New vaccines for goats and sheep tick diseases

Small ruminant piroplasmosis (theileriosis and babesiosis) is caused by the protozoan parasites Thelieria lestoquardi, T. uilenbergi and Babesia ovis, which infect sheep and goats causing disease, production loss and sometimes death.

The EU-funded project PIROVAC (Improvement of current and development of new vaccines for theileriosis and babesiosis of small ruminants) developed effective measures to tackle this global threat to agriculture. In addition to seven European countries, the project involved researchers from Argentina, China, Israel and Turkey.

Work aimed at improving existing vaccines included using attenuated microorganisms. An attenuated strain of T. lestoquardi was evaluated as a vaccine candidate. Partners performed extensive analyses to identify immunogenic parasite antigens and characterise them with respect to the immune responses they induce. These results should prove to be invaluable for the design of new vaccines.

Researchers identified several related genes, expressed them and used them for the production of polyclonal antisera. The antisera were used to study antigenicity, localisation within parasite/infected cells and regulated expression of the recombinant proteins.

Sequencing the genomes of the parasites and subsequent bioinformatics analysis allowed searches for host-pathogen interaction. Ex vivo experiments using sheep cell lines revealed involvement of two different types of blood cells (B lymphocytes and monocytes) in parasitic infection. Cytotoxic T lymphocytes participated in protective immune response against T. lestoquardi infection. Established nested polymerase chain reaction assays provided efficient diagnostics for piroplasmosis.

PIROVAC has contributed to understanding host-pathogen interactions, which is the key to developing sustainable therapy. They developed tools for the characterisation of both innate and adaptive immunity of the small ruminants that are an integral part of their therapeutic strategy.

Dissemination was designed to fuel all-important collaboration between relevant players. These included project meetings, exchange visits, publications, press releases and brochures. The project also co-organised a major conference "Emerging and Re-Emerging Epidemics Affecting Global Health" held in 2012 in Orvieto, Italy.

Ticks transmit more microbial and protozoan pathogens than any other arthropod group. In the wake of global warming, chances of disease transmission to humans and animals is increasing. PIROVAC research results promise to have a positive impact on checking small ruminant disease, especially for resource-poor farmers in semi-arid areas.