SCAN: Identification of B. bovis in cattle from Central and Southern regions of Portugal and molecular characterization of two new B. bovis genes

Abstract
Babesia bovis (B. bovis) is a bovine parasite transmitted by ticks from the Ixodidae family of hemoprotozoan which induce the destruction of the host’s erythrocytes as a consequence of an intra-erythrocyte phase in their life cycle. It is responsible for clinical symptoms such as anemia, hemoglobinuria and jaundice [1]. Babesiosis has been responsible for promoting economic losses on livestock from tropical and sub-tropical regions affecting both human and animal health, resulting in increased mortality rates of cattle [2]. There are no effective killed or subunit vaccines available, and attenuated live vaccines currently being used against B. bovis have the disadvantage of pathogen co-transmission and a short shelf-life.
In Portugal there is almost no information available about the presence of B. bovis in cattle, however there are at least 3 classes of ticks identified that are competent for transmission of B. bovis: Ixodes ricinius, Rhipicephalus bursa and Rhipicephalus (Boophilus) annulatus. Here we report the presence of B. bovis in Central and Southern regions of Portugal by serological and molecular biology techniques.
By searching the recently available B. bovis genome sequence, two novel B. bovis proteins were identified for further characterization: a B. bovis protein with homology to the Plasmodium falciparum PFS 230 homologue and a B. bovis protein with homology to the Toxoplasma gondii microneme (MIC) protein. Importantly, PFS 230 is a protein expressed on the surface of P. falciparum gametes containing conserved sexual stage domain motifs, which has been previously identified as a malaria transmission-blocking vaccine candidate [3]. MICs are key mediators of cytoadherence and invasion for T. gondii, and also have a function in cellular adhesion and link the parasite actin-myosin system to the host surface, aiding in parasite entry into the host cell [4]. Homologues of these two genes are expressed in B. bovis merozoites, are immunogenic in infected cattle, and are able to elicit neutralization sensitive antibodies. Although the exact cellular localization and function of these novel B. bovis proteins remains to be further defined, the data suggests that they have potential as candidates for subunit vaccine development.


[1] Uilenberg, G. 2006. Babesia – A historical overview. Veterinary Parasitology, 138, 3-10.
[2] McCrosker, P.J. 1981. The global importance of babesiosis. In: M. Ristic and J.P Kreier (ed.), Babesiosis-1981. Academic Press, Inc., New York, pp. 1-24.
[3] Roeffen W., Geeraedts F., Eling W., Beckers P., Kumar N., Lensen T., Sauerwein R. (1995) Transmission Blockade of Plasmodium falciparum Malaria by
Anti-Pfs230-Specific Antibodies Is Isotype Dependent. Infection and Immunity, 63, 467–471.
[4] Hager, K.M., Carruthers, V.B. 2008. MARveling at parasite invasion. Trends in Parasitology, 24, 51-54.


Short CV
1998-2003 – Degree in Biotechnology by Universidade Independente.
2002-2004 – Research assistant at the Biomolecular Diagnostic Laboratory, ITQB/IBET in the project “Development of an optical immunosensor for veterinary diagnostics”
2004-2008 – PhD fellowship by Fundação para a Ciência e Tecnologia, since October of 2004, in a research work entitled "Development of diagnostic methods of Babesia sp. and identification of vaccines candidates" at the Biomolecular Diagnostic Laboratory, ITQB/IBET.