Submitted to: International Journal for Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 15, 2001
Publication Date: February 23, 2002
Citation: JENKINS, M.C., BASZLER, T., BJORKMAN, C., SCHARES, G., WILLIAMS, D. DIAGNOSIS AND SEROEPIDEMIOLOGY OF NEOSPORA CANINUM-ASSOCIATED ABORTION. INTERNATIONAL JOURNAL FOR PARASITOLOGY. 32: 631-636. 2002.
Interpretive Summary: Reproductive failure, such as abortion and birth of diseased calves, is a common problem to dairy facilities. There are many potential causes for reproductive failure including bacteria, viruses, protozoa and even chemicals. Diagnosing the cause of abortion in dairy cattle is important in developing strategies for preventing such problems in the future. However, the aborted fetus is often not available for testing and thus tests must rely on the presence of antibodies in the cow against specific pathogens. A number of test have been developed for this purpose including enzyme-linked immunosorbent assay, immunofluorescence assay; both of which test for the presence of antibodies to the parasite Neospora caninum. Also, molecular tests, such as polymerase chain reaction (PCR), have been developed that detect the parasite in tissue of the aborted fetus. Although these tests are sensitive and specific for the parasite, they must tbe used in conjunction with clinical evaluation of the aborted fetus. The judicious use of these tests will help in the control of bovine neosporosis and stemming the outbreaks of Neospora caninum-associated abortion in dairy cattle.
A roundtable was conducted at the VIIIth International Coccidiosis Conference on Neospora diagnosis with particular emphasis on strategies to diagnosis bovine abortion. The strength and weakness of different assays for N. caninum infection and whether these methods have resulted in the over-diagnosis of neosporosis was discussed. It was evident that each diagnostic method, namely histology, immunohistochemistry, molecular detection, and serological assays were, under certain circumstances, valuable in assessing the role of N. caninum in abortion. Histological, immunohistochemical (IHC), and molecular detection assays are of outstanding importance for the examination of tissues of aborted fetuses. While histology and immunohistochemistry allow direct assessment of pathomorphological changes caused by infection, molecular detection assays such as polymerase chain reaction (PCR) are superior because of higher sensitivity and specificity in identifying N. caninum in fetal tissues. Serological tests, such enzyme-linked immunosorbent assay (ELISA), are useful in determining whether an animal has been infected with N. caninum. Seroepidemiological approaches allow one to assess an abortion problem at a herd level and when used in conjunction with certain statistical methods are able to confirm a suspected N. caninum-associated abortion.