Neglected Aspects About Toxoplasmosis in Immune Deficiencies: Time to Attention!

Resumo

Toxoplasmosis is a zoonotic disease with a wide global distribution, caused by the obligate intracellular protozoan Toxoplasma gondii. It is recognized as an important foodborne illness, although it is not yet formally included in the global list of neglected diseases. Its occurrence is frequently associated with contexts of social vulnerability, low sanitation coverage, immunosuppression, and lack of knowledge about its life cycle. The parasite has three infective forms—tachyzoites, bradyzoites, and sporozoites—and a heteroxenic cycle involving felines as definitive hosts. In immunocompromised individuals, the infection can progress to severe forms, often resulting from the reactivation of latent infections. In this context, the tissue microenvironment and the parasite-host interaction play a central role in disease progression, influencing immunological, inflammatory, and metabolic mechanisms that determine the clinical outcome. The objectives of this article were: To identify mortality related to toxoplasmosis in different regions of Brazil. Identifying gaps and proposing priorities for health education. This is a descriptive epidemiological study on toxoplasmosis mortality in different regions of Brazil, based on secondary data obtained from the Ministry of Health's Toxoplasmosis Panel. Additionally, an integrative review focusing on primary health care was conducted, encompassing clinical, immunological, epidemiological, and therapeutic aspects of toxoplasmosis, especially in immunocompromised populations. The findings show that toxoplasmosis mortality in Brazil has a heterogeneous distribution, with predominantly high rates in the North Region throughout the years analyzed (2019–2024), followed by variations in the Central-West, Northeast, and Southeast regions. States such as Acre, Tocantins, and Amapá stand out with persistently high rates, while states like São Paulo have lower rates, possibly due to greater surveillance in at-risk populations, such as transplant recipients. These data reflect regional inequalities in access to diagnosis, epidemiological surveillance, and health care. Toxoplasmosis, although highly prevalent, remains underdiagnosed, especially in immunosuppressed individuals, in whom reactivation of the infection can result in severe manifestations such as encephalitis and disseminated forms, often fatal. The literature highlights a relevant association with conditions such as AIDS, neoplasms, and the use of immunosuppressive therapies, including anti-TNF-α, which can trigger reactivation of the parasite. Furthermore, kidney transplant recipients constitute a high-risk group, with high mortality when diagnosis is delayed. From a pathophysiological point of view, the tissue microenvironment plays a fundamental role in the dynamics of the infection, being characterized by immunometabolic alterations that favor the persistence of the parasite. Cytokine modulation, the action of immune system cells, and the subversion of cellular mechanisms, such as lysosomal function, contribute to the maintenance of chronic infection. The possible association between toxoplasmosis and neoplasms is discussed, although there is no established causal evidence, highlighting the need for more robust studies in the area of ​​immunoparasitology. The use of natural products with potential antiparasitic activity does not replace conventional treatment, as they are aimed at the parasite's life cycle. It is concluded that toxoplasmosis remains a significant public health problem, especially in immunocompromised populations, where it can present high mortality rates. The unequal distribution of mortality in Brazil highlights weaknesses in surveillance, diagnosis, and healthcare access systems, reinforcing the need to strengthen primary care and health education strategies. A deeper understanding of the infection microenvironment and the immunological mechanisms involved contributes to the advancement of scientific knowledge and the development of new therapeutic approaches. The urgency of investments in research, epidemiological surveillance, public policies, and health education actions that prioritize vulnerable populations, aiming to reduce morbidity and mortality associated with toxoplasmosis, is emphasized.