[Prevalence and public-health-aspects of toxoplasmosis]

Ocular toxoplasmosis: a review of the current diagnostic and therapeutic approaches

PURPOSE

This review aims to summarize the current knowledge concerning the clinical features, diagnostic work-up and therapeutic approach of ocular toxoplasmosis focusing mainly on the postnatally acquired form of the disease.

METHODS

A meticulous literature search was performed in the PubMed database. A supplementary search was made in Google Scholar to complete the collected items.

RESULTS

Ocular toxoplasmosis is one of the most frequent infectious etiologies of posterior uveitis. It typically presents with retinochoroiditis. Setting an accurate diagnosis depends to a considerable degree on detecting characteristic clinical characteristics. In addition to the evaluation of clinical features, the diagnosis of toxoplasmosis relies at a large degree on serologic testing. The detection of the parasite DNA in the aqueous or vitreous humor can provide evidence for a definitive diagnosis. The current mainstay for the treatment, if necessary, is the use of oral antibiotic with systemic corticosteroids. Recent evidence suggests other therapeutic approaches, such as intravitreal antibiotics can be used.

CONCLUSION

Recent developments in the diagnostic and therapeutic approach have contributed to preventing or limiting vision loss of patients suffering from ocular toxoplasmosis. Further studies are required to provide a better understanding of epidemiology, pathogenesis, diagnosis, and treatment with a significant impact on the management of this challenging clinical entity.

The impact of socioeconomic factors on the efficiency of voluntary toxoplasmosis screening during pregnancy: a population-based study

BACKGROUND

Congenital toxoplasmosis is associated with severe complications. German state health insurance covers rubella, but not toxoplasmosis, immunity screening. We analysed the effect of socioeconomic factors on the efficiency of private toxoplasmosis screening during pregnancy.

METHODS

Toxoplasmosis and rubella screening data (n = 5402 mothers) were collected within the population-based Survey of Neonates in Pomerania (SNiP).

RESULTS

At the first-trimester screening, 34.4 % (88.1 %) of expecting mothers were immune to toxoplasmosis (rubella). Susceptibility for toxoplasmosis (rubella) was observed in 39.6 % (8.9 %) and 25.8 % (2.95 %) were not tested. Data on a 2(nd) screening were available in a subgroup of women with negative immunity showing less than 45 % participation rate. Active toxoplasmosis (no rubella) infection was observed in 0.3 % (n = 17) of pregnant women. A multiple logistic regression model (AIC = 719.67; AUC = 0.725) revealed that the likelihood of participating in a second toxoplasmosis screening increased among women with a good level of education and a steady partnership and decreased with paternal unemployment and the absence of breastfeeding. The highest probability of non-participation in toxoplasmosis screening was found among women with temporal burden and family responsibilities. A cost-benefit analysis showed that covering general screening for toxoplasmosis with health insurance saved costs.

CONCLUSION

Toxoplasmosis carried a substantial risk of infection during pregnancy. Although increased socioeconomic status was positively associated with the participation in toxoplasmosis screening, this was not the case when pregnant women had strong temporal burden and family responsibilities. This data supports the need for toxoplasmosis screening among pregnant women as a general healthcare benefit covered by insurance.

Detection of toxoplasmosis in patients with end-stage renal disease by enzyme-linked immunosorbent assay and polymerase chain reaction methods

Toxoplasmosis caused by Toxoplasma gondii is an opportunistic infection. In healthy individuals, the infection is largely asymptomatic, but in immunocompromised people the parasite can become widely disseminated, causing severe toxoplasmosis. In patients undergoing haemodialysis, the phagocytic process shows a highly significant impairment. Therefore, this study aimed to investigate toxoplasmosis in patients with end-stage renal disease (ESRD) undergoing haemodialysis in Ahvaz hospitals, southwest of Iran. A total of 280 patients and 100 healthy subjects participated in this study. The presence of serum IgM and IgG antibodies against T. gondii was detected by ELISA and the presence of Toxoplasma parasites in whole blood was evaluated by GRA6 PCR. Anti-T. gondii IgG antibodies were detected in 82 (29.3 %) haemodialysis patients and 26 (26 %) controls. In addition, anti-T. gondii IgM antibodies were detected in 7.9 % of patients and in 4 % of controls. For both the antibodies, the differences were statistically significant (P < 0.05). PCR was performed with DNA extracted from blood samples of all patients and controls. PCR gave positive results with four of the 280 blood samples from patients but none for the control blood samples. The results revealed a high percentage of positivity for Toxoplasma antibodies in patients with ESRD undergoing haemodialysis and also confirmed the parasite in whole blood, indicating disseminated infection in these patients. Patients undergoing dialysis have a higher rate of active infection with Toxoplasma likely due to reactivation of a chronic infection. Thus, parasitological examinations of ESRD patients should be periodically carried out for monitoring and evaluating the possible dissemination of toxoplasmosis during haemodialysis.

Peptide microarray analysis of in silico-predicted epitopes for serological diagnosis of Toxoplasma gondii infection in humans

Toxoplasma gondii infections occur worldwide in humans and animals. In immunocompromised or prenatally infected humans, T. gondii can cause severe clinical symptoms. The identification of specific epitopes on T. gondii antigens is essential for the improvement and standardization of the serological diagnosis of toxoplasmosis. We selected 20 peptides mimicking linear epitopes on GRA1, GRA2, GRA4, and MIC3 antigenic T. gondii proteins in silico using the software ABCpred. A further 18 peptides representing previously published epitopes derived from GRA1, SAG1, NTPase1, and NTPase2 antigens were added to the panel. A peptide microarray assay was established to prove the diagnostic performance of the selected peptides with human serum samples. Seropositive human serum samples (n = 184) were collected from patients presenting with acute toxoplasmosis (n = 21), latent T. gondii infection (n = 53), and inactive ocular toxoplasmosis (n = 10) and from seropositive forest workers (n = 100). To adjust the cutoff values for each peptide, sera from seronegative forest workers (n = 75) and patients (n = 65) were used. Univariate logistic regression suggested the significant diagnostic potential of eight novel and two previously published peptides. A test based on these peptides had an overall diagnostic sensitivity of 69% (100% in ocular toxoplasmosis patients, 86% in acutely infected patients, 81% in latently infected patients, and 57% in seropositive forest workers). The analysis of seronegative sera performed with these peptides revealed a diagnostic specificity of 84%. The results of our study suggest that the use of a bioinformatic approach for epitope prediction in combination with peptide microarray testing is a powerful method for the selection of T. gondii epitopes as candidate antigens for serological diagnosis.