Toxoplasmosis is the pathology caused by the protozoan Toxoplasma gondii (Nicolle and Manceaux, 1908) and that presents very unique characteristics in relation to other parasites of the phylum Apicomplexa (Dubey, 2010; Sercunde et al., 2016). Counterintuitively, there is great genetic diversity within this species, leading to a heterogeneous pathogenicity profile (Dubey and Su, 2009).

It has been shown that, around the world, more than 60% of certain populations become infected with T. gondii at some point in their lives, and in the United States, about 11% of the population aged 6 years or older has also been infected, demonstrating a relevant capacity for this pathogen to spread (CDC, 2018). In Brazil, the consumption of vegetables contaminated with oocysts seems to be the major factor in the incidence of toxoplasmosis (Balbino et al., 2022).

Despite the high serological prevalence, clinical manifestations of this disease are less frequent. Transplacental infection can cause abortion, premature birth, ocular lesions, generalized lymph node involvement, etc., and in immunocompromised individuals, the infection usually leads to severe forms, such as cerebral and ocular, with a wide variety of replication niches (Neves, 2016; Durieux et al., 2022).

Regarding the cellular immune response against toxoplasmosis, the anti-parasitic activity exhibited by interferon-γ (IFN-γ) secreted by T lymphocytes, seems to be fundamental to combat the pathogen and depends on the release of interleukin-12 (IL-12) by dendritic cells and neutrophils (Mashayekhi et al., 2011; Biswas et al., 2017). Despite the intracellular reach of this pathway, T. gondii is capable of actively proliferating in macrophages and thus has a high potential for dissemination and resistance, but little is known about other immune cells (Wu et al., 2022).

In order to clarify how the intensity of T. gondii infection influences different types of cell groups in the blood and how these influence the proliferation of this pathogen, the present study was undertaken to correlate the inoculum concentrations and amount of post-infection parasites with porcine hematological parameters (including one biochemical) through in vitro culture.