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Journal ArticleDOI

Epidemiology and Control of Neosporosis and Neospora caninum

TL;DR: This review is focused mainly on the epidemiology and control of neosporosis in cattle, but worldwide seroprevalences of N. caninum in animals and humans are tabulated.
Abstract: Neospora caninum is a protozoan parasite of animals. Until 1988, it was misidentified as Toxoplasma gondii. Since its first recognition in dogs in 1984 and the description of the new genus and species Neospora caninum in 1988, neosporosis has emerged as a serious disease of cattle and dogs worldwide. Abortions and neonatal mortality are a major problem in livestock operations, and neosporosis is a major cause of abortion in cattle. Although antibodies to N. caninum have been reported, the parasite has not been detected in human tissues. Thus, the zoonotic potential is uncertain. This review is focused mainly on the epidemiology and control of neosporosis in cattle, but worldwide seroprevalences of N. caninum in animals and humans are tabulated. The role of wildlife in the life cycle of N. caninum and strategies for the control of neosporosis in cattle are discussed.

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Citations
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Journal ArticleDOI
TL;DR: A large number of pathogens that are directly or indirectly transmitted by rodents are described and a simplified rodent disease model is discussed.
Abstract: Rodents are the most abundant and diversified order of living mammals in the world. Already since the Middle Ages we know that they can contribute to human disease, as black rats were associated with distribution of plague. However, also in modern times rodents form a threat for public health. In this review article a large number of pathogens that are directly or indirectly transmitted by rodents are described. Moreover, a simplified rodent disease model is discussed.

757 citations


Cites background from "Epidemiology and Control of Neospor..."

  • ...Among cattle, both horizontal and vertical transmission can occur (Dubey et al. 2007)....

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  • ...Abortions and neonatal mortality are a major problem in livestock operations, and neosporosis is a major cause of abortion in cattle (Dubey et al. 2007)....

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  • ...Presence and the number of farm dogs (definitive hosts) has shown to be a risk factor for seropositivity in cattle (Dubey et al. 2007)....

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  • ...Thus, the zoonotic potential remains uncertain (Dubey et al. 2007)....

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Journal ArticleDOI
TL;DR: This review is focused on current status of neosporosis in animals based on papers published in the last five years and strategies for control and prevention are discussed.

559 citations


Cites background from "Epidemiology and Control of Neospor..."

  • ...It is now generally accepted that the presence of farm dogs increases the chance of N. caninum infection in cattle (Dubey et al., 2007a; VanLeeuwen et al., 2010a)....

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  • ...Fatal neosporosis has been diagnosed previously in a 16 day old rhinoceros, and in wild cervids (reviewed in Dubey, 2003a; Dubey et al., 2007a)....

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  • ...The transmission rate increases with gestational age perhaps nary Par J.P. Dubey, G. Schares / Veteri related to placental vascularization because the placenta seems to be more permeable in the last trimester (Dubey et al., 2006, 2007a)....

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  • ...Many controls measures have been discussed to reduce N. caninum infection in cattle (Dubey et al., 2007a), including embryo transfer, artificial insemination of seropositive dams with semen from beef bulls, culling, replacement heifers, chemotherapy, and vaccination....

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  • ...…et al. (2008) Mexico Aguascalientes Urban 116 20 ELISA IDEXX Cruz-Vázquez et al. (2008) Dairy farms 152 40.7 Durango City Pound 101 2 IFAT 1:25 Dubey et al. (2007b) Peru Farm 122 14.8 IFAT 1:50 Vega et al. (2010) Poland Clinics 257 21.7 ELISA Goździk et al. (2011) Clinics 110 16.3 IFAT 1:50…...

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Journal ArticleDOI
TL;DR: This estimate of global losses due to N. caninum, with the identification of clear target markets (countries, as well as cattle industries), should provide an incentive to develop treatment options and/or vaccines.

398 citations


Cites background from "Epidemiology and Control of Neospor..."

  • ...The epidemic, ‘‘storm-like’’ pattern is the most devastating, and costly, with a large proportion (>10%) of at risk (‘‘in-calf’’) cows aborting over a short period of time (Dubey et al., 2007)....

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  • ...%) of at risk (‘‘in-calf’’) cows aborting over a short period of time (Dubey et al., 2007)....

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Journal ArticleDOI
TL;DR: Oocyst shedding from the intestinal tract of a dingo demonstrates that dingoes are definitive hosts of Neospora caninum and horizontal transmission of N.caninum from dingoes to farm animals and wildlife may occur in Australia.

230 citations


Cites background from "Epidemiology and Control of Neospor..."

  • ...Neospora caninum (Apicomplexa: Sarcocystidae) has been identified as a major protozoan infection of cattle worldwide, causing significant reproductive disease such as abortion outbreaks (Dubey et al., 2007)....

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Journal ArticleDOI
TL;DR: The ecological niches occupied by these species are influenced by a relatively small number of gene products which operate at the host-parasite interface and that the dominance of vertical transmission in N. caninum may be associated with the evolution of reduced virulence in this species.
Abstract: Toxoplasma gondii is a zoonotic protozoan parasite which infects nearly one third of the human population and is found in an extraordinary range of vertebrate hosts. Its epidemiology depends heavily on horizontal transmission, especially between rodents and its definitive host, the cat. Neospora caninum is a recently discovered close relative of Toxoplasma, whose definitive host is the dog. Both species are tissue-dwelling Coccidia and members of the phylum Apicomplexa; they share many common features, but Neospora neither infects humans nor shares the same wide host range as Toxoplasma, rather it shows a striking preference for highly efficient vertical transmission in cattle. These species therefore provide a remarkable opportunity to investigate mechanisms of host restriction, transmission strategies, virulence and zoonotic potential. We sequenced the genome of N. caninum and transcriptomes of the invasive stage of both species, undertaking an extensive comparative genomics and transcriptomics analysis. We estimate that these organisms diverged from their common ancestor around 28 million years ago and find that both genomes and gene expression are remarkably conserved. However, in N. caninum we identified an unexpected expansion of surface antigen gene families and the divergence of secreted virulence factors, including rhoptry kinases. Specifically we show that the rhoptry kinase ROP18 is pseudogenised in N. caninum and that, as a possible consequence, Neospora is unable to phosphorylate host immunity-related GTPases, as Toxoplasma does. This defense strategy is thought to be key to virulence in Toxoplasma. We conclude that the ecological niches occupied by these species are influenced by a relatively small number of gene products which operate at the host-parasite interface and that the dominance of vertical transmission in N. caninum may be associated with the evolution of reduced virulence in this species.

221 citations


Cites background from "Epidemiology and Control of Neospor..."

  • ...Unlike Toxoplasma, Neospora appears not to be zoonotic, having a more restricted host range [10,11] in which it occupies a unique ecological niche showing a striking capacity for highly efficient vertical transmission in bovines [12]....

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References
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Journal ArticleDOI
TL;DR: Dogs are a definitive host of Neospora caninum, and mice inoculated with canine faecal extracts were monitored for evidence of neosporosis using a variety of morphologic, immunohistologic, serologic, and genetic analyses.

1,069 citations

Journal ArticleDOI
TL;DR: Neospora caninum is a recently recognized protozoan parasite of animals, which until 1988 was misidentified as Toxoplasma gondii, and its life cycle is unknown.

963 citations


"Epidemiology and Control of Neospor..." refers background in this paper

  • ...In most cases of neonatal neosporosis, clinical signs are not apparent until 5 to 7 weeks after birth (133)....

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Journal Article
TL;DR: A newly identified parasite, Neospora caninum, structurally distinct from T gondii, was found in 10 dogs and formed meronts in many tissues of the dogs, especially the brain and spinal cord.
Abstract: Histologic sections and case histories from 23 dogs with proven fatal toxoplasmosis-like illness at the Angell Memorial Animal Hospital were reviewed. Toxoplasma gondii was identified in 13 dogs. A newly identified parasite, Neospora caninum, structurally distinct from T gondii, was found in 10 dogs. The newly discovered organism, belonging to a new genus and new species, formed meronts in many tissues of the dogs, especially the brain and spinal cord. Neospora caninum was located directly in the host cell cytoplasm without a parasitophorous vacuole; it divided by endodyogeny, contained more than 11 rhoptries, and did not react with the anti-T gondii serum in the immunoperoxidase test. Meningoencephalomyelitis and myositis were the main lesions associated with N caninum. Ulcerative and fistulous dermatitis was the major lesion in 1 dog.

787 citations


"Epidemiology and Control of Neospor..." refers background in this paper

  • ...Until 1988, it was misdiagnosed as Toxoplasma gondii (138)....

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  • ...(138), neosporosis has emerged as a serious disease of cattle and dogs worldwide....

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Journal ArticleDOI
TL;DR: Information on biology, diagnosis, epidemiology and control of neosporosis in animals, a major cause of abortion in cattle in many countries, is reviewed.
Abstract: Neospora caninum is a coccidian parasite of animals. It is a major pathogen for cattle and dogs and it occasionally causes clinical infections in horses, goats, sheep, and deer. Domestic dogs are the only known definitive hosts for N. caninum. It is one of the most efficiently transmitted parasite of cattle and up to 90% of cattle in some herds are infected. Transplacental transmission is considered the major route of transmission of N. caninum in cattle. Neospora caninum is a major cause of abortion in cattle in many countries. To elicit protective immunity against abortion in cows that already harbor a latent infection is a major problem. This paper reviews information on biology, diagnosis, epidemiology and control of neosporosis in animals.

770 citations


"Epidemiology and Control of Neospor..." refers background in this paper

  • ...caninum-associated abortions have been diagnosed in many countries (129, 130), there are only a few data based on examination of a large numbers of aborted fetuses....

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  • ...num (130) and the pathogenesis and diagnosis of neosporo-...

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Journal Article
TL;DR: Neospora caninum infection was diagnosed in 5 young dogs from 2 litters with a common parentage that developed hind limb paresis 5 to 8 weeks after birth and was isolated in cell cultures, mice, and dogs inoculated with infected canine tissues.
Abstract: Neospora caninum infection was diagnosed in 5 young dogs from 2 litters with a common parentage. The pups were born healthy, but developed hind limb paresis 5 to 8 weeks after birth. The predominant lesions were polyradiculoneuritis and granulomatous polymyositis. Neospora caninum was seen microscopically in sections of naturally infected pups, and was isolated in cell cultures, mice, and dogs inoculated with infected canine tissues. Antibodies to N caninum were detected in sera of infected dogs by indirect fluorescent antibody test.

664 citations