The relation of secondary sex ratio and miscarriage history with Toxoplasma gondii infection

A Review of Immunological and Neuropsychobehavioral Effects of Latent Toxoplasmosis on Humans

Toxoplasmosis as a zoonotic disease has a worldwide distribution and can infect a wide range of animal hosts, as well as at least one third of the world's human population. The disease is usually mild or asymptomatic in immunocompetent individuals, but dormant tissue cysts survive especially in the brain for the host lifespan, known as latent toxoplasmosis (LT). Recent studies suggest that LT can have certain neurological, immunological psychological and behavioural effects on human including schizophrenia, bipolar disorder, Alzheimer's disease, depression, suicide anxiety and sleeping disorders. LT effects are controversial, and their exact mechanisms of action is not yet fully understood. This review aims to provide an overview of the potential effects, their basic mechanisms including alteration of neurotransmitter levels, immune activation in the central nervous system and induction of oxidative stress. Additionally, beneficial effects of LT, and an explanation of the effects within the framework of manipulation hypothesis, and finally, the challenges and limitations of the current research are discussed.

Effects of male hepatitis B virus infection and serostatus on sperm quality, pregnancy outcomes, and neonatal outcomes following intrauterine insemination

OBJECTIVE

To evaluate the impact of male hepatitis B virus (HBV) infection and serostatus on sperm quality, pregnancy outcomes, and neonatal outcomes following intrauterine insemination for infertility.

DESIGN AND METHODS

We retrospectively analyzed data from 962 infertile couples undergoing intrauterine insemination treatment at a single center. The case group comprised 212 infertile couples with male HBV infection, and the control group comprised 750 noninfected infertile couples. The couples were further divided into subgroups according to their hepatitis B e antigen (HBeAg)/anti-HBe status: hepatitis B surface antigen (HBsAg)+HBeAg- (group A), HBsAg+HBeAg+ (group B), and HBsAg-HBeAg- (control group). The main outcome parameters, including the seminal parameters, clinical pregnancy rate, miscarriage rate, live birth rate, preterm delivery rate, multiple pregnancy rate, delivery type, birth weight, and sex ratio, were compared.

RESULTS

A lower sperm acrosin activity, higher cesarean rate, and newborn sex ratio were observed in the HBV-infected group and group A in comparison with the control group (P < 0.05). However, the standard sperm parameters, clinical pregnancy rate, miscarriage rate, live birth rate, preterm delivery, and birth weight showed no statistically significant differences among the groups.

CONCLUSION

Male HBV infection does not adversely impact standard sperm parameters or pregnancy outcomes but can influence sperm acrosin activity and some neonatal outcomes. Moreover, the effect may vary among different HBV serostatuses.

Molecular Detection of Toxoplasma gondii Oocytes in Soil Samples from Guilan Province, Northern Iran

Background

Soil is an appropriate substrate for the storage and transmission of oocytes of Toxoplasma gondii. Ingestion of soil contaminated with T. gondii oocysts is a major transmission route of human and animal toxoplasmosis. The present study was carried out to investigate soil contamination with T. gondii oocysts in urban and rural areas of Guilan Province, northern Iran.

Methods

Overall, 208 soil samples were collected from 16 cities and villages in Guilan Province, northern Iran from Oct 2020 to Nov 2021. Soil samples were investigated using modified sucrose flotation technique. Real-time polymerase chain reaction was used to detect presence of T. gondii DNAs in the samples. Positive samples were further analyzed using nested polymerase chain reaction for GRA6 gene. Moreover, six selected positive samples were used for amplifying and sequencing of the GRA6 gene.

Results

Overall, 31 samples were positive for T. gondii with frequency of 14.9% and ranging from 10.9% in rural areas to 16.3% in urban areas. Statistical analysis showed significant differences between the seasons (P=0.003). The phylogenetic analysis illustrated that our six sequences were similar and closely related to Type I strain of T. gondii.

Conclusion

Results showed relatively high levels (14.9%) of T. gondii oocytes in soil samples of Guilan Province, northern Iran, which provided essential data for the effective prevention and control of toxoplasmosis in the region.

Aggravation of cognitive impairments in the valproic acid-induced animal model of autism in BALB/c mice infected with Toxoplasma gondii

PURPOSE

Toxoplasmosis is a disease caused by infection with a type of coccidial protozoan parasite called Toxoplasma gondii. The relationship between toxoplasmosis and cognitive disorders in neurodegenerative diseases has been proven. There is also evidence that children born to Toxoplasma-infected mothers are more likely to develop autism.

METHODS

In the present study, Toxoplasma-infected pregnant BALB/c mice were given valproic acid to induce autism in their male offspring, and their social behaviors, learning, and memory were examined. Chronic toxoplasmosis was established in BALB/c mice by intraperitoneal injection of cyst form of T. gondii. To induce autism, 600 mg/kg of valproic acid was injected intraperitoneally into mice on the 12.5th day of pregnancy. The behavioral experiments, such as social interaction, novel object recognition, and passive avoidance tasks, were performed on male offspring at 50 days.

RESULTS

Toxoplasma and valproic acid during the embryonic period caused social communication deficits and disrupted recognition memory and avoidance memory in offspring. Our findings showed that administering valproic acid to Toxoplasma-infected mothers exacerbates cognitive disorders in their offspring.

Associations between Toxoplasma gondii Infection and Multiple Sclerosis: A Case-Control Seroprevalence Study

Background

Currently, there are conflicting reports on the associations between Toxoplasma gondii infection and multiple sclerosis (MS) in humans. In the present study, a case-control study was carried out to assess associations between seropositivity to T. gondii infection and MS.

Methods

This case-control study was carried out on 200 MS patients (cases) attended in Sina Hospital affiliated to Tehran University of Medical Sciences, Tehran, Iran, and 200 healthy subjects from the general population of the same city, March to July 2017. Blood samples were collected from individuals and were examined using Enzyme-linked immunosorbent assay (ELISA) for the presence of T. gondii IgG antibodies and the IgG-positive samples were further analyzed for specific anti-T. gondii IgM.

Results

The overall seroprevalence of anti-T. gondii IgG was 44.2% (177/400) in 121 (60.5%) sera of the 200 MS patients (cases) and 56 (28.0%) sera of the 200 controls (OR = 3.94; 95% CI: 2.59-5.99; P < 0.001). Seroprevalence of T. gondii infection in MS patients increased significantly with increasing of age (P < 0.001). In the control group, no statistically significant differences were seen between the seroprevalence of T. gondii infection in various age groups (P = 0.858). Moreover, no statistically significant relationships were reported between the seropositivity to T. gondii and the sex for the cases and controls (P>0.05). Anti-T. gondii IgM antibodies were not detected in anti-T. gondii IgG positive patients.

Conclusion

T. gondii infection might be a probability risk factor for MS. However, further studies are necessary to describe clearly the roles of T. gondii infection in MS.

Adverse pregnancy outcomes in Toxoplasma gondii seropositive Hispanic women

AIMS

Chronic Toxoplasma gondii infection is not thought to affect pregnancy or birth outcomes, but there are few prospective studies. The study aims were T. gondii immunoglobulin G measurement and relationship of chronic T. gondii infection with gestational age at birth and adverse pregnancy outcomes in 690 Hispanic women in Tampa, Florida.

METHODS

Hispanic women, born either in the United States or in Latin America or the Caribbean had a venous blood sample drawn to measure T. gondii IgG and T. gondii serotype at the first prenatal visit, along with collection of demographic and health-related measures. Seropositive and seronegative women were followed throughout their pregnancy. Gestational age, infant weights, and adverse pregnancy outcomes (miscarriages, preterm births) were compared in the two groups.

RESULTS

There were 740 women of self-reported Hispanic ethnicity screened and enrolled in Tampa, Florida, with 690 having birth data extracted from the electronic health record (538 T. gondii negative and 152 T. gondii seropositive). T. gondii seropositivity was 22.4% and the majority (83%) had high avidity titers, indicating chronic infection. Compared to T. gondii seronegative Hispanic women, seroseropositive women had more smaller for gestational age infants and higher prevalences of miscarriages and preterm birth.

CONCLUSION

This is one of the largest longitudinal cohort studies of women with chronic T. gondii infection followed through pregnancy. There was a higher percentages of adverse pregnancy outcomes in this group compared to T. gondii seronegative controls. The mechanism for this is unknown and warrants reexamination of the dogma that chronic T. gondii infection in pregnant women has no significant clinical consequences.

Toxoplasma gondii Infection in Immunocompromised Patients in Iran (2013-2022): A Systematic Review and Meta-Analysis

Background

Toxoplasma gondii infection (toxoplasmosis) has the potential to cause a serious disease in immunocompromised patients and can be fatal in this population. We conducted a systematic review and meta-analysis to assess comprehensively the pooled seroprevalence of toxoplasmosis among immunocompromised patients including HIV/AIDS patients, cancer patients, and transplant recipients in Iran.

Methods

PubMed, Web of Science, Scopus, Embase, and Google Scholar databases (international) and Scientific Information Database (SID), Magiran, IranMedex, and IranDoc databases (national) were systematically searched for all reports that possibly contained data for T. gondii prevalence in different immunocompromised populations in Iran between 2013 and 2022.

Results

Overall, IgG seroprevalence rate of toxoplasmosis in Iranian immunocompromised patients was 45.1% (95% confidence interval (CI), 37.4-52.9). IgG seroprevalence rate of toxoplasmosis in 12 studies that included 2279 cancer patients, 19 studies that included 2565 HIV/AIDS patients and in 3 studies that included 200 transplant recipients was 43.6% (95% CI, 30.2-57.0), 45.9% (95% CI, 34.8-57.1) and 45.8% (95% CI, 32.5-59.0), respectively. Moreover, IgM seroprevalence rate in the 26 studies was 2.6% (95% CI, 1.4-3.7).

Conclusion

Our findings represent a high seroprevalence rate of Toxoplasma IgG among immunocompromised patients. Health improvement and education toward prevention of toxoplasmosis is of great importance for these susceptible populations.

The Impact of Latent Toxoplasma gondii Infection on Spontaneous Abortion History and Pregnancy Outcomes: A Large-Scale Study

BACKGROUND

Toxoplasma gondii (TG), a zoonotic protozoan parasite, belongs to a group of TORCH infectious agents, which can cause severe damage to the fetus if a primary infection occurs during pregnancy. After primary infection, TG rests lifelong in human organisms causing a latent infection. Most studies have analyzed the consequences of acute, but not latent, TG infection. This study analyzed the impact of latent toxoplasmosis on spontaneous abortion history, pregnancy complication rate and neonatal outcome.

METHODS

IgG and IgM anti-TG antibodies were tested in 806 pregnant women who were consulted at the Timisoara Clinical Emergency Hospital between 2008 and 2010. Demographic data, obstetrical history, and data about the pregnancy complications, birth and neonate were collected for each woman and comparisons between the groups, with and without latent TG infection, were made.

RESULTS

This study did not show differences between groups regarding the history of spontaneous abortion (OR = 1.288, p = 0.333), cesarean section (OR = 1.021, p = 0.884), placental abruption (OR 0.995, p = 0.266), pregnancy-induced hypertension rate (OR 1.083, p = 0.846), secondary sex ratio (1.043, p = 0.776), 1' APGAR score at birth (p = 0.544), gestational age at birth (p = 0.491) or birth weight (p = 0.257).

CONCLUSIONS

The observed differences between the rate of pregnancy complications in the two groups of pregnant women with and without latent infection with TG, did not reach a statistical significance.

Nuclear Factor AP2X-4 Governs the Expression of Cell Cycle- and Life Stage-Regulated Genes and is Critical for Toxoplasma Growth

Toxoplasma gondii is a ubiquitous pathogen infecting one third of the world's population and diverse animals. It has a complex life cycle alternating among different developmental stages, which contributes to its transmission and pathogenesis. The parasite has a sophisticated gene regulation network that enables timely expression of genes at designated stages. However, little is known about the underlying regulatory mechanisms. Here, we identified an AP2 family transcription factor named TgAP2X-4, which was crucial for parasite growth during the acute infection stage. TgAP2X-4 deletion leads to reduced expression of many genes that are normally upregulated during the M phase of the cell cycle. These include genes that encode rhoptry neck proteins that are key for parasite invasion. As a result, the Δap2X-4 mutant displayed significantly decreased efficiency of host cell invasion. Transcriptomic analyses suggested that TgAP2X-4 also regulates a large group of genes that are typically induced during chronic infection, such as BAG1 and LDH2. Given the diverse impacts on gene expression, TgAP2X-4 inactivation results in severely impaired parasite growth, as well as drastic attenuation of parasite virulence and complete inability to form chronic infection. Therefore, TgAP2X-4 represents a candidate for antitoxoplasmic drug and vaccine designs. IMPORTANCE Toxoplasma gondii has a complicated gene regulation network that allows "just in time" expression of genes to cope with the physiological needs at each stage during the complex life cycle. However, how such regulation is achieved is largely unknown. Here, we identified a transcription factor named TgAP2X-4 that is critical for the growth and life cycle progression of the parasite. Detailed analyses found that TgAP2X-4 regulated the expression of many cell cycle-regulated genes, including a subset of rhoptry genes that were essential for the parasites to enter host cells. It also regulated the expression of many genes involved in the development of chronic infection. Because of the diverse impacts on gene expression, TgAP2X-4 inactivation caused reduced parasite growth in vitro and attenuated virulence in vivo. Therefore, it is a potential target for drug or vaccine designs against Toxoplasma infections.

Molecular detection of Toxoplasma gondii in chicken hearts from markets and retail stores in Northern Iran

Detection of Toxoplasma gondii in chicken products indicates risk of transmission to consumers. The objective of the current study was to investigate the molecular prevalence of T. gondii in free-ranging and industrial chickens in Guilan province, Northern Iran. A total of 150 chicken heart samples including 75 free-range and 75 industrial chickens were collected from farmers' markets and chicken retailers in Guilan, Northern Iran, between October 2017 and August 2018. Genomic DNA were extracted from samples and examined for evidence of T. gondii using polymerase chain reaction (PCR) targeting the B1 gene. The B1-positive samples were further analyzed by nested-PCR for SAG1 gene. Of the 150 samples, T. gondii DNA fragments were detected in 59 (39.3%), including 30 (40%) free-range and 29 (38.7%) industrial chicken. No significant differences of T. gondii DNA detection was observed between the free-range and industrial chicken samples (p = 0.73). Four selected positive samples were used for amplifying and sequencing of the SAG1 gene. The results revealed that all four sequences of SAG1 had 100% similarity with T. gondii sequences previously isolated from an AIDS/HIV patient in Mazandaran province, Northern Iran. Furthermore, the phylogenetic analysis demonstrated that all four sequences were closely related to Type I of T. gondii. However, our Type I identification is preliminary and needs to be confirmed by further multilocus sequence typing (MLST) analysis. The findings of the present study provide new data about the presence of T. gondii DNA in chicken hearts in the study area. These results confirm that chicken can be used as sentinels for environment contamination; however, further studies are needed to determine the viability of T. gondii in chicken hearts from Iran for risk assessment.

Synthesis and anti-Toxoplasma activity of indole-triazole compounds on tachyzoites of RH strain

Background

Conventional treatment for toxoplasmosis have severe side effects and the inability to completely eradicate the disease. Therefore, the acquisition of new anti-Toxoplasma drugs has always been of interest among researchers. In the present study, we prepare a new indole-triazole derivatives and evaluated their potential anti-parasitic activity against tachyzoites of Toxoplasma RH strain.

Materials and methods

In this study, after synthesis of the two new compounds of indole-triazole, the effect of their different concentrations (2–1024 μg/ml) were determined on Toxoplasma tachyzoites using flow cytometry. Furthermore, tachyzoites were exposed to different concentrations of compounds (4, 16, 64, 265, 1024 μg/ml) for 1.5 h and their infectivity were evaluated in BALB/c mice.

Results

The flow cytometry results indicated the benzyl derivative of indole-triazole in various concentrations had a lethal effect on tachyzoites between 11.93% and 89.66%, while the naphthalene derivative had a lethality of 26.63%–66.82%. The infectivity analysis showed that the survival time of mice at concentrations of 1024 μg/ml and 512 μg/ml of benzyl derivatives was significantly increased (P = 0.008 and P = 0.016, respectively), compared to that in the negative control group. Furthermore, survival time of mice was statistically significant at the concentration of 1024 μg/ml for naphthyl derivative (P = 0.012).

Conclusion

Findings of the current study suggested indole triazole compounds, based on their structure and enzymes targeting, have a considerable effect on tachyzoites of T. gondii RH strain and can be considered as a new anti-Toxoplasma agent.

•

The Benzyl and Naphtyl derivatives of Indol-triazol have dose dependently effect on tachyzoites of T.gondii RH strain.

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The placement of naphthyl next to indole-triazole have dose dependently effects on Toxoplasma tachyzoites.

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The benzyl derivative of Indole triazole showed an ability of over 80% in eliminating Toxoplasma tachyzoites.

Utility of blood as the clinical specimen for the diagnosis of ocular toxoplasmosis using uracil DNA glycosylase-supplemented loop-mediated isothermal amplification and real-time polymerase chain reaction assays based on REP-529 sequence and B1 gene

BACKGROUND

Ocular infection with Toxoplasma gondii is a major preventable cause of blindness, especially in young people. The aim of the present study was to assess detection rate of T. gondii DNA in blood samples of clinically diagnosed of ocular toxoplasmosis using uracil DNA glycosylase-supplemented loop-mediated isothermal amplification (UDG-LAMP) and real-time quantitative PCR (qPCR) based on REP-529 and B1.

METHODS

One hundred and seventeen patients with clinically diagnosed ocular toxoplasmosis (OT) were participated in the study as well as 200 control patients. Peripheral blood samples were assessed using UDG-LAMP and qPCR techniques targeting REP-529 and B1.

RESULTS

Detection limits of qPCR using REP-529 and B1 were estimated as 0.1 and 1 fg of T. gondii genomic DNA, respectively. The limits of detection for UDG-LAMP using REP-529 and B1 were 1 and 100 fg, respectively. In this study, 18 and 16 patients were positive in qPCR using REP-529 and B1, respectively. Based on the results of UDG-LAMP, 15 and 14 patients were positive using REP-529 and B1, respectively. Results of the study on patients with active ocular lesion showed that sensitivity of REP-529 and BI targets included 64 and 63%, respectively using qPCR. Sensitivity of 62 and 61%, were concluded from UDG-LAMP using REP-529 and B1 in the blood cases of active ocular lesion. qPCR was more sensitive than UDG-LAMP for the detection of Toxoplasma gondii DNA in peripheral blood samples of patients with clinically diagnosed toxoplasmic chorioretinitis. Furthermore, the REP-529 included a better detection rate for the diagnosis of ocular toxoplasmosis in blood samples, compared to that the B1 gene did. Moreover, the qPCR and UDG-LAMP specificity assessments have demonstrated no amplifications of DNAs extracted from other microorganisms based on REP-529 and B1.

CONCLUSIONS

Data from the current study suggest that qPCR and UDG-LAMP based on the REP-529 are promising diagnostic methods for the diagnosis of ocular toxoplasmosis in blood samples of patients with active chorioretinal lesions.

Prevalence and Predictors of Toxoplasma gondii Infection in Psychiatric Inpatients in Fars Province, Southern Iran

BACKGROUND

Psychiatric patients are at increased risk of exposure to Toxoplasma gondii infection, which may be linked to their living facilities and behaviors. Limited knowledge on the prevalence of T. gondii infection and its associated risk factors in psychiatric patients are available to the international medical communities. Thus, the aim of the current study was to assess seroprevalence of T. gondii and its associated risk factors in psychiatric inpatients in Fars Province, southern Iran.

METHODS

This cross-sectional study was carried out on psychiatric patients hospitalized in Ibn Sina Hospital affiliated to Shiraz University of Medical Sciences, Fars Province, southern Iran, March to July 2021. Blood samples were collected from 318 psychiatric patients and assessed for the detection of IgG against T. gondii using enzyme-linked immunosorbent assay (ELISA). Moreover, structured questionnaires were completed for the participants at the time of sampling. Logistic regression analysis was used to assess possible associations between the latent toxoplasmosis and the variables.

RESULTS

The overall seroprevalence of anti-T. gondii IgG in psychiatric inpatients was 22.3% (71/318; 95% CI = 17.9-27.3). Multivariate analyses revealed that age > 30 years [adjusted odds ratio (AOR) = 2.24, 95% CI = 1.10-4.60, p = 0.03], contact with cats (AOR = 2.52, 95% CI = 1.14-5.58, p = 0.03), raw vegetable consumption (AOR = 3.65, 95% CI = 1.74-7.65, p = 0.001), raw/undercooked meat consumption (AOR = 4.30, 95% CI = 1.47-12.63, p = 0.008), suicide attempt (AOR = 3.77, 95% CI = 1.58-8.97, p = 0.003) and cigarette smoking history (AOR = 0.38, 95% CI = 0.17-0.83, p = 0.02) were independent risk factors for T. gondii infection.

CONCLUSION

The current results demonstrated that contact with cats, raw vegetable consumption and raw/undercooked meat consumption were independent risk factors for T. gondii seropositivity. Moreover, the current study showed significant associations between seropositivity of T. gondii and suicide attempts as well as negative associations between seropositivity of T. gondii and cigarette smoking in psychiatric inpatients using multivariate logistic regression.

Assessment of an In-House Enzyme-Linked Immunosorbent Assay and IgG Avidity Test Based on SAG1 and GRA7 Proteins for Discriminating between Acute and Chronic Toxoplasmosis in Humans

To improve serodiagnostic methods for diagnosis of acute from chronic toxoplasmosis, an economical in-house enzyme-linked immunosorbent assay (ELISA) for measuring Toxoplasma-specific IgG, IgM, and IgG avidity has been developed and assessed based on use of various Toxoplasma gondii antigens, including SAG1, GRA7, and a combination of SAG1 and GRA7 (SAG1+GRA7), as well as Toxoplasma lysate antigens (TLAs). Performances of in-house IgM, IgG, and IgG avidity assays were compared to those of ELISA commercial kits and VIDAS Toxo IgG avidity. A set of 138 sera from patients with acquired T. gondii infection and seronegative people were assessed. Receiver operating characteristic (ROC) analysis revealed an area under curve (AUC) of 0.98, 0.97, 0.99, and 0.99 for IgM-TLAs, IgM-SAG1, IgM-GRA7, and IgM-SAG1+GRA7, respectively. Furthermore, AUC was calculated as 0.99, 0.99, 0.98, and 0.99 for IgG-TLAs, IgG-SAG1, IgG-GRA7, and IgG-SAG1+GRA7, respectively. The current study showed that GRA7 included 100% sensitivity for the detection of Toxo IgM, while SAG1 included 89.7% sensitivity. Furthermore, the highest specificity (97.2%) to detect Toxo IgM was achieved using SAG1+GRA7 antigen. For the detection of Toxo IgG, the highest sensitivity (100%) was recorded for SAG1+GRA7, followed by TLAs (97.9%). The SAG1+GRA7 showed the greatest potential for assessing avidity of IgG antibodies, with 97.1% sensitivity and 96.6% specificity compared to those of VIDAS Toxo IgG avidity. The preliminary results have promised better discriminations between acute and chronic infections using a combination of SAG1 and GRA7 recombinant antigens compared to those using TLAs.

Toxoplasma gondii infection and spontaneous abortion: A systematic review and meta-analysis

Toxoplasmosis is one of the most common parasitic infections in humans, which is caused by Toxoplasma gondii. It is usually asymptomatic but primary infection in a pregnant woman can cause severe consequences in the fetus such as miscarriage. This study aimed to estimate the global prevalence of T. gondii infection in women with spontaneous abortion. It also evaluates the possible relationship between recent Toxoplasma infection and miscarriage. Five electronic databases were reviewed. We used the random effects model and 95% confidence intervals(CI) to determine the overall prevalence and odds ratio (OR). Heterogeneity was calculated using Cochran's Q test and I² statistic. The included studies were divided into three sub-groups based on antibody class against T. gondii and the existence of parasite DNA. Based on PCR, the pooled random-effects estimates that the prevalence of T. gondii infection in women with abortion was 10% (95% CI 7-14%). The pooled random effect favored a statistically significant increased risk of latent Toxoplasma infection [OR = 1.84; 95% CI: 1.41-2.40, P < 0.001] and recent infection [OR = 3.72; 95% CI: 2.21-6.26, P < 0.001] in women with spontaneous abortions. In recent infections, significant pooled ORs of positive association were observed in women with miscarriage [OR = 4.2; 95% CI: 2.04-8.85; χ2 = 17.2; I² = 42.0%, P = 0.07]. This study demonstrates that recent T. gondii infection is associated with an elevated risk of spontaneous abortion. Further studies concerning all risk factors related to toxoplasmosis, and undertaking confirmatory tests at the time of abortion should be performed to investigate the impact of T. gondii infection and spontaneous abortion.

Seroepidemiological study of toxoplasmosis in women referred to a pre-marriage counseling center in Alborz Province, Iran

Objectives

The aim of the current study was to assess prevalence of Toxoplasma infection and its associated risk factors in women of childbearing-age in central Iran.

Results

Of 400 serum samples assessed for anti-T. gondii antibodies, 81 (20.25%) samples were positive for anti-T. gondii antibodies, including 74 positive samples (91.3%) for anti-T. gondii IgG and seven positive samples (8.7%) for IgG and IgM. Of seven IgG and IgM positive samples, five and two samples were high and low in IgG avidity, respectively. Based on PCR analysis, Toxoplasma infection was detected in one sample with anti-T. gondii IgM and low IgG avidity. The Chi-square test showed significant correlations of T. gondii seropositivity with history of undercooked meat consumption and contacts with cats (p < 0.05). In the present study, 79.75% of the participants were negative for IgG against T. gondii infection. Furthermore, recently acquired Toxoplasma infection was found using IgG avidity and PCR assays among women of childbearing-age in the study area, which would increase the risk of their fetus becoming infected. Educational program and antenatal screening of childbearing-age women for T. gondii infection may be important primary prevention strategies and help reduce the risk of congenital toxoplasmosis in this population.

The relationship between Toxoplasma gondii infection in mothers and neonate's gender

BACKGROUND

The secondary sex ratio can be affected by various factors such as stress, immunosuppression, and age of parents in addition to mother infectious disease (Maternal infections). Toxoplasmosis is one of the critical maternal parasitic infections during pregnancy. Besides the complications of the acute form of the disease, hormonal shifts, and even alterations in the secondary sex ratio can be induced by the manipulative activity of the chronic form of the disease. Therefore, this study aimed to evaluate the correlation between Toxoplasma gondii infection in mothers and neonate's gender.

METHODS

In this case-control study, 137 seropositive mothers to Anti-Toxoplasma IgG(case) was compared to 137 age-matched subject Toxoplasma-seronegative mothers(control) in terms of their neonate's gender. These individuals were randomly selected based on exclusions and inclusions criteria of the study from among 2014 mothers who had been tested for Toxoplasma infection during pregnancy from 2015 to 2018 in Shiraz, Iran.

RESULTS

From a total of 2014 studied pregnant mothers, 326 (16.2%) mothers were seropositive to anti-Toxoplasma IgG, and 1688 (83.8%) were negative for IgG. It was found that the numbers of female and male neonates were 136 (45.48%) and 163 (54.51%) in the control group whereas, they were 165 (49.84%) and 166 (50.15%) in the case group, respectively. The sex ratio was 1.006:1 in Toxoplasma-seropositive and 1.2:1 in Toxoplasma-seronegative mothers. The number of male and females offsprings indicated a significant difference in Toxoplasma-seronegative mothers (54.5%, p = .015). Moreover, comparing the number of males and females between the two randomly selected groups showed that female gender is significantly more than male gender in seropositive mothers to Toxoplasma (54.8%, p = .014), which means that of 301 females, 165 offspring were born to seropositive mothers. No significant difference was observed for the sex ratio of aborted fetuses between groups. However, in the Toxoplasma-seropositive group, the sex ratio of aborted fetuses showed that the aborted male fetuses were significantly higher in number. (31 male vs 13 female, p < .001).

CONCLUSION

Comprehensively, a significant relationship was found between chronic Toxoplasma infection and secondary sex ratio. However, it is suggested that this relationship be investigated in further studies as well as an animal study.

Role of Toxoplasma gondii IgG Avidity Testing in Discriminating between Acute and Chronic Toxoplasmosis in Pregnancy

Risk of mother-to-child transmission of Toxoplasma gondii during pregnancy is much greater in women who are exposed to primary T. gondii infection (toxoplasmosis) after conception compared to those who were exposed to the infection before conception. Therefore, laboratory tests that help classify recent primary toxoplasmosis are important tools for the management of pregnant women suspected to have T. gondii exposure. Detection of Toxoplasma IgM (Toxo IgM) is a sensitive indicator of primary toxoplasmosis, but the indicator specificity is low because sometimes natural IgM antibodies react with Toxoplasma antigens in the absence of the infection. Furthermore, Toxo IgM sometimes persists in blood serum for several months or years following the primary infection. In recent decades, Toxo IgG avidity assay has been used as a standard diagnostic technique for a better estimation of the infection acquisition time and identification of the primary T. gondii infection during pregnancy. Avidity is described as the aggregate strength; by which, a mixture of polyclonal IgG molecules reacts with multiple epitopes of the proteins. This parameter matures gradually within 6 months of the primary infection. A high Toxo IgG avidity index allows a recent infection (less than 4 months) to be excluded, whereas a low Toxo IgG avidity index indicates a probable recent infection with no exclusions of the older infections. This minireview is based on various aspects of T. gondii IgG avidity testing, including (i) description of avidity and basic methods used in primary studies on T. gondii IgG avidity and primary infections; (ii) importance of IgG avidity testing in pregnancy; (iii) result summary of the major studies on the use of T. gondii IgG avidity assay in pregnancy; (iv) brief explanation of the T. gondii IgG avidity values in newborns; (v) result summary of the major studies on T. gondii IgG avidity and PCR; (vi) discussion of commercially available T. gondii IgG avidity assays, including newer automated assays; and (vii) current issues and controversies in diagnosis of primary T. gondii infections in pregnancy.

The influence of exposure to Toxoplasma Gondii on host lipid metabolism

BACKGROUND

Mounting evidence suggested a complex correlation between host lipid metabolism and Toxoplasma gondii (T. gondii) infection. However, the inherent association between T. gondii infection and host lipid state remains elusive either in mice or in human hosts.

METHODS

Through a study in a sample of 1045 healthy participants from eastern China, we determined the association of T. gondii infection and host lipid levels using serological methods. We then examined the host lipid levels in C57BL/6 J mice at both acute and chronic T. gondii infection stages (for a period up to 36 weeks post infection).

RESULTS

In our case-control study, T. gondii seropositive individuals had higher low-density lipoproteins (LDL) (P = 0.0043) and total cholesterol (TC) (P = 0.0134) levels compared to seronegative individuals. Furthermore, individuals with LDL (OR = 3.25; 95% CI:1.60-6.61) and TC (OR = 2.10; 95% CI:1.22-3.63) levels above the upper limit of normal range had higher odds ratio to be T. gondii IgG positive. Consistently, in vivo data revealed that a significantly increased LDL level was first observed at early acute stage but plateaued to later time (chronic infection with T. gondii).

CONCLUSIONS

In both healthy population and T. gondii-infected mice, seropositive individuals had higher LDL level. Individuals with positive T. gondii IgG had more odds of being with LDL and TC abnormality. Latent T. gondii infection is common worldwide, potential medical interventions to host lipid metabolism may be a breakthrough point to the prevention and control of this parasite infection.

The effects of toxoplasmosis on sex ratio at birth

Toxoplasmosis affects about one third of human population worldwide. It has a wide range of effects on the health, immunity, behaviour, and both prenatal and postnatal outcomes of infected hosts, including humans. Among these effects, stage of infection-specific shifts in secondary sex ratio were described about ten years ago both in humans and in artificially infected mice. In both women and female mice, in the early stage of infection the probability of giving birth of sons significantly increases, up to 260 sons to every 100 daughters. In the late stages of infection, the probability of giving birth to sons markedly decreases to as low as 78 to every 100 daughters. An ecological correlation study shows that the effect of latent toxoplasmosis on human population biology and demography can be large. In fact, the effect of prevalence of toxoplasmosis on a nationwide sex ratio was the third strongest effect from the effects of 15 factors included in the analysis. It has been suggested that toxoplasmosis-associated concentration of steroid hormones or glucose may be the proximal cause in the sex ratio shift. A more parsimonious explanation of the upward secondary sex ratio shift is found in a lower stringency of quality control of embryos, whose side-effect is increased survival rate of the more immunogenic male embryos in immunosuppressed infected females. The most parsimonious explanation of the downward secondary sex ratio shift relies on the Trivers-Willard hypothesis, which predicts an adaptive shift to more daughters in females with impaired health or lower socioeconomic status.

The relation of serum prolactin levels and Toxoplasma infection in humans

BACKGROUND

Toxoplasma gondii is an intracellular protozoan parasite distributed worldwide. Although the infection is benign in immunocompetent individuals, it is life threatening and complicated in immunocompromised patients and fetuses of pregnant women who received their first exposure to T. gondii during the pregnancy. Prolactin (PRL) is a hormone that is secreted by the pituitary gland, and it is confirmed that it plays a role in the immune system. The present study was carried out to assess the possible relation between serum PRL levels and Toxoplasma infection frequency in human.

METHODS

In this cross-sectional study, 343 serum samples (240 from women and 103 from men) were collected from individuals who were referred for PRL checking in laboratories of Karaj, Iran. Blood samples were collected, and sera were separated and analyzed for the detection of anti-Toxoplasma IgG antibody by ELISA method. The levels of PRL were measured by Roche Elecsys 2010 analyzer, electrochemiluminescence technology.

RESULTS

Of 343 sera, 110 samples (32%) consisting of samples from 42 men and 68 women had anti-T. gondii IgG antibody. The prevalence of T. gondii infection in women with high PRL levels was lower than that in the comparison group with normal levels of PRL and the relationship between these two parameters was statistically significant (P=0.016). In women with hyperprolactinemia, by increasing of PRL levels, the prevalence of T. gondii infection was reduced.

CONCLUSION

The results of the current study confirmed the previous studies based on immunoregulatory role of PRL and indicated that high levels of PRL could be related to Toxoplasma seronegativity in women.