Urological detection of specific antibodies against Neospora caninum infection in mice: A prospect for novel diagnostic approach of Neospora

The intracellular protozoan parasite Neospora caninum is incriminated to induce drastic economic losses in both livestock and pet animal industries. Neosporosis is primarily characterized by abortion in cattle and paralytic symptoms in dogs. Because there are no effective treatments or vaccines, diagnosis is critical for Neospora control. Thus, diversification of laboratory tests and specimens used for diagnosis of N. caninum is an essential scientific endeavor to judge and select the most appropriate diagnostic tool. Herein, we provide the first evidence for the utility of urine samples for demonstration of specific antibodies against N. caninum employing an experimentally infected murine model. Specific antibodies to recombinant N. caninum dense granule 7, surface antigen 1, and lysate antigen were assayed using different antibodies-based ELISAs. Urine based IgG ELISA efficiently discriminated between infected mice (acute or chronic infection), and those of non-infected mice. This effect was also noticed for IgG1 and IgG2a suggesting the utility of urine for assessment of T-helper 2- and T-helper 1-mediated immunities, respectively. In addition, reactivity of specific antibody in urine was also confirmed against parasites when indirect fluorescent antibody test was employed. Usefulness of urine as an additional clinical sample for Neospora diagnosis was confirmed via comparison with the relevant control non-infected and infected mouse sera as reference samples. Because of minimum invasiveness and ease of urine collection, this approach might offer new diagnostic opportunities for N. caninum either for the field or research purposes. However, further studies are required to extrapolate this preliminary study and results in the animal species of interest particularly in dogs.