Seroprevalence and risk factors associated with T. gondii infection in pregnant individuals from a Brazilian Amazon municipality

Knowledge Gaps and Educational Opportunities in Congenital Toxoplasmosis: A Narrative Review of Brazilian and Global Perspectives

Congenital toxoplasmosis is a parasitic disease caused by the transmission of the protozoan Toxoplasma gondii during pregnancy that can potentially cause severe consequences for the fetus or neonates. The disease disproportionately impacts the global population and is generally correlated with the Human Development Index. Despite its prevalence, there are knowledge gaps among pregnant women and healthcare providers regarding the prevention, diagnosis, and treatment of this condition. This narrative review aimed to examine the current state of knowledge of toxoplasmosis among both groups, with a focus on exploring the Brazilian and global perspectives and highlighting opportunities for enhancing education and communication. A search was conducted across five databases, and 60 studies were selected (23 in Brazil and 37 worldwide). Quantitative analysis revealed that general knowledge of toxoplasmosis among pregnant women is notably poor, with 66% of Brazilian women and 72% of women worldwide lacking sufficient understanding. Among those with some knowledge, the most recognized association is with cats (46% in Brazil and 38% worldwide), followed by raw or undercooked meat (27% in Brazil and 25% worldwide), and improperly sanitized vegetables or water (15% in Brazil and 21% worldwide). Similarly, gaps in knowledge were found among healthcare providers. Difficulty with IgG avidity test interpretation is higher in Brazil (43%) compared to worldwide (18%). The most recognized association is with cats (66% in Brazil and 74% worldwide), followed by raw or undercooked meat (49% in Brazil and 70% worldwide), and improperly sanitized vegetables or water (31% in Brazil and 32% worldwide). These findings emphasize the need for tailored local and global public health educational initiatives to enhance knowledge of toxoplasmosis among pregnant women and healthcare providers.

Serosurvey of Toxoplasma gondii and Toxocara spp. co-infection in pregnant women in low-income areas of Brazil

Introduction

Despite human toxoplasmosis and toxocariasis having been listed among the top six most neglected parasitic zoonoses worldwide, presenting similar associated risk factors and transmission routes, few studies have been conducted in pregnant women and the consequences of concurrent infection remain to be fully established. Accordingly, the present study has serologically assessed the co-infection and associated risk factors for Toxoplasma gondii and Toxocara spp. in pregnant women, assisted by the public Unified National Health System (SUS) in southeastern Brazil.

Materials and Methods

Blood samples were collected and tested for IgG antibodies against Toxoplasma gondii by chemiluminescence immunoassay and against Toxocara spp. by enzyme-linked immunosorbent assay (ELISA). An epidemiological questionnaire was applied to gather socioeconomic information to assess the risk factors associated with seropositivity to toxocariasis/toxoplasmosis by univariate analysis followed by logistic regression.

Results

Overall, seropositivity was 69/280 (24.6, 95% CI: 19.96-30.01) for T. gondii and 56/280 (20.0, 95% CI: 15.73-25.08) for Toxocara spp. Co-infection was observed in 25/280 (8.9, 95% CI: 6.12-12.85) pregnant women, with increased odds (OR: 3.3, CI 95%: 1.77-6.14, p = 0.0002). Logistic regression revealed that a higher educational level (high school or college) significantly reduced the likelihood of co-infection seropositivity, owning cats increased the odds of toxocariasis, and older pregnant women presented significantly higher T. gondii seropositivity.

Conclusion

Co-infection herein highlights the importance of educational programs in the prevention of toxocariasis and toxoplasmosis in pregnant women and other high-risk populations.

Impact of chronic toxoplasmosis in pregnancy: association between maternal seropositivity for Toxoplasma gondii IgG antibodies and fetal growth restriction

Insults caused by acute infections during the gestational period on fetal development are known; however, new evidence suggests that chronic infectious diseases can also impact the maternal immune status and lead to negative consequences for the neonate. This study investigated the association between the prevalence of specific antibodies in pregnant women and alterations in fetal development at birth. A follow-up study evaluated women during the gestational period and their respective newborns at delivery time. The pregnant women were tested for the presence of antibodies to infectious agents: Toxoplasma gondii (T. gondii), cytomegalovirus (CMV), syphilis, human immunodeficiency virus (HIV), hepatitis B and C. Semi-structured questionnaires were administered to the pregnant women at the time of recruitment after obtaining informed consent. Detailed information about the newborns was extracted from medical records. The seroprevalence of chronic T. gondii infection, as determined by the presence of IgG antibodies against the protozoan, was found to be 56.2%, while the overall prevalence of CMV IgG antibodies was 96.3%. Non-primiparous pregnant women from socio-economic classes, less affluent groups, and skilled working-class individuals had higher chances of testing positive for specific T. gondii IgG antibodies. Newborns classified as small for gestational age represented 12.9% of the total. Those born to mothers seropositive for anti-T. gondii IgG antibodies were 9.4 times more likely to be born small for gestational age (p = 0.035). The results suggest that chronic T. gondii infection may contribute to higher rates of newborns with growth restriction. These findings add to a growing body of evidence regarding the impact of chronic infectious diseases on intrauterine fetal development.

Toxoplasma gondii exposure in Brazilian indigenous populations, their dogs, environment, and healthcare professionals

Although Toxoplasma gondii exposure has been reported in indigenous populations worldwide, a One Health approach has not been applied to date. This study concurrently assessed T. gondii exposure in indigenous populations, and their dogs, environment, and indigenous or non-indigenous healthcare professionals (HPs). Human and dog serum samples from 9 indigenous communities in Brazil were assessed by indirect immunofluorescence antibody test for anti-T. gondii antibodies. Soil samples (30 per community) were processed with PCR to amplify T. gondii DNA. Associated risk factors and seroprevalence were analyzed using logistic regression models. Human seropositivity and type of water source were assessed by generalized linear mixed model (GLMM) with binomial error distribution, and game meat consumption with chi-squared test. Overall, 225/463 (49%) indigenous persons were seropositive for anti-T. gondii antibodies. Of all the HPs, 67/168 (40%) were positive, and included 54/147 (37%) positive non-indigenous HPs. Indigenous persons more likely to be seropositive compared with non-indigenous HPs (OR: 1.63; 95% CI: 1.11-2.39). A total of 97/253 (38%) dogs were seropositive and highly associated with seropositive owners (p < 0.001). Based on univariate analysis for indigenous individuals, state location of community (p < 0.001), ethnicity (p < 0.001), consumption of game meat (p < 0.001), type of water source (p < 0.001), and educational level (p = 0.026) were associated with seropositivity. Logistic regression showed that indigenous seropositivity was associated with eating game meat (p = 0.002), drinking water from rivers (p < 0.001), and inversely proportional to the educational level. According to univariate analysis for non-indigenous HP, age (p = 0.005), frequency of visits to the indigenous populations (p < 0.001), consumption of water at the indigenous communities (p < 0.001), and ingestion of raw meat (p = 0.023) were associated with T. gondii seropositivity. Logistic regression revealed living outdoors (p = 0.042), habit of hunting (p = 0.008), and drinking river water (p = 0.007) as risk factors associated to seropositivity in dogs. In addition, indigenous communities lacking water treatment had higher seroprevalence for all groups including indigenous persons (GLMM; z = -7.153; p < 0.001), their dogs (GLMM; z = -2.405; p = 0.0162), and all HPs (GLMM; z = -2.420; p = 0.0155). Human seropositivity was associated with that of their dogs (p < 0.001). A single soil sample, out of 270 (0.37%), was positive for T. gondii by PCR. Our results indicate water source is a risk for human and dog toxoplasmosis in indigenous communities; both share similar exposure. Moreover, quality water access was shown to be crucial to prevent toxoplasmosis in both total and non-indigenous HPs who work in these indigenous communities.

Effects of Toxoplasma gondii infection on cognition, symptoms, and response to digital cognitive training in schizophrenia

Studies indicate that neuroscience-informed digital cognitive training can remediate cognitive impairments in schizophrenia, but the factors contributing to these deficits and response to treatment remain unclear. Toxoplasma gondii is a neuroinvasive parasite linked to cognitive decline that also presents a higher prevalence in schizophrenia. Here, we compared the cognition and symptom severity of IgG seropositive (TOXO+; n = 25) and seronegative (TOXO-; n = 35) patients who participated in a randomized controlled trial of digital cognitive training. At baseline, TOXO+ subjects presented lower global cognition than TOXO- (F = 3.78, p = 0.05). Specifically, TOXO+ subjects showed worse verbal memory and learning (F = 4.48, p = 0.03), social cognition (F = 5.71, p = 0.02), and higher antibody concentrations were associated with increased negative (r = 0.42, p = 0.04) and total (r = 0.40, p = 0.04) schizophrenia symptoms. After training, the TOXO+ group showed higher adherence to the intervention (X² = 9.31, p = 0.03), but there were no differences in changes in cognition and symptoms between groups. These findings highlight the association between seropositivity to T. gondii and deteriorated cognition and symptoms in schizophrenia. Further research is needed to assess the specific efficacy of digital cognitive training on this population.