Toxoplasmosis--a global threat. Correlation of latent toxoplasmosis with specific disease burden in a set of 88 countries

A meta-analysis of the prevalence of Toxoplasma gondii in animals and humans in Ethiopia

BACKGROUND

Toxoplasmosis is a worldwide zoonosis. The objectives of this study were to estimate the prevalence and assess the potential risk factors of Toxoplasma gondii infections in animals and humans in Ethiopia by using meta-analytical methods.

METHODS

Published studies on T. gondii in animals and humans in Ethiopia were searched in Medline, Google Scholar and the lists of references of articles. Eligible studies were selected by using inclusion and exclusion criteria. The risks of within and across study biases, and the variations in prevalence estimates attributable to heterogeneities were assessed. Pooled prevalence was estimated by the DerSimonian and Laird random effects model.

RESULTS

Thirty two studies were eligible and data from 5689 animals and 5718 humans were used for quantitative syntheses. The pooled IgG seroprevalence in cats, small ruminants and humans were estimated at 87.72% (95% CI = 78.63, 93.28), 34.59% (95% CI = 21.08, 51.12) and 74.73% (95% CI = 61.85, 84.36), respectively. The odds of infections were higher in pregnant than in non pregnant women (OR = 3.96), in individuals that had contact with cats than those with no contact (OR = 2.53), and in urban than in rural inhabitants (OR = 2.06).

CONCLUSIONS

Toxoplasmosis is highly prevalent and could be a cause of considerable reproductive wastage in small ruminants and multiple diseases in humans in Ethiopia. Public education on preventive measures could help reduce the transmission of the parasite to humans.

Toxoplasma gondii exposure in patients suffering from mental and behavioral disorders due to psychoactive substance use

Background

Toxoplasma gondii infection has been associated with psychiatric diseases. However, there is no information about the link between this infection and patients with mental and behavioral disorders due to psychoactive substance use.

Methods

We performed a case-control study with 149 psychiatric patients suffering from mental and behavioral disorders due to psychoactive substance use and 149 age- and gender-matched control subjects of the general population. We searched for anti-T. gondii IgG and IgM antibodies in the sera of participants by means of commercially available enzyme-linked immunoassays. Seroprevalence association with socio-demographic, clinical and behavioral characteristics in psychiatric patients was also investigated.

Results

Anti-T. gondii IgG antibodies were present in 15 (10.1%) of 149 cases and in 14 (9.4%) of 149 controls (P = 1.0). Anti-T. gondii IgM antibodies were found in 11 (7.4%) of the 149 cases and in 16 (10.7%) of the 149 controls (P = 0.31). No association of T. gondii exposure with socio-demographic characteristics of patients was found. Multivariate analysis of clinical and behavioral characteristics of cases showed that T. gondii seropositivity was positively associated with consumption of opossum meat (OR = 10.78; 95% CI: 2.16-53.81; P = 0.003) and soil flooring at home (OR = 11.15; 95% CI: 1.58-78.92; P = 0.01), and negatively associated with suicidal ideation (OR = 0.17; 95% CI: 0.05-0.64; P = 0.008).

Conclusions

Mental and behavioral disorders due to psychoactive substance use do not appear to represent an increased risk for T. gondii exposure. This is the first report of a positive association of T. gondii exposure with consumption of opossum meat. Further studies to elucidate the role of T. gondii infection in suicidal ideation and behavior are needed to develop optimal strategies for the prevention of infection with T. gondii.

NLR proteins and parasitic disease

Parasitic diseases are a serious global health concern. Many of the most common and most severe parasitic diseases, including Chagas' disease, leishmaniasis, and schistosomiasis, are also classified as neglected tropical diseases and are comparatively less studied than infectious diseases prevalent in high income nations. The NLRs (nucleotide-binding domain leucine-rich-repeat-containing proteins) are cytosolic proteins known to be involved in pathogen detection and host response. The role of NLRs in the host response to parasitic infection is just beginning to be understood. The NLR proteins NOD1 and NOD2 have been shown to contribute to immune responses during Trypanosoma cruzi infection, Toxoplasma gondii infection, and murine cerebral malaria. The NLRP3 inflammasome is activated by T. cruzi and Leishmania amazonensis but also induces pathology during infection with schistosomes or malaria. Both the NLRP1 and NLRP3 inflammasomes respond to T. gondii infection. The NLRs may play crucial roles in human immune responses during parasitic infection, usually acting as innate immune sensors and driving the inflammatory response against invading parasites. However, this inflammatory response can either kill the invading parasite or be responsible for destructive pathology. Therefore, understanding the role of the NLR proteins will be critical to understanding the host defense against parasites as well as the fine balance between homeostasis and parasitic disease.

Prevalence of IgG Antibodies to Toxoplasma gondii in Veterinary and Undergraduate Students at Virginia Tech, Blacksburg, Virginia

Toxoplasma gondii is a globally distributed parasitic protozoan that infects humans and other warm-blooded vertebrates. Felids are the only definitive host for T. gondii, and they excrete oocysts in their faeces. The national prevalence in humans is declining in the United States. This zoonotic organism is of particular interest due to its importance in pregnant women, in individuals with altered immune systems, and in reactivated ocular infections. Exposure to the parasite in humans is usually associated with consumption of raw or undercooked meat or by accidental ingestion of oocysts. It was hypothesized that veterinary students would have a greater chance at exposure to the parasite than an average population of undergraduate students due to increased contact with cats who are infected. A commercially available ELISA was used to examine serum samples from 336 students (252 veterinary students and 84 undergraduate students) at Virginia Polytechnic Institute and State University and the Virginia-Maryland Regional College of Veterinary Medicine for serum IgG antibodies to T. gondii antigen. The prevalence of T. gondii in these subjects was 5.6% in veterinary school students (n = 252) and 2.4% in undergraduates (n = 84). There was no significant difference (P > 0.05) in the prevalence of T. gondii antibodies in veterinary versus undergraduate students. The overall prevalence of 4.8% in all students in this study reflects the continuing decline of antibodies to T. gondii in humans in the United States.

Management of toxoplasmic retinochoroiditis during pregnancy, postpartum period and lactation: clinical observations

Background

During pregnancy and labor, the immune response is physiologically impaired and women are more susceptible to infections. Since many drugs may have potentially adverse effects on the fetus and newborn, less aggressive treatment regimens should be considered in pregnant and lactating patients. The aim of our study was to present the management of toxoplasmic retinochoroiditis during pregnancy, postpartum period, and lactation.

Material/Methods

A retrospective study was undertaken of the clinical records of 24 women during pregnancy, postpartum period, and lactation who were referred in the years 1994–2014 to the Department of Zoonoses and Tropical Diseases or the Department of Ophthalmology, Medical University of Warsaw for toxoplasmic retinochoroiditis. The diagnosis was based on the typical ophthalmoscopic picture, confirmed by serological testing using an ELISA method.

Results

A total of 28 attacks of toxoplasmic retinochoroiditis were observed in 24 patients during pregnancy, postpartum period, and lactation. The choice of treatment was guided by the character and location of the inflammatory lesion and the gestational age. Topical (steroidal/nonsteroidal eye drops) and systemic treatments with spiramycin or azithromycin, Fansidar (pyrimethamine 25 mg/sulfadoxine 500 mg), and prednisone were used.

Conclusions

Management of toxoplasmic retinochoroiditis during pregnancy, postpartum period, or lactation must be individualized and guided by the gestational age and location of the active lesion. Women of childbearing age with toxoplasma ocular lesions should be informed by their doctors about possible active recurrences during pregnancy and followed carefully by an ophthalmologist when pregnant.

Do pregnancy, postpartum period and lactation predispose to recurrent toxoplasmic retinochoroiditis?

Backgrund

The aim of the study was a statistical analysis of the possible effects of pregnancy, postpartum period, and lactation on increased risk for reactivation of toxoplasmic retinochoroiditis.

Material/Methods

A retrospective study was undertaken of the clinical records of 661 patients referred with the diagnosis of acute toxoplasmic retinochoroiditis to the Department of Zoonoses and Tropical Diseases, Medical University of Warsaw and to the Department of Ophthalmology, Medical University of Warsaw in the years 1994–2014.

This group of inpatients consisted of 213 women of child-bearing age (18 to 40 years). Reactivation of toxoplasmic retinochoroiditis was observed in 24 women aged 15 to 39 years who were pregnant, in the postpartum period, or lactating.

To compare the rate of the relapses in pregnant/lactating patients vs. non-pregnant/non-lactating patients, the Fisher exact test was used. Calculations were performed with WinPepi software (Abramson JH (2004) WINPEPI (PEPI-for-Windows) for epidemiologists. Epidemiologic Perspectives & Innovations, 2005, 1: 6).

Results

A total of 28 reactivations of toxoplasmic retinochoroiditis were observed (16 episodes in pregnancy, 4 in the postpartum period, and 8 during lactation) in 24 women aged 15 to 39 years. In 3 women, multiple episodes were reported (in early pregnancy and the postpartum period in 2 women, and during 2 pregnancies and lactation in 1 woman). Statistical analysis showed that the risk of an episode of toxoplasmic retinochoroiditis is 7.4-fold higher in pregnancy compared to the non-pregnant/non-lactating women (p<0.0001).

Conclusions

Women of childbearing age with toxoplasma ocular lesions should be informed by their doctors about possible active recurrences during pregnancy and should be followed carefully by an ophthalmologist when pregnant.

Interaction between Helicobacter pylori and latent toxoplasmosis and demographic variables on cognitive function in young to middle-aged adults

Helicobacter pylori and latent toxoplasmosis are widespread diseases that have been associated with cognitive deficits and Alzheimer's disease. We sought to determine whether interactions between Helicobacter pylori and latent toxoplasmosis, age, race-ethnicity, educational attainment, economic status, and general health predict cognitive function in young and middle-aged adults. To do so, we used multivariable regression and multivariate models to analyze data obtained from the United States' National Health and Nutrition Examination Survey from the Centers for Disease Control and Prevention, which can be weighted to represent the US population. In this sample, we found that 31.6 percent of women and 36.2 percent of men of the overall sample had IgG Antibodies against Helicobacter pylori, although the seroprevalence of Helicobacter pylori varied with sociodemographic variables. There were no main effects for Helicobacter pylori or latent toxoplasmosis for any of the cognitive measures in models adjusting for age, sex, race-ethnicity, educational attainment, economic standing, and self-rated health predicting cognitive function. However, interactions between Helicobacter pylori and race-ethnicity, educational attainment, latent toxoplasmosis in the fully adjusted models predicted cognitive function. People seropositive for both Helicobacter pylori and latent toxoplasmosis - both of which appear to be common in the general population - appear to be more susceptible to cognitive deficits than are people seropositive for either Helicobacter pylori and or latent toxoplasmosis alone, suggesting a synergistic effect between these two infectious diseases on cognition in young to middle-aged adults.

The immunomodulatory effects of rolipram abolish drug-resistant latent phase of Toxoplasma gondii infection in a murine model

Background:

Latent toxoplasmosis always has the risk of reactivation leading to significant sequelae. The available medications, for chronic toxoplasmosis, are awfully limited by resistance of Toxoplasma cysts. Therefore, there is a growing necessity for novel therapeutic approaches. Agents increasing cAMP levels and downregulating proinflammatory cytokine could inhibit Toxoplasma conversion to the bradyzoite stage. This study explores a potential immunomodulatory effect of rolipram, a PDE4 inhibitor, on the course of experimental toxoplasmosis and links this role to deterrence of the resistant chronic phase of the disease.

Materials and methods:

Mice infected with low pathogenic strain of Toxoplasma gondii were treated with rolipram for three weeks. The effect of rolipram was evaluated through tissue injury scoring, brain cyst count, specific IgG titers as well as TNF-α, IFN-γ and IL-12 assays.

Results:

Rolipram was partially able to prevent the progression to chronic toxoplasmosis. Toxoplasma brain cyst burden showed a 74% reduction while Toxoplasma-induced inflammatory foci per liver area and nucleated cells per inflammatory focus were significantly reduced: 57.14% and 61.3% respectively. Significant reduction of TNF-α (84.6%), IFN-γ (76.7%) and IL-12 (71%) levels was demonstrated along with significant inhibition of anti-Toxoplasma antibody response.

Conclusion:

Rolipram efficiently modulated the Toxoplasma-induced immunological changes with a consequent remission of chronic toxoplasmosis. This study is the first to report the utilization of PDE4 inhibitors as possible immune modulators of chronic phase of Toxoplasma infection.

Serological Study on Cytomegalovirus and Toxoplasma Gondii in Thalassemia Major Patients of Yazd, Iran

BACKGROUND

Beta-thalassemia patients receive blood products from blood transfusion centers repeatedly. Blood transfusion can transmit Cytomegalovirus (CMV) and Toxoplasma gondii. The aim of this study was serological evaluation of these two infectious agents in thalassemia patients.

MATERIALS AND METHODS

In a cross-sectional study, the enzyme-linked immunosorbent assay (ELISA) testing was performed to detect IgM and IgG antibodies against CMV and Toxoplasma gondii in 96 thalassemia patients (under 18 years) and 144 healthy people. Data were analyzed by SPSS software and Chi-square test.

RESULTS

A significant difference was observed in CMVIgM antibody levels between test groups in women (p<0.05). The prevalence of CMV IgM, CMV IgG, Toxo-IgG, and Toxo IgM antibodies in thalassemia patients were 5.2%, 95.9%, 16%, and 0%, respectively.

CONCLUSION

In all thalassemia patients, Cytomegalovirus IgG is higher than healthy people. In addition, CMV IgM antibodies are higher in female patients. Antibody screening (IgM) on blood products for detecting Cytomegalovirus is necessary, but for Toxoplasma gondii is not necessary in the Yazd transfusion center.

Effects of latent toxoplasmosis on autoimmune thyroid diseases in pregnancy

BACKGROUND

Toxoplasmosis, one of the most common zoonotic diseases worldwide, can induce various hormonal and behavioural alterations in infected hosts, and its most common form, latent toxoplasmosis, influences the course of pregnancy. Autoimmune thyroid diseases (AITD) belong to the well-defined risk factors for adverse pregnancy outcomes. The aim of this study was to investigate whether there is a link between latent toxoplasmosis and maternal AITD in pregnancy.

METHODS

Cross-sectional study in 1248 consecutive pregnant women in the 9-12th gestational weeks. Serum thyroid-stimulating hormone (TSH), thyroperoxidase antibodies (TPOAb), and free thyroxine (FT4) were assessed by chemiluminescence; the Toxoplasma status was detected by the complement fixation test (CFT) and anti-Toxoplasma IgG enzyme-linked immunosorbent assay (ELISA).

RESULTS

Overall, 22.5% of the women were positive for latent toxoplasmosis and 14.7% were screened positive for AITD. Women with latent toxoplasmosis had more often highly elevated TPOAb than the Toxoplasma-negative ones (p = 0.004), and latent toxoplasmosis was associated with decrease in serum TSH levels (p = 0.049). Moreover, we found a positive correlation between FT4 and the index of positivity for anti-Toxoplasma IgG antibodies (p = 0.033), which was even stronger in the TPOAb-positive Toxoplasma-positive women, (p = 0.014), as well as a positive correlation between FT4 and log2 CFT (p = 0.009).

CONCLUSIONS

Latent toxoplasmosis was associated with a mild increase in thyroid hormone production in pregnancy. The observed Toxoplasma-associated changes in the parameters of AITD are mild and do not seem to be clinically relevant; however, they could provide new clues to the complex pathogenesis of autoimmune thyroid diseases.

The Austrian Toxoplasmosis Register, 1992-2008

BACKGROUND

We aimed to determine the incidence of primary gestational infections with Toxoplasma gondii and congenital toxoplasmosis in Austria, a country with a nationwide prenatal serological screening program since 1974.

METHODS

We analyzed retrospective data from the Austrian Toxoplasmosis Register of pregnant women with Toxoplasma infection and their offspring with births between 1992 and 2008, identified by the prenatal mandatory screening program. Treatment was administered to women from diagnosis of a Toxoplasma infection until delivery. Infected infants were treated up to 1 year of life routinely. Clinical manifestations in infected infants were monitored at least for 1 year and documented in the register.

RESULTS

The Austrian Toxoplasmosis Register included 2147 pregnant women with suspected Toxoplasma infection. Annually, 8.5 per 10 000 women acquired Toxoplasma infection during pregnancy, and 1.0 per 10 000 infants had congenital toxoplasmosis (13% mean transmission rate). Our data showed that women treated according to the Austrian scheme had a 6-fold decrease in the maternofetal transmission rate compared to women without treatment.

CONCLUSIONS

Results from the Austrian Toxoplasmosis Register show the efficiency of the prenatal screening program. Our results are of clinical relevance for infants, healthcare systems, and policy makers to consider preventive Toxoplasma screening as a potential tool to reduce the incidence of congenital toxoplasmosis.