Congenital toxoplasmosis remains a neglected disease in Tocantins, despite its high prevalence and potential to cause severe sequelae and disabilities in the population. This study aimed to describe the epidemiological profile of congenital toxoplasmosis cases from 2020 to 2024 among residents of Tocantins, based on sociodemographic characteristics and the spatial distribution of its occurrence. 

Methods: This was an observational, ecological study with a quantitative approach, using secondary data obtained from the Notifiable Diseases Information System (SINAN) through the Tabnet/Datasus platform. 

Results: During the study period, 798 cases of congenital toxoplasmosis were reported. The prevalence of the disease was 69 cases per 10,000 live births.

Most of the newborns reported with congenital toxoplasmosis were male, of mixed race (brown color), and residents of the Medio Norte Araguaia and Capim Dourado Health Regions. The main diagnostic tool was laboratory testing, and the vast majority of cases evolved to cure; however, there was a high rate of loss to follow-up over time. 

Conclusion: Given the observed scenario, it is essential that public health policies for the prevention of toxoplasmosis in Tocantins be integrated with educational and social initiatives, with the aim of reducing inequalities and increasing the effectiveness of prevention efforts.

SUS             : Unified Health System 

SINAN        : Notifiable Diseases Information System 

DATASUS  : Department of Information of the Unified Health System 

IBGE          : Brazilian Institute of Geography and Statistics 

SINASC    : Live Birth Information System 

Toxoplasmosis is a worldwide zoonosis caused by an intracellular protozoan capable of infecting birds, humans and other mammals. It presents a varied clinical picture, from asymptomatic infection to extremely serious systemic manifestations [1,2].

Toxoplasma gondii, the etiologic agent of toxoplasmosis, has a life cycle with three main forms, all of which are capable of causing infection: tachyzoites (which occur during the acute phase or reactivation of the disease and are able to cross the placenta and infect the fetus); bradyzoites (which are found in the tissues of humans and all animals infected by the protozoan); and sporozoites, which are found inside oocysts (formed exclusively in the intestines of felines, their definitive hosts) [3].

The disease is transmitted in a variety of ways, either directly or indirectly, and can be via the oral route through the consumption of food and/or water contaminated with oocysts or meat and meat products containing tissue cysts. Another form of transmission is via the transplacental route, carried out by the active form of the parasite when the mother acquires the infection during pregnancy. In addition to these, there are other, rarer forms of transmission: inhalation through contaminated aerosols, through accidental inoculation, blood transfusion or through organ transplantation [4].

Most cases of toxoplasmosis are asymptomatic or present with very nonspecific symptoms, often confused with symptoms common to other diseases such as dengue fever, cytomegalovirus or infectious mononucleosis. Even in the absence of symptoms, the diagnosis of Toxoplasma gondii infection during pregnancy is extremely important, with the main objective of preventing congenital toxoplasmosis and its sequelae [5].

Special attention is justified due to the considerable probability of impact on the fetus. The anatomical and functional complications associated with congenital toxoplasmosis range from restricted intrauterine growth to clinical manifestations and sequelae such as microphthalmia, eye lesions, microcephaly, hydrocephalus, cerebral calcifications, pneumonitis, and hepatosplenomegaly and skin rash [3].

Complications in the fetus are more serious when the mother is infected early in pregnancy, and may cause spontaneous abortion, premature birth, neonatal death or malformations. Infected children may present the classic signs and symptoms of congenital toxoplasmosis (hydrocephalus, retinochoroiditis, cerebral calcification and mental retardation) or may be born normal and develop sequelae during childhood or even in adulthood [6].

It is speculated worldwide that for every ten thousand newborns, approximately 5(five) children suffer from congenital toxoplasmosis. Furthermore, it is the cause of 1.3 million years of life lost or years of life with disability in people diagnosed with the disease, due to sequelae caused by the disease, such as bilateral chorioretinitis, hydrocephalus and intracranial calcification [7].

In less severe cases, other eye lesions may appear, such as retinal degeneration and neurological damage. Regarding eye damage caused by toxoplasmosis, the typical manifestation is focal necrotizing retinochoroiditis accompanied by vitreous reaction, often associated with healed satellite lesions; there is a maculo discal predilection and the lesions are usually equal to or smaller than one disc diameter [8].

The risk of congenital transmission increases with the length of pregnancy. The risks of transmission to the fetus vary according to the period of infection. There is a 2% risk of transmission to the fetus in the periconceptional period; 15% in the first trimester; 25% in the second and 65% in the third trimester. In the last month of pregnancy, this risk can reach 100% of cases. Regarding the severity of the congenital disease, it is high when it occurs at the beginning of pregnancy and decreases with gestational age [9].

Treatment and monitoring of the disease are available, free of charge and comprehensively, through the Unified Health System (SUS), and serology for IgG and IgM of Toxoplasma gondii is mandatory in the 1st and 3rd trimesters during prenatal consultations [10]. If the pregnant woman's IgM and IgG tests are non-reactive, the serology should be repeated at the beginning of the 2nd and 3rd trimesters of pregnancy. This screening is essential, as it allows the identification of pregnant women susceptible to the disease for subsequent monitoring, enabling prevention and early detection measures [11].

Congenital toxoplasmosis has an estimated global incidence of 190,100 cases per year, representing approximately 1.5 cases per 1,000 live births. The main concern is the lack of uniformity in prenatal screening, not only between different countries, but also within the same country. In European countries, for example, only those with a high incidence of the disease have adopted prenatal screening, such as France, Austria and Slovenia. In the United Kingdom, where congenital toxoplasmosis is considered rare, there is not even a universal serological screening program [12].

In Brazil, the prevalence of toxoplasmosis is high, ranging from 64.9% to 91.6%, depending on the region. A high percentage (50-80%) of women of childbearing age are IgG positive. Between 20-50% of women of reproductive age are susceptible (IgG and IgM negative) and are at risk of acquiring the infection during pregnancy. Studies conducted in Brazil have shown that between 5-23 infected children are born for every 10,000 live births [12].

Congenital toxoplasmosis was included in the list of diseases subject to compulsory notification in 2016 through Ordinance No. 204, of February 17, 2016 [13]. However, until May 2020, there were no records of the disease in the Notifiable Diseases Information System (SINAN) of the Brazilian Ministry of Health, demonstrating how neglected the disease still was [14].

In view of the above, considering the significance and magnitude of congenital toxoplasmosis in the morbidity of the local population, especially its capacity to generate sequelae and consequent permanent disability, it is clear that there is a need to disclose the epidemiological profile, highlighting the distribution according to the triad of person, time and place of the disease in Tocantins, an essential condition for the construction of a plan aimed at reducing morbidity and organizing the Health Care Network to assist toxoplasmosis.

This is an observational, retrospective, ecological study with a quantitative approach, using SINAN as the data source, through the Tabnet database of the Department of Information of the Unified Health System (Datasus) and the Brazilian Institute of Geography and Statistics (IBGE).

Descriptive epidemiological studies aim to delimit the distribution of diseases or health-related circumstances, according to time, place and/or characteristics of individuals. It examines how the incidence or prevalence of a certain disease varies according to certain aspects such as sex, age, education, race, among others [15].

It is classified as retrospective, since the data on patients already exist and has a quantitative approach because it is related to the collection and analysis of estimated data on variables, identification, connections and deductions of a given population, using statistical techniques and consolidating the information obtained in tables, graphs, maps and others. Based on the information obtained through data processing, it is possible to outline the epidemiological profile of the disease in a certain period, favoring the development of control measures in public health leading to health promotion [16].

The study was carried out in the state of Tocantins, located in the northern region of Brazil. In the last census in 2022, its population was 1,511,460 inhabitants, with a population density of 5.45 inhabitants per square kilometer and a high human development index of 0.731 [17], distributed across eight health regions: “Bico do Papagaio”, “Medio Norte Araguaia”, “Cerrado Araguaia Tocantins”, “Cantão”, “Amor Perfeito”, “Capim Dourado”, “Island of Bananal” and “Sudeste”.

Exclusively secondary and anonymized data were used during the month of May 2025, collected directly from the SINAN database, a system responsible for storing notifications and investigations of cases of diseases and conditions present in the national list of diseases with compulsory notification, enabling health diagnoses to be carried out, contributing to identifying the epidemiological scenario of certain areas [18].

To include data in the study, all notifications that constituted the official database of congenital toxoplasmosis in SINAN were considered, with the municipality of residence reported as one of the 139 municipalities in the state of Tocantins, regardless of the place of diagnosis, in the period from 2020 to 2024.

To calculate prevalence, data on births registered in the Live Birth Information System (SINASC), collected on May 23, 2025, were used. Data from 2020 to 2023 are definitive, however, due to the SINASC data entry routine; data for 2024 are still partial and subject to change.

Among the variables available for public consultation through the Tabnet/Datasus system, those with the potential to achieve the study's purpose were selected, characterizing the epidemiological profile through the triad of person, time, and place. Thus, the following were used: year of notification, municipality of residence, age group, sex, classification, evolution, and confirmation criteria.

The response fields that were marked with the option “not applicable”, “ignored” or had no marking (empty) were grouped into the same category called “ignored”. The collected data were then tabulated, processed and organized in spreadsheets in Microsoft Office Excel 2016.

Since this is a study that used secondary public data as its source, made available by Datasus, and because it does not present variables that allow the identification of the individuals studied, authorization from the Research Ethics Committee is not required. However, as established in Resolution No. 466/2012 [19] and Resolution No. 510/2016 of the National Health Council [20].

During the period from 2020 to 2024, 798 cases of congenital toxoplasmosis were reported in the state of Tocantins in newborns under 1 year of age. In the same period, 115,013 births were registered in SINASC (partial data from 2024), representing a prevalence of approximately 69 cases per 10,000 births in the state.

The sociodemographic data of the participants in this study were analyzed and are presented in Table 1. The most frequent profile affected by congenital toxoplasmosis was male and brown children. It is important to highlight the high number of notifications that ignore the collection of data on race/color (n=106/13.3%).

Source: prepared by the author, 2025

Table 1: Sociodemographic characteristics of reported cases of Congenital Toxoplasmosis, Tocantins, Brazil, 2020-2024.

Regarding the spatial distribution of the disease in Tocantins (Table 2), there is a balance in the occurrence of cases, with records in all 08 (eight) Health Regions. The Health Region that had the majority of reported cases was “Medio Norte Araguaia” with 253 cases (31.6%), followed by “Capim 

Dourado” which recorded 203 cases of congenital toxoplasmosis (25.4%). It is important to highlight that this leading role in the number of notifications is proportional to the population of these regions, the most populous in the State.

Source: prepared by the author, 2025

Table 2: Spatial distribution of notifications of Congenital Toxoplasmosis by Health Region, according to municipality of residence, Tocantins, Brazil, 2020-2024.

In the other Health Regions, the number of notifications also demonstrated coherence related to the population residing in them. There were 100 cases in “Bico do Papagaio” (12.5%); 99 in “Cerrado Araguaia Tocantins” (12.4%); 70 in “Island of Bananal” (8.7%) and the lowest number was reserved for the less populated regions: “Cantão” with 42 cases (5.6%); “Amor Perfeito” with 20 cases (2.5%) and “Sudeste” with 11 cases (1.3%).

Regarding temporality, in the period evaluated, 798 cases of congenital toxoplasmosis were reported in the state of Tocantins. The year with the highest number of notifications was 2023, with 33.8% of the total cases (n=270) and the year with the lowest occurrence was 2021 with 97 cases (12.1%). It is worth noting that this lower number of records may have been influenced by underreporting caused by the Covid-19 pandemic (Graph 1).

Source: prepared by the author, 2025

Graph 1: Distribution of reported cases of Congenital Toxoplasmosis by year of notification, Tocantins, Brazil, 2020 to 2024.

When analyzing the follow-up of reported cases (Table 3), it was observed that according to the classification, 54.8% (n=437) of the cases were confirmed, while 11.6% (n=92) were discarded. In addition, 4.6% (37) were inconclusive and 7.1% (n=57) were ignored.

Source: prepared by the author, 2025

Table 3: Distribution of reported cases of Congenital Toxoplasmosis, according to follow-up, Tocantins, Brazil, 2020 to 2024.

Furthermore, regarding the evolution of the cases, most mothers were cured, representing 43.1% (n=344) of the evolutions, 34.3% (n=274) of the cases had their clinical evolution ignored, 0.3% (n=2) evolved with deaths due to the condition and 0.4% (n=3) evolved with deaths due to another cause. Finally, considering the criteria used for notification, 51.4% (n=410) used laboratory criteria, 14.2% (n=113) used clinical-epidemiological criteria and 12.5% (n=100) ignored this data.

The present study aimed to outline the epidemiological profile and spatial distribution of congenital toxoplasmosis in the state of Tocantins, based on data collected between 2020 and 2024. The analysis of the results allowed us to identify demographic, temporal, spatial, and follow-up patterns associated with the occurrence of the disease, providing important support for the development of preventive strategies and interventions in the context of public health.

In the state of Tocantins, from 2020 to 2024, we had 798 notifications of the disease among 115,013 registered births, that is, a prevalence of approximately 69 infected children for every 10,000 live births, a value significantly higher than those found in a similar study in state of Piauí, which recorded the highest prevalence in 2022, with a total of 20.36 cases for every 10,000 live births [21].

Regarding the distribution by race, only 111 cases (14%) occurred in newborns classified as white, while there were 553 cases (69.3%) in mixed race and 10 cases (1.2%) in black. Although these numbers may partly reflect the demographic composition of Tocantins, it is possible that inequalities in access to information and health services influence epidemiological surveillance and treatment of the disease among different ethnic groups. A significant consideration regarding this variable was the high number of “Ignored” records found; 106 newborns did not have their race reported at the time of notification (13.3%).

The predominance of cases regarding race corroborates the findings of a recent study conducted in the Northeast Region of Brazil, where 74% were mixed race [22]and in a study in Piauí that indicated a mixed race predominance of 83.17% (21). However, it differs from a similar study carried out in Santa Catarina, where no statistically significant differences were identified between whites and blacks, yellows or browns [23].

The relative frequency of cases in the indigenous population of 2.1% (n=17) is proportionally coherent when compared with the constituent characteristics of the general population, where 1.32% of the state's population declared themselves indigenous in the last census carried out in 2022 [17].

Regarding the distribution of cases by sex of the universe of 798 cases, 415 (52%) cases were in boys and 383 in girls (48%), a situation similar to that found in a study in state of Bahia [24], of Piauí [21] and in Santa Catarina [23]. It is noted that the numbers of cases among men and women are very close, showing that there is no predilection between sexes.

In the opposite direction, a study carried out in the state of Pará found a predominance of 78.26% of cases of congenital toxoplasmosis in females in the population analyzed, however, a caveat should be noted regarding the sample size, which is not very representative due to the low number of individuals used for the calculation [25].

Regarding spatial distribution, according to the literature, there is still little known about any pattern that characterizes it; old records indicate that there would be a higher frequency of cases of toxoplasmosis in large cities than in small or rural cities (26). This finding was confirmed in Tocantins, where the health regions that house the largest urban centers, “Medio Norte Araguaia” with 253 cases (31.6%) and “Capim Dourado” with 203 cases (25.4%) were also those that reported the most cases.

However, more recent studies point to the predominance of cases of congenital toxoplasmosis in rural and peri-urban regions in a spatial analysis carried out in the state of Minas Gerais [27]. To justify the differences between the studies, it is assumed that the population in rural areas has less access to health services and, therefore, is not identified in studies with a design such as this research.

Considering the entire time frame used in the research, a linear increasing behavior was observed in the number of notifications between the years 2020 to 2023, with the exception of 2021, the year of the pandemic, a period in which there was a decrease in the number of diseases requiring compulsory notification, caused by the decrease in the demand for health services by the population, [28].

The incidence rate of congenital toxoplasmosis in 2020 was 4.8 per 1,000 LB, reaching a peak in 2023 with 11.7 cases for every 1,000 LB, an increase of approximately 144% in the period. This upward trend in the number of cases was also observed in a study carried out in the state of Bahia [24].

Regarding the diagnostic results, 437 cases (54.8%) were confirmed, while 92 (11.6%) were discarded and 37 (4.6%) remained inconclusive, which reinforces the importance of standardizing laboratory tests and adequate monitoring of newborns with suspected infection. The “Ignored/Blank” category recorded 57 cases (7.1%), indicating possible errors in data collection or filling, which compromises a more accurate analysis.

In the present analysis, it was observed that 51.4% of case confirmations were made using laboratory criteria, a percentage well below that found in a study carried out in Piauí of almost 90% of cases that used laboratory testing as a diagnostic tool [21].

Regarding the evolution of cases, 344 newborns (43.1%) were cured, which reflects the effectiveness of monitoring and treatment of toxoplasmosis, which is mainly carried out by Primary Care, since it is recognized that there is no exact standard for treating congenital toxoplasmosis.

The best strategy is to use measures based on health promotion on primary prevention in educational programs with dietary hygiene guidelines to reduce infection in pregnant women and, consequently, in the fetus [14].

The cure rate found in Tocantins, however, is low when compared to the results obtained in Piauí (84.68%), but in relation to deaths due to toxoplasmosis, in this same survey in Piauí, the rate was 1.28% (21), much higher than that found in Tocantins, which was 0.3% in the period evaluated, results that point to a low mortality rate directly associated with the disease.

However, 274 cases (34.3%) were classified as "Unknown/Blank", which indicates gaps in the registration and clinical monitoring of these patients. This scenario is worrying, as it compromises information on routines and standards established in the epidemiological surveillance of congenital toxoplasmosis in all health services, which would contribute to the production of a reliable profile and the expansion of knowledge about the disease throughout the country [29].

Finally, the high number of losses in follow-up of reported cases stands out, around 175 (21.9%) of the total. These losses may be associated with discards caused by a change in the initial diagnosis, by the failure to close the aforementioned notification or even by the exclusion of the investigation in SINAN.

This study outlined an epidemiological profile and spatial distribution of congenital toxoplasmosis in the state of Tocantins, demonstrating the relevance of the infection as a public health problem. The greater concentration of cases in the brown and black population suggests the need for more focused attention on more vulnerable populations and the implementation of public policies aimed at correcting historical distortions, especially in access to public health services in Brazil.

The data on clinical evolution demonstrate that most cases evolved to cure, which reflects the effectiveness of the available treatments. However, the significant number of cases without recorded outcomes suggests failures in monitoring and data collection, highlighting the importance of improving notification and epidemiological surveillance systems to ensure an adequate response.

Given the results presented, it is essential that public health policies for the prevention of toxoplasmosis in Tocantins be integrated with educational and social initiatives, with the aim of reducing inequalities and increasing the effectiveness of prevention. Expanding access to early diagnosis and treatment, combined with improvements in sanitation and nutrition conditions, is essential to contain the spread of the disease and prevent infant and fetal morbidity and mortality, in addition to contributing significantly to the reduction of permanent disabilities in the population.

Therefore, the fight against toxoplasmosis requires intersectoral efforts and an evidence-based approach, capable of meeting local specificities and promoting equity in access to health services. The continuation of awareness campaigns, combined with the training of health professionals and the improvement of surveillance systems, will be crucial to ensuring a positive impact in the long term, reducing not only the incidence of the disease, but also the associated social and economic impacts.

The authors declare that they have no economic interests or conflicts of interest.