Toxoplasmosis is a zoonotic disease caused by the protozoan Toxoplasma gondii. Up to a third of the global human population is estimated to carry a T. gondii infection, which can result in severe complications in immunocompromised individuals and pregnant women [1]. T. gondii can infect humans but also any warm-blooded animal and its definitive host is the Felidae family (mostly cats) where it undergoes its sexual reproductive cycle with the release of infectious oocysts. Most of the studies on T. gondii rely on tissue cysts or tachyzoites which can be obtained either by the use of laboratory intermediate hosts or by cell culture, respectively. However, working on oocysts is trickier as it involves the experimental infection of cats. Therefore, there are still unrevealed parts of the sexual cycle of the parasite, due to the difficulties to obtain such oocysts. In the last couple of years, with the approval of the local ethic committee, representing French Ministry of Research and Innovation, we performed vaccination and challenge trials on cats with a genetically modified vaccine candidate against T. gondii. Despite an immunogenic and safe vaccine candidate, it did not protect animals from oocysts shedding after the challenge with a wild-type strain of T. gondii [2]. This challenge mimicking a first natural infection, the antibodies produced after it, protect the cats from a second oocysts shedding. Therefore, at the end of the experimental trials, the animals have been included in an adoption program, within the larger frame of a general agreement between the National Veterinary School of Alfort and animal-care associations for the retreat and welfare of laboratory animals. These trials allowed us to develop an expertise in obtaining oocysts from experimentally infected cats, which the scientific community can benefit from. 1. Jones, J. L. & Dubey, J. P. Clin. Infect. Dis. (2012). 2. Le Roux D., Djokic V. (...) Blaga R. – Vaccine (2020)