Introduction: A third of the world's population is affected by toxoplasmosis, a zoonosis with significant impact. Congenital toxoplasmosis (CT) occurs after a primary infection during pregnancy, potentially leading to severe neurological and systemic symptoms. In Spain there is a lack of updated information.

Objective: To understand the situation of congenital toxoplasmosis in Spain from a "One Health" perspective and apply this knowledge to the healthcare field to enhance detection, treatment, and control.

Materials and Methods: A multidisciplinary approach study has been designed, involving researchers from various healthcare fields (medical, parasitological, veterinary, and public health) organized through the Spanish Working Group on Toxoplasmosis (GET-TOXO). It applies to epidemiological knowledge in both human and animal environments, focusing on improving diagnosis, prevention, and control. The study aims to identify the incidence of CT and its clinical, epidemiological, and molecular characteristics. This will be achieved by analyzing seroprevalence and incidence in pregnant women and animals of different species. Immunological and molecular techniques will be developed to enhance diagnostic capabilities. Molecular characterization of T. gondii isolates from humans and animals will be conducted using an 11-marker analysis with RFLP-PCR, aiming to determine the potential relationship between genotypes and pathology, as well as their implications in epidemiology and control.

Results: Preliminary results are presented. CT has been a notifiable disease since 2015, but there is an underreporting to the National Epidemiological Surveillance Network (RENAVE). Only 17 cases of CT were reported to RENAVE from 2010-20, while analysis of the Specialized Primary Care Attention Registry (RAE-CMBD) identified 547 hospital discharges with this diagnosis in the same period (3% of reported cases). Molecular characterization of T. gondii isolates analyzed so far showed genotype II as the most prevalent, along with types I and III and atypical genotypes.

Conclusions: The lack of information on CT in Spain requires a thorough analysis, active case review and ongoing epidemiological studies in human and animal settings within the "One Health" approach. Establishing the required detection and control measures is essential, mainly in pregnant women.

Funding: FIS-AESI PI 21CIII/0031 Project, Health Research Fund, ISCIII, Ministry of Science and Innovation.