1
|
Bowater RO, Gummow B, Mackie T, Thompson AR, Hayes DA, Goudkamp K, Taylor JD. Toxoplasmosis epidemic in a population of urbanised allied rock-wallabies (Petrogale assimilis) on Magnetic Island (Yunbenun), North Queensland. Aust Vet J 2024; 102:256-263. [PMID: 38361144 DOI: 10.1111/avj.13319] [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: 05/09/2023] [Revised: 12/26/2023] [Accepted: 01/21/2024] [Indexed: 02/17/2024]
Abstract
A mortality event involving 23 allied rock-wallabies (Petrogale assimilis) displaying neurological signs and sudden death occurred in late April to May 2021 in a suburban residential area directly adjacent to Magnetic Island National Park, on Magnetic Island (Yunbenun), North Queensland, Australia. Three allied rock-wallabies were submitted for necropsy, and in all three cases, the cause of death was disseminated toxoplasmosis. This mortality event was unusual because only a small, localised population of native wallabies inhabiting a periurban area on a tropical island in the Great Barrier Reef World Heritage Area were affected. A disease investigation determined the outbreak was likely linked to the presence of free-ranging feral and domesticated cats inhabiting the area. There were no significant deaths of other wallabies or wildlife in the same or other parts of Magnetic Island (Yunbenun) at the time of the outbreak. This is the first reported case of toxoplasmosis in allied rock-wallabies (Petrogale assimilis), and this investigation highlights the importance of protecting native wildlife species from an infectious and potentially fatal parasitic disease.
Collapse
Affiliation(s)
- R O Bowater
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Solander Road, Townsville, 4811, Queensland, Australia
| | - B Gummow
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Solander Road, Townsville, 4811, Queensland, Australia
- Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | - T Mackie
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Solander Road, Townsville, 4811, Queensland, Australia
| | - A R Thompson
- Department of Primary Industries, Parks, Water and Environment, Animal Health Laboratory, 165 Westbury Road, Prospect, Launceston, Tasmania, 7250, Australia
| | - D A Hayes
- Launceston General Hospital, Launceston, Tasmania, 7250, Australia
| | - K Goudkamp
- Nelly Bay, Magnetic Island, Queensland, 4819, Australia
| | - J D Taylor
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Solander Road, Townsville, 4811, Queensland, Australia
| |
Collapse
|
2
|
Yang L, Ren H, Zhu N, Mao G, Li J, Su C, Jiang Y, Yang Y. Epidemiology and isolation of viable Toxoplasma gondii strain from macropods. Heliyon 2023; 9:e13960. [PMID: 36938389 PMCID: PMC10015192 DOI: 10.1016/j.heliyon.2023.e13960] [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: 12/05/2022] [Revised: 02/10/2023] [Accepted: 02/16/2023] [Indexed: 03/04/2023] Open
Abstract
Wallabies and other marsupials are highly susceptible to Toxoplasma gondii. In this study, 26 macropod samples were collected (8 red kangaroos, 4 Parma wallabies, 8 red-necked wallabies, 5 albino red-necked wallabies and 1 Eastern grey kangaroo), including tissue (n = 9) and serum (n = 17) samples. According to the modified agglutination test (MAT) results (cutoff 1:25), 50% (95% Cl: 32.06-67.94%) of the macropods had T. gondii antibodies. Among them, species, survival state, and sampling date were risk factors for T. gondii susceptibility (P < 0.05). T. gondii DNA was detected in two (cases #14 and #15) of the nine cases obtained from macropod tissues. One viable T. gondii strain (TgRooCHn4) was isolated from an albino red-necked wallaby (Macropus rufogriseus, case #14) via bioassay in mice. TgRooCHn4 belongs to ToxoDB genotype #3, using the 10 multilocus PCR-RFLP markers. The ROP18 and ROP5 gene allele types of TgRooCHn4 were 2/2, which was predicted to be non-lethal to mice. The virulence of TgRooCHn4 tachyzoites was avirulent in mice. Most macropods sampled from Hernan province in 2021 and 2022 were positive with T. gondii infection. A flood occurred in July 2021 in Zhengzhou from Henan province may promote the transmission of T. gondii oocysts. To our knowledge, this is the first T. gondii strain isolated from albino red-necked wallaby. However, further investigation is required to enhance our understanding of the transmission and prevention of toxoplasmosis in sensitive zoo animals.
Collapse
Affiliation(s)
- Liulu Yang
- Veterinary Pathology, Henan Agricultural University, Zhengzhou, PR China
| | - Hongjie Ren
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou, PR China
| | - Niuping Zhu
- Veterinary Pathology, Henan Agricultural University, Zhengzhou, PR China
| | - Gaohui Mao
- Veterinary Pathology, Henan Agricultural University, Zhengzhou, PR China
| | | | - Chunlei Su
- Department of Microbiology, University of Tennessee, Knoxville, USA
| | - Yibao Jiang
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou, PR China
- Corresponding author.
| | - Yurong Yang
- Veterinary Pathology, Henan Agricultural University, Zhengzhou, PR China
- Corresponding author.
| |
Collapse
|
3
|
Ferreira LB, Furtado JM, Charng J, Franchina M, Matthews JM, Molan AAL, Hunter M, Mackey DA, Smith JR. Prevalence of Toxoplasmic Retinochoroiditis in an Australian Adult Population: a Community-Based Study. Ophthalmol Retina 2022; 6:963-968. [PMID: 35568370 DOI: 10.1016/j.oret.2022.04.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 04/27/2022] [Accepted: 04/28/2022] [Indexed: 11/24/2022]
Abstract
OBJECTIVE Toxoplasmic retinochoroiditis is the most common clinical manifestation of an infection with the protozoan parasite, Toxoplasma gondii. Up to 50% of the human population is estimated to be infected with T. gondii. However, the epidemiology of toxoplasmic retinochoroiditis is not widely reported. We sought to estimate the prevalence of toxoplasmic retinochoroiditis in Australia using data collected as part of the Busselton Healthy Ageing Study. DESIGN Cross-sectional, community-based, prospective cohort study. PARTICIPANTS 5,020 Australian adults (2,264 men and 2,756 women; age range of 45-69 years and median age of 58 years). METHODS Retinal color photographs centered on the optic disc and macula were captured on a digital retinal camera following dilation of the pupils. Three uveitis-subspecialized ophthalmologists assessed each pigmented retinal lesion, and complete concordance of opinion was required to assign a toxoplasmic etiology. Serum T. gondii immunoglobulin (Ig)G levels were measured for those participants with retinal lesions judged to be toxoplasmic retinochoroiditis. MAIN OUTCOME MEASURES Prevalence of toxoplasmic retinochoroiditis. RESULTS Eight participants (0.16%) had retinal lesions that were considered to have the characteristic appearance of toxoplasmic retinochoroiditis, plus detectable serum T. gondii IgG, consistent with the diagnosis of toxoplasmic retinochoroiditis. On the assumption that 23.81% of retinal lesions occur at the posterior pole, as reported in a community-based survey conducted in Brazil (Sci Rep. 2021;11:3420), the prevalence of toxoplasmic retinochoroiditis was estimated at 0.67% or 1 per 149 persons. CONCLUSIONS Toxoplasmic retinochoroiditis is common in Australian adults. Efforts to quantify and address risk factors for human infection with T. gondii are justified.
Collapse
Affiliation(s)
- Lisia B Ferreira
- Flinders University College of Medicine and Public Health, Adelaide, Australia
| | - João M Furtado
- Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, Brazil
| | - Jason Charng
- Centre for Ophthalmology and Visual Science, Lions Eye Institute
| | - Maria Franchina
- Centre for Ophthalmology and Visual Science, Lions Eye Institute
| | - Janet M Matthews
- Flinders University College of Medicine and Public Health, Adelaide, Australia
| | - Aus A L Molan
- Edith Cowan University, Perth, Australia; PathWest Laboratory Medicine WA, Perth, Australia
| | - Michael Hunter
- School of Population and Global Health, University of Western Australia, Perth, Australia
| | - David A Mackey
- Centre for Ophthalmology and Visual Science, Lions Eye Institute
| | - Justine R Smith
- Flinders University College of Medicine and Public Health, Adelaide, Australia; Queensland Eye Institute, Brisbane, Australia.
| |
Collapse
|
4
|
Campbell K, Paparini A, Gomez AB, Cannell B, Stephens N. Fatal toxoplasmosis in Little Penguins (Eudyptula minor) from Penguin Island, Western Australia. Int J Parasitol Parasites Wildl 2022; 17:211-217. [PMID: 35198375 PMCID: PMC8850582 DOI: 10.1016/j.ijppaw.2022.02.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 02/08/2022] [Accepted: 02/08/2022] [Indexed: 11/18/2022]
Abstract
Routine post mortems of deceased penguins from Penguin Island, Western Australia, found that a temporal cluster of cases presented with characteristic gross and microscopic changes, namely birds in good body condition with hepatomegaly and splenomegaly, multifocal hepatic and splenic necrosis and numerous, 1–2 μm diameter protozoan parasites within the necrotic foci. Electron microscopy identified the protozoa as belonging to the phylum Apicomplexa. Molecular investigations by PCR gave inconsistent results. PCR performed by an external laboratory identified a novel Haemoproteus spp. organism in samples from 4 of 10 cases from this group, while PCR at Murdoch University identified Toxoplasma gondii in 12 of 13 cases (including 9 of the 10 assayed at the external laboratory). Immunohistochemistry of formalin fixed tissues also identified Toxoplasma in the hepatic and splenic lesions. The distinctive mortalities which were observed in this group of penguins are attributed to a fulminant toxoplasmosis, with a concurrent Haemoproteus infection in some cases. Though the clinical signs of infection are unknown, the gross and microscopic appearance at post mortem is sufficiently characteristic to allow a diagnosis to be made on these features. Definitive confirmation of Toxoplasma infection can be made by immunohistochemistry or PCR. Deaths in Little Penguins were associated with necrosis in the liver and spleen. The necrotic lesions contained protozoa, free and in cysts. The protozoa were identified as Toxoplasma by PCR and immunohistochemistry.
Collapse
Affiliation(s)
- Kym Campbell
- Department of Primary Industries and Regional Development, Kensington, WA, Australia
- Corresponding author.
| | - Andrea Paparini
- Econumerics Consultants, Hilton, WA, Australia
- College of Science, Health, Engineering and Education, Murdoch University, Murdoch, WA, Australia
| | - Adriana Botero Gomez
- Department of Diagnostic Genomics, Pathwest Laboratory Medicine, QEII Medical Centre, Nedlands, WA, Australia
| | - Belinda Cannell
- Department of Diagnostic Genomics, Pathwest Laboratory Medicine, QEII Medical Centre, Nedlands, WA, Australia
- Oceans Institute, University of Western Australia, Crawley, 6009, WA, Australia
| | - Nahiid Stephens
- College of Science, Health, Engineering and Education, Murdoch University, Murdoch, WA, Australia
| |
Collapse
|
5
|
McKay PA, Hufschmid J, Meredith AL, Zendejas-Heredia PA, Moseby KE. Seroprevalence of Toxoplasma gondii in burrowing bettongs (Bettongia lesueur): a comparison of cat-free and cat-exposed populations. AUST J ZOOL 2022. [DOI: 10.1071/zo22010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
6
|
Dubey JP, Murata FHA, Cerqueira-Cézar CK, Kwok OCH, Su C, Grigg ME. Recent aspects on epidemiology, clinical disease, and genetic diversity of Toxoplasma gondii infections in Australasian marsupials. Parasit Vectors 2021; 14:301. [PMID: 34090502 PMCID: PMC8180119 DOI: 10.1186/s13071-021-04793-4] [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: 03/15/2021] [Accepted: 05/20/2021] [Indexed: 11/13/2022] Open
Abstract
Background Toxoplasma gondii infections are common in humans and animals worldwide. Among all intermediate hosts of T. gondii, captive marsupials from Australia and New Zealand are highly susceptible to clinical toxoplasmosis. However, most free-range marsupials establish chronic T. gondii infection. Infected marsupial meat may serve as a source of T. gondii infection for humans. Differences in mortality patterns in different species of kangaroos and other marsupials are not fully understood. Lifestyle, habitat, and the genotype of T. gondii are predicted to be risk factors. For example, koalas are rarely exposed to T. gondii because they live on treetops whereas wallabies on land are frequently exposed to infection. Methods The present review summarizes worldwide information on the prevalence of clinical and subclinical infections, epidemiology, and genetic diversity of T. gondii infecting Australasian marsupials in their native habitat and among exported animals over the past decade. The role of genetic types of T. gondii and clinical disease is discussed. Results Fatal toxoplasmosis has been diagnosed in captive Australasian marsupials in Argentina, Chile, China, Germany, Hungary, Japan, Spain, Turkey, and the USA. Most deaths occurred because of disseminated toxoplasmosis. Genetic characterization of T. gondii strains isolated from fatal marsupial infections identified Type III as well as atypical, nonclonal genotypes. Fatal toxoplasmosis was also diagnosed in free-ranging wombats (Vombatus ursinus) in Australia. Genetic characterization of DNA amplified directly from host tissues of subclinical culled kangaroos at slaughter identified many mixed-strain infections with both atypical and recombinant genotypes of T. gondii. Conclusions Most Australasian marsupials in their native land, Australia and New Zealand, have high prevalence of T. gondii, and kangaroo meat can be a source of infection for humans if consumed uncooked/undercooked. The genotypes prevalent in kangaroos in Australia and New Zealand were genetically distinct from those isolated or genotyped from most macropods in the USA and other countries. Thus, clinical toxoplasmosis in marsupials imported from Australia is most likely to occur from infections acquired after importation. Graphic abstract ![]()
Collapse
Affiliation(s)
- Jitender P Dubey
- United States Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal Parasitic Diseases Laboratory, Building 1001, Beltsville, MD, 20705-2350, USA.
| | - Fernando H A Murata
- United States Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal Parasitic Diseases Laboratory, Building 1001, Beltsville, MD, 20705-2350, USA
| | - Camila K Cerqueira-Cézar
- United States Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal Parasitic Diseases Laboratory, Building 1001, Beltsville, MD, 20705-2350, USA
| | - Oliver C H Kwok
- United States Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal Parasitic Diseases Laboratory, Building 1001, Beltsville, MD, 20705-2350, USA
| | - Chunlei Su
- Department of Microbiology, University of Tennessee, Knoxville, TN, 37996-0845, USA
| | - Michael E Grigg
- Molecular Parasitology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20895, USA
| |
Collapse
|
7
|
Díaz-Delgado J, Kellerman TE, Auckland L, Ferro PJ, Groch KR, Gomez G, Hamer SA. Trypanosoma cruzi Genotype I and Toxoplasma gondii Co-infection in a Red-Necked Wallaby. J Comp Pathol 2020; 179:52-58. [PMID: 32958148 DOI: 10.1016/j.jcpa.2020.07.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 06/17/2020] [Accepted: 07/15/2020] [Indexed: 11/19/2022]
Abstract
While the health effects of trypanosomes in Australian mammals in their native range are not fully understood, there is evidence of an impact in those species introduced to other geographical regions. Here we report the pathological and molecular features of concurrent fatal trypanosomiasis and toxoplasmosis in an adult female captive red-necked wallaby (syn. Bennett's wallaby; Macropus rufogriseus) from Bee County, Texas, USA. The animal exhibited no clinical signs prior to sudden death. On necropsy, the main findings were generalized organ congestion and bilateral renal petechiation. Microscopically, the main finding was lymphohistiocytic and necrotizing pancarditis with intrasarcoplasmic protozoal pseudocysts containing amastigotes and occasional intrahistiocytic amastigotes, morphologically compatible with Trypanosoma cruzi, as well as rare intrasarcoplasmic protozoal tissue cysts with zoites morphologically compatible with Toxoplasma gondii. Other lesions included acute centrilobular to panlobular necrotizing hepatitis with intrahepatocellular T. gondii cysts, necrotizing splenitis, pulmonary oedema with fibrin, histiocytosis and rare fibrin microthrombi, and acute renal tubular degeneration with proteinosis and pigmented casts suggestive of haemoglobinuria or myoglobinuria. Immunohistochemical labelling confirmed intralesional T. gondii cysts and molecular analyses identified T. cruzi genotype I and T. gondii. This is a unique case that, to the best of our knowledge, represents the first description of T. cruzi and T. gondii co-infection, as well as the first record of naturally occurring infection T. cruzi genotype I infection in macropodids. This case adds to the epidemiological knowledge on Chagas disease in the USA, particularly in Texas where there is a high prevalence of human and canine trypanosomiasis.
Collapse
Affiliation(s)
- J Díaz-Delgado
- Texas A&M Veterinary Medical Diagnostic Laboratory, College Station, USA.
| | | | - L Auckland
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas, USA
| | - P J Ferro
- Texas A&M Veterinary Medical Diagnostic Laboratory, College Station, USA
| | - K R Groch
- Department of Veterinary Pathobiology, Texas A&M University, College Station, Texas, USA
| | - G Gomez
- Texas A&M Veterinary Medical Diagnostic Laboratory, College Station, USA
| | - S A Hamer
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas, USA
| |
Collapse
|
8
|
Ross AK, Lowry J, Elphinstone A, Lawes JC. Toxoplasma gondii seroprevalence in endangered bridled nailtail wallabies and co-occurring species. AUSTRALIAN MAMMALOGY 2020. [DOI: 10.1071/am19030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The parasite Toxoplasma gondii can infect any warm-blooded species; however, seroprevalence in most species remains largely unknown. In this study we examined the presence of T. gondii antibodies in captured individuals in the two remaining wild populations and one captive population of endangered bridled nailtail wallabies (Onychogalea fraenata). Samples from cats (Felis catus), rabbits (Oryctolagus cuniculus) and dogs (Canis lupus) were also taken opportunistically during invasive species control at the two wild populations. Seventy-one wallabies, sixteen cats, four rabbits, and two dogs’ blood samples were tested for T. gondii using a modified agglutination test. Half of the tested feral cats (n = 8) were seropositive and all intermediate hosts were seronegative for T. gondii antibodies. This unexpected result suggests a loss of infected individuals before capture and testing, or parasite infectivity being suppressed by Queensland’s hot, dry climate.
Collapse
|
9
|
Su R, Dong H, Li T, Jiang Y, Yuan Z, Su C, Zhang L, Yang Y. Toxoplasma gondii in four captive kangaroos ( Macropus spp.) in China: Isolation of a strain of a new genotype from an eastern grey kangaroo ( Macropus giganteus). INTERNATIONAL JOURNAL FOR PARASITOLOGY-PARASITES AND WILDLIFE 2019; 8:234-239. [PMID: 30923671 PMCID: PMC6423483 DOI: 10.1016/j.ijppaw.2019.03.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Revised: 03/07/2019] [Accepted: 03/09/2019] [Indexed: 12/11/2022]
Abstract
Marsupials are highly susceptible to Toxoplasma gondii infection. Here, we report T. gondii infection in four kangaroos from a zoo in China. Kangaroos were imported into China in 2000 and were since bred in zoo. In 2017-2018, four kangaroos died due to respiratory system disease or injury. The bodies were submitted to the laboratory to test for T. gondii infection. Antibodies to T. gondii were found in 75% (3/4) of the kangaroos via the modified agglutination test with the cut-off 1:25. Cysts were observed in the histopathological sections of tongue and diaphragm or squashes of fresh myocardium in two kangaroos. These cysts were confirmed as T. gondii by immunohistochemical staining and molecular biological analysis. One viable T. gondii strain was isolated from one kangaroo and designated as TgRooCHn1. DNA from T. gondii tachyzoites obtained from cell culture was characterized by 10 PCR-RFLP markers and the virulence genes ROP5 and ROP18. The genotype of this isolate did not match with any known genotypes; it was designated as ToxoDB#292. The virulence of TgRooCHn1 (104 tachyzoites) was non-lethal to mice, and it formed tissue cysts. To our knowledge, the present study is the first isolation of ToxoDB#292 strain from kangaroo. Improvemets for captive settings were initiated, including greater attention being paied to birds and stray cats, fed frozen meat for carnivores.
Collapse
Affiliation(s)
- Ruijing Su
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, PR China
| | - Hui Dong
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, PR China
| | | | - Yibao Jiang
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, PR China
| | - Ziguo Yuan
- Key Laboratory of Zoonosis of Ministry of Agriculture and Rural Affairs, South China Agricultural University, Guangzhou, PR China
| | - Chunlei Su
- Department of Microbiology, University of Tennessee, Knoxville, USA
| | - Longxian Zhang
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, PR China
| | - Yurong Yang
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, PR China
| |
Collapse
|
10
|
Simon JA, Pradel R, Aubert D, Geers R, Villena I, Poulle ML. A multi-event capture-recapture analysis of Toxoplasma gondii seroconversion dynamics in farm cats. Parasit Vectors 2018; 11:339. [PMID: 29884240 PMCID: PMC5994099 DOI: 10.1186/s13071-018-2834-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 04/06/2018] [Indexed: 11/11/2022] Open
Abstract
Background Domestic cats play a key role in the epidemiology of the parasite Toxoplasma gondii by excreting environmentally-resistant oocysts that may infect humans and other warm-blooded animals. The dynamics of Toxoplasma gondii seroconversion, used as a proxy for primo-infection dynamics, was investigated in five cat populations living on farms. Methods Serological tests on blood samples from cats were performed every three months over a period of two years, for a total of 400 serological tests performed on 130 cats. Variations in seroconversion rates and associated factors were investigated using a multi-event capture-recapture modelling approach that explicitly accounted for uncertainties in cat age and serological status. Results Seroprevalence varied between farms, from 15 to 73%, suggesting differential exposure of cats to T. gondii. In farms with high exposure, cats could become infected before reaching the age of six months. Seroconversion rates varied from 0.42 to 0.96 seroconversions per cat per year and were higher in autumn and winter than in spring and summer. Conclusion Our results suggest inter-farm and seasonal variations in the risks of exposure to T. gondii oocysts for humans and livestock living on farms. The paper also discusses the role of young cats in the maintenance of environmental contamination by T. gondii oocysts on farms. Electronic supplementary material The online version of this article (10.1186/s13071-018-2834-4) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Julie Alice Simon
- Université de Reims Champagne-Ardenne, Laboratoire de Parasitologie - Mycologie, EA 3800, UFR Médecine, SFR CAP-SANTÉ, 51 rue Cognacq Jay, 51095, Reims, France. .,Université de Reims Champagne-Ardenne, Centre d'Etude et de Formation en Eco-Ethologie (URCA, CERFE), 5 rue de la Héronnière, 08240, Boult-aux-Bois, France.
| | - Roger Pradel
- Centre d'Ecologie Fonctionnelle et Evolutive (CEFE) UMR 5175, CNRS - Université de Montpellier - Université Paul Valéry - EPHE, 1919 route de Mende, 34293, Montpellier 5, France
| | - Dominique Aubert
- Université de Reims Champagne-Ardenne, Laboratoire de Parasitologie - Mycologie, EA 3800, UFR Médecine, SFR CAP-SANTÉ, 51 rue Cognacq Jay, 51095, Reims, France.,Laboratoire de Parasitologie-Mycologie, Centre National de Référence de la Toxoplasmose, Hôpital Maison Blanche, CHU Reims, 45 rue Cognacq Jay, 51092, Reims, France
| | - Régine Geers
- Université de Reims Champagne-Ardenne, Laboratoire de Parasitologie - Mycologie, EA 3800, UFR Médecine, SFR CAP-SANTÉ, 51 rue Cognacq Jay, 51095, Reims, France.,Laboratoire de Parasitologie-Mycologie, Centre National de Référence de la Toxoplasmose, Hôpital Maison Blanche, CHU Reims, 45 rue Cognacq Jay, 51092, Reims, France
| | - Isabelle Villena
- Université de Reims Champagne-Ardenne, Laboratoire de Parasitologie - Mycologie, EA 3800, UFR Médecine, SFR CAP-SANTÉ, 51 rue Cognacq Jay, 51095, Reims, France.,Laboratoire de Parasitologie-Mycologie, Centre National de Référence de la Toxoplasmose, Hôpital Maison Blanche, CHU Reims, 45 rue Cognacq Jay, 51092, Reims, France
| | - Marie-Lazarine Poulle
- Université de Reims Champagne-Ardenne, Laboratoire de Parasitologie - Mycologie, EA 3800, UFR Médecine, SFR CAP-SANTÉ, 51 rue Cognacq Jay, 51095, Reims, France.,Université de Reims Champagne-Ardenne, Centre d'Etude et de Formation en Eco-Ethologie (URCA, CERFE), 5 rue de la Héronnière, 08240, Boult-aux-Bois, France
| |
Collapse
|
11
|
Abstract
Wildlife parasitology is a highly diverse area of research encompassing many fields including taxonomy, ecology, pathology and epidemiology, and with participants from extremely disparate scientific fields. In addition, the organisms studied are highly dissimilar, ranging from platyhelminths, nematodes and acanthocephalans to insects, arachnids, crustaceans and protists. This review of the parasites of wildlife in Australia highlights the advances made to date, focussing on the work, interests and major findings of researchers over the years and identifies current significant gaps that exist in our understanding. The review is divided into three sections covering protist, helminth and arthropod parasites. The challenge to document the diversity of parasites in Australia continues at a traditional level but the advent of molecular methods has heightened the significance of this issue. Modern methods are providing an avenue for major advances in documenting and restructuring the phylogeny of protistan parasites in particular, while facilitating the recognition of species complexes in helminth taxa previously defined by traditional morphological methods. The life cycles, ecology and general biology of most parasites of wildlife in Australia are extremely poorly understood. While the phylogenetic origins of the Australian vertebrate fauna are complex, so too are the likely origins of their parasites, which do not necessarily mirror those of their hosts. This aspect of parasite evolution is a continuing area for research in the case of helminths, but remains to be addressed for many other parasitic groups.
Collapse
|
12
|
Differential Gamma Interferon- and Tumor Necrosis Factor Alpha-Driven Cytokine Response Distinguishes Acute Infection of a Metatherian Host with Toxoplasma gondii and Neospora caninum. Infect Immun 2017; 85:IAI.00173-17. [PMID: 28348050 DOI: 10.1128/iai.00173-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Accepted: 03/18/2017] [Indexed: 01/05/2023] Open
Abstract
Toxoplasma gondii and Neospora caninum (both Apicomplexa) are closely related cyst-forming coccidian parasites that differ significantly in their host ranges and ability to cause disease. Unlike eutherian mammals, Australian marsupials (metatherian mammals) have long been thought to be highly susceptible to toxoplasmosis and neosporosis because of their historical isolation from the parasites. In this study, the carnivorous fat-tailed dunnart (Sminthopsis crassicaudata) was used as a disease model to investigate the immune response and susceptibility to infection of an Australian marsupial to T. gondii and N. caninum The disease outcome was more severe in N. caninum-infected dunnarts than in T. gondii-infected dunnarts, as shown by the severity of clinical and histopathological features of disease and higher tissue parasite burdens in the tissues evaluated. Transcriptome sequencing (RNA-seq) of spleens from infected dunnarts and mitogen-stimulated dunnart splenocytes was used to define the cytokine repertoires. Changes in mRNA expression during the time course of infection were measured using quantitative reverse transcription-PCR (qRT-PCR) for key Th1 (gamma interferon [IFN-γ] and tumor necrosis factor alpha [TNF-α]), Th2 (interleukin 4 [IL-4] and IL-6), and Th17 (IL-17A) cytokines. The results show qualitative differences in cytokine responses by the fat-tailed dunnart to infection with N. caninum and T. gondii Dunnarts infected with T. gondii were capable of mounting a more effective Th1 immune response than those infected with N. caninum, indicating the role of the immune response in the outcome scenarios of parasite infection in this marsupial mammal.
Collapse
|
13
|
Maldonado YA, Read JS. Diagnosis, Treatment, and Prevention of Congenital Toxoplasmosis in the United States. Pediatrics 2017; 139:peds.2016-3860. [PMID: 28138010 DOI: 10.1542/peds.2016-3860] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
|
14
|
Barbieri MM, Kashinsky L, Rotstein DS, Colegrove KM, Haman KH, Magargal SL, Sweeny AR, Kaufman AC, Grigg ME, Littnan CL. Protozoal-related mortalities in endangered Hawaiian monk seals Neomonachus schauinslandi. DISEASES OF AQUATIC ORGANISMS 2016; 121:85-95. [PMID: 27667806 DOI: 10.3354/dao03047] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Protozoal infections have been widely documented in marine mammals and may cause morbidity and mortality at levels that result in population level effects. The presence and potential impact on the recovery of endangered Hawaiian monk seals Neomonachus schauinslandi by protozoal pathogens was first identified in the carcass of a stranded adult male with disseminated toxoplasmosis and a captive monk seal with hepatitis. We report 7 additional cases and 2 suspect cases of protozoal-related mortality in Hawaiian monk seals between 2001 and 2015, including the first record of vertical transmission in this species. This study establishes case definitions for classification of protozoal infections in Hawaiian monk seals. Histopathology and immunohistochemistry were the primary diagnostic modalities used to define cases, given that these analyses establish a direct link between disease and pathogen presence. Findings were supported by serology and molecular data when available. Toxoplasma gondii was the predominant apicomplexan parasite identified and was associated with 100% of mortalities (n = 8) and 50% of suspect cases (n = 2). Incidental identification of sarcocysts in the skeletal muscle without tissue inflammation occurred in 4 seals, including one co-infected with T. gondii. In 2015, 2 cases of toxoplasmosis were identified ante-mortem and shared similar clinical findings, including hematological abnormalities and histopathology. Protozoal-related mortalities, specifically due to toxoplasmosis, are emerging as a threat to the recovery of this endangered pinniped and other native Hawaiian taxa. By establishing case definitions, this study provides a foundation for measuring the impact of these diseases on Hawaiian monk seals.
Collapse
Affiliation(s)
- Michelle M Barbieri
- National Oceanic and Atmospheric Administration, Pacific Islands Fisheries Science Center, Protected Species Division, Hawaiian Monk Seal Research Program, Honolulu, HI 96818, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Brennan A, Donahoe SL, Beatty JA, Belov K, Lindsay S, Briscoe KA, Šlapeta J, Barrs VR. Comparison of genotypes of Toxoplasma gondii in domestic cats from Australia with latent infection or clinical toxoplasmosis. Vet Parasitol 2016; 228:13-16. [DOI: 10.1016/j.vetpar.2016.06.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 05/29/2016] [Accepted: 06/04/2016] [Indexed: 10/21/2022]
|
16
|
Mawson PR, Hampton JO, Dooley B. Subsidized commercial harvesting for cost-effective wildlife management in urban areas: A case study with kangaroo sharpshooting. WILDLIFE SOC B 2016. [DOI: 10.1002/wsb.656] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Jordan O. Hampton
- Ecotone Wildlife Veterinary Services; P.O. Box 76 Inverloch VIC 3996 Australia
| | - Brendan Dooley
- Department of Parks and Wildlife Western Australia; Locked Bag 104, Bentley Delivery Centre; WA 6983 Australia
| |
Collapse
|
17
|
Hillman AE, Lymbery AJ, Thompson RA. Is Toxoplasma gondii a threat to the conservation of free-ranging Australian marsupial populations? Int J Parasitol Parasites Wildl 2016; 5:17-27. [PMID: 27141439 PMCID: PMC4840267 DOI: 10.1016/j.ijppaw.2015.12.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 12/07/2015] [Accepted: 12/11/2015] [Indexed: 11/25/2022]
Abstract
It has often been asserted that Australian marsupial species are particularly susceptible to Toxoplasma gondii infection and to clinical toxoplasmosis following infection. This implicates T. gondii as a potential threat to marsupial population viability, and contrasts to what is known of T. gondii in populations of several other host species. We reviewed the literature, and found a lack of scientifically robust evidence addressing the occurrence of T. gondii infection in free-ranging populations of Australian marsupial species, and the impacts of the infection on population health. Key limitations included a lack of studies in free-ranging marsupial populations, study findings susceptible to substantial chance influences, and selection, misclassification and confounding biases. The lack of scientifically robust data available on this topic indicates that assertions that free-ranging populations of Australian marsupials are particularly susceptible to T. gondii infection and to toxoplasmosis are premature. The threat of T. gondii to the viability of free-ranging marsupial populations should therefore be regarded, at this stage, as a hypothesis.
Collapse
|
18
|
Cooper MK, Šlapeta J, Donahoe SL, Phalen DN. Toxoplasmosis in a Pet Peach-Faced Lovebird (Agapornis roseicollis). THE KOREAN JOURNAL OF PARASITOLOGY 2015; 53:749-53. [PMID: 26797444 PMCID: PMC4725224 DOI: 10.3347/kjp.2015.53.6.749] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 09/22/2015] [Accepted: 09/29/2015] [Indexed: 11/23/2022]
Abstract
Toxoplasma gondii atypical type II genotype was diagnosed in a pet peach-faced lovebird (Agapornis roseicollis) based on histopathology, immunohistochemistry, and multilocus DNA typing. The bird presented with severe neurological signs, and hematology was suggestive of chronic granulomatous disease. Gross post-mortem examination revealed cerebral hemorrhage, splenomegaly, hepatitis, and thickening of the right ventricular free wall. Histologic sections of the most significant lesions in the brain revealed intralesional protozoan organisms associated with malacia, spongiform changes, and a mild histiocytic response, indicative of diffuse, non-suppurative encephalitis. Immunohistochemistry confirmed the causative organisms to be T. gondii. DNA isolated from the brain was used to confirm the presence of T. gondii DNA. Multilocus genotyping based on SAG1, altSAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico markers demonstrated the presence of ToxoDB PCR-RFLP genotype #3 and B1 gene as atypical T. gondii type II. The atypical type II strain has been previously documented in Australian wildlife, indicating an environmental transmission route.
Collapse
Affiliation(s)
- Madalyn K Cooper
- Veterinary Parasitology, Faculty of Veterinary Science, University of Sydney, New South Wales 2006, Australia
| | - Jan Šlapeta
- Veterinary Parasitology, Faculty of Veterinary Science, University of Sydney, New South Wales 2006, Australia
| | - Shannon L Donahoe
- Veterinary Parasitology, Faculty of Veterinary Science, University of Sydney, New South Wales 2006, Australia
| | - David N Phalen
- Veterinary Parasitology, Faculty of Veterinary Science, University of Sydney, New South Wales 2006, Australia
| |
Collapse
|
19
|
Cooper MK, Phalen DN, Donahoe SL, Rose K, Šlapeta J. The utility of diversity profiling using Illumina 18S rRNA gene amplicon deep sequencing to detect and discriminate Toxoplasma gondii among the cyst-forming coccidia. Vet Parasitol 2015; 216:38-45. [PMID: 26801593 DOI: 10.1016/j.vetpar.2015.12.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 12/10/2015] [Accepted: 12/14/2015] [Indexed: 12/21/2022]
Abstract
Next-generation sequencing (NGS) has the capacity to screen a single DNA sample and detect pathogen DNA from thousands of host DNA sequence reads, making it a versatile and informative tool for investigation of pathogens in diseased animals. The technique is effective and labor saving in the initial identification of pathogens, and will complement conventional diagnostic tests to associate the candidate pathogen with a disease process. In this report, we investigated the utility of the diversity profiling NGS approach using Illumina small subunit ribosomal RNA (18S rRNA) gene amplicon deep sequencing to detect Toxoplasma gondii in previously confirmed cases of toxoplasmosis. We then tested the diagnostic approach with species-specific PCR genotyping, histopathology and immunohistochemistry of toxoplasmosis in a Risso's dolphin (Grampus griseus) to systematically characterise the disease and associate causality. We show that the Euk7A/Euk570R primer set targeting the V1-V3 hypervariable region of the 18S rRNA gene can be used as a species-specific assay for cyst-forming coccidia and discriminate T. gondii. Overall, the approach is cost-effective and improves diagnostic decision support by narrowing the differential diagnosis list with more certainty than was previously possible. Furthermore, it supplements the limitations of cryptic protozoan morphology and surpasses the need for species-specific PCR primer combinations.
Collapse
Affiliation(s)
- Madalyn K Cooper
- Faculty of Veterinary Science, University of Sydney, Sydney, NSW 2006, Australia
| | - David N Phalen
- Faculty of Veterinary Science, University of Sydney, Sydney, NSW 2006, Australia
| | - Shannon L Donahoe
- Faculty of Veterinary Science, University of Sydney, Sydney, NSW 2006, Australia
| | - Karrie Rose
- Australian Registry of Wildlife Health, Taronga Conservation Society Australia, Mosman, NSW 2088, Australia
| | - Jan Šlapeta
- Faculty of Veterinary Science, University of Sydney, Sydney, NSW 2006, Australia.
| |
Collapse
|
20
|
Donahoe SL, Šlapeta J, Knowles G, Obendorf D, Peck S, Phalen DN. Clinical and pathological features of toxoplasmosis in free-ranging common wombats (Vombatus ursinus) with multilocus genotyping of Toxoplasma gondii type II-like strains. Parasitol Int 2015; 64:148-53. [DOI: 10.1016/j.parint.2014.11.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 11/11/2014] [Accepted: 11/13/2014] [Indexed: 11/29/2022]
|
21
|
Toxoplasma gondii superinfection and virulence during secondary infection correlate with the exact ROP5/ROP18 allelic combination. mBio 2015; 6:e02280. [PMID: 25714710 PMCID: PMC4358003 DOI: 10.1128/mbio.02280-14] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The intracellular parasite Toxoplasma gondii infects a wide variety of vertebrate species globally. Infection in most hosts causes a lifelong chronic infection and generates immunological memory responses that protect the host against new infections. In regions where the organism is endemic, multiple exposures to T. gondii likely occur with great frequency, yet little is known about the interaction between a chronically infected host and the parasite strains from these areas. A widely used model to explore secondary infection entails challenge of chronically infected or vaccinated mice with the highly virulent type I RH strain. Here, we show that although vaccinated or chronically infected C57BL/6 mice are protected against the type I RH strain, they are not protected against challenge with most strains prevalent in South America or another type I strain, GT1. Genetic and genomic analyses implicated the parasite-secreted rhoptry effectors ROP5 and ROP18, which antagonize the host’s gamma interferon-induced immunity-regulated GTPases (IRGs), as primary requirements for virulence during secondary infection. ROP5 and ROP18 promoted parasite superinfection in the brains of challenged survivors. We hypothesize that superinfection may be an important mechanism to generate T. gondii strain diversity, simply because two parasite strains would be present in a single meal consumed by the feline definitive host. Superinfection may drive the genetic diversity of Toxoplasma strains in South America, where most isolates are IRG resistant, compared to North America, where most strains are IRG susceptible and are derived from a few clonal lineages. In summary, ROP5 and ROP18 promote Toxoplasma virulence during reinfection. Toxoplasma gondii is a widespread parasite of warm-blooded animals and currently infects one-third of the human population. A long-standing assumption in the field is that prior exposure to this parasite protects the host from subsequent reexposure, due to the generation of protective immunological memory. However, this assumption is based on clinical data and mouse models that analyze infections with strains common to Europe and North America. In contrast, we found that the majority of strains sampled from around the world, in particular those from South America, were able to kill or reinfect the brains of hosts previously exposed to T. gondii. The T. gondii virulence factors ROP5 and ROP18, which inhibit key host effectors that mediate parasite killing, were required for these phenotypes. We speculate that these results underpin clinical observations that pregnant women previously exposed to Toxoplasma can develop congenital infection upon reexposure to South American strains.
Collapse
|
22
|
Fancourt BA, Nicol SC, Hawkins CE, Jones ME, Johnson CN. Beyond the disease: Is Toxoplasma gondii infection causing population declines in the eastern quoll (Dasyurus viverrinus)? Int J Parasitol Parasites Wildl 2014; 3:102-12. [PMID: 25161908 PMCID: PMC4142269 DOI: 10.1016/j.ijppaw.2014.05.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 04/15/2014] [Accepted: 05/14/2014] [Indexed: 02/08/2023]
Abstract
Disease is often considered a key threat to species of conservation significance. For some, it has resulted in localised extinctions and declines in range and abundance. However, for some species, the assertion that a disease poses a significant threat of extinction is based solely on correlative or anecdotal evidence, often inferred from individual clinical case reports. While a species' susceptibility to a disease may be demonstrated in a number of individuals, investigations rarely extend to measuring the impact of disease at the population level and its contribution, if any, to population declines. The eastern quoll (Dasyurus viverrinus) is a medium-sized Australian marsupial carnivore that is undergoing severe and rapid decline in Tasmania, its last refuge. Reasons for the decline are currently not understood. Feral cats (Felis catus) may be undergoing competitive release following the ongoing decline of the Tasmanian devil (Sarcophilus harrisii), with cats suppressing eastern quolls through increased predation, competition, exclusion or exposure to diseases such as toxoplasmosis. To investigate the effects of Toxoplasma gondii infection, eastern quoll populations at four sites were regularly screened for the seroprevalence of T. gondii-specific IgG antibodies. Seroprevalence was approximately five times higher at sites with declining quoll populations, and there was a negative association between seroprevalence and quoll abundance. However, T. gondii infection did not reduce quoll survival or reproduction. Despite a high susceptibility to T. gondii infection, eastern quoll populations do not appear to be limited by the parasite or its resultant disease. Significantly higher seroprevalence is a signal of greater exposure to feral cats at sites where eastern quolls are declining, suggesting that increased predation, competition or exclusion by feral cats may be precipitating population declines.
Collapse
Affiliation(s)
- Bronwyn A. Fancourt
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, TAS 7001, Australia
| | | | | | | | | |
Collapse
|
23
|
López Acosta GLK, Peña J, Brieva CI. INFECCIÓN POR PROTOZOARIOS EN INDIVIDUOS DE TITÍ BEBE LECHE (<i>S. fuscicollis</i>), TITÍ CABEZA BLANCA (<i>S. oedipus</i>), TITÍ ARDILLA (<i>S. sciureus</i>), SURICATA (<i>S. suricatta</i>) Y WALLABIE (<i>M. rufogriseus</i>). REVISTA DE LA FACULTAD DE MEDICINA VETERINARIA Y DE ZOOTECNIA 2014. [DOI: 10.15446/rfmvz.v61n2.44678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
|
24
|
Donahoe SL, Rose K, Slapeta J. Multisystemic toxoplasmosis associated with a type II-like Toxoplasma gondii strain in a New Zealand fur seal (Arctocephalus forsteri) from New South Wales, Australia. Vet Parasitol 2014; 205:347-53. [PMID: 25123611 DOI: 10.1016/j.vetpar.2014.07.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 07/18/2014] [Accepted: 07/21/2014] [Indexed: 12/11/2022]
Abstract
We report the first confirmed case of toxoplasmosis in an Australian pinniped. Presence of Toxoplasma gondii DNA was detected in the brain of a free-ranging subadult New Zealand fur seal (Arctocephalus forsteri) with nonsuppurative meningoencephalitis, hypophysitis, posterior uveitis, retrobulbar cellulitis, and myocarditis associated with protozoan cysts and tachyzoites. The emaciated seal stranded moribund on a beach in northern Sydney in New South Wales. Histopathology coupled with specific immunohistochemistry and PCR assays confirmed the presence of T. gondii. The T. gondii sample (NZfs8825) identified in this study has an identical genotype as the type II (ToxoDB PCR-RFLP genotype #1) based on the direct sequencing and virtual RFLP of multilocus DNA markers including SAG1, 5'- and 3'-SAG2, alt.SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico. Direct sequencing of T. gondii B1 DNA marker from the T. gondii sample (NZfs8825) identified a type II-like strain, based on presence of non-archetypal B1 gene polymorphisms previously reported as unique to Australia. This study suggests that T. gondii oocysts originating from mainland Australia, which has a large population of feral cats, may act as a disease threat to native marine fauna. Therefore, emerging toxoplasmosis in the Arctic has a relevant parallel in the Southern Ocean within Australian waters with yet unknown relevance to Antarctica.
Collapse
Affiliation(s)
- Shannon L Donahoe
- Faculty of Veterinary Science, University of Sydney, Sydney, NSW, Australia
| | - Karrie Rose
- Taronga Conservation Society Australia, Mosman, NSW, Australia; School of Public Health, Tropical Medicine and Rehabilitation Sciences, James Cook University, Townsville, QLD, Australia
| | - Jan Slapeta
- Faculty of Veterinary Science, University of Sydney, Sydney, NSW, Australia.
| |
Collapse
|
25
|
Abstract
AbstractThe woylie Bettongia penicillata is categorized as Critically Endangered, having declined by c. 90% between 1999 and 2006. The decline continues and the cause is not fully understood. Within a decline diagnosis framework we characterized the nature of the decline and identified potential causes, with a focus on the species’ largest populations, located in south-west Western Australia. We described the spatio-temporal pattern of the decline, and several attributes that are common across sites. We categorized the potential causes of the decline as resources, predators, disease and direct human interference. Based on the available evidence the leading hypothesis is that disease may be making woylies more vulnerable to predation but this remains to be tested. No substantial recoveries have been sustained to date, and one of the three remaining indigenous populations now appears to be extinct. Therefore, verifying the factors causing the decline and those limiting recovery is becoming increasingly urgent. Active adaptive management can be used to test putative agents, such as introduced predators. Insurance populations and ecological monitoring should also be included in an integrated conservation and management strategy for the species.
Collapse
|
26
|
Thompson RCA. Parasite zoonoses and wildlife: One Health, spillover and human activity. Int J Parasitol 2013; 43:1079-88. [PMID: 23892130 PMCID: PMC7126848 DOI: 10.1016/j.ijpara.2013.06.007] [Citation(s) in RCA: 188] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 06/21/2013] [Accepted: 06/22/2013] [Indexed: 01/16/2023]
Abstract
This review examines parasite zoonoses and wildlife in the context of the One Health triad that encompasses humans, domestic animals, wildlife and the changing ecosystems in which they live. Human (anthropogenic) activities influence the flow of all parasite infections within the One Health triad and the nature and impact of resulting spillover events are examined. Examples of spillover from wildlife to humans and/or domestic animals, and vice versa, are discussed, as well as emerging issues, particularly the need for parasite surveillance of wildlife populations. Emphasis is given to Trypanosoma cruzi and related species in Australian wildlife, Trichinella, Echinococcus, Giardia, Baylisascaris, Toxoplasma and Leishmania.
Collapse
Affiliation(s)
- R C Andrew Thompson
- School of Veterinary and Health Sciences, Murdoch University, Murdoch, WA 6150, Australia.
| |
Collapse
|
27
|
Fatal toxoplasmosis associated with an atypical Toxoplasma gondii strain in a Bennett's wallaby (Macropus rufogriseus) in Spain. Vet Parasitol 2013; 196:523-7. [DOI: 10.1016/j.vetpar.2013.03.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Revised: 02/19/2013] [Accepted: 03/01/2013] [Indexed: 11/23/2022]
|
28
|
Evidence of the three main clonalToxoplasma gondiilineages from wild mammalian carnivores in the UK. Parasitology 2013; 140:1768-76. [DOI: 10.1017/s0031182013001169] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
SUMMARYToxoplasma gondiiis a zoonotic pathogen defined by three main clonal lineages (types I, II, III), of which type II is most common in Europe. Very few data exist on the prevalence and genotypes ofT. gondiiin the UK. Wildlife can act as sentinel species forT. gondiigenotypes present in the environment, which may subsequently be transmitted to livestock and humans. DNA was extracted from tissue samples of wild British carnivores, including 99 ferrets, 83 red foxes, 70 polecats, 65 mink, 64 badgers and 9 stoats. Parasite DNA was detected using a nested ITS1 PCR specific forT. gondii, PCR positive samples were subsequently genotyped using five PCR–RFLP markers.Toxoplasma gondiiDNA was detected within all these mammal species and prevalence varied from 6·0 to 44·4% depending on the host. PCR–RFLP genotyping identified type II as the predominant lineage, but type III and type I alleles were also identified. No atypical or mixed genotypes were identified within these animals. This study demonstrates the presence of alleles for all three clonal lineages with potential for transmission to cats and livestock. This is the first DNA-based study ofT. gondiiprevalence and genotypes across a broad range of wild British carnivores.
Collapse
|
29
|
Hollings T, Jones M, Mooney N, McCallum H. Wildlife disease ecology in changing landscapes: Mesopredator release and toxoplasmosis. INTERNATIONAL JOURNAL FOR PARASITOLOGY-PARASITES AND WILDLIFE 2013; 2:110-8. [PMID: 24533323 PMCID: PMC3862529 DOI: 10.1016/j.ijppaw.2013.02.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Revised: 02/09/2013] [Accepted: 02/14/2013] [Indexed: 11/20/2022]
Abstract
Changing ecosystem dynamics are increasing the threat of disease epidemics arising in wildlife populations. Several recent disease outbreaks have highlighted the critical need for understanding pathogen dynamics, including the role host densities play in disease transmission. In Australia, introduced feral cats are of immense concern because of the risk they pose to native wildlife through predation and competition. They are also the only known definitive host of the coccidian parasite, Toxoplasma gondii, the population-level impacts of which are unknown in any species. Australia’s native wildlife have not evolved in the presence of cats or their parasites, and feral cats may be linked with several native mammal declines and extinctions. In Tasmania there is emerging evidence that feral cat populations are increasing following wide-ranging and extensive declines in the apex predator, the Tasmanian devil, from a consistently fatal transmissible cancer. We assess whether feral cat density is associated with the seroprevalence of T. gondii in native wildlife to determine whether an increasing population of feral cats may correspond to an increased level of risk to naive native intermediate hosts. We found evidence that seroprevalence of T. gondii in Tasmanian pademelons was lower in the north-west of Tasmania than in the north-east and central regions where cat density was higher. Also, samples obtained from road-killed animals had significantly higher seroprevalence of T. gondii than those from culled individuals, suggesting there may be behavioural differences associated with infection. In addition, seroprevalence in different trophic levels was assessed to determine whether position in the food-web influences exposure risk. Higher order carnivores had significantly higher seroprevalence than medium-sized browser species. The highest seroprevalence observed in an intermediate host was 71% in spotted-tailed quolls (Dasyurus maculatus), the largest mammalian mesopredator, in areas of low cat density. Mesopredator release of cats may be a significant issue for native species conservation, potentially affecting the population viability of many endangered species.
Collapse
Affiliation(s)
- Tracey Hollings
- University of Tasmania, School of Zoology, Private Bag 5, Hobart, TAS 7001, Australia
| | - Menna Jones
- University of Tasmania, School of Zoology, Private Bag 5, Hobart, TAS 7001, Australia
| | - Nick Mooney
- Department of Primary Industries, Parks, Water and Environment, GPO Box 44, Hobart, TAS 7001, Australia
| | - Hamish McCallum
- Griffith University, School of Environment, 170 Kessels Rd, Nathan, QLD 4111, Australia
| |
Collapse
|
30
|
A high prevalence of Toxoplasma in Australian chickens. Vet Parasitol 2013; 196:209-11. [PMID: 23394799 DOI: 10.1016/j.vetpar.2013.01.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 01/14/2013] [Accepted: 01/16/2013] [Indexed: 01/29/2023]
Abstract
A small survey was undertaken of commercially reared free-range chickens in Western Australia using serology and molecular detection. Eighteen out of 20 serum samples showed antibody responses with titers of 1:64 in 5 chickens and ≥ 1:128 in 13 chickens. DNA extracted from 22 out of 50 tissue samples, 10 brains and 12 spleens, were positive by nested PCR, and sequencing at the B1 locus on DNA from 3 brain and 3 spleen samples confirmed that 2 isolates were Toxoplasma gondii, Type I, and 4 Type II/III. The high prevalence of Toxoplasma infection found in commercial, free-range chickens raises public health issues with respect to both exposure in the workplace, during carcass processing, and subsequent transmission during food handling and/or consumption as food. The results of this study emphasize the need for more data on the incidence of Toxoplasma infection in domestic animals and humans in Australia.
Collapse
|
31
|
Pan S, Thompson RCA, Grigg ME, Sundar N, Smith A, Lymbery AJ. Western Australian marsupials are multiply infected with genetically diverse strains of Toxoplasma gondii. PLoS One 2012; 7:e45147. [PMID: 23028812 PMCID: PMC3454407 DOI: 10.1371/journal.pone.0045147] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 08/13/2012] [Indexed: 11/18/2022] Open
Abstract
Five different organs from 16 asymptomatic free-ranging marsupial macropods (Macropus rufus, M. fuliginosus, and M. robustus) from inland Western Australia were tested for infection with Toxoplasma gondii by multi-locus PCR-DNA sequencing. All macropods were infected with T. gondii, and 13 had parasite DNA in at least 2 organs. In total, 45 distinct T. gondii genotypes were detected. Fourteen of the 16 macropods were multiply infected with genetically distinct T. gondii genotypes that often partitioned between different organs. The presence of multiple T. gondii infections in macropods suggests that native mammals have the potential to promote regular cycles of sexual reproduction in the definitive felid host in this environment.
Collapse
Affiliation(s)
- Shuting Pan
- School of Veterinary and Biomedical Sciences, Murdoch University, Perth, Western Australia, Australia
| | - R. C. Andrew Thompson
- School of Veterinary and Biomedical Sciences, Murdoch University, Perth, Western Australia, Australia
| | - Michael E. Grigg
- Molecular Parasitology Unit, Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Diseases, Bethesda, Maryland, United States of America
| | - Natarajan Sundar
- Molecular Parasitology Unit, Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Diseases, Bethesda, Maryland, United States of America
| | - Andrew Smith
- School of Veterinary and Biomedical Sciences, Murdoch University, Perth, Western Australia, Australia
| | - Alan J. Lymbery
- Fish Health Unit, School of Veterinary and Biomedical Sciences, Murdoch University, Perth, Western Australia, Australia
- * E-mail:
| |
Collapse
|
32
|
|
33
|
Elmore SA, Jenkins EJ, Huyvaert KP, Polley L, Root JJ, Moore CG. Toxoplasma gondiiin Circumpolar People and Wildlife. Vector Borne Zoonotic Dis 2012; 12:1-9. [DOI: 10.1089/vbz.2011.0705] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Stacey A. Elmore
- Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, Saskatchewan
| | - Emily J. Jenkins
- Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, Saskatchewan
| | - Kathryn P. Huyvaert
- Department of Fish, Wildlife, and Conservation Biology, Colorado State University, Fort Collins, Colorado
| | - Lydden Polley
- Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, Saskatchewan
| | - J. Jeffrey Root
- United States Department of Agriculture, Wildlife Services, National Wildlife Research Center, Fort Collins, Colorado
| | - Chester G. Moore
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado
| |
Collapse
|
34
|
Wendte JM, Gibson AK, Grigg ME. Population genetics of Toxoplasma gondii: new perspectives from parasite genotypes in wildlife. Vet Parasitol 2011; 182:96-111. [PMID: 21824730 PMCID: PMC3430134 DOI: 10.1016/j.vetpar.2011.07.018] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Toxoplasma gondii, a zoonotic protozoal parasite, is well-known for its global distribution and its ability to infect virtually all warm-blooded vertebrates. Nonetheless, attempts to describe the population structure of T. gondii have been primarily limited to samples isolated from humans and domesticated animals. More recent studies, however, have made efforts to characterize T. gondii isolates from a wider range of host species and geographic locales. These findings have dramatically changed our perception of the extent of genetic diversity in T. gondii and the relative roles of sexual recombination and clonal propagation in the parasite's lifecycle. In particular, identification of novel, disease-causing T. gondii strains in wildlife has raised concerns from both a conservation and public health perspective as to whether distinct domestic and sylvatic parasite gene pools exist. If so, overlap of these cycles may represent regions of high probability of disease emergence. Here, we attempt to answer these key questions by reviewing recent studies of T. gondii infections in wildlife, highlighting those which have advanced our understanding of the genetic diversity and population biology of this important zoonotic pathogen.
Collapse
Affiliation(s)
- Jered M. Wendte
- Molecular Parasitology Unit, Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-0425, USA
- Department of Veterinary Pathobiology, Oklahoma State University Center for Veterinary Health Sciences, Stillwater, OK, 74074, USA
| | - Amanda K. Gibson
- Molecular Parasitology Unit, Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-0425, USA
| | - Michael E. Grigg
- Molecular Parasitology Unit, Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-0425, USA
- Department of Veterinary Pathobiology, Oklahoma State University Center for Veterinary Health Sciences, Stillwater, OK, 74074, USA
| |
Collapse
|
35
|
Lymbery AJ, Thompson RCA. The molecular epidemiology of parasite infections: tools and applications. Mol Biochem Parasitol 2011; 181:102-16. [PMID: 22027028 DOI: 10.1016/j.molbiopara.2011.10.006] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 10/10/2011] [Accepted: 10/12/2011] [Indexed: 10/16/2022]
Abstract
Molecular epidemiology, broadly defined, is the application of molecular genetic techniques to the dynamics of disease in a population. In this review, we briefly describe molecular and analytical tools available for molecular epidemiological studies and then provide an overview of how they can be applied to better understand parasitic disease. A range of new molecular tools have been developed in recent years, allowing for the direct examination of parasites from clinical or environmental samples, and providing access to relatively cheap, rapid, high throughput molecular assays. At the same time, new analytical approaches, in particular those derived from coalescent theory, have been developed to provide more robust estimates of evolutionary processes and demographic parameters from multilocus, genotypic data. To date, the primary application of molecular epidemiology has been to provide specific and sensitive identification of parasites and to resolve taxonomic issues, particularly at the species level and below. Population genetic studies have also been used to determine the extent of genetic diversity among populations of parasites and the degree to which this diversity is associated with different host cycles or epidemiologically important phenotypes. Many of these studies have also shed new light on transmission cycles of parasites, particularly the extent to which zoonotic transmission occurs, and on the prevalence and importance of mixed infections with different parasite species or intraspecific variants (polyparasitism). A major challenge, and one which is now being addressed by an increasing number of studies, is to find and utilize genetic markers for complex traits of epidemiological significance, such as drug resistance, zoonotic potential and virulence.
Collapse
Affiliation(s)
- A J Lymbery
- Fish Health Unit, School of Veterinary and Biomedical Sciences, Murdoch University, Murdoch WA 6150, Australia.
| | | |
Collapse
|
36
|
Thompson R, Conlan J. Emerging issues and parasite zoonoses in the SE Asian and Australasian region. Vet Parasitol 2011; 181:69-73. [DOI: 10.1016/j.vetpar.2011.04.025] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
37
|
Dubey JP, Velmurugan GV, Rajendran C, Yabsley MJ, Thomas NJ, Beckmen KB, Sinnett D, Ruid D, Hart J, Fair PA, McFee WE, Shearn-Bochsler V, Kwok OCH, Ferreira LR, Choudhary S, Faria EB, Zhou H, Felix TA, Su C. Genetic characterisation of Toxoplasma gondii in wildlife from North America revealed widespread and high prevalence of the fourth clonal type. Int J Parasitol 2011; 41:1139-47. [PMID: 21802422 DOI: 10.1016/j.ijpara.2011.06.005] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Revised: 06/21/2011] [Accepted: 06/22/2011] [Indexed: 10/17/2022]
Abstract
Little is known of the genetic diversity of Toxoplasma gondii circulating in wildlife. In the present study wild animals, from the USA were examined for T. gondii infection. Tissues of naturally exposed animals were bioassayed in mice for isolation of viable parasites. Viable T. gondii was isolated from 31 animals including, to our knowledge for the first time, from a bald eagle (Haliaeetus leucocephalus), five gray wolves (Canis lupus), a woodrat (Neotoma micropus), and five Arctic foxes (Alopex lagopus). Additionally, 66 T. gondii isolates obtained previously, but not genetically characterised, were revived in mice. Toxoplasma gondii DNA isolated from these 97 samples (31+66) was characterised using 11 PCR-restriction fragment length polymorphism (RFLP) markers (SAG1, 5'- and 3'-SAG2, alt.SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 and Apico). A total of 95 isolates were successfully genotyped. In addition to clonal Types II, and III, 12 different genotypes were found. These genotype data were combined with 74 T. gondii isolates previously characterised from wildlife from North America and a composite data set of 169 isolates comprised 22 genotypes, including clonal Types II, III and 20 atypical genotypes. Phylogenetic network analysis showed limited diversity with dominance of a recently designated fourth clonal type (Type 12) in North America, followed by the Type II and III lineages. These three major lineages together accounted for 85% of strains in North America. The Type 12 lineage includes previously identified Type A and X strains from sea otters. This study revealed that the Type 12 lineage accounts for 46.7% (79/169) of isolates and is dominant in wildlife of North America. No clonal Type I strain was identified among these wildlife isolates. These results suggest that T. gondii strains in wildlife from North America have limited diversity, with the occurrence of only a few major clonal types.
Collapse
Affiliation(s)
- J P Dubey
- United States Department of Agriculture, Agricultural Research Service, Animal and Natural Resources Institute, Animal Parasitic Diseases Laboratory, Building 1001, Beltsville, MD 20705-2350, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
38
|
King JS, McAllan B, Spielman DS, Lindsay SA, Hůrková-Hofmannová L, Hartigan A, Al-Qassab SE, Ellis JT, Slapeta J. Extensive production of Neospora caninum tissue cysts in a carnivorous marsupial succumbing to experimental neosporosis. Vet Res 2011; 42:75. [PMID: 21635733 PMCID: PMC3121614 DOI: 10.1186/1297-9716-42-75] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Accepted: 06/02/2011] [Indexed: 11/21/2022] Open
Abstract
Experimental infections of Sminthopsis crassicaudata, the fat-tailed dunnart, a carnivorous marsupial widely distributed throughout the arid and semi-arid zones of Australia, show that this species can act as an intermediate host for Neospora caninum. In contrast to existing models that develop relatively few N. caninum tissue cysts, dunnarts offer a new animal model in which active neosporosis is dominated by tissue cyst production. The results provide evidence for a sylvatic life cycle of N. caninum in Australia between marsupials and wild dogs. It establishes the foundation for an investigation of the impact and costs of neosporosis to wildlife.
Collapse
Affiliation(s)
- Jessica S King
- Faculty of Veterinary Science, University of Sydney, NSW 2006, Australia.
| | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Wendte JM, Miller MA, Lambourn DM, Magargal SL, Jessup DA, Grigg ME. Self-mating in the definitive host potentiates clonal outbreaks of the apicomplexan parasites Sarcocystis neurona and Toxoplasma gondii. PLoS Genet 2010; 6:e1001261. [PMID: 21203443 PMCID: PMC3009688 DOI: 10.1371/journal.pgen.1001261] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Accepted: 11/23/2010] [Indexed: 12/24/2022] Open
Abstract
Tissue-encysting coccidia, including Toxoplasma gondii and Sarcocystis neurona, are heterogamous parasites with sexual and asexual life stages in definitive and intermediate hosts, respectively. During its sexual life stage, T. gondii reproduces either by genetic out-crossing or via clonal amplification of a single strain through self-mating. Out-crossing has been experimentally verified as a potent mechanism capable of producing offspring possessing a range of adaptive and virulence potentials. In contrast, selfing and other life history traits, such as asexual expansion of tissue-cysts by oral transmission among intermediate hosts, have been proposed to explain the genetic basis for the clonal population structure of T. gondii. In this study, we investigated the contributing roles self-mating and sexual recombination play in nature to maintain clonal population structures and produce or expand parasite clones capable of causing disease epidemics for two tissue encysting parasites. We applied high-resolution genotyping against strains isolated from a T. gondii waterborne outbreak that caused symptomatic disease in 155 immune-competent people in Brazil and a S. neurona outbreak that resulted in a mass mortality event in Southern sea otters. In both cases, a single, genetically distinct clone was found infecting outbreak-exposed individuals. Furthermore, the T. gondii outbreak clone was one of several apparently recombinant progeny recovered from the local environment. Since oocysts or sporocysts were the infectious form implicated in each outbreak, the expansion of the epidemic clone can be explained by self-mating. The results also show that out-crossing preceded selfing to produce the virulent T. gondii clone. For the tissue encysting coccidia, self-mating exists as a key adaptation potentiating the epidemic expansion and transmission of newly emerged parasite clones that can profoundly shape parasite population genetic structures or cause devastating disease outbreaks. The parasites Toxoplasma gondii and Sarcocystis neurona have lifecycles that include a sexual stage in a definitive host and an asexual stage in intermediate hosts. For T. gondii, laboratory studies have demonstrated that the sexual stage can serve the dual purpose of producing new, virulent genotypes through recombination and promoting expansion of single clones via self-mating. Self-mating and other life history traits of T. gondii, including transmission of asexual stages among intermediate hosts, are assumed to account for the clonal population genetic structure of this organism. However, the relative contributions of sexual recombination and self-mating verses other life history traits in causing disease outbreaks or in shaping Toxoplasma's population genetic structure have not been verified in nature, nor have these traits been extensively examined in related parasites. To address this knowledge gap, we conducted population genetic analyses on T. gondii and S. neurona strains isolated from naturally occurring outbreaks affecting humans and sea otters, respectively. Our results identify self-mating as a key trait potentiating disease outbreaks through the rapid amplification of a single clone into millions of infectious units. Selfing is likely a key adaptation for enhancing transmission of recently emerged, recombinant clones and reshaping population genetic structures among the tissue-cyst coccidia.
Collapse
Affiliation(s)
- Jered M. Wendte
- Molecular Parasitology Unit, Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- Department of Veterinary Pathobiology, Oklahoma State University Center for Veterinary Health Sciences, Stillwater, Oklahoma, United States of America
- Howard Hughes Medical Institute–National Institutes of Health Research Scholars Program, Bethesda, Maryland, United States of America
| | - Melissa A. Miller
- Marine Wildlife Veterinary Care and Research Center (CDFG-OSPR), Santa Cruz, California, United States of America
| | - Dyanna M. Lambourn
- Washington Department of Fish and Wildlife, Lakewood, Washington, United States of America
| | - Spencer L. Magargal
- Molecular Parasitology Unit, Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - David A. Jessup
- Marine Wildlife Veterinary Care and Research Center (CDFG-OSPR), Santa Cruz, California, United States of America
| | - Michael E. Grigg
- Molecular Parasitology Unit, Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- Department of Veterinary Pathobiology, Oklahoma State University Center for Veterinary Health Sciences, Stillwater, Oklahoma, United States of America
- * E-mail:
| |
Collapse
|
40
|
Parasites, emerging disease and wildlife conservation. Int J Parasitol 2010; 40:1163-70. [PMID: 20452354 DOI: 10.1016/j.ijpara.2010.04.009] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2010] [Revised: 04/27/2010] [Accepted: 04/29/2010] [Indexed: 11/24/2022]
Abstract
In this review some emerging issues of parasite infections in wildlife, particularly in Australia, are considered. We discuss the importance of understanding parasite biodiversity in wildlife in terms of conservation, the role of wildlife as reservoirs of parasite infection, and the role of parasites within the broader context of the ecosystem. Using a number of parasite species, the value of undertaking longitudinal surveillance in natural systems using non-invasive sampling and molecular tools to characterise infectious agents is illustrated in terms of wildlife health, parasite biodiversity and ecology.
Collapse
|