Socioeconomic factors associated with infection by Toxoplasma gondii and Toxocara canis in children

The intense contact of children with domestic animals or environments contaminated with faeces of these animals, together with habits related to lack of hygiene, can facilitate infection by zoonoses. The study evaluated the seroprevalence and risk factors associated with toxoplasmosis and toxocariasis in schoolchildren in the city of Jataizinho, Paraná. Of the 412 children aged 4-15 years, 56.8% (234/412) presented antibodies reactive to Toxoplasma gondii, 42.5% (175/412) presented antibodies reactive to Toxocara canis, and 27.4% (113/412) were reactive for the two species. The analysis of risk factors showed that prevalence of toxoplasmosis and toxocariasis was associated with the level of education of the child's mother (less than eight years of schooling), age range (10-15 years) and the presence of cats in the residence. In addition, family income (up to a minimum wage), presence of a dog, the habit of playing in soil/sand and eosinophilia were associated with Toxocara canis infection. There was an association between the two zoonoses (p < .01), indicating the existence of coinfection. The results show high prevalence of these two important zoonoses, alerting to the need of implementing control measures in order to reduce the incidence and risks of sequelae in children.

Rosuvastatin revert memory impairment and anxiogenic-like effect in mice infected with the chronic ME-49 strain of Toxoplasma gondii

The aim of this study was to investigate the effect of rosuvastatin treatment on memory impairment, and anxiogenic-like effects in mice chronically infected with Toxoplasma gondii. For this, Balb/c mice were infected orally with chronic ME-49 strain of Toxoplasma gondii. Oral treatment with rosuvastatin (40mg/kg/day) started on the 51^st day post-infection and was performed daily for 21 days. After completion of treatment, anxiety-like effects and locomotion were investigated in the open field (OF) test, whereas novel object recognition (NOR) test was used for evaluation of short- and long-term memory. At the end of the experiments, the brain was collected for Toxoplasma gondii DNA quantification and histopathological analysis. Infection with ME-49 strain decreased the time spent in the center of OF, indicating an anxiogenic effect, without affecting total and peripheral locomotion. Rosuvastatin treatment inhibited the change in the center time. Besides, pharmacological treatment increased total and central locomotion in both non-infected and infected animals. Infection also impaired both short- and long-term memory in the NOR test, and these effects were reverted by rosuvastatin treatment. In addition to effects in behavioral changes, rosuvastatin also reduced parasite load in the brain and attenuated signs of brain inflammation such as perivascular cuffs, inflammatory cell infiltration and tissue damage. These findings indicate for the first time the efficacy of rosuvastatin in treatment of memory impairment and anxiogenic effect evoked by infection with Toxoplasma gondii. These effects might be mediated by reduced cyst load, which in turn decrease inflammation and damage in the brain.

First report of detection of Toxoplasma gondii DNA in oysters (Crassostrea sp.) in the state of Maranhão

Abstract The aim of this study was to report on detection of Toxoplasma gondii DNA in oysters (Crassostrea sp.) in the state of Maranhão. To conduct this study, 200 farmed oysters were acquired in the municipality of Raposa and 100 in Paço do Lumiar; and a further 100 oysters were taken from the natural stock in the municipality of Primeira Cruz. This total of 400 specimens sampled was divided into 80 pools composed of five animals each. The gills and visceral mass of each oyster were removed for DNA extraction (per pool of oysters), using a commercial kit. The nested PCR technique (with the primer SAG-1) was then used to investigate any presence of protozoa. This molecular technique demonstrated the presence of DNA of T. gondii in 2.5% of the pools of oysters (n = 2/80): these oysters were exclusively from farms. The results from this study allow the conclusion that oysters of the genus Crassostrea that are farmed in the state of Maranhão are capable of filtering oocysts of T. gondii and maintaining them in their tissues. They are therefore potential sources of contamination for humans and other animals.

Saliva collection and detection of anti- T. gondii antibodies of low-income school-age children as a learning strategy on hygiene, prevention and transmission of toxoplasmosis

School-age children are a social group in which blood collection for laboratory testing can be perceived as an invasive procedure, with low acceptance and tolerance of stakeholders. This problem could be circumvented by replacing serum samples with saliva. For this purpose, and to make the collection of saliva samples playful and instructive for children, educational activities on hygiene and toxoplasmosis transmission and prevention were performed using toys and audiovisual tools. The target audience consisted of 7-10 year-old children from low-income families who attended public schools in the city of São Paulo. Saliva samples were used in a previously described in-house Enzyme-Linked Immunosorbent Assays (ELISA) to detect anti- Toxoplasma gondii IgG antibodies and establish the immunological status of each of the participants. One year later, children’s memory and fixation of concepts regarding hygiene habits, as well as transmission and prevention of toxoplasmosis were tested in the same schools, by means of a questionnaire application, using students who did not participate in the first intervention as controls. The prevalence of positive anti- T. gondii IgG among students was 50% (82/164). One year later, 45 children had more knowledge on toxoplasmosis (28/45 vs 29/147) and they drew the cat’s involvement in the transmission of toxoplasmosis more often than controls (28/45 vs 29/147). Sorted according to the presence of specific IgG in saliva, recovered positive students presented worse memory of the above cited knowledge as did saliva-negative IgG students, but both groups had isolated higher frequency of fixed knowledge than non-intervened students. Our data show that there is a high prevalence of T. gondii infection in school-children from low-income areas; saliva is an alternative to blood for anti- T. gondii IgG detection; and a one-day educational intervention in school-children was effective in promoting knowledge fixation on hygiene and toxoplasmosis transmission and prevention after one year.

Large-scale study of Toxoplasma and Cytomegalovirus shows an association between infection and serious psychiatric disorders

BACKGROUND

Common infectious pathogens have been associated with psychiatric disorders, self-violence and risk-taking behavior.

METHODS

This case-control study reviews register data on 81,912 individuals from the Danish Blood Donor Study to identify individuals who have a psychiatric diagnosis (N = 2591), have attempted or committed suicide (N = 655), or have had traffic accidents (N = 2724). For all cases, controls were frequency matched by age and sex, resulting in 11,546 participants. Plasma samples were analyzed for immunoglobulin G (IgG) antibodies against Toxoplasma gondii and cytomegalovirus (CMV).

RESULTS

T. gondii was detected in 25·9% of the population and was associated with schizophrenia (odds ratio [OR], 1·47; 95% confidence interval [CI], 1·03-2·09). Accounting for temporality, with pathogen exposure preceding outcome, the association was even stronger (IRR, 2·78; 95% CI, 1·27-6·09). A very weak association between traffic accident and toxoplasmosis (OR, 1·11; 95% CI, 1·00-1·23, p = 0.054) was found. CMV was detected in 60·8% of the studied population and was associated with any psychiatric disorder (OR, 1·17; 95% CI, 1·06-1·29), but also with a smaller group of neurotic, stress-related, and somatoform disorders (OR, 1·27; 95% CI, 1·12-1·44), and with attempting or committing suicide (OR, 1·31; 95% CI, 1·10-1·56). Accounting for temporality, any psychiatric disorder (IRR, 1·37; 95% CI, 1·08-1·74) and mood disorders (IRR, 1·43; 95% CI, 1·01-2·04) were associated with exposure to CMV. No association between traffic accident and CMV (OR, 1·06; 95% CI, 0·97-1·17) was found.

CONCLUSIONS

This large-scale serological study is the first study to examine temporality of pathogen exposure and to provide evidence of a causal relationship between T. gondii and schizophrenia, and between CMV and any psychiatric disorder.

No evidence for airborne transmission of Toxoplasma gondii in a very high prevalence area in Lancaster County

Background:

Toxoplasma gondii (T. gondii) has been associated with acute food-borne illness, chronic low-grade inflammation, neuropsychiatric conditions and reactivation of chronic latent infection in immunocompetent hosts. Primary infection with T. gondii in pregnant women can lead to congenital toxoplasmosis. In addition to well-known oral tissue-cyst or oocyst ingestion, we hypothesized that the very high prevalence of T. gondii in certain populations exposed to agricultural dust could be, in part, a consequence of airborne infection with oocysts.

Methods:

Wo collected environmental dust samples from an area with a reportedly high T. gondii seroprevalence in the Old Order Amish population, in Lancaster, Pennsylvania. Samples included: a) air filters from air-conditioning units; b) swabs of settled dust; and c) vacuum filters containing airborne field dust. Pools of the swabs and shredded sub-samples of the air filters were fed to pigs, with inoculation into mice of heart tissue from seroconverted pigs. We also investigated the presence of T. gondii DNA using PCR amplification.

Results:

Only one pig seroconverted. However, bioassay of pig heart tissue further inoculated into mice showed no evidence of T. gondii infection. Consistently, no evidence of T. gondii DNA was revealed in any sample.

Conclusions:

No evidence of airborne transmission was found in the environmental samples that were examined.

Lower performance of Toxoplasma-infected, Rh-negative subjects in the weight holding and hand-grip tests

BACKGROUND

Toxoplasma, a protozoan parasite of cats, infects many species of intermediate and paratenic hosts, including about one-third of humans worldwide. After a short phase of acute infection, the tissue cysts containing slowly dividing bradyzoites are formed in various organs and toxoplasmosis proceeds spontaneously in its latent form. In immunocompetent subjects, latent toxoplasmosis was considered asymptomatic. However, dozens of studies performed on animals and humans in the past twenty years have shown that it is accompanied by a broad spectrum of specific behavioural, physiological and even morphological changes. In human hosts, the changes often go in the opposite direction in men and women, and are mostly weaker or non-existent in Rh-positive subjects.

METHODS

Here, we searched for the indices of lower endurance of the infected subjects by examining the performance of nearly five hundred university students tested for toxoplasmosis and Rh phenotype in two tests, a weight holding test and a grip test.

RESULTS

The results confirmed the existence of a negative association of latent toxoplasmosis with the performance of students, especially Rh-negative men, in these tests. Surprisingly, but in an accordance with some already published data, Toxoplasma-infected, Rh-positive subjects expressed a higher, rather than lower, performance in our endurance tests.

DISCUSSION

Therefore, the results only partly support the hypothesis for the lower endurance of Toxoplasma infected subjects as the performance of Rh-positive subjects (representing majority of population) correlated positively with the Toxoplasma infection.

Ocular Lesions in Congenital Toxoplasmosis in Santa Isabel do Ivaí, Paraná, Brazil

We verified clinical and psychopedagogic aspects of congenital cases with ocular sequelae, 13 years after toxoplasmosis outbreak in Santa Isabel do Ivaí, and current seroprevalence of this zoonosis in pregnant women. Audiologic and ophthalmologic evaluations were performed in congenital cases, in addition to collection of clinical and psychopedagogic data. In pregnant women, current seroprevalence was observed. Among affected teenagers, 2 of 5 are behind in school grade, and 4 of 5 reported learning difficulties, requiring psychopedagogic monitoring, as well as ocular complaints. We observed predominance of small, scarred, dispersed, type II chorioretinal lesions (hypopigmented halo and hyperpigmented central area), and 1 case of ocular relapse. All patients presented normal audiologic assessment. Among 131 pregnant women, 62 (47.3%) were seronegative and 39 (29.8%) were IgG reactive. Only 1 reported acquiring infection during the outbreak. This is one of the few studies in Brazil showing the outcome of congenital toxoplasmosis, a decade after infection, in one of the world's largest outbreaks.

The association of Toxoplasma gondii infection with neurocognitive deficits in a population-based analysis

PURPOSE

To examine the relationship between infection with Toxoplasma gondii (toxo) and cognition.

METHODS

Multivariate logistic regression was used to test the association of toxo seropositivity with indices of cognitive function among over 4,200 adults in the third National Health and Nutrition Examination Survey.

RESULTS

Toxo-seropositive participants were more likely than seronegative participants to score in the worst quartile of the simple reaction time test (OR 1.3, 95 % CI 1.0, 1.6), symbol-digit substitution test (SDST, OR 1.5, 95 % CI 1.2, 1.9) and the serial-digit learning test (trials to criterion) (SDLTNT, OR 1.4, 95 % CI 1.1, 1.8) in models adjusted for age, race/ethnicity, gender and foreign birth. After further adjustment for all cofactors, the association between toxo seropositivity and these outcomes was no longer significant. However, seropositivity was associated with worse scores on the SDST (OR 2.9, 95 % CI 1.8, 4.8) among those in the lowest income category and the SDLTNT (OR 1.5, 95 % CI 1.1, 2.5) among those foreign born.

CONCLUSIONS

Toxo seropositivity may be associated with poor cognitive test scores in certain subgroups; however, causation cannot be established in this cross-sectional study.