The host–parasite relationship in bovine neosporosis

Innes, Elisabeth A.; Wright, Steve; Bartley, Paul M.; Maley, S.W.; Macaldowie, C.; Esteban-Redondo, I.; Buxton, D.

doi:10.1016/j.vetimm.2005.07.004

Cited by 136 publications

(127 citation statements)

References 41 publications

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“…Infection in a pregnant animal may result in abortion, or in the birth of a weak calf, although in the majority of cases a clinically healthy but persistently infected calf is born. Different factors affect the outcome of neosporosis during the pregnancy, including the quantity and duration of parasitaemia in the recrudescence and the effectiveness of both the foetal and maternal immune response against the parasite (Innes et al 2005, Collantes-Fernández et al 2006b, Dubey et al 2006. Additionally, other factors such as strain virulence may play an important role.…”

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confidence: 99%

Isolation and biological characterisation of a new isolate of Neospora caninum from an asymptomatic calf in Brazil

García-Melo¹,

Regidor‐Cerrillo

Ortega‐Mora

et al. 2009

Acta Parasitologica

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Neospora caninum is a tissue-cyst forming parasite that has been recognized worldwide as a cause of abortion in cattle. Despite the ubiquitous distribution of this parasite and its broad range of hosts, the number of N. caninum isolates obtained to date is limited. In addition, the majority of isolates have been obtained from clinically affected hosts, therefore potentially biasing this population towards more virulent isolates. This report describes the isolation and biological characterisation of a new N. caninum isolate, Nc-Goiás 1, obtained from an asymptomatic, naturally infected calf from Brazil. This new isolate was identified as a member of the N. caninum species by polymerase chain reaction (PCR) using specific primers based on the N. caninum internal transcribed spacer 1 (ITS-1) sequence, and was genetically identified at multiple loci using microsatellite analysis. Finally, a pathogenicity study was conducted in a BALB/c mice model. All Nc-Goiás 1-infected mice survived without exhibiting any clinical signs. Further pathogenic characterisation of this isolate suggested that Nc-Goiás 1 is less virulent than other N. caninum isolates (Nc-Liv and Nc-1) studied in this mouse model. This is the first report of the isolation and biological characterisation of N. caninum from an infected but clinically healthy calf in South America.

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mentioning

confidence: 99%

Isolation and biological characterisation of a new isolate of Neospora caninum from an asymptomatic calf in Brazil

García-Melo¹,

Regidor‐Cerrillo

Ortega‐Mora

et al. 2009

Acta Parasitologica

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“…As for vertical transmission of N. caninum, infected heifers that become healthy adults may transmit the agent to the fetus, which is especially vulnerable, thereby maintaining the parasite in the herd (ANDERSON et al, 1997;INNES et al, 2005). Transplacental transmission has been reported in at least 36.8% of neosporosis-positive heifers and may reach 100% in experimental infections WILLIAMS, et al, 2000;INNES, et al, 2005;VIANA et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Association between seropositivity for Neospora caninum and reproductive performance of beef heifers in the Pantanal of Mato Grosso do Sul, Brazil

Andreotti¹,

Barros²,

Pereira³

et al. 2010

RBPV

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Neospora caninum is an obligate intracellular parasite that can infect domestic and wild canids, ruminants, and horses. The purpose of this study was to evaluate the association between the presence of antibodies to N. caninum and reproductive loss in beef heifers in the South Pantanal region of Mato Grosso, Brazil. A total of 1098 heifers were evaluated from breeding to calving with regard to reproductive performance, and serology for neosporosis was assayed by indirect immunofluorescence reaction. The prevalence of N. caninum in cows that had failed to conceive was 22.13% higher than in those that had conceived (p < 0.0001), indicating a significant correlation between non-conception and presence of anti-N. caninum antibodies. The extraction rates for seropositive and seronegative heifers were 28.24 and 50.12%, respectively, with a statistically significant value (p < 0.0001) that showed a decrease of 44% in the extraction rate of seropositive animals. The results emphasize the importance of diagnosis for monitoring of neosporosis in primiparous cows, and indicators of seropositive females as a factor in strategies for culling the beef cattle herd.Keywords: Reproduction, bovine, diagnostic, abortion, Neospora caninum. ResumoNeospora caninum é um parasita intracelular obrigatório que pode infectar canídeos domésticos e selvagens, ruminantes e equídeos. Neste trabalho estudou-se a associação entre soropositividade para Neospora caninum e perda reprodutiva em novilhas de corte na região do Pantanal Sul-Mato-Grossense. Foram avaliadas 1098 novilhas da estação de reprodução ao nascimento dos bezerros com relação ao desempenho reprodutivo e realizada a sorologia para N. caninum através da reação de imunofluorescência indireta. A soroprevalência de N. caninum nas vacas que falhara na concepção foi 22,13% maior que nas que conceberam (p < 0,0001), indicando que há uma correlação significativa entre a não concepção e a presença de anticorpos anti-N. caninum. As taxas de desfrute para as novilhas soropositivas e soronegativas para neosporose foram de 28,24 e 50,12%, respectivamente, mostrando uma redução de 44% na taxa de desfrute de novilhas soropositivas para N. caninum. Ressalta-se a importância do monitoramento do diagnóstico da neosporose em primíparas, e o indicador de fêmeas soropositivas como um fator nas estratégias de descarte no rebanho bovino de corte.Palavras-chave: Reprodução, bovinos, diagnóstico, aborto, Neospora caninum.

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“…The parasite was described and named by Dubey et al (1988a, b), and was later also reported in various species of livestock, including cattle, sheep, goats, horses and deer (reviewed by Dubey andLindsay 1996, Hemphill 1999). However, most importantly, the current evidence strongly indicates that infection with N. caninum represents a major cause of reproductive failure in cattle worldwide , Innes et al 2005. The exact phylogenetical relationship of N. caninum to other members of the Apicomplexa has been, and still is, a matter of controversial discussions (Tenter and Johnson 1997, Heydorn and Mehlhorn 2002.…”

Section: Introductionmentioning

confidence: 99%

“…However, in special situations, such as pregnancy, bradyzoites can get reactivated, and the partial immunoincompetence of a pregnant dam, namely the decrease of an efficient Th-1 response and shift to Th-2, leads to limited suppression of the cell mediated immunity which normally keeps tachyzoite proliferation in check (reviewed by Innes et al 2002Innes et al , 2005Quinn et al 2002). This can contribute to the reactivation of bradyzoites and reconversion to tachyzoites, and can then lead to infection of the placenta and the foetus with N. caninum tachyzoites.…”

Section: Introductionmentioning

confidence: 99%

“…These interactions occur on two levels. On one hand, it is the complex relationship with the host immune system, which decides the fate of this parasite once it enters the host organism Innes et al 2002Innes et al , 2005Quinn et al 2002). On the other hand, N. caninum can only survive, proliferate and proceed during most stages of its life cycle as an intracellular parasite, thus the processes which lead to host cell invasion and intracellular development are of crucial importance (Hemphill 1999;Hemphill et al 2004).…”

Section: Introductionmentioning

confidence: 99%

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Neospora caninum and neosporosis — recent achievements in host and parasite cell biology and treatment

Hemphill

Gottstein

2006

Acta Parasitologica

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Neospora caninum is an apicomplexan parasite, which owes its importance to the fact that it represents the major infectious cause of bovine abortion worldwide. Its life cycle is comprised of three distinct stages: Tachyzoites, representing the proliferative and disease-causing stage, bradyzoites, representing a slowly replicating, tissue cyst-forming stage, and sporozoites, which represent the end product of a sexual process taking place within the intestinal tissue of the final canine host. Tachyzoites are capable of infecting a large variety of host cells in vitro and in vivo, while bradyzoites have been found mainly within the central nervous system. In order to survive, proliferate, and proceed in its life cycle, N. caninum has evolved some amazing features. First, the parasite profits immensely from its ability to interact with, and invade, a large number of host cell types. Secondly, N. caninum exploits its capability to respond to alterations in living conditions by converting into another stage (tachyzoite-to-bradyzoite or vice versa). Thirdly, this parasite has evolved mechanisms that modulate its host cells according to its own requirements, and these must, especially in the case of the bradyzoite stage, involve mechanisms that ensure long term survival of not only the parasite but also of the host cell. These three key events (host cell invasion -stage conversion -host cell modulation) represent potential targets for intervention. In order to elucidate the molecular and cellular bases of these important features of N. caninum, cell culture-based approaches and laboratory animal models are extensively exploited. In this review, we will summarize the present knowledge and achievements related to host cell and parasite cell biology.

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The host–parasite relationship in bovine neosporosis

Cited by 136 publications

References 41 publications

Isolation and biological characterisation of a new isolate of Neospora caninum from an asymptomatic calf in Brazil

Isolation and biological characterisation of a new isolate of Neospora caninum from an asymptomatic calf in Brazil

Association between seropositivity for Neospora caninum and reproductive performance of beef heifers in the Pantanal of Mato Grosso do Sul, Brazil

Neospora caninum and neosporosis — recent achievements in host and parasite cell biology and treatment

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