Heifers inoculated with Neospora caninum live tachyzoites at prepubertal age reactivate their infection during gestation

BURUCUA M; CIRONE K; CAMPERO L; ORTEGA-MORA L; HECKER Y; MALDONADO RIVERA, J.E.; CHEUQUEPAN VALENZUELA F; MARIN MS; FIORANI F; DORSCH M; CANTON GJ; MOORE D

Berna

Congreso; 6th International Meeting on Apicomplexa in Farm Animals; 2022

Neospora caninum is recognised for causing cattle abortion, provoking severe economiclosses in the livestock industry worldwide. The aim of the present study was to evaluate thereactivation and foetal infection in pregnant heifers inoculated with live N. caninum tachyzoitesbefore puberty. A total of 15 30-month-old pregnant heifers were allocated into four groups: animalsinoculated with live tachyzoites of NC-Argentina LP1 isolate before puberty and challenged with livetachyzoites of NC-1 strain at 210 days of gestation (DG) (Group A); animals mock inoculated beforepuberty and challenged with NC-1 strain at 210 DG (Group B), animals inoculated before pubertybut not subsequently challenged (Group C); and noninfected and nonchallenged animals (Group D).The results of this study showed that 100% of animals infected before puberty (Groups A and C)suffered reactivation of the infection at the seventh month of gestation. In addition, in three andtwo calves from Groups A and C, respectively, congenital infection was confirmed. Interestingly, weprovide evidence that the use of live N. caninum tachyzoites in young animals as a strategy to induce protection is neither safe nor effective