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Benavides J, González-Warleta M, Arteche-Villasol N, Pérez V, Mezo M, Gutiérrez-Expósito D. Ovine Neosporosis: The Current Global Situation. Animals (Basel) 2022; 12:ani12162074. [PMID: 36009665 PMCID: PMC9405361 DOI: 10.3390/ani12162074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 07/17/2022] [Accepted: 08/10/2022] [Indexed: 11/16/2022] Open
Abstract
Simple Summary This review summarizes the current global situation of Neospora caninum infection in sheep by referring to all of the available descriptions of natural ovine neosporosis to date, focusing on epidemiology, clinical signs, lesions, and diagnosis. The data suggest that ovine neosporosis is more prevalent than currently thought, that it has increased in the last few decades, and that it should now be considered in the differential diagnosis when investigating abortion in sheep. Abstract In the past 20 years, Neospora caninum infection in sheep has been reported in at least 31 countries worldwide from all sheep-rearing continents (Europe, Asia, the Americas, Africa, and Oceania), and its role as an abortifacient agent is becoming more evident. Most studies of ovine neosporosis have focused on its epidemiology, based primarily on serological analysis, with only a few studies investigating the actual presence of the parasite by PCR and/or IHC. Individual seroprevalence rates were highly variable between countries, and even between regions within the same country, ranging from 0.0% to 67.4% positive. Furthermore, most of the studies were not directly comparable due to differences in experimental designs, sample sizes, husbandry systems, ecological factors, and serological tests (e.g., IFAT, ELISA, MAT, Western blot). The latter, along with the scarcity of studies on the relevance of N. caninum as an abortifacient agent, may bias the perception of the importance of this disease. This review summarizes the situation of N. caninum infection in sheep using all available published studies describing natural ovine neosporosis. The epidemiology shows that ovine neosporosis is found worldwide, and it poses a relevant risk to the sustainability of sheep flocks.
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Affiliation(s)
- Julio Benavides
- Instituto de Ganadería de Montaña, CSIC-University of Leon, Grulleros, 24346 León, Spain
| | - Marta González-Warleta
- Centro de Investigaciones Agrarias de Mabegondo, Parasitology Laboratory, Axencia Galega da Calidade Alimentaria (AGACAL)-Xunta de Galicia, Ctra, Betanzos a Mesón do Vento km 7, Abegondo, 15318 A Coruña, Spain
| | - Noive Arteche-Villasol
- Instituto de Ganadería de Montaña, CSIC-University of Leon, Grulleros, 24346 León, Spain
- Animal Health Department, Faculty of Veterinary, University of Leon, Campus de Vegazana s/n, 24071 León, Spain
| | - Valentín Pérez
- Instituto de Ganadería de Montaña, CSIC-University of Leon, Grulleros, 24346 León, Spain
- Animal Health Department, Faculty of Veterinary, University of Leon, Campus de Vegazana s/n, 24071 León, Spain
| | - Mercedes Mezo
- Centro de Investigaciones Agrarias de Mabegondo, Parasitology Laboratory, Axencia Galega da Calidade Alimentaria (AGACAL)-Xunta de Galicia, Ctra, Betanzos a Mesón do Vento km 7, Abegondo, 15318 A Coruña, Spain
| | - Daniel Gutiérrez-Expósito
- Instituto de Ganadería de Montaña, CSIC-University of Leon, Grulleros, 24346 León, Spain
- Animal Health Department, Faculty of Veterinary, University of Leon, Campus de Vegazana s/n, 24071 León, Spain
- Correspondence:
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Dynamics of Neospora caninum-Associated Abortions in a Dairy Sheep Flock and Results of a Test-and-Cull Control Programme. Pathogens 2021; 10:pathogens10111518. [PMID: 34832673 PMCID: PMC8625302 DOI: 10.3390/pathogens10111518] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 11/03/2021] [Accepted: 11/17/2021] [Indexed: 11/17/2022] Open
Abstract
Neospora caninum is an apicomplexan parasite that can cause abortions and perinatal mortality in sheep. Although ovine neosporosis has been described worldwide, there is a lack of information about the relationship between N. caninum serostatus and the reproductive performance. In this study, we described the infection dynamics in a dairy sheep flock with an abortion rate up to 25% and a N. caninum seroprevalence of 32%. Abortions were recorded in 36% and 9% of seropositive and seronegative sheep, respectively. Seropositive sheep were more likely to abort twice (OR = 4.44) or three or more times (OR = 10.13) than seronegative sheep. Endogenous transplacental transmission was the main route of transmission since 86% of seropositive sheep had seropositive offspring. Within dams that had any abortion, seropositive sheep were more likely than seronegative ones to have female descendants that aborted (OR = 8.12). The slight increase in seropositivity with the age, the low percentage of animals with postnatal seroconversion or with low avidity antibodies, and the seropositivity of one flock dog, indicated that horizontal transmission might have some relevance in this flock. A control programme based on selective culling of seropositive sheep and replacement with seronegative animals was effective in reducing the abortion rate to 7.2%.
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Clune T, Lockwood A, Hancock S, Bruce M, Thompson AN, Beetson S, Campbell AJ, Glanville E, Brookes D, Trengove C, O'Handley R, Jacobson C. Neospora caninum is not an important contributor to poor reproductive performance of primiparous ewes from southern Australia: evidence from a cross-sectional study. Parasitol Res 2021; 120:3875-3882. [PMID: 34599357 DOI: 10.1007/s00436-021-07328-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 09/22/2021] [Indexed: 11/29/2022]
Abstract
Neospora caninum has been implicated as a sporadic cause of abortion and perinatal deaths in sheep flocks globally. However, its significance as a reproductive pathogen for sheep in Australia remains unknown. The aims of this study were to (i) determine the seroprevalence of N. caninum in Australian breeding ewes and (ii) examine if natural exposure to N. caninum is associated with poor reproductive performance of primiparous ewes in southern Australia. Thirty flocks of primiparous ewes (aged 1-2 years old at lambing) from 28 farms in three states (Western Australia, South Australia and Victoria) were monitored between mating and lamb marking. Blood samples were also collected from multiparous mature ewes (aged 3 years or older) at each farm. Seroprevalence for anti-N. caninum IgG using indirect ELISA was determined for a subset of primiparous ewes that were predominantly determined to be pregnant and subsequently failed to rear a lamb (n = 1279) and randomly selected mature multiparous ewes with unknown reproductive status (n = 558). Neopsora caninum apparent seroprevalence was 0.16% (95% confidence interval 0.03%, 0.5%) in primiparous ewes, with seropositivity identified in two ewes from farms located in South Australia and Victoria. There was no evidence of seropositivity in mature ewes with apparent seroprevalence 0% (0%, 0.45%). These findings suggest that N. caninum infection was not widespread in primiparous ewes or mature multiparous ewes on these farms, and exposure to N. caninum infection was unlikely to explain abortion and perinatal mortalities observed for primiparous ewes.
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Affiliation(s)
- Thomas Clune
- Centre for Animal Production and Health, Food Futures Institute, Murdoch University, 90 South Street, Murdoch, Western Australia, 6150, Australia
| | - Amy Lockwood
- Centre for Animal Production and Health, Food Futures Institute, Murdoch University, 90 South Street, Murdoch, Western Australia, 6150, Australia
| | - Serina Hancock
- Centre for Animal Production and Health, Food Futures Institute, Murdoch University, 90 South Street, Murdoch, Western Australia, 6150, Australia
| | - Mieghan Bruce
- Centre for Animal Production and Health, Food Futures Institute, Murdoch University, 90 South Street, Murdoch, Western Australia, 6150, Australia
| | - Andrew N Thompson
- Centre for Animal Production and Health, Food Futures Institute, Murdoch University, 90 South Street, Murdoch, Western Australia, 6150, Australia
| | - Sue Beetson
- Centre for Animal Production and Health, Food Futures Institute, Murdoch University, 90 South Street, Murdoch, Western Australia, 6150, Australia
| | - Angus J Campbell
- Nossal Institute for Global Health, Melbourne School of Population and Global Health, University of Melbourne, Victoria, 3010, Australia.,Mackinnon Project, Faculty of Veterinary & Agricultural Sciences, University of Melbourne, Werribee, Victoria, 3030, Australia
| | - Elsa Glanville
- Mackinnon Project, Faculty of Veterinary & Agricultural Sciences, University of Melbourne, Werribee, Victoria, 3030, Australia
| | - Daniel Brookes
- Mackinnon Project, Faculty of Veterinary & Agricultural Sciences, University of Melbourne, Werribee, Victoria, 3030, Australia
| | - Colin Trengove
- School of Animal and Veterinary Science, University of Adelaide, Roseworthy, South Australia, 5371, Australia
| | - Ryan O'Handley
- School of Animal and Veterinary Science, University of Adelaide, Roseworthy, South Australia, 5371, Australia
| | - Caroline Jacobson
- Centre for Animal Production and Health, Food Futures Institute, Murdoch University, 90 South Street, Murdoch, Western Australia, 6150, Australia.
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