regional state of Ethiopia; spatiotemporal analysis and environmental suitability modeling with an ensemble approach. Prev Vet Med 2020; 184:105155. [PMID: 33002656 DOI: 10.1016/j.prevetmed.2020.105155] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 09/11/2020] [Accepted: 09/15/2020] [Indexed: 11/19/2022]
Abstract
Anthrax is one of the most neglected tropical disease affecting humans, livestock, and wildlife worldwide. The disease is caused by soil-borne spore-forming bacteria called Bacillus anthracis. A machine learning algorithm with the biomod2 package of R software was used to develop a predictive map for the Amhara regional state of Ethiopia. One hundred twenty-eight georeferenced confirmed outbreak reports of anthrax in livestock and 11 bioclimatic, eight soil characteristics, and three livestock density variables were used to train the model. The algorithm was set to run 3-fold with a total of 27 outputs for the nine selected models. An ensemble model was developed with ROC evaluation metrics set at 0.8. The ensemble model showed an improved performance than the individual models (KAPPA, TSS, and ROC values of 0.86, 0.93, and 0.99, respectively). Variables like annual precipitation (22.51 %), precipitation of warmest quarter (14.17 %), precipitation of wettest month (11.61 %), cattle density (9.67 %), sheep density (6.6 %), annual maximum temperature (6.17 %), altitude/elevation (5.24 %), and sand content (4.83 %) contributed the highest share in the ensemble model. The predicted suitable areas were primarily in the Central and Southern parts of the region. West Gojam and South Gondar zones were found highly suitable; while parts of Waghemira, North Wollo, and South Wollo were not significantly suitable. Besides, East Gojam, North Gondar, and Awi administrative zones were also reasonably suitable to Bacillus anthracis. The study can be used as a basis in the planning of prevention and control approaches of anthrax outbreaks in the region. Administrative zones like West Gojam, South Gondar, Awi, and East Gojam have to be prioritized as a risky-areas in the planning of preventive measures of anthrax in the region.
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Affiliation(s)
- Ayalew Assefa
- Sekota Dryland Agricultural Research Center, Sekota, Ethiopia.
| | - Amare Bihon
- Woldia University, School of Veterinary Medicine, Woldia, Ethiopia
| | - Abebe Tibebu
- Sekota Dryland Agricultural Research Center, Sekota, Ethiopia
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22
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Romero-Alvarez D, Peterson AT, Salzer JS, Pittiglio C, Shadomy S, Traxler R, Vieira AR, Bower WA, Walke H, Campbell LP. Potential distributions of Bacillus anthracis and Bacillus cereus biovar anthracis causing anthrax in Africa. PLoS Negl Trop Dis 2020; 14:e0008131. [PMID: 32150557 PMCID: PMC7082064 DOI: 10.1371/journal.pntd.0008131] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 03/19/2020] [Accepted: 02/11/2020] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Bacillus cereus biovar anthracis (Bcbva) is an emergent bacterium closely related to Bacillus anthracis, the etiological agent of anthrax. The latter has a worldwide distribution and usually causes infectious disease in mammals associated with savanna ecosystems. Bcbva was identified in humid tropical forests of Côte d'Ivoire in 2001. Here, we characterize the potential geographic distributions of Bcbva in West Africa and B. anthracis in sub-Saharan Africa using an ecological niche modeling approach. METHODOLOGY/PRINCIPAL FINDINGS Georeferenced occurrence data for B. anthracis and Bcbva were obtained from public data repositories and the scientific literature. Combinations of temperature, humidity, vegetation greenness, and soils values served as environmental variables in model calibrations. To predict the potential distribution of suitable environments for each pathogen across the study region, parameter values derived from the median of 10 replicates of the best-performing model for each pathogen were used. We found suitable environments predicted for B. anthracis across areas of confirmed and suspected anthrax activity in sub-Saharan Africa, including an east-west corridor from Ethiopia to Sierra Leone in the Sahel region and multiple areas in eastern, central, and southern Africa. The study area for Bcbva was restricted to West and Central Africa to reflect areas that have likely been accessible to Bcbva by dispersal. Model predicted values indicated potential suitable environments within humid forested environments. Background similarity tests in geographic space indicated statistical support to reject the null hypothesis of similarity when comparing environments associated with B. anthracis to those of Bcbva and when comparing humidity values and soils values individually. We failed to reject the null hypothesis of similarity when comparing environments associated with Bcbva to those of B. anthracis, suggesting that additional investigation is needed to provide a more robust characterization of the Bcbva niche. CONCLUSIONS/SIGNIFICANCE This study represents the first time that the environmental and geographic distribution of Bcbva has been mapped. We document likely differences in ecological niche-and consequently in geographic distribution-between Bcbva and typical B. anthracis, and areas of possible co-occurrence between the two. We provide information crucial to guiding and improving monitoring efforts focused on these pathogens.
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Affiliation(s)
- Daniel Romero-Alvarez
- Department of Ecology & Evolutionary Biology and Biodiversity Institute, University of Kansas, Lawrence, Kansas, United States of America
| | - A. Townsend Peterson
- Department of Ecology & Evolutionary Biology and Biodiversity Institute, University of Kansas, Lawrence, Kansas, United States of America
| | - Johanna S. Salzer
- Bacterial Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Claudia Pittiglio
- Food and Agriculture Organization of the United Nations, Animal Health Service, Animal Production and Health Division, Rome, Italy
| | - Sean Shadomy
- Food and Agriculture Organization of the United Nations, Animal Health Service, Animal Production and Health Division, Rome, Italy
- One Health Office, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Rita Traxler
- Bacterial Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Antonio R. Vieira
- Bacterial Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - William A. Bower
- Bacterial Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Henry Walke
- Bacterial Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Lindsay P. Campbell
- Florida Medical Entomology Laboratory, Department of Entomology and Nematology, IFAS | University of Florida, Vero Beach, Florida, United States of America
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Yang A, Mullins JC, Van Ert M, Bowen RA, Hadfield TL, Blackburn JK. Predicting the Geographic Distribution of the Bacillus anthracis A1.a/Western North American Sub-Lineage for the Continental United States: New Outbreaks, New Genotypes, and New Climate Data. Am J Trop Med Hyg 2020; 102:392-402. [PMID: 31802730 PMCID: PMC7008322 DOI: 10.4269/ajtmh.19-0191] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 10/23/2019] [Indexed: 11/07/2022] Open
Abstract
Bacillus anthracis, the causative pathogen of anthrax, is a spore-forming, environmentally maintained bacterium that continues to be a veterinary health problem with outbreaks occurring primarily in wildlife and livestock. Globally, the genetic populations of B. anthracis include multiple lineages, and each may have different ecological requirements and geographical distributions. It is, therefore, essential to identify environmental associations within lineages to predict geographical distributions and risk areas with improved accuracy. Here, we model the ecological niche and predict the geography of the most widespread sublineage of B. anthracis in the continental United States using updated MERRA-derived (Modern Era Retrospective analysis for Research and Applications; the NASA atmospheric data reanalysis of satellite information with multiple data products) bioclimate variables (i.e., MERRAclim data) and updated soil variables. We filter the occurrence data associated with the A1.a/Western North American sub-lineage of B. anthracis from historical anthrax outbreaks using the multiple-locus variable-number tandem repeat system. In addition, we also incorporate recent cases associated with B. anthracis A1.a sub-lineage from 2008 to 2012 in Montana, Colorado, and Texas. Our results provide the predicted distribution of the A1.a sub-lineage of B. anthracis for the United States with better predictive accuracy and higher spatial resolution than previous estimates. Our prediction serves as an improved disease risk map to better inform anthrax surveillance and control in the United States, particularly the Dakotas and Montana where this sub-lineage is persistent.
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Affiliation(s)
- Anni Yang
- Spatial Epidemiology & Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, Florida
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida
| | | | - Matthew Van Ert
- Spatial Epidemiology & Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, Florida
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida
| | - Richard A. Bowen
- Animal Reproduction and Biotechnology Laboratory, Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | - Ted L. Hadfield
- Spatial Epidemiology & Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, Florida
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida
| | - Jason K. Blackburn
- Spatial Epidemiology & Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, Florida
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida
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24
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Zincke D, Norris MH, Kurmanov B, Hadfield TL, Blackburn JK. Nucleotide polymorphism assay for the identification of west African group Bacillus anthracis: a lineage lacking anthrose. BMC Microbiol 2020; 20:6. [PMID: 31910798 PMCID: PMC6947953 DOI: 10.1186/s12866-019-1693-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 12/24/2019] [Indexed: 11/14/2022] Open
Abstract
Background The exosporium of the anthrax-causing Bacillus anthracis endospores display a tetrasaccharide composed of three rhamnose residues and an unusual sugar termed anthrose. Anthrose is a proposed potential target for immunotherapy and for specific detection of B. anthracis. Although originally thought to be ubiquitous in B. anthracis, previous work identified an anthrose negative strain from a West African lineage isolated from cattle that could represent a vaccine escape mutant. These strains carry genes required for expression of the anthrose operon but premature stop codons resulting from an 8-bp insertion in BAS3320 (an amino-transferase) and a C/T substitution at position 892 of the BAS3321 (a glycosyltransferase) gene prevent anthrose expression. Various other single nucleotide polymorphisms (SNPs) have been identified throughout the operon and could be the basis for detection of anthrose-deficient strains. Results In this study, we evaluated rhAmp genotypic assays based on SNPs at positions 892 and 1352 of BAS3321 for detection and differentiation of anthrose negative (Ant−) West African strains. Discrimination of anthrose negative West African isolates was achieved with as low as 100 fg of DNA, whereas consistent genotyping of Sterne necessitated at least 1 pg of DNA. Conclusions Screening of a global panel of B. anthracis isolates showed anthrose-expressing alleles are prevalent worldwide whereas the anthrose-deficient phenotype is to date limited to West Africa. Our work also revealed a third, previously unreported anthrose genotype in which the operon is altogether missing from a Polish B. anthracis isolate.
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Affiliation(s)
- Diansy Zincke
- Spatial Epidemiology & Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, FL, USA.,Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Michael H Norris
- Spatial Epidemiology & Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, FL, USA.,Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Berzhan Kurmanov
- Spatial Epidemiology & Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, FL, USA.,Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Ted L Hadfield
- Spatial Epidemiology & Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, FL, USA.,Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Jason K Blackburn
- Spatial Epidemiology & Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, FL, USA. .,Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA.
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25
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Linking Geospatial and Laboratory Sciences to Define Mechanisms behind Landscape Level Drivers of Anthrax Outbreaks. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16193747. [PMID: 31590291 PMCID: PMC6801504 DOI: 10.3390/ijerph16193747] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 09/27/2019] [Accepted: 10/01/2019] [Indexed: 11/16/2022]
Abstract
Background: A seasonal predictor of anthrax outbreaks is rainfall, which may be approximated by NDVI using remote sensing. How rainfall or vegetative green-up influences bacterial physiology or microecology to drive anthrax outbreaks is not known. Methods: Rainfall and NDVI dependency of anthrax epizootics was demonstrated with global and local phenological analysis. Growth analysis of B. anthracis in response to pH and calcium gradients was carried out. The influence of pH and calcium levels on expression of toxin and sporulation related proteins in broth culture models was characterized using engineered B. anthracis luminescent reporter strains. Results: Short-term bacterial growth and longer-term bacterial survival were altered by pH and calcium. These conditions also played a major role in pagA and sspB promoter-driven luminescent expression in B. anthracis. Conclusions: Rainfall induced cycling of pH and calcium in soils plays a plausible role in amplifying spore load and persistence in endemic anthrax zones. Observed evidence of B. anthracis favoring soil alkalinity and high soil calcium levels in the environment were linked to physiological conditions that promote bacterial growth, survival, toxin secretion and spore formation; illustrating the utility of bringing laboratory-based (controlled) microbiology experiments into the fold of zoonotic disease ecology.
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Muturi M, Gachohi J, Mwatondo A, Lekolool I, Gakuya F, Bett A, Osoro E, Bitek A, Thumbi SM, Munyua P, Oyas H, Njagi ON, Bett B, Njenga MK. Recurrent Anthrax Outbreaks in Humans, Livestock, and Wildlife in the Same Locality, Kenya, 2014-2017. Am J Trop Med Hyg 2019; 99:833-839. [PMID: 30105965 PMCID: PMC6159598 DOI: 10.4269/ajtmh.18-0224] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Epidemiologic data indicate a global distribution of anthrax outbreaks associated with certain ecosystems that promote survival and viability of Bacillus anthracis spores. Here, we characterized three anthrax outbreaks involving humans, livestock, and wildlife that occurred in the same locality in Kenya between 2014 and 2017. Clinical and epidemiologic data on the outbreaks were collected using active case finding and review of human, livestock, and wildlife health records. Information on temporal and spatial distribution of prior outbreaks in the area was collected using participatory epidemiology. The 2014-2017 outbreaks in Nakuru West subcounty affected 15 of 71 people who had contact with infected cattle (attack rate = 21.1%), including seven with gastrointestinal, six with cutaneous, and two with oropharyngeal forms of the disease. Two (13.3%) gastrointestinal human anthrax cases died. No human cases were associated with infected wildlife. Of the 54 cattle owned in 11 households affected, 20 died (attack rate = 37%). The 2015 outbreak resulted in death of 10.5% of the affected herbivorous wildlife at Lake Nakuru National Park, including 745 of 4,500 African buffaloes (species-specific mortality rate = 17%) and three of 18 endangered white rhinos (species-specific mortality rate = 16%). The species mortality rate ranged from 1% to 5% for the other affected wildlife species. Participatory epidemiology identified prior outbreaks between 1973 and 2011 in the same area. The frequency and severity of outbreaks in this area suggests that it is an anthrax hotspot ideal for investigating risk factors associated with long-term survival of anthrax spores and outbreak occurrence.
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Affiliation(s)
| | - John Gachohi
- Washington State University Global Health Program-Kenya, Washington State University, Pullman, Washington
| | | | | | | | | | - Eric Osoro
- Washington State University Global Health Program-Kenya, Washington State University, Pullman, Washington
| | - Austine Bitek
- Food and Agriculture Organization of the United Nations, Nairobi, Kenya
| | - S Mwangi Thumbi
- Washington State University Global Health Program-Kenya, Washington State University, Pullman, Washington
| | - Peninah Munyua
- Division of Global Health Protection, United States Centers for Disease Control and Prevention, Nairobi, Kenya
| | - Harry Oyas
- Kenya Directorate of Veterinary Services, Nairobi, Kenya
| | | | - Bernard Bett
- International Livestock Research Institute, Nairobi, Kenya
| | - M Kariuki Njenga
- Washington State University Global Health Program-Kenya, Washington State University, Pullman, Washington
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27
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Carlson CJ, Kracalik IT, Ross N, Alexander KA, Hugh-Jones ME, Fegan M, Elkin BT, Epp T, Shury TK, Zhang W, Bagirova M, Getz WM, Blackburn JK. The global distribution of Bacillus anthracis and associated anthrax risk to humans, livestock and wildlife. Nat Microbiol 2019; 4:1337-1343. [PMID: 31086311 DOI: 10.1038/s41564-019-0435-4] [Citation(s) in RCA: 124] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 03/22/2019] [Indexed: 01/25/2023]
Abstract
Bacillus anthracis is a spore-forming, Gram-positive bacterium responsible for anthrax, an acute infection that most significantly affects grazing livestock and wild ungulates, but also poses a threat to human health. The geographic extent of B. anthracis is poorly understood, despite multi-decade research on anthrax epizootic and epidemic dynamics; many countries have limited or inadequate surveillance systems, even within known endemic regions. Here, we compile a global occurrence dataset of human, livestock and wildlife anthrax outbreaks. With these records, we use boosted regression trees to produce a map of the global distribution of B. anthracis as a proxy for anthrax risk. We estimate that 1.83 billion people (95% credible interval (CI): 0.59-4.16 billion) live within regions of anthrax risk, but most of that population faces little occupational exposure. More informatively, a global total of 63.8 million poor livestock keepers (95% CI: 17.5-168.6 million) and 1.1 billion livestock (95% CI: 0.4-2.3 billion) live within vulnerable regions. Human and livestock vulnerability are both concentrated in rural rainfed systems throughout arid and temperate land across Eurasia, Africa and North America. We conclude by mapping where anthrax risk could disrupt sensitive conservation efforts for wild ungulates that coincide with anthrax-prone landscapes.
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Affiliation(s)
- Colin J Carlson
- National Socio-Environmental Synthesis Center, University of Maryland, Annapolis, MD, USA.,Department of Biology, Georgetown University, Washington, Washington DC, USA
| | - Ian T Kracalik
- Spatial Epidemiology & Ecology Research Lab, Department of Geography, University of Florida, Gainesville, FL, USA.,Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Noam Ross
- EcoHealth Alliance, New York, NY, USA
| | - Kathleen A Alexander
- Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VA, USA
| | - Martin E Hugh-Jones
- School of the Coast and Environment, Louisiana State University, Baton Rouge, LA, USA
| | - Mark Fegan
- AgriBio, Centre for Agribiosciences, Biosciences Research, Department of Economic Development, Jobs, Transport and Resources, Bundoora, Victoria, Australia
| | - Brett T Elkin
- Department of Environment and Natural Resources, Government of the Northwest Territories, Yellowknife, Northwest Territories, Canada
| | - Tasha Epp
- Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Todd K Shury
- Parks Canada Agency, Saskatoon, Saskatchewan, Canada
| | - Wenyi Zhang
- Center for Disease Surveillance & Research, Institute of Disease Control and Prevention of PLA, Beijing, China
| | | | - Wayne M Getz
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, CA, USA
| | - Jason K Blackburn
- Spatial Epidemiology & Ecology Research Lab, Department of Geography, University of Florida, Gainesville, FL, USA. .,Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA.
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Rao S, Traxler R, Napetavaridze T, Asanishvili Z, Rukhadze K, Maghlakelidze G, Geleishvili M, Broladze M, Kokhreidze M, Reynolds D, Shadomy S, Salman M. Risk factors associated with the occurrence of anthrax outbreaks in livestock in the country of Georgia: A case-control investigation 2013-2015. PLoS One 2019; 14:e0215228. [PMID: 31048838 PMCID: PMC6497231 DOI: 10.1371/journal.pone.0215228] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 03/28/2019] [Indexed: 12/01/2022] Open
Abstract
Introduction Anthrax is considered endemic in livestock in Georgia. In 2007, the annual vaccination became the responsibility of livestock owners, while contracting of private veterinarians was not officially required. Six years later, due to increase in human outbreaks associated with livestock handling, there is a need to find out the risk factors of livestock anthrax in Georgia. Objective To identify exposures and risk factors associated with livestock anthrax. Methods A matched case-control study design was used to recruit the owners of individual livestock anthrax cases that occurred between June 2013 and May 2015, and owners of unaffected livestock from within (“village control”) and outside the village (“area control”). We collected data about the case and control livestock animals’ exposure and risk factors within the one-month prior to the disease onset of the case livestock (or matched case for the controls). We used logistic regression analysis (univariate and multivariable) to calculate the odds ratios of exposures and risk factors. Results During the study period, 36 anthrax cases met the case definition and were enrolled in the study; 67 matched village control livestock and 71 matched area control livestock were also enrolled. The findings from multivariable logistic regression analysis demonstrate that vaccination within the last two years significantly reduced the odds of anthrax in cattle (OR = 0.014; 95% Confidence interval = <0.001, 0.99). The other factors that were significantly protective against anthrax were ‘animals being in covered fence area/barn’ (OR = 0.065; p-value = 0.036), and ‘female animal being pregnant or milking compared to heifer’ (OR = 0.006; p-value = 0.037). Conclusions The information obtained from this study has involved and been presented to decision makers, used to build technical capacity of veterinary staff, and to foster a One Health approach to the control of zoonotic diseases which will optimize prevention and control strategies. Georgia has embedded the knowledge and specific evidence that vaccination is a highly protective measure to prevent anthrax deaths among livestock, to which primary emphasis of the anthrax control program will be given. Education of livestock keepers in Georgia is an overriding priority.
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Affiliation(s)
- Sangeeta Rao
- Department of Clinical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
- * E-mail:
| | - Rita Traxler
- Centers for Disease Control and Prevention (CDC), Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases (NCEZID), Atlanta, Georgia, United States of America
| | - Tsira Napetavaridze
- National Food Agency (NFA) of Ministry of Environmental Protection and Agriculture of Georgia (MEPA), Tbilisi, Georgia
| | - Zviad Asanishvili
- National Food Agency (NFA) of Ministry of Environmental Protection and Agriculture of Georgia (MEPA), Tbilisi, Georgia
| | - Ketevan Rukhadze
- Department of Rural Development and Vocational Education (DRDVE) of Georgian Institute of Public Affairs (GIPA), Tbilisi, Georgia
| | | | | | - Mariam Broladze
- National Center for Disease Control and Prevention, Tbilisi, Georgia
| | - Maka Kokhreidze
- Laboratory of the Ministry of Agriculture (LMA), Tbilisi, Georgia
| | - Debby Reynolds
- Department of Clinical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Sean Shadomy
- CDC One Health Office, NCEZID, Atlanta, Georgia, United States of America
| | - Mo Salman
- Department of Clinical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
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Sloyer KE, Burkett-Cadena ND, Yang A, Corn JL, Vigil SL, McGregor BL, Wisely SM, Blackburn JK. Ecological niche modeling the potential geographic distribution of four Culicoides species of veterinary significance in Florida, USA. PLoS One 2019; 14:e0206648. [PMID: 30768605 PMCID: PMC6377124 DOI: 10.1371/journal.pone.0206648] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 02/06/2019] [Indexed: 11/19/2022] Open
Abstract
Epizootic hemorrhagic disease (EHD) is a viral arthropod-borne disease affecting wild and domestic ruminants, caused by infection with epizootic hemorrhagic disease virus (EHDV). EHDV is transmitted to vertebrate animal hosts by biting midges in the genus Culicoides Latreille (Diptera: Ceratopogonidae). Culicoides sonorensis Wirth and Jones is the only confirmed vector of EHDV in the United States but is considered rare in Florida and not sufficiently abundant to support EHDV transmission. This study used ecological niche modeling to map the potential geographical distributions and associated ecological variable space of four Culicoides species suspected of transmitting EHDV in Florida, including Culicoides insignis Lutz, Culicoides stellifer (Coquillett), Culicoides debilipalpis Hoffman and Culicoides venustus Lutz. Models were developed with the Genetic Algorithm for Rule Set Production in DesktopGARP v1.1.3 using species occurrence data from field sampling along with environmental variables from WorldClim and Trypanosomiasis and Land use in Africa. For three Culicoides species (C. insignis, C. stellifer and C. debilipalpis) 96-98% of the presence points were predicted across the Florida landscape (63.8% - 72.5%). For C. venustus, models predicted 98.00% of presence points across 27.4% of Florida. Geographic variations were detected between species. Culicoides insignis was predicted to be restricted to peninsular Florida, and in contrast, C. venustus was predicted to be primarily in north Florida and the panhandle region. Culicoides stellifer and C. debilipalpis were predicted nearly statewide. Environmental conditions also differed by species, with some species' ranges predicted by more narrow ranges of variables than others. The Normalized Difference Vegetation Index (NDVI) was a major predictor of C. venustus and C. insignis presence. For C. stellifer, Land Surface Temperature, Middle Infrared were the most limiting predictors of presence. The limiting variables for C. debilipalpis were NDVI Bi-Annual Amplitude and NDVI Annual Amplitude at 22.5% and 28.1%, respectively. The model outputs, including maps and environmental variable range predictions generated from these experiments provide an important first pass at predicting species of veterinary importance in Florida. Because EHDV cannot exist in the environment without the vector, model outputs can be used to estimate the potential risk of disease for animal hosts across Florida. Results also provide distribution and habitat information useful for integrated pest management practices.
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Affiliation(s)
- Kristin E. Sloyer
- Florida Medical Entomology Laboratory, University of Florida, Vero Beach, Florida, United States of America
| | - Nathan D. Burkett-Cadena
- Florida Medical Entomology Laboratory, University of Florida, Vero Beach, Florida, United States of America
| | - Anni Yang
- Spatial Epidemiology and Ecology Research Laboratory, Geography Department, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - Joseph L. Corn
- Southeastern Cooperative Wildlife Disease Study, University of Georgia, Athens, Georgia, United States of America
| | - Stacey L. Vigil
- Southeastern Cooperative Wildlife Disease Study, University of Georgia, Athens, Georgia, United States of America
| | - Bethany L. McGregor
- Florida Medical Entomology Laboratory, University of Florida, Vero Beach, Florida, United States of America
| | - Samantha M. Wisely
- Department of Wildlife, Ecology and Conservation, University of Florida, Gainesville, Florida, United States of America
| | - Jason K. Blackburn
- Spatial Epidemiology and Ecology Research Laboratory, Geography Department, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
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Mwakapeje ER, Ndimuligo SA, Mosomtai G, Ayebare S, Nyakarahuka L, Nonga HE, Mdegela RH, Skjerve E. Ecological niche modeling as a tool for prediction of the potential geographic distribution of Bacillus anthracis spores in Tanzania. Int J Infect Dis 2019; 79:142-151. [DOI: 10.1016/j.ijid.2018.11.367] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 11/24/2018] [Accepted: 11/27/2018] [Indexed: 01/06/2023] Open
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Lepheana RJ, Oguttu JW, Qekwana DN. Temporal patterns of anthrax outbreaks among livestock in Lesotho, 2005-2016. PLoS One 2018; 13:e0204758. [PMID: 30356323 PMCID: PMC6200195 DOI: 10.1371/journal.pone.0204758] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 09/13/2018] [Indexed: 11/22/2022] Open
Abstract
Background Although 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. Methods Secondary 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. Results A 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. Conclusion The 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.
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Affiliation(s)
- Relebohile Juliet Lepheana
- Section Veterinary Public Health, Department of Paraclinical Science, Faculty of Veterinary Sciences, University of Pretoria, Pretoria, South Africa
| | - James Wabwire Oguttu
- Department of Agriculture and Animal Health, College of Agriculture and Environmental Sciences, University of South Africa, Florida Science Campus, Johannesburg, South Africa
| | - Daniel Nenene Qekwana
- Section Veterinary Public Health, Department of Paraclinical Science, Faculty of Veterinary Sciences, University of Pretoria, Pretoria, South Africa
- * E-mail:
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Vieira AR, Salzer JS, Traxler RM, Hendricks KA, Kadzik ME, Marston CK, Kolton CB, Stoddard RA, Hoffmaster AR, Bower WA, Walke HT. Enhancing Surveillance and Diagnostics in Anthrax-Endemic Countries. Emerg Infect Dis 2018; 23. [PMID: 29155651 PMCID: PMC5711320 DOI: 10.3201/eid2313.170431] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Naturally occurring anthrax disproportionately affects the health and economic welfare of poor, rural communities in anthrax-endemic countries. However, many of these countries have limited anthrax prevention and control programs. Effective prevention of anthrax outbreaks among humans is accomplished through routine livestock vaccination programs and prompt response to animal outbreaks. The Centers for Disease Control and Prevention uses a 2-phase framework when providing technical assistance to partners in anthrax-endemic countries. The first phase assesses and identifies areas for improvement in existing human and animal surveillance, laboratory diagnostics, and outbreak response. The second phase provides steps to implement improvements to these areas. We describe examples of implementing this framework in anthrax-endemic countries. These activities are at varying stages of completion; however, the public health impact of these initiatives has been encouraging. The anthrax framework can be extended to other zoonotic diseases to build on these efforts, improve human and animal health, and enhance global health security.
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Abstract
During emerging disease outbreaks, public health, emergency management officials and decision-makers increasingly rely on epidemiological models to forecast outbreak progression and determine the best response to health crisis needs. Outbreak response strategies derived from such modelling may include pharmaceutical distribution, immunisation campaigns, social distancing, prophylactic pharmaceuticals, medical care, bed surge, security and other requirements. Infectious disease modelling estimates are unavoidably subject to multiple interpretations, and full understanding of a model's limitations may be lost when provided from the disease modeller to public health practitioner to government policymaker. We review epidemiological models created for diseases which are of greatest concern for public health protection. Such diseases, whether transmitted from person-to-person (Ebola, influenza, smallpox), via direct exposure (anthrax), or food and waterborne exposure (cholera, typhoid) may cause severe illness and death in a large population. We examine disease-specific models to determine best practices characterising infectious disease outbreaks and facilitating emergency response and implementation of public health policy and disease control measures.
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Carlson CJ, Getz WM, Kausrud KL, Cizauskas CA, Blackburn JK, Bustos Carrillo FA, Colwell R, Easterday WR, Ganz HH, Kamath PL, Økstad OA, Turner WC, Kolstø AB, Stenseth NC. Spores and soil from six sides: interdisciplinarity and the environmental biology of anthrax (Bacillus anthracis). Biol Rev Camb Philos Soc 2018; 93:1813-1831. [PMID: 29732670 DOI: 10.1111/brv.12420] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Revised: 03/27/2018] [Accepted: 04/03/2018] [Indexed: 12/11/2022]
Abstract
Environmentally transmitted diseases are comparatively poorly understood and managed, and their ecology is particularly understudied. Here we identify challenges of studying environmental transmission and persistence with a six-sided interdisciplinary review of the biology of anthrax (Bacillus anthracis). Anthrax is a zoonotic disease capable of maintaining infectious spore banks in soil for decades (or even potentially centuries), and the mechanisms of its environmental persistence have been the topic of significant research and controversy. Where anthrax is endemic, it plays an important ecological role, shaping the dynamics of entire herbivore communities. The complex eco-epidemiology of anthrax, and the mysterious biology of Bacillus anthracis during its environmental stage, have necessitated an interdisciplinary approach to pathogen research. Here, we illustrate different disciplinary perspectives through key advances made by researchers working in Etosha National Park, a long-term ecological research site in Namibia that has exemplified the complexities of the enzootic process of anthrax over decades of surveillance. In Etosha, the role of scavengers and alternative routes (waterborne transmission and flies) has proved unimportant relative to the long-term persistence of anthrax spores in soil and their infection of herbivore hosts. Carcass deposition facilitates green-ups of vegetation to attract herbivores, potentially facilitated by the role of anthrax spores in the rhizosphere. The underlying seasonal pattern of vegetation, and herbivores' immune and behavioural responses to anthrax risk, interact to produce regular 'anthrax seasons' that appear to be a stable feature of the Etosha ecosystem. Through the lens of microbiologists, geneticists, immunologists, ecologists, epidemiologists, and clinicians, we discuss how anthrax dynamics are shaped at the smallest scale by population genetics and interactions within the bacterial communities up to the broadest scales of ecosystem structure. We illustrate the benefits and challenges of this interdisciplinary approach to disease ecology, and suggest ways anthrax might offer insights into the biology of other important pathogens. Bacillus anthracis, and the more recently emerged Bacillus cereus biovar anthracis, share key features with other environmentally transmitted pathogens, including several zoonoses and panzootics of special interest for global health and conservation efforts. Understanding the dynamics of anthrax, and developing interdisciplinary research programs that explore environmental persistence, is a critical step forward for understanding these emerging threats.
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Affiliation(s)
- Colin J Carlson
- National Socio-Environmental Synthesis Center (SESYNC), University of Maryland, Annapolis, MD 21401, U.S.A.,Department of Biology, Georgetown University, Washington, DC 20057, U.S.A
| | - Wayne M Getz
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA 94720, U.S.A.,School of Mathematical Sciences, University of KwaZulu-Natal, PB X 54001, Durban 4000, South Africa
| | - Kyrre L Kausrud
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, PO Box 1066 Blindern, N-0316, Oslo, Norway
| | - Carrie A Cizauskas
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA 94720, U.S.A
| | - Jason K Blackburn
- Spatial Epidemiology & Ecology Research Lab, Department of Geography, University of Florida, Gainesville, FL 32611, U.S.A.,Emerging Pathogens Institute, University of Florida, Gainesville, FL, U.S.A
| | - Fausto A Bustos Carrillo
- Department of Epidemiology & Department of Biostatistics, School of Public Health, University of California, Berkeley, CA 94720-7360, U.S.A
| | - Rita Colwell
- CosmosID Inc., Rockville, MD 20850, U.S.A.,Center for Bioinformatics and Computational Biology, University of Maryland Institute for Advanced Computer Studies, University of Maryland, College Park, MD 20742, U.S.A.,Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, U.S.A
| | - W Ryan Easterday
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, PO Box 1066 Blindern, N-0316, Oslo, Norway
| | - Holly H Ganz
- UC Davis Genome Center, University of California, Davis, CA 95616, U.S.A
| | - Pauline L Kamath
- School of Food and Agriculture, University of Maine, Orono, ME 04469, U.S.A
| | - Ole A Økstad
- Centre for Integrative Microbial Evolution and Section for Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, PO Box 1068 Blindern, N-0316, Oslo, Norway
| | - Wendy C Turner
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12222, U.S.A
| | - Anne-Brit Kolstø
- Centre for Integrative Microbial Evolution and Section for Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, PO Box 1068 Blindern, N-0316, Oslo, Norway
| | - Nils C Stenseth
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, PO Box 1066 Blindern, N-0316, Oslo, Norway
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Carlson CJ, Dougherty E, Boots M, Getz W, Ryan SJ. Consensus and conflict among ecological forecasts of Zika virus outbreaks in the United States. Sci Rep 2018; 8:4921. [PMID: 29563545 PMCID: PMC5862882 DOI: 10.1038/s41598-018-22989-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 03/02/2018] [Indexed: 12/11/2022] Open
Abstract
Ecologists are increasingly involved in the pandemic prediction process. In the course of the Zika outbreak in the Americas, several ecological models were developed to forecast the potential global distribution of the disease. Conflicting results produced by alternative methods are unresolved, hindering the development of appropriate public health forecasts. We compare ecological niche models and experimentally-driven mechanistic forecasts for Zika transmission in the continental United States. We use generic and uninformed stochastic county-level simulations to demonstrate the downstream epidemiological consequences of conflict among ecological models, and show how assumptions and parameterization in the ecological and epidemiological models propagate uncertainty and produce downstream model conflict. We conclude by proposing a basic consensus method that could resolve conflicting models of potential outbreak geography and seasonality. Our results illustrate the usually-undocumented margin of uncertainty that could emerge from using any one of these predictions without reservation or qualification. In the short term, ecologists face the task of developing better post hoc consensus that accurately forecasts spatial patterns of Zika virus outbreaks. Ultimately, methods are needed that bridge the gap between ecological and epidemiological approaches to predicting transmission and realistically capture both outbreak size and geography.
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Affiliation(s)
- Colin J Carlson
- National Socio-Environmental Synthesis Center, University of Maryland, Annapolis, MD, 21401, USA.
- Department of Biology, Georgetown University, Washington, DC, 20057, USA.
| | - Eric Dougherty
- Department of Environmental Science, Policy and Management, University of California Berkeley, Berkeley, CA, 94720-3112, USA
| | - Mike Boots
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA, 94720-3112, USA
| | - Wayne Getz
- Department of Environmental Science, Policy and Management, University of California Berkeley, Berkeley, CA, 94720-3112, USA
- Schools of Mathematical Sciences, University of KwaZulu, Natal, South Africa
| | - Sadie J Ryan
- Schools of Life Sciences, University of KwaZulu, Natal, South Africa
- Department of Geography, University of Florida, Gainesville, FL, 32601, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, 32610, USA
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