A competitive PCR assay for quantitative detection of Neospora caninum

A quantitative-competitive PCR (QC-PCR) assay was developed for measurement of Neospora caninum levels in the tissues of infected animals. A molecule was synthesised for use in PCR as a competitor to the target Neospora-specific Nc5 genomic sequence. The assay was used to evaluate the relative level of parasites in the brain and lungs of mouse pups in a model of vertical transmission of N. caninum. Infection on day 11 of gestation resulted in similar levels of parasites in all offspring. The assay should be useful in evaluation of vaccines against Neospora infection. Incorporation of the competitor molecule in the detection assay also provides a control for PCR failure and facilitates identification of truly negative samples. (C) 1999 Australian Society for Parasitology Inc. Published by Elsevier Science Ltd. All rights reserved.