Vaccines and drugs against Neospora caninum, an important apicomplexan causing abortion in cattle and other farm animals

Abstract:

The apicomplexan parasite Neospora caninum represents an important abortion-causing parasite in cattle. The economic impact of neosporosis has led to considerable investments to develop vaccines that would prevent infection and abortion. Live-attenuated vaccines have been shown to confer some protection against N. caninum infection, but may cause problems due to regulatory issues and other drawbacks. Therefore, efforts have been undertaken to develop recombinant subunit vaccines based on antigens involved in adhesion/invasion or other parasite–host cell interaction processes. Concerning chemotherapeutical agents, the currently known arsenal of active drugs that act against N. caninum is limited to a small number of compounds with suitable in vitro properties including low inhibition constants, parasitocidal effects, and low cytotoxicity. For in vivo studies, mostly small laboratory animal models that mimic cerebral infection, acute disease, and fetal loss upon infection during pregnancy have been applied for the assessment of vaccines or drug candidates. However, only a small number of recombinant vaccines and drug candidates have met the expectations, and small laboratory models for neosporosis need to be standardized in order to be able to compare the results of different laboratories. Few vaccines and compounds have made it into trials involving ruminant models such as cattle or sheep, including live-attenuated vaccines and the anticoccidial drug toltrazuril. We here summarize the current status of vaccine and drug development for neosporosis.

Keywords::

• neosporosis
• anti-infective agents
• chemotherapy
• immunotherapy
• vaccine
• drug target

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Vaccines and drugs against Neospora caninum, an important apicomplexan causing abortion in cattle and other farm animals [Corrigendum]

Acknowledgments

We gratefully acknowledge the financial support by a combined NIH/USDA program (dual use therapeutics for cryptosporidiosis, toxoplasmosis, and neosporosis; grant no 1 R01 HD080670_01), and the Swiss National Science Foundation (grant no 310030_146162).

Disclosure

The authors report no conflicts of interest in this work.