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Subedi D, Pantha S, Jyoti S, Gautam B, Kaphle K, Yadav RK, Ghimire S, Dhakal S. Anthrax in Humans, Animals, and the Environment and the One Health Strategies for Anthrax Control. Pathogens 2024; 13:773. [PMID: 39338965 PMCID: PMC11435069 DOI: 10.3390/pathogens13090773] [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: 07/29/2024] [Revised: 08/30/2024] [Accepted: 09/04/2024] [Indexed: 09/30/2024] Open
Abstract
Anthrax is a notorious disease of public health importance caused by Bacillus anthracis. The causative agent can also be used as a biological weapon. Spores of these bacteria can sustain extreme environmental conditions and remain viable in soil for decades. Domestic and wild ruminants are highly susceptible to this pathogen, which usually presents as a peracute to acute disease. In humans, cutaneous anthrax is frequent but pulmonary and enteric anthrax are more serious. Humans, animals, and the environment are all involved, making anthrax a perfect target for a One Health approach. The environment plays a key role in disease transmission. At a time when the One Health concept is not mere slogans, collaborative efforts of medical professionals, veterinarians, and environmental scientists will be valuable for the prevention and control of this disease. In this review, we discussed the transmission dynamics of anthrax in the environment, animals, and humans, as well as One Health strategies to control and prevent anthrax.
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Affiliation(s)
- Deepak Subedi
- Paklihawa Campus, Institute of Agriculture and Animal Science (IAAS), Tribhuvan University, Siddarthanagar 32900, Nepal
- Department of Poultry Science, University of Georgia, Athens, GA 30602, USA
| | - Saurav Pantha
- Paklihawa Campus, Institute of Agriculture and Animal Science (IAAS), Tribhuvan University, Siddarthanagar 32900, Nepal
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, 1800 Denison Avenue, Manhattan, KS 66506, USA
| | - Sumit Jyoti
- Paklihawa Campus, Institute of Agriculture and Animal Science (IAAS), Tribhuvan University, Siddarthanagar 32900, Nepal
- Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, PE C1A 4P3, Canada
| | - Bickal Gautam
- Paklihawa Campus, Institute of Agriculture and Animal Science (IAAS), Tribhuvan University, Siddarthanagar 32900, Nepal
| | - Krishna Kaphle
- Paklihawa Campus, Institute of Agriculture and Animal Science (IAAS), Tribhuvan University, Siddarthanagar 32900, Nepal
| | - Rakesh Kumar Yadav
- Paklihawa Campus, Institute of Agriculture and Animal Science (IAAS), Tribhuvan University, Siddarthanagar 32900, Nepal
- Department of Pharmacology, Dalian Medical University, Dalian 116041, China
| | - Shristi Ghimire
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, 1800 Denison Avenue, Manhattan, KS 66506, USA
| | - Santosh Dhakal
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, 1800 Denison Avenue, Manhattan, KS 66506, USA
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John L, Shekede MD, Gwitira I, Mazhindu AN, Pfukenyi DM, Chikerema S. Modelling climate change impacts on the spatial distribution of anthrax in Zimbabwe. BMC Public Health 2024; 24:632. [PMID: 38418986 PMCID: PMC10900681 DOI: 10.1186/s12889-024-17856-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 01/23/2024] [Indexed: 03/02/2024] Open
Abstract
BACKGROUND In Zimbabwe, anthrax is endemic with outbreaks being reported almost annually in livestock, wildlife, and humans over the past 40 years. Accurate modelling of its spatial distribution is key in formulating effective control strategies. In this study, an Ensemble Species Distribution Model was used to model the current and future distribution of anthrax occurrence in Zimbabwe. METHODS Bioclimatic variables derived from the Beijing Climate Centre Climate System Model were used to model the disease. Collinearity testing was conducted on the 19 bioclimatic variables and elevation to remove redundancy. Variables that had no collinearity were used for anthrax habitat suitability modelling. Two future climate change scenarios for different Representative Concentration Pathways (RCP), RCP4.5 and RCP8.5 were used. Model evaluation was done using true skill, Kappa statistics and receiver operating characteristics. RESULTS The results showed that under current bioclimatic conditions, eastern and western districts of Zimbabwe were modelled as highly suitable, central districts moderately suitable and southern parts marginally suitable for anthrax occurrence. Future predictions demonstrated that the suitable (8%) and highly suitable (7%) areas for anthrax occurrence would increase under RCP4.5 scenario. In contrast, a respective decrease (11%) and marginal increase (0.6%) of suitable and highly suitable areas for anthrax occurrence were predicted under the RCP8.5 scenario. The percentage contribution of the predictors varied for the different scenarios; Bio6 and Bio18 for the current scenario, Bio2, Bio4 and Bio9 for the RCP4.5 and Bio3 and Bio15 for the RCP8.5 scenarios. CONCLUSIONS The study revealed that areas currently suitable for anthrax should be targeted for surveillance and prevention. The predicted future anthrax distribution can be used to guide and prioritise surveillance and control activities and optimise allocation of limited resources. In the marginally to moderately suitable areas, effective disease surveillance systems and awareness need to be put in place for early detection of outbreaks. Targeted vaccinations and other control measures including collaborative 'One Health' strategies need to be implemented in the predicted highly suitable areas. In the southern part where a high decrease in suitability was predicted, continued monitoring would be necessary to detect incursions early.
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Affiliation(s)
- Learnmore John
- Department of Geography Geospatial Sciences and Earth Observation, Faculty of Science, University of Zimbabwe, Harare, Zimbabwe
| | - Munyaradzi Davis Shekede
- Department of Geography Geospatial Sciences and Earth Observation, Faculty of Science, University of Zimbabwe, Harare, Zimbabwe.
- Department of Geospatial Sciences and Earth Observation, National Geospatial and Space Agency, Number 630 Churchill Road, Mt Pleasant, Harare, Zimbabwe.
| | - Isaiah Gwitira
- Department of Geography Geospatial Sciences and Earth Observation, Faculty of Science, University of Zimbabwe, Harare, Zimbabwe
| | - Aldridge Nyasha Mazhindu
- Department of Geography Geospatial Sciences and Earth Observation, Faculty of Science, University of Zimbabwe, Harare, Zimbabwe
| | - Davies Mubika Pfukenyi
- Department of Veterinary Sciences, Faculty of Animal and Veterinary Sciences, Botswana University of Agriculture and Natural Resources (BUAN), Gaborone, Botswana
| | - Silvester Chikerema
- Department of Clinical Veterinary Studies, Faculty of Veterinary Science, University of Zimbabwe, Harare, Zimbabwe
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Maison RM, Priore MR, Brown VR, Bodenchuk MJ, Borlee BR, Bowen RA, Bosco-Lauth AM. Feral Swine as Indirect Indicators of Environmental Anthrax Contamination and Potential Mechanical Vectors of Infectious Spores. Pathogens 2023; 12:pathogens12040622. [PMID: 37111508 PMCID: PMC10142851 DOI: 10.3390/pathogens12040622] [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: 03/28/2023] [Revised: 04/12/2023] [Accepted: 04/19/2023] [Indexed: 04/29/2023] Open
Abstract
Anthrax is a disease that affects livestock, wildlife, and humans worldwide; however, its relative impacts on these populations remain underappreciated. Feral swine (Sus scrofa) are relatively resistant to developing anthrax, and past serosurveys have alluded to their utility as sentinels, yet empirical data to support this are lacking. Moreover, whether feral swine may assist in the dissemination of infectious spores is unknown. To address these knowledge gaps, we intranasally inoculated 15 feral swine with varying quantities of Bacillus anthracis Sterne 34F2 spores and measured the seroconversion and bacterial shedding over time. The animals also were inoculated either one or three times. The sera were evaluated by enzyme-linked immunosorbent assay (ELISA) for antibodies against B. anthracis, and nasal swabs were cultured to detect bacterial shedding from the nasal passages. We report that the feral swine developed antibody responses to B. anthracis and that the strength of the response correlated with the inoculum dose and the number of exposure events experienced. Isolation of viable bacteria from the nasal passages of the animals throughout the study period suggests that feral swine may assist in the spread of infectious spores on the landscape and have implications for the identification of environments contaminated with B. anthracis as well as the exposure risk to more susceptible hosts.
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Affiliation(s)
- Rachel M Maison
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80521, USA
| | - Maggie R Priore
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO 80521, USA
| | - Vienna R Brown
- U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center, Fort Collins, CO 80521, USA
| | - Michael J Bodenchuk
- U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, San Antonio, TX 78269, USA
| | - Bradley R Borlee
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO 80521, USA
| | - Richard A Bowen
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80521, USA
| | - Angela M Bosco-Lauth
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80521, USA
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Milstein MS, Shaffer CA, Suse P, Marawanaru A, Heinrich DA, Larsen PA, Wolf TM. A mixed-methods approach to understanding domestic dog health and disease transmission risk in an indigenous reserve in Guyana, South America. PLoS Negl Trop Dis 2022; 16:e0010469. [PMID: 35687596 PMCID: PMC9223617 DOI: 10.1371/journal.pntd.0010469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 06/23/2022] [Accepted: 05/04/2022] [Indexed: 11/19/2022] Open
Abstract
Domestic dogs (Canis lupus familiaris) can transmit a variety of pathogens due to their ubiquitousness in urban, rural and natural environments, and their close interactions with wildlife and humans. In this study, we used a mixed-methods approach to assess the role of domestic dogs as potential intermediaries of disease transmission from wildlife to humans among indigenous Waiwai in the Konashen Community Owned Conservation Area, Guyana. To address these objectives we 1) performed physical examinations and collected biological samples to assess Waiwai domestic dog health, and 2) administered questionnaires to characterize the role of dogs in the community and identify potential transmission pathways between wildlife, dogs, and humans. We observed ectoparasites on all dogs (n = 20), including: fleas (100%), ticks (15%), botflies (30%), and jigger flea lesions (Tunga penetrans) (80%). Ten percent of dogs were seropositive for Ehrlichia canis/ewingii, 10% were positive for Dirofilaria immitis, and one dog was seropositive for Leishmania infantum. All dogs (n = 20) were seronegative for: canine distemper virus, Brucella canis, Leptospira serovars, Trypanosoma cruzi, Anaplasma phagocytophilum/platys and Borrelia burgdorferi. Our questionnaire data revealed that the Waiwai remove ectoparasites from their dogs, clean up dog feces, and administer traditional and/or Western medicine to their dogs. White blood cell, strongyle-type ova, and eosinophil counts were lower in dogs that were not frequently used for hunting, dogs that did receive traditional and/or western medicine, and dogs that were frequently kept in elevated dog houses, although differences were not statistically significant. While our results suggest that the Waiwai have developed cultural practices that may promote dog health and/or prevent zoonotic disease transmission, more research is necessary to determine the efficacy of these practices. Our study provides important data on the health of dogs and the potential for disease transmission to humans in a zoonotic hotspot. Domestic dogs are found throughout the world and interact closely with both wildlife and humans. Dogs can harbor numerous diseases that can be transmitted to other domestic and wildlife species, and human populations. They can serve as bridges, moving diseases between unconnected populations. Additionally, dogs can help in the early detection of wildlife and human diseases. Therefore, understanding what pathogens domestic dogs harbor can inform both wildlife and human health. In this study, we performed physical examinations, collected biological samples, and administered questionnaires to assess dog health and understand the role of dogs as potential bridges of disease transmission from wildlife to humans among indigenous Waiwai in the Konashen Community Owned Conservation Area, Guyana. On physical exam, we observed ectoparasites on all dogs, however, few pathogens were detected with diagnostic screening. Our questionnaire data revealed that the Waiwai engage in husbandry practices that may promote Waiwai dog health.
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Affiliation(s)
- Marissa S. Milstein
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America
- Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America
- * E-mail:
| | - Christopher A. Shaffer
- Department of Anthropology, Grand Valley State University, Allendale, Michigan, United States of America
| | - Phillip Suse
- Masakenari Village, Konashen Indigenous District, Region 9, Guyana
| | - Aron Marawanaru
- Masakenari Village, Konashen Indigenous District, Region 9, Guyana
| | - Daniel A. Heinrich
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Peter A. Larsen
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Tiffany M. Wolf
- Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America
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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: 9] [Impact Index Per Article: 4.5] [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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Ashenefe Wassie B, Fantaw S, Mekonene Y, Teshale AM, Yitagesu Y, Tsige E, Getahun D, Tasew G, Abichu G, Moges B, Abate E, Abayneh T, Zeru T, Belay Z, Mor SM. First PCR Confirmed anthrax outbreaks in Ethiopia—Amhara region, 2018–2019. PLoS Negl Trop Dis 2022; 16:e0010181. [PMID: 35143510 PMCID: PMC8865639 DOI: 10.1371/journal.pntd.0010181] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 02/23/2022] [Accepted: 01/18/2022] [Indexed: 11/19/2022] Open
Abstract
Background
Anthrax is a disease that affects humans and animals. In Ethiopia, anthrax is a reportable disease and assumed to be endemic, although laboratory confirmation has not been routinely performed until recently. We describe the findings from the investigation of two outbreaks in Amhara region.
Methods
Following reports of suspected outbreaks in Wag Hamra zone (Outbreak 1) and South Gondar zone (Outbreak 2), multi-sectoral teams involving both animal and public health officials were deployed to investigate and establish control programs. A suspect case was defined as: sudden death with rapid bloating or bleeding from orifice(s) with unclotted blood (animals); and signs compatible with cutaneous, ingestion, or inhalation anthrax ≤7 days after exposure to a suspect animal (humans). Suspect human cases were interviewed using a standard questionnaire. Samples were collected from humans with suspected anthrax (Outbreak 1 and Outbreak 2) as well as dried meat of suspect animal cases (Outbreak 2). A case was confirmed if a positive test was returned using real-time polymerase chain reaction (qPCR).
Results
In Outbreak 1, a total of 49 cows died due to suspected anthrax and 22 humans developed symptoms consistent with cutaneous anthrax (40% attack rate), two of whom died due to suspected ingestion anthrax. Three people were confirmed to have anthrax by qPCR. In Outbreak 2, anthrax was suspected to have caused the deaths of two livestock animals and one human. Subsequent investigation revealed 18 suspected cases of cutaneous anthrax in humans (27% attack rate). None of the 12 human samples collected tested positive, however, a swab taken from the dried meat of one animal case (goat) was positive by qPCR.
Conclusion
We report the first qPCR-confirmed outbreaks of anthrax in Ethiopia. Both outbreaks were controlled through active case finding, carcass management, ring vaccination of livestock, training of health professionals and outreach with livestock owners. Human and animal health authorities should work together using a One Health approach to improve case reporting and vaccine coverage.
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Affiliation(s)
| | - Surafel Fantaw
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Yonas Mekonene
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | | | | | | | | | - Geremew Tasew
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | | | - Beyene Moges
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Ebba Abate
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | | | - Taye Zeru
- Amhara Public Health Institute, Bahir Dar, Ethiopia
| | - Zewdu Belay
- Amhara Livestock Resource Development and Promotion Agency, Bahir Dar, Ethiopia
| | - Siobhan M. Mor
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
- International Livestock Research Institute, Addis Ababa, Ethiopia
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Maison RM, Pierce CF, Ragan IK, Brown VR, Bodenchuk MJ, Bowen RA, Bosco-Lauth AM. Potential Use for Serosurveillance of Feral Swine to Map Risk for Anthrax Exposure, Texas, USA. Emerg Infect Dis 2021; 27:3103-3110. [PMID: 34808089 PMCID: PMC8632180 DOI: 10.3201/eid2712.211482] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Anthrax is a disease of concern in many mammals, including humans. Management primarily consists of prevention through vaccination and tracking clinical-level observations because environmental isolation is laborious and bacterial distribution across large geographic areas difficult to confirm. Feral swine (Sus scrofa) are an invasive species with an extensive range in the southern United States that rarely succumbs to anthrax. We present evidence that feral swine might serve as biosentinels based on comparative seroprevalence in swine from historically defined anthrax-endemic and non–anthrax-endemic regions of Texas. Overall seropositivity was 43.7% (n = 478), and logistic regression revealed county endemicity status, age-class, sex, latitude, and longitude were informative for predicting antibody status. However, of these covariates, only latitude was statistically significant (β = –0.153, p = 0.047). These results suggests anthrax exposure in swine, when paired with continuous location data, could serve as a proxy for bacterial presence in specific areas.
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Mukarati NL, Matope G, de Garine-Wichatitsky M, Ndhlovu DN, Caron A, Pfukenyi DM. The pattern of anthrax at the wildlife-livestock-human interface in Zimbabwe. PLoS Negl Trop Dis 2020; 14:e0008800. [PMID: 33075049 PMCID: PMC7595623 DOI: 10.1371/journal.pntd.0008800] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 10/29/2020] [Accepted: 09/16/2020] [Indexed: 11/18/2022] Open
Abstract
Anthrax is an important but neglected zoonosis in southern Africa and elsewhere which occurs naturally in herbivorous wildlife and livestock. Fatal outbreaks in animals are spaced by potentially extended periods of non-activity during which the bacterium is maintained in soil. The ecology of the pathogen in the multi-host system and the environment is still not fully understood. This study investigated the patterns of anthrax in Zimbabwe in order to better understand the occurrence of disease in susceptible wildlife and livestock and hence its control. The study used available data in governmental reports between 1995 and 2018 and structured interviewer-administered questionnaires of local communities in three porous wildlife-livestock-human interface sites where livestock/wildlife interactions were documented from previous researches. Two non-interface sites were also included for comparison based on known previous anthrax outbreaks. Respondents from non-interface sites had significantly higher odds (χ2 = 23.2, OR = 3.5, 2.1<OR<5.8, p<0.001) of reporting anthrax outbreaks than their counterparts at the interface. Overall 20.0% (74/372) of the respondents reported that some anthrax carcasses were left to dissipate into the environment indicating a risk of environmental contamination. In livestock a total of 214 outbreaks with 2911 losses (mainly cattle) were recorded between 2000 and 2018, while 10 outbreaks with 3171 deaths were noted in wildlife. In humans 99 outbreaks were recorded involving 903 individual cases with 16 fatalities due to enteric infections following the consumption of infected meat between 2010 and 2018. Since its first incidence in wildlife in 2004–2005 in the south-eastern Lowveld of Zimbabwe, anthrax appears to be establishing endemic status along the Zambezi River basin. The disease has expanded spatially affecting 45 (72.6%) of the country’s 62 rural districts in a single decade. Thus, robust multi-disciplinary efforts are encouraged for surveillance and disease containment measures to minimize its impact on livestock, wildlife and humans. Anthrax is an expanding zoonotic and tropical disease which negatively impacts livestock, wildlife and human health ultimately impacting livelihoods and biodiversity conservation. In this work we have shown it to be a serious disease in Zimbabwe where its surveillance and control are sub-optimum even though it is causing serious losses in animals and human health. Observed practices such as the non-burial of infected carcasses subsequently contaminating the environment following anthrax outbreaks in animals, have most likely contributed to its expansion in geographic range and the increase in frequency of outbreaks. Since the late 1970s, the disease status has changed from that causing a low-level mortality in livestock, probably due to underreporting, to a common disease in livestock, wildlife and humans. It is hoped that by quantifying the impact of the disease across livestock, wildlife and human health and livelihoods, and establishing factors responsible for its continued expansion, adequate resources for surveillance and containment of anthrax will be allocated in order to improve rural livelihoods and also enhance wildlife conservation.
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Affiliation(s)
- Norman L. Mukarati
- Department of Clinical Veterinary Studies, Faculty of Veterinary Science, University of Zimbabwe, Mt. Pleasant, Harare, Zimbabwe
- * E-mail:
| | - Gift Matope
- Department of Paraclinical Veterinary Studies, Faculty of Veterinary science, University of Zimbabwe, Mt. Pleasant, Harare, Zimbabwe
| | - Michel de Garine-Wichatitsky
- ASTRE, CIRAD, INRA, Univ. de Montpellier, Montpellier, France
- CIRAD, UMR ASTRE, Bangkok, Thailand
- Faculty of Veterinary Medicine, Kasetsart University, Bangkok, Thailand
| | - Daud N. Ndhlovu
- Department of Clinical Veterinary Studies, Faculty of Veterinary Science, University of Zimbabwe, Mt. Pleasant, Harare, Zimbabwe
| | - Alexandre Caron
- ASTRE, CIRAD, INRA, Univ. de Montpellier, Montpellier, France
- CIRAD, RP-PCP, UMR ASTRE, Maputo, Mozambique
- Faculdade de Veterinária, Universidade Eduardo Mondlane, Maputo, Mozambique
| | - Davies M. Pfukenyi
- Department of Clinical Veterinary Studies, Faculty of Veterinary Science, University of Zimbabwe, Mt. Pleasant, Harare, Zimbabwe
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Mukarati NL, Ndumnego OC, Ochai SO, Jauro S, Loveridge A, van Heerden H, Matope G, Caron A, Hanyire TG, de Garine-Wichatitsky M, Pfukenyi DM. A serological survey of Bacillus anthracis reveals widespread exposure to the pathogen in free-range and captive lions in Zimbabwe. Transbound Emerg Dis 2020; 68:1676-1684. [PMID: 32964687 DOI: 10.1111/tbed.13842] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 08/24/2020] [Accepted: 09/14/2020] [Indexed: 11/29/2022]
Abstract
Numerous unknown factors influence anthrax epidemiology in multi-host systems, especially at wildlife/livestock/human interfaces. Serology tests for anti-anthrax antibodies in carnivores are useful tools in identifying the presence or absence of Bacillus anthracis in a range. These were employed to ascertain whether the disease pattern followed the recognized high- and low-risk anthrax zonation in Zimbabwe and also to establish whether anthrax was absent from Hwange National Park in which there have been no reported outbreaks. African lions (Panthera leo) (n = 114) drawn from free-range protected areas and captive game parks located in recognized high- and low-risk zones across Zimbabwe were tested for antibodies to anthrax PA antigen using the ELISA immunoassay. A random selection of 27 lion sera samples comprising 17 seropositive and 10 seronegative sera was further tested in the species-independent toxin neutralization assay (TNA) in order to validate the former as a surveillance tool for anthrax in African lions. Using the ELISA-PA immunoassay, 21.9% (25/114) of the lions tested positive for antibodies to anthrax. Seropositivity was recorded in all study areas, and there was no significant difference (p = .852) in seropositivity between lions in high- and low-risk anthrax zones. Also, there was no significant difference (McNemar's chi-square test = 0.9, p = .343) in the proportion of lions testing positive to anti-PA anthrax antibodies on ELISA-PA immunoassay compared with the TNA, with fair agreement between the two tests [kappa (K) statistic = 0.30; 0.08 < K<0.613]. Results of this study indicate that anthrax could be more widespread than 42 currently realized in Zimbabwe, and present in recognized high- and low-risk zones, including 43 where it has not been reported in over 20 years such as Hwange National Park. This is also the 44 first report documenting the presence of anthrax lethal toxin-neutralizing antibodies in naturally 45 infected carnivores, further confirming exposure to B. anthracis. The research results point to a 46 need for revisiting the currently recognized anthrax risk zones in Zimbabwe. This should be based 47 on improved surveillance of the disease in both wild and domestic animals for better understanding and control of the disease.
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Affiliation(s)
- Norman L Mukarati
- Faculty of Veterinary Science, University of Zimbabwe, Harare, Zimbabwe
| | - Okechukwu C Ndumnego
- Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa.,Moredun Scientific, Edinburgh, UK
| | - Sunday O Ochai
- Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | - Solomon Jauro
- Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | | | | | - Gift Matope
- Faculty of Veterinary Science, University of Zimbabwe, Harare, Zimbabwe
| | - Alexandre Caron
- ASTRE, Univ. de Montpellier, CIRAD, INRA, Montpellier, France.,CIRAD, UMR ASTRE, RP-PCP, Maputo, Mozambique.,Faculdade de Veterinária, Universidade Eduardo Mondlane, Maputo, Mozambique
| | | | - Michel de Garine-Wichatitsky
- ASTRE, Univ. de Montpellier, CIRAD, INRA, Montpellier, France.,CIRAD, UMR ASTRE, Bangkok, Thailand.,Faculty of Veterinary Medicine, Kasetsart University, Bangkok, Thailand
| | - Davies M Pfukenyi
- Faculty of Veterinary Science, University of Zimbabwe, Harare, Zimbabwe
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