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Humoral immune reaction of newborn calves congenitally infected with Neospora caninum and experimentally treated with toltrazuril

Haerdi, Corinne ; Haessig, Michael ; Sager, Heinz ; Greif, Gisela ; Staubli, Daniela ; Gottstein, Bruno

In: Parasitology Research, 2006, vol. 99, no. 5, p. 534-540

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    Titre
    • Humoral immune reaction of newborn calves congenitally infected with Neospora caninum and experimentally treated with toltrazuril
    Auteur
    • Haerdi, Corinne. Herd Health, Department of Farm Animals, Vetsuisse Faculty, University of Zurich, Winterthurerstr. 260, CH-8057, Zurich, Switzerland
    • Haessig, Michael. Herd Health, Department of Farm Animals, Vetsuisse Faculty, University of Zurich, Winterthurerstr. 260, CH-8057, Zurich, Switzerland
    • Sager, Heinz. Institute of Parasitology, Vetsuisse Faculty, University of Bern, Laenggass-Strasse 122, CH-3012, Bern, Switzerland
    • Greif, Gisela. Bayer HealthCare AG, Animal Health, 51368, Leverkusen, Germany
    • Staubli, Daniela. Institute of Parasitology, Vetsuisse Faculty, University of Bern, Laenggass-Strasse 122, CH-3012, Bern, Switzerland
    • Gottstein, Bruno. Institute of Parasitology, Vetsuisse Faculty, University of Bern, Laenggass-Strasse 122, CH-3012, Bern, Switzerland
    Type de document
    • Postprint
    Classification
    • Biologie, Sciences de la vie
    Identifiant OAI-PMH
    • oai:doc.rero.ch:318292
    Summary
    Neospora caninum is widely recognized as one of the most important infectious organisms causing abortion and stillbirth in cattle. This parasite causes severe economical losses worldwide. Infection is mostly passed vertically from mother to calf during pregnancy. Under certain circumstances, an infection can lead to abortion, but in most cases it results in a chronically infected calf, which itself will represent the next endogenously infectious generation. So far, no reliable therapeutic or metaphylactic tool has been developed. One possibility to control the problem may consist of treating newborn calves that became vertically infected by a persistently infected mother. This may allow parasite-free offspring. The aim of the present study was to address the questions: (1) can serology be used to assess efficiency of treatment in toltrazuril-medicated animals? and (2) is a strategic prevention measure possible by means of producing N. caninum-free calves from positive cows? Calves from Neospora-seropositive cows and heifers were randomly split into two different medication groups: 36 calves were medicated with toltrazuril and 36 calves obtained a placebo. Medication (20mg toltrazuril per kg bw) was administered three times, every second day, within the 7days post natum. Three months after medication, there was no difference in antibody reactivity between the two groups. At later time points (4-6months), however, significant differences were found, as explained by a strong humoral immunity after chemotherapeutical affection of parasites, while the placebo-treated animals only responded weakly to the persistent infection. In summary, we concluded that (1) serology was not an entirely appropriate tool to answer our initial question and (2) toltrazuril has the potential to eliminate N. caninum in newborn calves. As a consequence, we plan to follow up toltrazuril-medicated calves clinically and serologically over a longer period and investigate if they give birth to Neospora-free calves