Mares vaccinated at the end of pregnancy have a higher number of antibodies against equine pyroplasmosis

Maria Luiza De Grandi, journalist from Ciência Rural, Santa Maria RS, Brazil.

Fábio Leivas Leite, research of Universidade Federal de Pelotas (UFPel), Pelotas, Rio Grande do Sul, Brasil.

Logo of the Ciência Rural journalEquine piroplasmosis is an endemic disease in Brazil, the main cause of severe hemolytic anemia in horses, and one of its etiological agents is the hemoparasite Theileria equi. The bacterium Streptococcus equi subspecies equi is a microorganism responsible for causing strangles, a disease with high morbidity and one of the most common that affects the upper part of the equine respiratory tract. With the aim of determining total specific IgG in vaccinated mares and their foals, researchers from the Pelotas Federal University (UFPel) produced the article Passive immunity in foals from mares vaccinated against Theileira equi and Streptococcus equi subspecies equi, published in Ciência Rural (vol. 52, no. 8).

To arrive at the results, the scientists accompanied 32 pairs of mares and their respective foals at the Center for Teaching and Experimentation in Equine Culture in Palma (CEEEP), located at University of Pelotas (UFPel). All mares were crossbred, multiparous and aged between 10 and 15 years and had their gestation monitored by ultrasound.

Photo: adult horse and baby horse walking in a pasture.

Image: Pixabay.


Foals were closely monitored for the first 24 hours of life. Bioinformatics exams were applied for the design and characterization of antigens (Theileria equi), Pichia pastors as a platform for expression of recombinant antigens, molecular (PRC) and immunological techniques (Western blot) in the selection of the S. equi sample used in the preparation of the vaccine used in the study, and immunological tests (ELISA) to assess humoral response.

The research demonstrated that mares vaccinated in the final third of gestation had higher total specific vaccine antibodies for both vaccines, with a similar profile of total specific IgG and subisotypes transferred to their foals.

According to researcher Fábio Leivas Leite, based on the present study, a vaccination schedule can be suggested, based on the age of the foal, to optimize control against Theileira equi and Streptococcus equi subspecies equi. “We think that the ideal would be the development of a recombinant vaccine to be used in the control of theileriosis, and to use the vaccine sample selection technology to be used in vaccine against strangles. The research contributes to a better understanding of the dynamics of the vaccine response in pregnant mares and their offspring”, concludes Leite.


CRAIGO, J.K., et al. Development of a high throughput, semiautomated, infectious center cell-based ELISA for Equine Infectious Anemia Virus. Journal of Virological Methods [online]. 2021, vol. 185, no. 2, pp. 221-227 [viewed 23 February 2023]. Available from:

ROTSCHILD, C.M. Equine Piroplasmosis. Journal of Equine Veterinary Science [online]. 2013, vol. 33, no. 7, pp. 497-508 [viewed 23 February 2023]. Available from:

To read the article, access

SANTOS, A.C. Passive immunity in foals born from mares vaccinated against Theileira equi and Streptococcus equi subspecies equi. Cienc. Rural [online]. 2022, vol. 52, no. 8, e20210182 [viewed 23 February 2023]. Available from:

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Como citar este post [ISO 690/2010]:

GRANDI, M.L. and LEITE, F.L. Mares vaccinated at the end of pregnancy have a higher number of antibodies against equine pyroplasmosis [online]. SciELO in Perspective | Press Releases, 2023 [viewed ]. Available from:


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