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Grant J, Hopcraft C, Laurenson MK. Markus Borner, a life at the conservation front line. Conserv Biol 2020; 34:769-770. [PMID: 32450619 DOI: 10.1111/cobi.13507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Affiliation(s)
- J Grant
- Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - C Hopcraft
- Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - M Karen Laurenson
- Africa Department, Frankfurt Zoological Society, Bernhard Grzimek-Allee 1, Frankfurt am Main, D60316, Germany
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Hilborn A, Pettorelli N, Caro T, Kelly MJ, Laurenson MK, Durant SM. Cheetahs modify their prey handling behavior depending on risks from top predators. Behav Ecol Sociobiol 2018. [DOI: 10.1007/s00265-018-2481-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Gordon CH, Banyard AC, Hussein A, Laurenson MK, Malcolm JR, Marino J, Regassa F, Stewart AME, Fooks AR, Sillero-Zubiri C. Canine distemper in endangered Ethiopian wolves. Emerg Infect Dis 2016; 21:824-32. [PMID: 25898177 PMCID: PMC4412237 DOI: 10.3201/eid2105.141920] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Investigation into mortalities within endangered species can direct conservation efforts. The Ethiopian wolf (Canis simensis) is the world’s rarest canid; ≈500 wolves remain. The largest population is found within the Bale Mountains National Park (BMNP) in southeastern Ethiopia, where conservation efforts have demonstrated the negative effect of rabies virus on wolf populations. We describe previously unreported infections with canine distemper virus (CDV) among these wolves during 2005–2006 and 2010. Death rates ranged from 43% to 68% in affected subpopulations and were higher for subadult than adult wolves (83%–87% vs. 34%–39%). The 2010 CDV outbreak started 20 months after a rabies outbreak, before the population had fully recovered, and led to the eradication of several focal packs in BMNP’s Web Valley. The combined effect of rabies and CDV increases the chance of pack extinction, exacerbating the typically slow recovery of wolf populations, and represents a key extinction threat to populations of this highly endangered carnivore.
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Kennedy LJ, Randall DA, Knobel D, Brown JJ, Fooks AR, Argaw K, Shiferaw F, Ollier WER, Sillero-Zubiri C, Macdonald DW, Laurenson MK. Major histocompatibility complex diversity in the endangered Ethiopian wolf (Canis simensis). ACTA ACUST UNITED AC 2011; 77:118-25. [PMID: 21214524 DOI: 10.1111/j.1399-0039.2010.01591.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The major histocompatibility complex (MHC) influences immune response to infection and vaccination. In most species, MHC genes are highly polymorphic, but few wild canid populations have been investigated. In Ethiopian wolves, we identified four DLA (dog leucocyte antigen)-DRB1, two DLA-DQA1 and five DQB1 alleles. Ethiopian wolves, the world's rarest canids with fewer than 500 animals worldwide, are further endangered and threatened by rabies. Major rabies outbreaks in the Bale Mountains of southern Ethiopia (where over half of the Ethiopian wolf population is located) have killed over 75% of wolves in the affected sub-populations. In 2004, following a rabies outbreak, 77 wolves were vaccinated, and 19 were subsequently recaptured to monitor the effectiveness of the intervention. Pre- and post-vaccination rabies antibody titres were available for 18 animals, and all of the animals sero-converted after vaccination. We compared the haplotype frequencies of this group of 18 with the post-vaccination antibody titre, and showed that one haplotype was associated with a lower response (uncorrected P < 0.03). In general, Ethiopian wolves probably have an adequate amount of MHC variation to ensure the survival of the species. However, we sampled only the largest Ethiopian wolf population in Bale, and did not take the smaller populations further north into consideration.
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Affiliation(s)
- L J Kennedy
- Centre for Integrated Genomic Medical Research, University of Manchester, Manchester, UK.
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Dobson AP, Borner M, Sinclair ARE, Hudson PJ, Anderson TM, Bigurube G, Davenport TBB, Deutsch J, Durant SM, Estes RD, Estes AB, Fryxell J, Foley C, Gadd ME, Haydon D, Holdo R, Holt RD, Homewood K, Hopcraft JGC, Hilborn R, Jambiya GLK, Laurenson MK, Melamari L, Morindat AO, Ogutu JO, Schaller G, Wolanski E. Road will ruin Serengeti. Nature 2010; 467:272-3. [PMID: 20844519 DOI: 10.1038/467272a] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Knobel DL, Laurenson MK, Kazwala RR, Boden LA, Cleaveland S. A cross-sectional study of factors associated with dog ownership in Tanzania. BMC Vet Res 2008; 4:5. [PMID: 18230137 PMCID: PMC2262882 DOI: 10.1186/1746-6148-4-5] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Accepted: 01/29/2008] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Mass vaccination of owned domestic dogs is crucial for the control of rabies in sub-Saharan Africa. Knowledge of the proportion of households which own dogs, and of the factors associated with dog ownership, is important for the planning and implementation of rabies awareness and dog vaccination programmes, and for the promotion of responsible dog ownership. This paper reports the results of a cross-sectional study of dog ownership by households in urban and rural communities in the United Republic of Tanzania. RESULTS Fourteen percent (202) of 1,471 households surveyed were identified as dog-owning, with an average of 2.4 dogs per dog-owning household. The percentage of dog-owning households was highest in inland rural areas (24%) and lowest in coastal urban communities (7%). The overall human:dog ratio was 14:1. Multivariable logistic regression revealed that households which owned cattle, sheep or goats were much more likely to own dogs than households with no livestock. Muslim households were less likely to own dogs than Christian households, although this effect of religion was not seen among livestock-owning households. Households were more likely to own a dog if the head of the household was male; if they owned a cat; or if they owned poultry. Dog ownership was also broadly associated with larger, wealthier households. CONCLUSION The human:dog ratios in Tanzania are similar to those reported elsewhere in sub-Saharan Africa, although cultural and geographic variation is evident. Estimation of the number of owned dogs, and identification of household predictors of dog ownership, will enable targeted planning of rabies control efforts.
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Affiliation(s)
- Darryn L Knobel
- Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, Midlothian, EH25 9RG, UK
| | - M Karen Laurenson
- Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, Midlothian, EH25 9RG, UK
- Africa Regional Office, Frankfurt Zoological Society, P.O. Box 14935, Arusha, Tanzania
| | - Rudovick R Kazwala
- Department of Medicine and Public Health, Faculty of Veterinary Medicine, Sokoine University of Agriculture, P.O. Box 3021, Chuo Kikuu, Morogoro, Tanzania
| | - Lisa A Boden
- Centre for Infectious Disease, University of Edinburgh, Ashworth Laboratories, West Mains Road, Edinburgh, EH9 3JT, UK
| | - Sarah Cleaveland
- Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, Midlothian, EH25 9RG, UK
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Durant SM, Bashir S, Maddox T, Laurenson MK. Relating long-term studies to conservation practice: the case of the Serengeti Cheetah Project. Conserv Biol 2007; 21:602-11. [PMID: 17531039 DOI: 10.1111/j.1523-1739.2007.00702.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Although detailed, long-term scientific studies provide potentially crucial information for conservation, they are rare. Moreover, there is often a disjunction between scientists and managers that can affect whether scientific results are applied to help solve conservation problems. Long-term studies can promote increased communication between scientists and managers and hence offer an opportunity for constructive engagement between the two groups. We examined direct and indirect impacts of a 30-year study, the Serengeti Cheetah Project (SCP). Much of what is currently known about wild cheetahs comes from the SCP. In particular, the SCP has demonstrated that cheetahs have a combination of semisociality and ranging patterns that is unique among mammals. This system arises because cheetahs need to be mobile to avoid predators and competitors, yet maintain access to prey; this results in densities much lower than for other large carnivores and a requirement for large areas of heterogenous and connected habitat. The SCP started as a research project, but expanded into a national program, developing capacity for carnivore conservation within Tanzania. Long-term studies such as the SCP are uniquely placed to establish effective working relationships between scientists and managers, engage local and national institutions, and strengthen national capacity for biodiversity conservation. This process is best realized through the establishment of frameworks for conservation that seek to align scientific research with management needs. Long-term studies also play an important role in identifying international priorities for conservation. Nonetheless, the integration of science and management in conservation is a two-way process that requires concerted efforts by both sides to improve and maintain dialogue. Ultimately, conservation depends on people, and maintaining a commitment to a particular area over many years-such as through implementation of a long-term research project-helps establish mutual trust and respect, particularly when combined with development of local and national capacity for scientific research and conservation management.
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Affiliation(s)
- Sarah M Durant
- Institute of Zoology, Zoological Society of London, Regent's Park, London NW14RY, United Kingdom
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Cleaveland S, Mlengeya T, Kaare M, Haydon D, Lembo T, Laurenson MK, Packer C. The conservation relevance of epidemiological research into carnivore viral diseases in the serengeti. Conserv Biol 2007; 21:612-22. [PMID: 17531040 DOI: 10.1111/j.1523-1739.2007.00701.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Recent outbreaks of rabies and canine distemper in wildlife populations of the Serengeti show that infectious disease constitutes a significant cause of mortality that can result in regional extirpation of endangered species even within large, well-protected areas. Nevertheless, effective management of an infectious disease depends critically on understanding the epidemiological dynamics of the causative pathogen. Pathogens with short infection cycles cannot persist in small populations in the absence of a more permanent reservoir of infection. Development of appropriate interventions requires detailed data on transmission pathways between reservoirs and wildlife populations of conservation concern. Relevant data can be derived from long-term population monitoring, epidemic and case-surveillance patterns, genetic analyses of rapidly evolving pathogens, serological surveys, and intervention studies. We examined studies of carnivore diseases in the Serengeti. Epidemiological research contributes to wildlife conservation policy in terms of management of endangered populations and the integration of wildlife conservation with public health interventions. Long-term, integrative, cross-species research is essential for formulation of effective policy for disease control and optimization of ecosystem health.
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Affiliation(s)
- Sarah Cleaveland
- Wildlife and Emerging Diseases Section, Centre for Tropical Veterinary Medicine, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, Midlothian, EH25 9RG, United Kingdom.
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Laurenson MK, McKendrick IJ, Reid HW, Challenor R, Mathewson GK. Prevalence, spatial distribution and the effect of control measures on louping-ill virus in the Forest of Bowland, Lancashire. Epidemiol Infect 2007; 135:963-73. [PMID: 17346361 PMCID: PMC2870653 DOI: 10.1017/s0950268806007692] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The complex pathogen-host-vector system of the tick-borne louping-ill virus causes economic losses to sheep and red grouse in upland United Kingdom. This paper examines the spatial distribution, incidence and effect of control measures on louping-ill virus in the Bowland Fells of Lancashire. Seroprevalence in sheep at the beginning of the study varied within the area and was affected significantly by the frequency of acaricide treatment. There was a clear decrease over 5 years in the effective force of infection on farms implementing a vaccination programme, irrespective of acaricide treatment regime, however, only one third of farms apparently eliminated infection. On farms where vaccination did not occur or where vaccination was carried out intermittently, the estimated force of infection was variable or possibly increased. Thus, as befits a complex host-pathogen system, reductions in prevalence were not as dramatic as predicted; we discuss the potential explanations for these observations.
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Affiliation(s)
- M K Laurenson
- Wildlife and Emerging Diseases, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, UK.
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Haydon DT, Randall DA, Matthews L, Knobel DL, Tallents LA, Gravenor MB, Williams SD, Pollinger JP, Cleaveland S, Woolhouse MEJ, Sillero-Zubiri C, Marino J, Macdonald DW, Laurenson MK. Low-coverage vaccination strategies for the conservation of endangered species. Nature 2006; 443:692-5. [PMID: 17036003 DOI: 10.1038/nature05177] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2006] [Accepted: 08/15/2006] [Indexed: 01/13/2023]
Abstract
The conventional objective of vaccination programmes is to eliminate infection by reducing the reproduction number of an infectious agent to less than one, which generally requires vaccination of the majority of individuals. In populations of endangered wildlife, the intervention required to deliver such coverage can be undesirable and impractical; however, endangered populations are increasingly threatened by outbreaks of infectious disease for which effective vaccines exist. As an alternative, wildlife epidemiologists could adopt a vaccination strategy that protects a population from the consequences of only the largest outbreaks of disease. Here we provide a successful example of this strategy in the Ethiopian wolf, the world's rarest canid, which persists in small subpopulations threatened by repeated outbreaks of rabies introduced by domestic dogs. On the basis of data from past outbreaks, we propose an approach that controls the spread of disease through habitat corridors between subpopulations and that requires only low vaccination coverage. This approach reduces the extent of rabies outbreaks and should significantly enhance the long-term persistence of the population. Our study shows that vaccination used to enhance metapopulation persistence through elimination of the largest outbreaks of disease requires lower coverage than the conventional objective of reducing the reproduction number of an infectious agent to less than one.
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Affiliation(s)
- D T Haydon
- Division of Environmental and Evolutionary Biology, University of Glasgow, Glasgow G12 8QQ, UK.
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Affiliation(s)
- David W Macdonald
- Wildlife Conservation Research Unit, Zoology Department, University of Oxford, Tubney House, Abingdon Road, Tubney, Oxon OX13 5QL, United Kingdom
- Frankfurt Zoological Society, P.O. Box 14935, Arusha, Tanzania and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin Midlothian, EH25 9RG, United Kingdom
| | - M Karen Laurenson
- Frankfurt Zoological Society, P.O. Box 14935, Arusha, Tanzania and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin Midlothian, EH25 9RG, United Kingdom
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Abstract
This paper reviews the broader benefits of canine vaccination to human and animal health and welfare with an emphasis on the impacts of mass dog vaccination against rabies in countries of the less-developed world. Domestic dogs are the source of infection for the vast majority (>95%) of cases of human rabies worldwide, and dogs remain the principal reservoir throughout Africa and Asia. Canine vaccination against rabies has been shown to dramatically reduce the number of cases in dogs, the incidence of human animal-bite injuries (and hence the demand for costly post-exposure prophylaxis) and the likely number of human cases, primarily in children. Further benefits include the mitigation of the psychological consequences of rabies in a community, improved attitudes towards animals and animal welfare and reduced livestock losses from canine rabies. Mass vaccination has recently been used in the conservation management of wild carnivore populations threatened by transmission of rabies and canine distemper virus from domestic dog populations. Vaccination of wildlife hosts directly may also provide an option for mitigating infectious disease threats. The development of integrated control measures involving public health, veterinary, wildlife conservation and animal welfare agencies is needed to ensure that control of canine diseases becomes a reality in Africa and Asia. The tools and delivery systems are all available--all that is needed is the political will to free the world from the ongoing tragedy of these diseases.
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Affiliation(s)
- Sarah Cleaveland
- Wildlife and Emerging Disease Section, Centre for Tropical Veterinary Medicine, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Veterinary Centre, Roslin, Midlothian EH25 9RG, UK.
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Randall DA, Williams SD, Kuzmin IV, Rupprecht CE, Tallents LA, Tefera Z, Argaw K, Shiferaw F, Knobel DL, Sillero-Zubiri C, Laurenson MK. Rabies in endangered Ethiopian wolves. Emerg Infect Dis 2005; 10:2214-7. [PMID: 15663865 PMCID: PMC3323365 DOI: 10.3201/eid1012.040080] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
With rabies emerging as a particular threat to wild canids, we report on a rabies outbreak in a subpopulation of endangered Ethiopian wolves in the Bale Mountains, Ethiopia, in 2003 and 2004. Parenteral vaccination of wolves was used to manage the outbreak.
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Affiliation(s)
- Deborah A. Randall
- University of Oxford, Oxford, United Kingdom
- Ethiopian Wolf Conservation Programme, Addis Ababa, Ethiopia
| | - Stuart D. Williams
- University of Oxford, Oxford, United Kingdom
- Ethiopian Wolf Conservation Programme, Addis Ababa, Ethiopia
| | - Ivan V. Kuzmin
- Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | | | - Lucy A. Tallents
- University of Oxford, Oxford, United Kingdom
- Ethiopian Wolf Conservation Programme, Addis Ababa, Ethiopia
| | - Zelealem Tefera
- Ethiopian Wolf Conservation Programme, Addis Ababa, Ethiopia
| | - Kifle Argaw
- Ethiopian Wildlife Conservation Organisation, Addis Ababa, Ethiopia
| | - Fekadu Shiferaw
- Ethiopian Wildlife Conservation Organisation, Addis Ababa, Ethiopia
| | - Darryn L. Knobel
- Ethiopian Wolf Conservation Programme, Addis Ababa, Ethiopia
- University of Edinburgh, Edinburgh, United Kingdom
| | - Claudio Sillero-Zubiri
- University of Oxford, Oxford, United Kingdom
- Ethiopian Wildlife Conservation Organisation, Addis Ababa, Ethiopia
| | - M. Karen Laurenson
- University of Oxford, Oxford, United Kingdom
- University of Edinburgh, Edinburgh, United Kingdom
- Frankfurt Zoological Society, Arusha, Tanzania
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Gilbert L, Jones LD, Laurenson MK, Gould EA, Reid HW, Hudson PJ. Ticks need not bite their red grouse hosts to infect them with louping ill virus. Proc Biol Sci 2004; 271 Suppl 4:S202-5. [PMID: 15252984 PMCID: PMC1810039 DOI: 10.1098/rsbl.2003.0147] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
For pathogens transmitted by biting vectors, one of the fundamental assumptions is often that vector bites are the sole or main route of host infection. Here, we demonstrate experimentally a transmission route whereby hosts (red grouse, Lagopus lagopus scoticus) became infected with a member of the tick-borne encephalitis virus complex, louping ill virus, after eating the infected tick vector. Furthermore, we estimated from field observations that this mode of infection could account for 73-98% of all virus infections in wild red grouse in their first season. This has potential implications for the understanding of other biting vector-borne pathogens where hosts may ingest vectors through foraging or grooming.
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Affiliation(s)
- Lucy Gilbert
- Institute of Biological Sciences, University of Stirling, Stirling FK9 4LA, UK.
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Admasu E, Thirgood SJ, Bekele A, Karen Laurenson M. A note on the spatial ecology of African civet Civettictis civetta and common genet Genetta genetta in farmland in the Ethiopian Highlands. Afr J Ecol 2004. [DOI: 10.1111/j.1365-2028.2004.00496.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Smith GC, Gangadharan B, Taylor Z, Laurenson MK, Bradshaw H, Hide G, Hughes JM, Dinkel A, Romig T, Craig PS. Prevalence of zoonotic important parasites in the red fox (Vulpes vulpes) in Great Britain. Vet Parasitol 2003; 118:133-42. [PMID: 14651882 DOI: 10.1016/j.vetpar.2003.09.017] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
A national necropsy survey of red foxes was carried out across Great Britain to record Echinococcus, Trichinella and Toxoplasma. The survey did not record directly, or indirectly using coproantigen/PCR tests, evidence for the presence of Echinococcus multilocularis in 588 animals, although E. granulosus was suspected in six animals. Parasitological evidence for Trichinella spp. could not be found in 587 fox muscle digests, and a specific PCR test also failed to detect Toxoplasma in a sub-set of 61 random fox tongue biopsies. The upper 95% confidence interval for the above parasites was 0.60% (E. multilocularis), 0.60% (Trichinella spp.) and 5.6% (Toxoplasma). The commonest gut parasites were the hookworm Uncinaria stenocephala (41.3%) and the ascarid Toxocara canis (61.6%). This study also reports the second occurrence of Trichuris vulpis in Great Britain.
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Affiliation(s)
- G C Smith
- Central Science Laboratory, Sand Hutton, York YO41 1LZ, UK.
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20
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Norman R, Ross D, Laurenson MK, Hudson PJ. The role of non-viraemic transmission on the persistence and dynamics of a tick borne virus--Louping ill in red grouse ( Lagopus lagopus scoticus) and mountain hares ( Lepus timidus). J Math Biol 2003; 48:119-34. [PMID: 14745507 DOI: 10.1007/s00285-002-0183-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2002] [Indexed: 11/25/2022]
Abstract
There exist many tick borne infections that are of either economic or public health interest. Mathematical models have previously been used to describe the dynamics of these infections. However it has recently come to light that there is an alternative mechanism for the transmission of these diseases that has not been considered in a modelling framework. This is transmission through ticks co-feeding on non-viraemic hosts. This paper extends a simple mathematical model to include this alternative transmission mechanism. The model is used to describe the dynamics of Louping ill virus in red grouse (the viraemic host) and hares (the non-viraemic host). However, these results are applicable to many other systems. The model is analysed using joint threshold density curves. It is found that the presence of a non-viraemic host allows the virus to persist more readily than it would in the presence of a host that simply amplified the tick population. More importantly, if the level of non-viraemic transmission is high enough the virus can persist in the absence of the viraemic host. This result has important implications for the control of tick borne diseases.
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Affiliation(s)
- Rachel Norman
- Stirling Mathematical Ecology Group, Department of Computing Science and Mathematics, University of Stirling, Stirling, FK9 4LA, UK.
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Abstract
Many infectious agents, especially those that cause emerging diseases, infect more than one host species. Managing reservoirs of multihost pathogens often plays a crucial role in effective disease control. However, reservoirs remain variously and loosely defined. We propose that reservoirs can only be understood with reference to defined target populations. Therefore, we define a reservoir as one or more epidemiologically connected populations or environments in which the pathogen can be permanently maintained and from which infection is transmitted to the defined target population. Existence of a reservoir is confirmed when infection within the target population cannot be sustained after all transmission between target and nontarget populations has been eliminated. When disease can be controlled solely by interventions within target populations, little knowledge of potentially complex reservoir infection dynamics is necessary for effective control. We discuss the practical value of different approaches that may be used to identify reservoirs in the field.
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Affiliation(s)
- F Shiferaw
- Ethiopian Wildlife Conservation Organisation, Ministry of Agriculture, Addis Ababa
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Cleaveland S, Laurenson MK, Taylor LH. Diseases of humans and their domestic mammals: pathogen characteristics, host range and the risk of emergence. Philos Trans R Soc Lond B Biol Sci 2001; 356:991-9. [PMID: 11516377 PMCID: PMC1088494 DOI: 10.1098/rstb.2001.0889] [Citation(s) in RCA: 578] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Pathogens that can be transmitted between different host species are of fundamental interest and importance from public health, conservation and economic perspectives, yet systematic quantification of these pathogens is lacking. Here, pathogen characteristics, host range and risk factors determining disease emergence were analysed by constructing a database of disease-causing pathogens of humans and domestic mammals. The database consisted of 1415 pathogens causing disease in humans, 616 in livestock and 374 in domestic carnivores. Multihost pathogens were very prevalent among human pathogens (61.6%) and even more so among domestic mammal pathogens (livestock 77.3%, carnivores 90.0%). Pathogens able to infect human, domestic and wildlife hosts contained a similar proportion of disease-causing pathogens for all three host groups. One hundred and ninety-six pathogens were associated with emerging diseases, 175 in humans, 29 in livestock and 12 in domestic carnivores. Across all these groups, helminths and fungi were relatively unlikely to emerge whereas viruses, particularly RNA viruses, were highly likely to emerge. The ability of a pathogen to infect multiple hosts, particularly hosts in other taxonomic orders or wildlife, were also risk factors for emergence in human and livestock pathogens. There is clearly a need to understand the dynamics of infectious diseases in complex multihost communities in order to mitigate disease threats to public health, livestock economies and wildlife.
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Affiliation(s)
- S Cleaveland
- Centre for Tropical Veterinary Medicine, University of Edinburgh, Easter Bush, Roslin, Midlothian EH25 9RG, UK.
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Abstract
In some areas of Scotland, the prevalence of louping-ill virus has not decreased despite the vaccination of replacement ewes for over 30 years. The role of unvaccinated lambs in viral persistence was examined through a combination of an empirical study of infection rates of lambs and mathematical modelling. Serological sampling revealed that most lambs were protected by colostral immunity at turnout in May/June but were fully susceptible by the end of September. Between 8 and 83% of lambs were infected over the first season, with seroconversion rates greater in late rather than early summer. The proportion of lambs that could have amplified the louping-ill virus was low, however, because high initial titres of colostral antibody on farms with a high force of infection gave protection for several months. A simple mathematical model suggested that the relationship between the force of infection and the percentage of lambs that became viraemic was not linear and that the maximum percentage of viraemic lambs occurred at moderately high infection rates. Examination of the conditions required for louping-ill persistence suggested that the virus could theoretically persist in a sheep flock with over 370 lambs, if the grazing season was longer than 130 days. In practice, however, lamb viraemia is not a general explanation for louping-ill virus persistence as these conditions are not met in most management systems and because the widespread use of acaracides in most tick-affected hill farming systems reduces the number of ticks feeding successfully.
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Affiliation(s)
- M K Laurenson
- Institute of Biological Sciences, University of Stirling.
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Kelly MJ, Laurenson MK, FitzGibbon CD, Collins DA, Durant SM, Frame GW, Bertram BC, Caro TM. Demography of the Serengeti cheetah (Acinonyx jubatus) population: the first 25 years. J Zool (1987) 1998. [DOI: 10.1111/j.1469-7998.1998.tb00053.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Laurenson MK, Hudson PJ, McGuire K, Thirgood SJ, Reid HW. Efficacy of acaricidal tags and pour-on as prophylaxis against ticks and louping-ill in red grouse. Med Vet Entomol 1997; 11:389-393. [PMID: 9430120 DOI: 10.1111/j.1365-2915.1997.tb00427.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
This paper examines the efficacy of 10% lambdacyhalothrin-impregnated plastic tags and a deltamethrin pour-on preparation in protecting red grouse chicks from parasitism by ticks and subsequent infection with the louping-ill virus. In 1995, ten red grouse hens (Lagopus lagopus scoticus) in a free-living population in north-east Scotland were fitted with lambdacyhalothrin-impregnated plastic tags, glued to radio transmitters. Chicks of more than 10 days of age from a further ten untreated radio-collared hens were caught and fitted with individual tags to the ptagium. Both treatments significantly reduced tick burdens in the short term. The number of larvae and nymphs on chicks up to 45 days was less under both treatments than on control chicks and tagged chicks had fewer nymphs than chicks from treated hens. Nevertheless, treatments did not reduce viral infection rates nor increase survival to 10 weeks, possibly explained by incomplete treatment of tagged broods and/or direct or indirect mortality due to tags. In 1996 chicks in ten broods from hens with radio transmitters were individually treated at 14 days of age at a rate of 1 mg/kg of chick with a deltamethrin pour-on preparation. This preparation significantly reduced the number of larvae and nymphs on grouse chicks 7-10 days after application below the number on untreated controls. At 20 days from application, however, only larval numbers were lower on treated chicks. Nevertheless louping-ill virus infection prevalences were significantly reduced at 35 days of age and survival of chicks to 10 weeks increased.
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Abstract
African horse sickness (AHS) is a disease that affects equids, and is principally transmitted by Culicoides spp. that are biological vectors of AHS viruses (AHSV). The repeated spread of AHSV from sub-Saharan Africa to the Middle East, northern Africa and the Iberian peninsula indicate that a better understanding of AHS epizootiology is needed. African horse sickness has long been known to infect and cause mortality among domestic dogs that ingest virus contaminated meat, but it is uncertain what role carnivores play in transmission of the virus. We present evidence of widespread natural AHS infection among a diversity of African carnivore species. We hypothesize that such infection resulted from ingestion of meat and organs from AHS-infected prey species. The effect of AHS on the carnivores is unknown, as is their role in the maintenance cycle of the disease.
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Affiliation(s)
- K A Alexander
- Department of Veterinary Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, 95616, USA.
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Affiliation(s)
- M Karen Laurenson
- Department of Biological and Molecular Sciences, University of Stirling, Stirling, U.K
| | - Nadja Wielebnowski
- Ecology Graduate Group and Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, CA 95616 U.S.A
| | - T M Caro
- Center for Population Biology and Department of Wildlife, Fish. and Conservation Biology, University of California, Davis, CA 95616, U.S.A
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Parada L, Cabrera P, Burges C, Acuña A, Barcelona C, Laurenson MK, Gulland FM, Agulla J, Parietti S, Paolillo E. Echinococcus granulosus infections of dogs in the Durazno region of Uruguay. Vet Rec 1995; 136:389-91. [PMID: 7604519 DOI: 10.1136/vr.136.15.389] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The prevalence and distribution of Echinococcus granulosus in domestic dogs was examined in three dog populations in the Durazno region of Uruguay. The prevalence was 19.7 per cent in 704 dogs successfully purged with arecoline hydrobromide. Higher prevalences were detected in dogs from the rural area (30.0 per cent) and the village of La Paloma (25.9 per cent) than in the town of Sarandi del Yi (7.9 per cent). The frequency distribution of E granulosus was overdispersed (k, the negative binomial parameter = 0.08), with only a few animals harbouring heavy infections. The results of a questionnaire showed that the prevalence was greatest in male dogs, in dogs that were not kennelled, in dogs that had access to fields and in dogs that were not dosed with praziquantel. Dogs that were given raw sheep offal by their owners were no more likely to be parasitised than other dogs; this may reflect the inaccuracy of the owners' replies, or that the dogs were being infected outside their home.
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Affiliation(s)
- L Parada
- Fundacion de San Antonio de Padua, Sarandi del Yi, Durazno Region, Uruguay
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Hudson PJ, Norman R, Laurenson MK, Newborn D, Gaunt M, Jones L, Reid H, Gould E, Bowers R, Dobson A. Persistence and transmission of tick-borne viruses: Ixodes ricinus and louping-ill virus in red grouse populations. Parasitology 1995; 111 Suppl:S49-58. [PMID: 8632924 DOI: 10.1017/s0031182000075818] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The population dynamics of tick-borne disease agents and in particular the mechanisms which influence their persistence are examined with reference to the flavivirus that causes louping-ill in red grouse and sheep. Pockets of infection cause heavy mortality and the infection probably persists as a consequence of immigration of susceptible hosts. Seroprevalence is positively associated with temporal variations in vectors per host, although variation between areas is associated with the abundance of mountain hares. The presence of alternative tick hosts, particularly large mammals, provides additional hosts for increasing tick abundance. Grouse alone can not support the vectors and the pathogen but both can persist when a non-viraemic mammalian host supports the tick population and a sufficiently high number of nymphs bite grouse. These alternative hosts may also amplify virus through non-viraemic transmission by the process of co-feeding, although the relative significance of this has yet to be determined. Another possible route of infection is through the ingestion of vectors when feeding or preening. Trans-ovarial transmission is a potentially important mechanism for virus persistence but has not been recorded with louping-ill and Ixodes ricinus. The influence of non-viraemic hosts, both in the multiplication of vectors and the amplification of virus through non-viraemic transmission are considered significant for virus persistence.
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Affiliation(s)
- P J Hudson
- Department of Biological and Molecular Sciences, University of Stirling, UK
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Gasser RB, Parada L, Acuna A, Burges C, Laurenson MK, Gulland FM, Reichel MP, Paolillo E. Immunological assessment of exposure to Echinococcus granulosus in a rural dog population in Uruguay. Acta Trop 1994; 58:179-85. [PMID: 7709857 DOI: 10.1016/0001-706x(94)90012-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
An ELISA was used to screen a dog population in Uruguay (Sarandi Del Yi, Durazno District) for the prevalence of specific serum antibodies (IgG, IgA and IgE) to Echinococcus granulosus. The sensitivity (61%) and specificity (97%) of the ELISA were determined using well-defined serum groups. A total of 408 dogs from Sarandi del Yi and environs were screened serologically, and 29.7% (8.6-13.8% for each antibody class) of dogs had positive levels of antibody to E. granulosus. This antibody prevalence (exposure) was significantly higher than the percentage of dogs found to be positive for E. granulosus worms by arecoline purgation (7.6%). This level of exposure to E. granulosus determined by ELISA is considered unacceptable from a public health perspective. Measures will now focus on obtaining data on the true prevalence of current infection in this dog population and on determining the transmission patterns of the disease in this endemic region.
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Affiliation(s)
- R B Gasser
- Department of Veterinary Science, University of Melbourne, Werribee, Victoria, Australia
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Alexander KA, Holekamp K, MacLachlan NJ, Frank LG, Sawyer M, Osburn BI, Mills MGL, Lerche NW, Laurenson MK, McNutt JW, O'Brien SJ, House C, Smale L, Kat PW. Evidence of Natural Bluetongue Virus Infection among African Carnivores. Am J Trop Med Hyg 1994. [DOI: 10.4269/ajtmh.1994.51.568] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Gascoyne SC, King AA, Laurenson MK, Borner M, Schildger B, Barrat J. Aspects of rabies infection and control in the conservation of the African wild dog (Lycaon pictus) in the Serengeti region, Tanzania. Onderstepoort J Vet Res 1993; 60:415-20. [PMID: 7777330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Lycaon pictus is amongst the most endangered wildlife species in Africa. In 1990 rabies virus was isolated from the brain of an adult Lycaon found dead in the Serengeti region of Tanzania. One adult and six pups of the same pack feeding on the carcass showed clinical signs and rabies was suspected; within two days they had disappeared and are presumed to have died. Subsequently, two Lycaon packs in the Serengeti National Park were given inactivated rabies vaccine either by dart or by parenteral inoculation following anaesthesia. Lycaon sera which had been collected over the previous two years and sera collected pre- and post-vaccination were examined for the presence of rabies virus neutralizing antibody. Three of 12 unvaccinated Lycaon had antibody levels > 0.5 IU/ml; post-vaccination samples from two Lycaon showed increased antibody levels. Between four and ten months post-vaccination, at least four of the vaccinated animals had died from unknown causes. Issues relating to wildlife vaccination and veterinary intervention in conservation are discussed.
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Abstract
Rabies was confirmed as the cause of death of one African wild dog (Lycaon pictus) in the Serengeti region, Tanzania. One adult African wild dog in the same pack showed central nervous signs consistent with rabies infection. Inactivated rabies vaccine was administered intramuscularly to African wild dogs in two packs, by dart or by hand following anesthesia. These individuals comprised all known adults in the Serengeti National Park. In a limited study of seroprevalence of rabies antibody carried out at the time of vaccination, 3 of 12 African wild dogs sampled in the Serengeti had rabies serum neutralizing antibody titers before vaccination. Paired serum samples from two individuals sampled after vaccination showed increased antibody titers.
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Affiliation(s)
- S C Gascoyne
- Serengeti Wildlife Research Institute, Arusha, Tanzania
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Olmsted RA, Langley R, Roelke ME, Goeken RM, Adger-Johnson D, Goff JP, Albert JP, Packer C, Laurenson MK, Caro TM. Worldwide prevalence of lentivirus infection in wild feline species: epidemiologic and phylogenetic aspects. J Virol 1992; 66:6008-18. [PMID: 1382145 PMCID: PMC241478 DOI: 10.1128/jvi.66.10.6008-6018.1992] [Citation(s) in RCA: 133] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The natural occurrence of lentiviruses closely related to feline immunodeficiency virus (FIV) in nondomestic felid species is shown here to be worldwide. Cross-reactive antibodies to FIV were common in several free-ranging populations of large cats, including East African lions and cheetahs of the Serengeti ecosystem and in puma (also called cougar or mountain lion) populations throughout North America. Infectious puma lentivirus (PLV) was isolated from several Florida panthers, a severely endangered relict puma subspecies inhabiting the Big Cypress Swamp and Everglades ecosystems in southern Florida. Phylogenetic analysis of PLV genomic sequences from disparate geographic isolates revealed appreciable divergence from domestic cat FIV sequences as well as between PLV sequences found in different North American locales. The level of sequence divergence between PLV and FIV was greater than the level of divergence between human and certain simian immunodeficiency viruses, suggesting that the transmission of FIV between feline species is infrequent and parallels in time the emergence of HIV from simian ancestors.
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Affiliation(s)
- R A Olmsted
- Department of Microbiology, Georgetown University, Washington, D.C
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