Seroepidemiology of Toxoplasma infection in a metropolitan region of Brazil

Is the incidence of congenital toxoplasmosis declining?

Prenatal infection with the protozoan parasite Toxoplasma gondii can cause congenital toxoplasmosis (CT), an often fatal or lifelong-disabling condition. Several studies of human populations have reported temporal decreases in seroprevalence, suggesting declining CT incidence. However, the consistency of this trend among diverse populations remains unclear, as does its implication for prenatal screening programmes, the major intervention against CT. Using temporally resolved data on the seroprevalence of T. gondii in various countries, we discuss how the parasite's changing epidemiology may affect trends in CT incidence in varying and counterintuitive ways. We argue that parasite stage-specific serology could be helpful for understanding underlying causes of secular changes in seroprevalence. Furthermore, we highlight the importance of updating cost-effectiveness estimates of screening programmes, accounting for neuropsychiatric sequelae.

Seroprevalence and Risk Factors of Toxoplasma gondii Infection Among High-Risk Populations in Jiangsu Province, Eastern China

Toxoplasma gondii, an opportunistic protozoan, infects one-third of people worldwide and could lead to serious outcomes in immunodeficient or immunocompromised populations. The present study aimed to investigate the prevalence and risk factors for T. gondii infection among high-risk populations in Jiangsu Province, eastern China. We conducted a cross-sectional survey among 4 categories of populations in 13 prefectures including HIV/AIDS patients, livestock breeding/processing (B/P) staff, pregnant women, and cancer patients. We detected specific immunoglobulin G and M (IgG and IgM) levels for each participant using enzyme-linked immunosorbent assay (ELISA) and asked to complete a questionnaire for each participant that covered sociodemographic information as well as the basic knowledge of attitudes toward and the practices for the prevention of toxoplasmosis. A total of 5231 participants distributed across 13 prefecture-level cities was surveyed, including 2455 males and 2776 females. Total seropositivity rate in each population category was as follows: 9.08% (HIV/AIDS patients), 11.65% (livestock B/P staff), 5.50% (pregnant women), and 12.89% (cancer patients). We detected IgM positivity in HIV/AIDS patients (0.47%, 6/1289), livestock B/P staff (0.08%, 1/1330), and cancer patients (0.46%, 6/1303) but not in pregnant women. Further, we detected IgM+IgG positivity only in cancer patients (0.31%, 4/1303). The seropositivity rate for pregnant women was significantly lower, while cancer patients were significantly higher. Higher educational levels were associated with lower seropositivity rates for T. gondii infection. High seropositivity rates were associated with long period of HIV infection among HIV/AIDS patients, frequent contact with livestock among livestock breeding/processing staff and male older patients among cancer patients, respectively. Analysis of practices across all participants showed that frequent contact with pets in everyday life or using the same cutting board for both raw and cooked foods leads to higher seropositivity rates. Therefore, we obtained the seroprevalence and risk factors of toxoplasmosis among high-risk populations in Jiangsu Province which could provide evidence for the implementation of control measures in the near future.

Toxoplasmosis in immunocompetent Saudi women: Correlation with vitamin D

Objective:

Toxoplasma gondii (T. gondii) is a life-threatening parasite particularly infecting the immunocompromised women. Deficiency of vitamin D is well reported in several infectious disorders. This study was undertaken to investigate a correlation of vitamin D deficiency with the onset of T. gondii infection in immunocompetent women from the central of Saudi Arabia.

Methods:

Blood samples were collected from 304 Saudi women from the Qassim region of Saudi Arabia. Specific immunoassays were used to determine the levels of T. gondii immunoglobulin G and vitamin D. The SPSS and the Prism Graph Pad statistical software were used for the data analysis.

Results:

Out of 304 women, 18.8% were found to be positive for toxoplasmosis. Interestingly, the serum levels of vitamin D in toxoplasma positive cases were found to be significantly low as compared with the levels of vitamin D in toxoplasma negative cases. Moreover, sociodemographic risk factors such as age, residence location, and consumption of fruits/vegetables were also found to be associated with vitamin D deficiency and with the seroprevalence of toxoplasmosis.

Conclusion:

This study investigated a direct correlation of vitamin D deficiency with the severity of the toxoplasmosis in Saudi women. Therefore, it is predicted that vitamin D supplementation may provide protection against toxoplasma infection.

Elevated Toxoplasma gondii Infection Rates for Retinas from Eye Banks, Southern Brazil

We found significantly higher incidence of Toxoplasma gondii DNA in eye bank specimens from Joinville in southern Brazil (13/15, 87%) than in São Paulo (3/42, 7%; p = 2.1 × 10E–8). PCR DNA sequence analysis was more sensitive at locus NTS2 than at locus B1; a high frequency of mixed co-infections was detected.

Incidence of Symptomatic Congenital Toxoplasmosis During Ten Years in a Brazilian Hospital

BACKGROUND

Population seroprevalence and rates of mother-to-child transmission are important in determining the incidence of congenital toxoplasmosis. (CT) Mother-to-child transmission depends on the timing of acute maternal infection and treatment during pregnancy. The incidence of CT varies widely across geographic regions, ranging from 1 to 10 cases per 10,000 live births. The incidence of symptomatic disease varies from 0.15 to 0.34 cases per 10,000.

METHODS

This is a review of patients treated at a pediatric CT clinic at a university hospital in the south of Brazil, from 2004 to 2014.

RESULTS

The annual incidence of CT varied from 0 to 14 cases per 10,000 live births, with a mean incidence of 6 cases per 10,000 during the 10 years studied (CI 95%: 3.02-8.91). The incidence of symptomatic CT varied from 0 to 9 cases per 10,000 live births, with a mean incidence of 5 per 10,000 (CI 95%: 2.44-6.94). There were 5 (14.3%) asymptomatic cases. The main findings were retinochoroiditis (54%), intracranial calcifications (37.5%) and altered cerebrospinal fluid (37.5%).

CONCLUSIONS

The incidence of CT and the rate of symptomatic cases were in accordance with the previous data from other studies in Brazil, being significantly higher than in previous North American and European studies.

Toxoplasma gondii Infection and Premenstrual Dysphoric Disorder: A Cross-Sectional Study

Background

Premenstrual dysphoric disorder is a severe form of premenstrual syndrome. The influence of Toxoplasma gondii (T. gondii) infection on clinical features in women with this disorder has not been studied. Therefore, we determined the association of T. gondii infection with symptoms and signs in women suffering from premenstrual dysphoric disorder.

Methods

We performed a cross-sectional study of 151 women suffering from premenstrual dysphoric disorder. Anti-Toxoplasma IgG and IgM antibodies were detected in sera of the participants using enzyme-linked immunoassays (EIAs). In addition, T. gondii DNA was detected in whole blood of IgG seropositive participants using polymerase chain reaction. We obtained the clinical data of women with the aid of a questionnaire. The association of T. gondii infection with clinical characteristics of women was assessed by bivariate and multivariate analyses.

Results

Anti-T. gondii IgG antibodies were found in 10 (6.6%) of the 151 women studied. Of the 10 IgG seropositive women, four (40.0%) were positive for anti-T. gondii IgM antibodies, and one (10.0%) for T. gondii DNA. Mean number (25.8 ± 7.58) of premenstrual clinical characteristics in seropositive women was similar to that (29.22 ± 9.13) found in seronegative women (P = 0.25). Logistic regression showed that seropositivity to T. gondii was negatively associated with difficulty concentrating (OR: 0.18; 95% CI: 0.03 - 0.91; P = 0.03), and positively associated with out of control feeling or overwhelmed (OR: 9.00; 95% CI: 1.32 - 62.00; P = 0.02).

Conclusions

Results of this first study on the association of T. gondii infection and clinical characteristics of premenstrual dysphoric disorder suggest that this infection might be linked to some symptoms of this disorder. We report for the first time the association of T. gondii infection and out of control feeling or overwhelmed. Results warrant for further research on the role of T. gondii in premenstrual dysphoric disorder.

Genetic characterization of Toxoplasma gondii from autopsy proven cases of AIDS associated cerebral toxoplasmosis in South India

Toxoplasma gondii (T.gondii) infection can be devastating in the immunodeficient causing high morbidity and mortality. Due to limited availability of both diagnostic facilities and Highly Active Antiretroviral Therapy (HAART), toxoplasmosis continues to be a significant problem amongst Acquired Immuno Deficiency Syndrome (AIDS) patients in India. While scanty literature is available on T. gondii isolates in animals in India, little is known about the genetic diversity of the parasite in humans. Therefore, the present study investigated the genetic diversity of T. gondii in 25 confirmed cases of cerebral toxoplasmosis developing on the background of human immunodeficiency virus (HIV) infection/AIDS. PCR DNA sequencing was performed at four important genetic loci of T. gondii: BTUB, GRA6, alternative SAG2 (alt SAG2) and SAG3 on DNA from tissues obtained at postmortem. The amplified products from all the cases were successfully sequenced except at one locus for one case. Results of the present study suggest that majority of the patients (22/25; 88%) in South India are infected with strains that are recombinants of type II/III and/or strains representing T. gondii different from the archetypal lineages I, II, and III. In addition, clonal types III, MAS, and MAS variant genotypes were encountered. No clonal type I or II was seen in the present study. In addition, variants were observed at alt SAG2 and SAG3 but BTUB and GRA6 were highly conserved. Single nucleotide polymorphisms were observed mainly at two loci which are coding for surface antigens at alt SAG2 and SAG3. In conclusion, the present study reveals genetic diversity in India amongst strains of T. gondii from clinical cases of toxoplasmosis which is in accordance with other recent studies showing a high rate of genetic diversity in this parasite across the globe. There is a need to genotype T. gondii from different forms of toxoplasmosis in humans in India.

Seroprevalence and genetic characterization of Toxoplasma gondii in cancer patients in Anhui Province, Eastern China

Background

Recent studies have indicated the predominance of Toxoplasma gondii genotype Chinese 1 in animals in China. However, little is known of the genetic features of the parasite in humans. This study aims to determine the prevalence of anti-T. gondii antibodies based on which the genetic character of the parasite was identified in cancer patients in China.

Methods

A total of 1014 serum samples with malignant neoplasms were collected from six tertiary-care hospitals (HAUCM, APH, HAMU, XAH, FHH and HBMC) from January, 2012 to August, 2013. Antibodies against T. gondii were examined by enzyme-linked immunosorbent assay (ELISA). Blood samples were subsequently used for PCR assay to detect T. gondii DNA (gra6). The DNA positive samples were subjected to genotyping using a multiplex multilocus nested PCR-RFLP at 10 loci, including sag1, sag2, sag3, btub, gra6, l358, c22-8, c29-2, pk1 and apico. Samples from the patients were anonymous and only data with regard to age and gender was available at sample collection.

Results

Overall, 8.38% (85/1014) of the examined patients showed positive antibodies against T. gondii. Among them, 61 (6.02%) were seropositive only for IgG, 16 (1.58%) were only for IgM, and 8 (0.79%) were found to be positive for both IgG and IgM. The seroprevalence of antibodies to Toxoplasma ranged from 5.8% to 11.0%, without regional difference (χ² = 4.764, P = 0.445). No significant differences of the positive rates of T. gondii infection were noted in genders (male, 8.96%; female, 7.45%) (χ² = 0.707, P = 0.400) and in ages (χ² = 1.172, P = 0.947). Of 1014 DNA samples, 36 (3.55%) were positive for T. gondii by nested PCR at gra6 locus and nine gave rise to complete genotyping results. All samples with achieved PCR-RFLP genotyping showed a common genetic character of type Chinese 1 (ToxoDB#9).

Conclusion

Seroprevalence of toxoplasmosis in immunosuppressed individuals is rarely reported in China and we presented a positive rate of 8.38% in cancer patients. Toxoplasma genomic DNA genotyping demonstrated a common genetic character of Chinese 1, indicating a possible pathogenic origin of animals in human infection.

Seroepidemiology of Toxoplasma in a coastal region of Haiti: multiplex bead assay detection of immunoglobulin G antibodies that recognize the SAG2A antigen

Toxoplasma gondii is a globally distributed parasitic protozoan that infects most warm-blooded animals. We incorporated a bead coupled with recombinant SAG2A protein into our Neglected Tropical Disease (NTD) multiplex bead assay (MBA) panel and used it to determine Toxoplasma infection rates in two studies in Haiti. In a longitudinal cohort study of children aged 0-11 years, the infection rate varied with age reaching a maximum of 0·131 infections/year in children aged 3 years [95% confidence interval (CI) 0·065-0·204]. The median time to seroconversion was estimated to be 9·7 years (95% CI 7·6-∞). In a cross-sectional, community-wide survey of residents of all ages, we determined an overall seroprevalence of 28·2%. The seroprevalence age curve from the cross-sectional study also suggested that the force of infection varied with age and peaked at 0·057 infections/year (95% CI 0·033-0·080) at age 2·6 years. Integration of the Toxoplasma MBA into NTD surveys may allow for better estimates of the potential burden of congenital toxoplasmosis in underserved regions.

Seroepidemiology and risk factors of Toxoplasma gondii infection in undergraduate university female students in Jordan

This study estimated the seroprevalence and risk factors for acquiring Toxoplasma gondii infection by undergraduate female university students in Jordan. A cross-sectional study from September 2013 to July 2014 analysed 202 blood samples for IgG and IgM antibodies by enzyme-linked immunosorbent assay and a semi-constructed questionnaire was completed by participants to gather information about Toxoplasma infection risk factors. T. gondii IgG antibodies were detected in 66.5% of the females. Only one sample was positive for both IgG and IgM. Using χ2 test, six factors showed significant association with T. gondii infection (P ⩽ 0.01). The multivariate logistic regression model showed that female students living in houses, wet areas, with income >US $750/month and using spring (untreated) water were 47.42, 10.20, 5.00, 3.25 more times at risk to be seropositive for T. gondii, respectively, compared to female students living in apartments, dry areas, with income ≤ US $750/month and using treated water, respectively. This study concluded that T. gondii infection in female university students in Jordan is high and most women become infected before marriage; however, congenital toxoplasmosis is still likely to occur in Jordan. Thus, dissemination of protective measures and knowledge by healthcare professionals is essential especially for pregnant women.

Sero-epidemiology and risk factors for Toxoplasma gondii among pregnant women in Arab and African countries

The epidemiology of toxoplasmosis in pregnancy is a major issue for public health. Primary infection in pregnant women can lead to serious sequelae. This review examined current sero-epidemiology and risks factor data for Toxoplasma gondii in pregnant women in Arab and African countries. A systematic electronic search of published literature was conducted. Data were extracted from relevant studies. Seropositivity is high in both regions. African countries have higher seropositivity than Arab countries due to differences in risk factors. Data on T. gondii infection in pregnancy are scant in many countries, especially where there is lack of political stability. Identified risk factors included eating raw meat, proximity with cats, undercooked food, and increasing maternal age. Toxoplasmosis in pregnancy in Arab and African countries is an underestimated health problem. Further research is needed. This report is a foundation for strategies and policies for intervention needed to combat the consequences of congenital toxoplasmosis.

The global burden of congenital toxoplasmosis: a systematic review

OBJECTIVE

To estimate the global burden of congenital toxoplasmosis (CT), which results from infection of pregnant women with Toxoplasma gondii.

METHODS

The authors systematically searched 9 major databases for published and unpublished sources and established direct contact with the authors of source materials. Searches were country-specific. To be included, studies had to report on the incidence of CT, on positivity to Toxoplasma-specific IgM in infants and pregnant women (including seroconversion results) or on positivity to Toxoplasma-specific IgG in the general population. Various modelling techniques were used, depending on the country-specific data available, to estimate the CT incidence and burden in each country. These data were then synthesized into an estimate of the global incidence of CT and of the global burden of CT in disability-adjusted life years (DALYs).

FINDINGS

The global annual incidence of congenital toxoplasmosis was estimated to be 190,100 cases (95% credible interval, CI: 179,300-206,300). This was equivalent to a burden of 1.20 million DALYs (95% CI: 0.76-1.90). High burdens were seen in South America and in some Middle Eastern and low-income countries.

CONCLUSION

Congenital toxoplasmosis poses a substantial burden of poor health globally. Toxoplasmosis should be included in future updates of the global burden of disease and the corresponding data should be used to support public health interventions to reduce disease burden.

Toxoplasma gondii seroprevalence in Mali

The protozoan parasite Toxoplasma gondii is globally distributed, with considerable local variation in prevalence based on behavioral and environmental factors. To assess prevalence and estimate risk in Mali, we conducted a survey of 760 serum samples previously collected for malaria studies. A modified agglutination test detected antibodies in ∼27% of the adult population, with no significant differences between men and women, or between urban and rural study sites. In the village of Kolle, seroprevalence rose from 0% in infants (<1 yr, but after weaning of maternal immunoglobulin G) to 0.8% (1-5 yr), 2.7% (6-10), 11.3% (11-15), and 26.8% (>15); differences between the <10-, 11-15-, and >15-yr age groups were highly significant (P ≤ 0.01). We also observed an increase in anti- T. gondii antibody titers with age. Modeling the observed age distribution suggests a seroconversion rate of ∼1%/yr, indicating that congenital toxoplasmosis may be an under-appreciated public health concern in Mali.

Artemisinin reduces the level of antibodies to gliadin in schizophrenia

OBJECTIVE

To investigate if adjunctive artemisinin, an anti-malarial compound with in vivo activity against Toxoplasma gondii, reduces symptoms or antibodies in schizophrenia.

METHOD

N=66 outpatients with schizophrenia were randomized to receive 100mg of artemisinin twice a day or placebo for 10 weeks after a 2 week placebo run-in in addition to their usual psychiatric medications. Symptoms were assessed biweekly. Antibodies to toxoplasma and to gliadin, a food antigen, were assessed at the beginning and end of the trial.

RESULTS

A total of 57 participants (26 in the artemisinin arm and 31 in the placebo arm) completed the 12 weeks of the trial. The medication was well tolerated and there were no significant side effects associated with the treatment regimen. There was no significant difference in the change of positive, negative, general, or total PANSS symptoms between groups for all of the randomized patients or for just the completers. However, individuals in the artemisinin arm but not in the placebo arm had significant decreases in the levels of antibodies to gliadin (p<.0005, p>.2, respectively by paired t-test). Neither group had significant changes in antibodies to T. gondii.

CONCLUSIONS

The study did not demonstrate clinical benefit of adjunctive artemisinin for schizophrenia symptoms. The finding of reduced levels of antibodies to gliadin in the artemisinin group merits further study.

Seroprevalence of Toxoplasma gondii infection among immigrant and native pregnant women in Eastern Spain

In European countries, toxoplasma antenatal screening is recommended to prevent toxoplasmosis. The seroprevalence of these infections in immigrants can be different than in native population. From February 2006 to June 2010, a cross-sectional study was carried out in all pregnant women attended at a reference unit in Elche, Spain. An enzyme immunoassay was used for detection of IgG antibodies against Toxoplasma gondii. For each immigrant woman, one Spanish pregnant woman of the same age cared for in the same day was recruited (Spanish control group). A total of 1,627 migrant pregnant women participated in this study. The adherence to screening among migrants was 91.9% (95% CI, 90.5-93.1%), similar than that found in Spaniards (92.2%; 95% CI, 90.8-93-4%). Among migrant women, 619 were positive for IgG anti-T. gondii antibodies (41.4%; 95% CI, 38.9-43.9%), compared with 12.0% (95% CI, 10.5-13.8%) among Spaniards (odds ratio (OR), 5.2 (95% CI, 4.3-6.3). Seroprevalence in pregnant women from Latin America, northern Africa, Eastern Europe, Africa Sub-Saharan and Western Europe was higher than in the Spanish control group (OR, 5.4, 5.8, 6.5, 5.4, and 2.4, respectively; p < 0.001). No Asian pregnant woman was immune. Seroprevalence increased with increasing age in migrant pregnant women: 15-25 years, 38.2%; 26-35 years, 40.7%; and 36-45 years, 52.8%. The seroprevalence of T. gondii infection in migrant pregnant women living in Spain was higher than in the native population. However, no cases were found in Asian immigrants, highlighting the importance of primary prevention of this infection in pregnant women coming from that geographic region.

Modelling immunization strategies with cytomegalovirus vaccine candidates

In order to analyse the impact of vaccination against cytomegalovirus (CMV) on congenital infection incidence using current vaccines tested in phase II clinical trials, we simulated different scenarios by mathematical modelling, departing from the current vaccine characteristics, varying age at vaccination, immunity waning, vaccine efficacy and mixing patterns. Our results indicated that the optimal age for a single vaccination interval is from 2 to 6 months if there is no immunity waning. Congenital infection may increase if vaccine-induced immunity wanes before 20 years. Congenital disease should increase further when the mixing pattern includes transmission among children with a short duration of protection vaccine. Thus, the best vaccination strategy is a combined schedule: before age 1 year plus a second dose at 10–11 years. For CMV vaccines with low efficacy, such as the current ones, universal vaccination against CMV should be considered for infants and teenagers.