Neosporosis-Like Abortions in a Herd of Dairy Cattle

Thilsted, John P.; Dubey, J. P.

doi:10.1177/104063878900100301

Cited by 206 publications

(95 citation statements)

References 7 publications

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“…Corbellini et al (2000) caninum em tecidos com lesões características do protozoário não descarta a possibilidade do aborto ter sido causado por esse agente, pois sua distribuição pode ser esporá-dica e esparsa nos tecidos (Thilsted & Dubey 1989). Além disso, outras causas como presença de reações inflamató-rias e autólise podem afetar a morfologia e antigenicidade do protozoário, além de influenciar na marcação (Hattel et al 1998).…”

Section: Discussionunclassified

Causas de aborto bovino diagnosticadas no Setor de Patologia Veterinária da UFRGS de 2003 a 2011

et al. 2013

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Descrevem-se as causas de aborto bovino diagnosticadas no Setor de Patologia Veterinária da Universidade Federal do Rio Grande do Sul no período de janeiro de 2003 a dezembro de 2011. Um total de 490 fetos bovinos foi analisado neste período. Causas específicas de aborto foram encontradas em 46,7% dos casos. Infecções por protozoários, em especial Neospora caninum acometeram 33% dos casos (162/490). Bactérias com 6,3% (31/490), seguidas por fungos com 0,8% (4/490) dos casos, foram causas adicionais de abortos. Em dois fetos (0,4%), coinfecções por dois agentes foram identificadas. Causas não-infecciosas foram observadas em 3% dos abortos e Malformações congênitas em 2,6%.

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Section: Discussionunclassified

Causas de aborto bovino diagnosticadas no Setor de Patologia Veterinária da UFRGS de 2003 a 2011

et al. 2013

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“…Infection with Neospora caninum, an apicomplexan protozoan, can cause abortions in cattle (Thilsted and Dubey, 1989) and goats (Barr et al, 1992). Dogs are a definitive host (McAllister et al, 1998), and ruminants are intermediate hosts.…”

Section: Introductionmentioning

confidence: 99%

“…An alternative possibility is that cysts may develop if the establishing tachyzoite undergoes bradyzoite differentiation before multiplying. Cysts do not appear to arise from transformation of tachyzoites within large parasitophorous vacuoles.Infection with Neospora caninum, an apicomplexan protozoan, can cause abortions in cattle (Thilsted and Dubey, 1989) and goats (Barr et al, 1992). Dogs are a definitive host (McAllister et al, 1998), and ruminants are intermediate hosts.…”

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confidence: 99%

Neospora Caninum in Vitro: Evidence That the Destiny of a Parasitophorous Vacuole Depends on the Phenotype of the Progenitor Zoite

Tunev

McAllister

Anderson-Sprecher

et al. 2002

Journal of Parasitology

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We previously reported that Neospora caninum can be induced to express BAG1, a bradyzoite antigen, within 3 days of culture under stress conditions. The main goals of the present experiment were to increase the expression of BAG1 in vitro (in part by extending cultures for 9 days), to observe parasitophorous vacuoles at various points of stage differentiation, and to test the ability of organisms produced in vitro to function like mature bradyzoites. Expression of BAG1 and of a tachyzoite antigen (NcSAG1) was monitored using a double-label immunofluorescence assay. For the purpose of this study, organisms expressing NcSAG1 were designated as tachyzoites, those expressing BAG1 were designated as bradyzoites, and those expressing both antigens were designated as intermediate zoites. The greatest percentage of intermediate zoites and bradyzoites (14%) occurred in bovine monocytes maintained for 9 days. These bradyzoites did not appear to be functionally mature; they did not induce patent infections in dogs, in contrast to bradyzoites that were produced in chronically infected mice. In vitro, large parasitophorous vacuoles contained either a pure population of tachyzoites or a mixture of tachyzoites and intermediate zoites, which is indicative of asynchronous stage conversion of organisms within a vacuole. Bradyzoites were first observed within small vacuoles on day 6, and bradyzoites never shared vacuoles with tachyzoites. This finding suggests that vacuoles containing bradyzoites may develop only if the cell is invaded by a zoite that has already begun bradyzoite differentiation. An alternative possibility is that cysts may develop if the establishing tachyzoite undergoes bradyzoite differentiation before multiplying. Cysts do not appear to arise from transformation of tachyzoites within large parasitophorous vacuoles.Infection with Neospora caninum, an apicomplexan protozoan, can cause abortions in cattle (Thilsted and Dubey, 1989) and goats (Barr et al., 1992). Dogs are a definitive host (McAllister et al., 1998), and ruminants are intermediate hosts. Wild canids and wild ruminants are suspected to be a natural reservoir for the infection (Dubey et al., 1999;Barling et al., 2000). NIH-PA Author Manuscript Lindsay et al., 1992) and induce patent infections in the definitive host by carnivorism.Bradyzoites are needed for scientific investigation. First, bradyzoites are needed for investigation of the factors that induce recrudescence of latent infection. Recrudescence is responsible for vertical propagation of N. caninum within infected lines of cows (Björkman et al., 1996) and may also be a cause of systemic neosporosis in dogs. Second, a supply of bradyzoites could enable the development of an oral vaccine to prevent farm dogs from shedding N. caninum oocysts and thus infecting cattle.We previously reported that N. caninum can be induced to express BAG1, a bradyzoite antigen, within 3 days of culture in human fibroblasts under stress conditions (Weiss et al., 1999). The main goals of the present experime...

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“…The first report of abortion as a result of N. caninum infection in dairy cattle was in New Mexico (THILSTED & DUBEY, 1989).…”

Section: Introductionmentioning

confidence: 99%

PCR-based identification of Neospora caninum in the umbilical cord of a newborn calf in Brazil

Filho

Oliveira

et al. 2017

Cienc. Rural

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This study was conducted at a beef cattle breeding farm in the far southern region of Brazil. The birth of a calf with unilateral corneal opacity was immediately reported to the Laboratory of Parasitology, in the Universidade Federal de Pelotas, Rio Grande do Sul, Brazil; blood was collected from the cow and calf before colostrum intake. The umbilical cords from this calf and from six other healthy animals were collected. Serological examination, utilizing an indirect fluorescent antibody test, was done using a cut-off point of 1:100. Polymerase chain reaction (PCR) was also performed using the umbilical cord samples. Serological tests showed that the calf was positive for Neospora caninum at birth, with a titer of 1:1600; a titer of 1:3200 was reported in the dam. PCR, using umbilical cord tissue from the affected animal, was positive for the presence of this parasite, and the molecular identity of the amplified product was confirmed by sequencing. Therefore, the detection of N. caninum DNA in the umbilical cord represents a novel alternative test for the diagnosis of this parasitic infection in newborn calves that are clinically suspected to have neosporosis.

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Neosporosis-Like Abortions in a Herd of Dairy Cattle

Cited by 206 publications

References 7 publications

Causas de aborto bovino diagnosticadas no Setor de Patologia Veterinária da UFRGS de 2003 a 2011

Causas de aborto bovino diagnosticadas no Setor de Patologia Veterinária da UFRGS de 2003 a 2011

Neospora Caninum in Vitro: Evidence That the Destiny of a Parasitophorous Vacuole Depends on the Phenotype of the Progenitor Zoite

PCR-based identification of Neospora caninum in the umbilical cord of a newborn calf in Brazil

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