Toxocara infection in psychiatric inpatients: a case control seroprevalence study

Association between Toxocara Spp. Exposure and Schizophrenia: A Case-Control Study

Background

Toxocariasis is a zoonotic disease caused by the larvae of Toxocara canis or Toxocara cati. Patients with schizophrenia may be at higher risk of infection, possibly due to their cognitive and personal self-care impairments. We aimed to assess the association between Toxocara spp. exposure and schizophrenia.

Methods

This case-control study was conducted on 109 patients with schizophrenia admitted to Ibn Sina Hospital, Shiraz, Iran, and 104 age- and gender-matched healthy controls from May to September 2021. A questionnaire was obtained and serum samples were tested for IgG antibodies to Toxocara excretory/secretory (TES) antigens using an enzyme-linked immunosorbent assay (ELISA).

Results

Anti-Toxocara IgG was detected in 12 schizophrenic patients and 10 control subjects, giving respective seroprevalences of 11.0% (95% confidence interval [95% CI]=5.8-18.4%) and 9.6% (95% CI=4.7-17.0%). Univariate logistic analyses estimated an odds ratio (OR) of 1.16 (95% CI=0.44-3.16); however, it was not statistically significant (P=0.915). Individuals with a history of eating unwashed vegetables or fruits (23.1%, 95% CI=9.0-43.6, crude odds ratio [COR]=3.21, 95% CI=1.13-9.13) and rural residency (19.5%, 95% CI=8.8-34.9, COR=2.74, 95% CI=1.06-7.05) had significantly higher rates of seropositivity using the univariate logistic analyses. After multivariate logistic analyses, the differences were not statistically significant.

Conclusion

The toxocariasis seroprevalence among schizophrenic and healthy participants was not significantly different (11% vs. 9.6%). Since the disease severity, onset, and cognitive sequelae are not the same among schizophrenic patients, clinically matched studies with larger samples are required to address the current inconsistency between the studies.

Prevalence of Toxocara eggs in Latin American parks: a systematic review and meta-analysis

Introduction

Toxocariasis is an infection caused in canines, felines, humans, and other vertebrates by species of the genus Toxocara, such as T. canis and T. cati. The embryonated eggs of these parasites are the main form of acquisition of the infection both for definitive hosts, such as the dog and the cat, respectively and for paratenic hosts, such as humans and other vertebrates. Toxocariasis infection in humans causes visceral larva migrans syndrome. When deposited on park soils, environmental contamination becomes a risk for environmental, human, and animal health.

Objective

To systemically estimate the prevalence of Toxocara spp. eggs in park soils in Latin America.

Methods

A systematic review and meta-analysis were performed to evaluate the prevalence of Toxocara eggs in park soils in Latin America, defined by copro-parasitological, molecular and immunological techniques. We searched PubMed, Scopus, Web of Sciences, Embase, LILACS and SciELO for studies published from 1900 through 28 January 2023. A meta-analysis was performed using a random-effects model to calculate the pooled prevalence and 95% confidence intervals (95% CI). Heterogeneity was measured through I2 statistics.

Results

Forty-nine studies (2,508 parks and 12,833 samples) were included, of whom 44 had a low risk of bias. The pooled prevalence of Toxocara eggs in parks in Latin America was 50.0% (95% CI: 40.0%-60.0%). Argentina had the highest prevalence of Toxocara eggs in parks (100%), followed by Brazil (66%) and Venezuela (63%). The pooled prevalence of Toxocara eggs in soil samples was 20.0% (95% CI: 14.0%-26.0%); in faecal samples, it was 13.0% (95% CI: 6.0%-23.0%).

Conclusion

The presence of Toxocara canis eggs in public parks in Latin America is a zoonotic and public health threat for the people who go to these places, especially if children play on the ground with dirt or contaminated objects; since many pet owners and general public are not adequately informed about the mode of transmission of this parasite.

The role of helminths in the development of non-communicable diseases

Non-communicable diseases (NCDs) like cardiovascular disease, chronic respiratory diseases, cancers, diabetes, and neuropsychiatric diseases cause significant global morbidity and mortality which disproportionately affect those living in low resource regions including low- and middle-income countries (LMICs). In order to reduce NCD morbidity and mortality in LMIC it is imperative to understand risk factors associated with the development of NCDs. Certain infections are known risk factors for many NCDs. Several parasitic helminth infections, which occur most commonly in LMICs, have been identified as potential drivers of NCDs in parasite-endemic regions. Though understudied, the impact of helminth infections on the development of NCDs is likely related to helminth-specific factors, including species, developmental stage and disease burden. Mechanical and chemical damage induced by the helminth in combination with pathologic host immune responses contribute to the long-term inflammation that increases risk for NCD development. Robust studies from animal models and human clinical trials are needed to understand the immunologic mechanisms of helminth-induced NCDs. Understanding the complex connection between helminths and NCDs will aid in targeted public health programs to reduce helminth-induced NCDs and reduce the high rates of morbidity that affects millions of people living in parasite-endemic, LMICs globally.

Toxocariasis-associated urinary system diseases: a systematic review of reported cases

BACKGROUND

Toxocariasis is a neglected tropical disease caused by Toxocara canis and Toxocara cati. Toxocara species can involve many organs, such as the brain, heart and lungs, however, the urinary system involvement of toxocariasis is largely unknown.

METHODS

We performed a systematic review to identify cases infected with urinary tract toxocariasis.

RESULTS

We identified seven cases that were eligible to be reviewed. Among the included citations, four studies reported bladder involvement and three reported kidney involvement. Fever, urinary, and abdominal presentations were amongst the most important clinical symptoms. Eosinophilic cystitis and nephrotic syndrome were the most common diagnoses.. The treatment regimen included a combination of anthelmintic drugs and steroids.

CONCLUSIONS

In cases of urinary tract presentations accompanied by eosinophilia or histopathologic findings suggestive of parasitic infection, toxocariasis should be included in the list of differential diagnoses, especially in endemic areas.

Neurocognitive domains and neuropathological changes in experimental infection with Trypanosoma brucei brucei in Wistar rats

Trypanosoma brucei brucei causes animal trypanosomiasis in several vertebrates and human African trypanosomiasis. Previous studies have only explored the incidence, clinical symptoms, haematology and biochemical changes associated with the disease. The behavioral manipulation hypothesis posits that parasites alter the behavior of host to increase the reproductive abilities of such parasites. Hence, the present study was carried out to investigate changes in behavior and cognition following experimental infection of T. brucei brucei in rat model.

This study involved two groups of animals (uninfected control and T. brucei infected) with 8 rats per group. After confirmation of parasitaemia in the infected rats both groups were assessed to investigate if infection led to behavioral alterations and neuropathological changes using the open field, social interaction and forelimb suspension tests. Immunohistochemistry was performed on brain tissues using glial fibrillary acidic protein and anticalbindin-D28k, antibodies.

We demonstrated that T. brucei infection triggered a significant decrease in exploratory activity, anxiety-like behavior, altered recognition of social novelty and reduced hanging latency in the hanging wire test. Immunohistochemistry revealed significant astrocytosis, loss of dendritic spines and reduction of Purkinje cell layer of the cerebellum.

These results demonstrate that T. brucei infection induce signs of anxiety, impaired motor co-ordination with degeneration and loss of Purkinje cells.

Toxocara infection/exposure and the risk of schizophrenia: a systematic review and meta-analysis

Toxocariasis is an important neglected disease that could have a role in the development of some neurological disorders, such as schizophrenia (SCZ). We performed the first systematic review and meta-analysis on observational studies to evaluate the possible association between Toxocara infection/exposure and SCZ. Systematic searching (PubMed, Scopus, Web of Science and Google Scholar) was performed, up to 15 August 2020, to identify the relevant studies. We used a random effects meta-analysis model to generate the pooled OR and 95% CIs. The research process resulted in the identification of six studies related to the subject of interest entailing 411 SCZ patients and 2047 controls. Our results demonstrated that the SCZ patients (15%; 95% CI 6.8 to 29.9%) had higher pooled seroprevalence of Toxocara infection/exposure than the control group (3.3%; 95% CI 1.1 to 9.4%), showing a significant association (pooled OR, 4.06; 95% CI 1.14 to 14.43). Our findings suggested that Toxocara infection/exposure might have an important but neglected contribution to SCZ development. However, further well-designed and large-scale observational studies are needed to illuminate this association. Because many other environmental and genetic factors may be strong confounders, more mechanistic/experimental studies in animal models are also necessary to further define the mechanism of this association.

Seroepidemiology of human toxocariasis in North Africa

Seroprevalence studies on human toxocariasis help to assess the burden and the morbidity associated with this zoonosis. This review searched the seroprevalence studies and case reports in six North African countries: Algeria, Egypt, Libya, Morocco, Sudan and Tunisia, since 1990. The search also included studies on the environmental factors related to the risk of transmission. Most of the published epidemiological studies were done in Egypt. Cross-sectional and case-control studies in Egypt demonstrated that toxocariasis is a significant zoonosis that could be associated with conditions like bronchial asthma allergies and certain neuropsychiatric disorders. The population at risk of this infection includes all ages, both genders, in contact with dogs, resident in rural areas with poor housing conditions. The publications from Tunisia, Morocco and Algeria are limited to case reports and retrospective analyses of cases, but the disease is probably under-diagnosed in these three countries. There are no published reports on human toxocariasis in Libya and Sudan during the period covered by the review. Animal studies confirm high infection rates of dogs with Toxocara canis in North Africa. There is also evidence of wide-spread contamination of soil and water with Toxocara spp. eggs. Moreover, the use of untreated wastewater for irrigation in parts of North Africa could be a source of contamination of agricultural products with eggs of Toxocara spp. Population-based studies on human toxocariasis are recommended, using standardized diagnostic tests. These surveys should also assess risk factors to guide preventive measures.

Seroprevalence estimates for toxocariasis in people worldwide: A systematic review and meta-analysis

Background

Human toxocariasis is an important neglected disease. We performed a systematic review and meta-analysis study to estimate the global and regional prevalence of anti-Toxocara serum antibodies (referred to as ‘T-seroprevalence’) in human populations around the world.

Methods

We searched five international databases (PubMed, EMBASE, Web of Science, SciELO and Scopus) for seroprevalence studies published from 1 January 1980 to 15 March 2019. We used random effect models to calculate the overall T-seroprevalence (with 95% CIs) in all six WHO regions and worldwide. We also conducted subgroup and linear meta-regression analyses to evaluate the impact of socio-demographic, geographical and climatic parameters on seroprevalence.

Results

We identified 250 eligible studies (253 datasets) comprising 265,327 participants in 71 countries for inclusion in the present meta-analysis. The estimated global T-seroprevalence rate was 19.0% (95%CI, 16.6–21.4%; 62,927/265,327); seroprevalence was highest in the African region (37.7%; 25.7–50.6%) and lowest in the Eastern Mediterranean region (8.2%; 5.1–12.0%). The pooled seroprevalence for other WHO regions was 34.1% (20.2–49.4%) in the South-East Asia; 24.2% (16.0–33.5%) in the Western Pacific; 22.8% (19.7–26.0%) in the American; and 10.5% (8.5–12.8%) in the European regions. A significantly higher T-seroprevalence was associated with a lower income level; lower human development index (HDI); lower latitude; higher humidity; higher temperature; and higher precipitation (P-value < 0.001). Potential risk factors associated with seropositivity to Toxocara included male gender; living in a rural area; young age; close contact with dogs, cats or soil; consumption of raw meat; and the drinking of untreated water.

Conclusions

The present findings indicate high levels of infection with, or exposure to Toxocara spp. in many countries, which calls for increased attention to human toxocariasis and improved measures to prevent adverse health risks of this disease.

There have been many epidemiological studies on the seroprevalence of Toxocara infection or toxocariasis in humans in individual countries, but there has been no systematic review/meta-analysis to estimate the extent of Toxocara infection or exposure in human populations worldwide. By reviewing 250 studies of 265,327 people from 71 countries, we provide the first comprehensive global estimates of T-seroprevalence in humans to date. The findings indicate that almost one fifth (19%) of the world’s human population is seropositive to Toxocara. The highest seroprevalence rates were found in Africa (37.7%) and the lowest in the Eastern Mediterranean region (8.2%). Individual countries with high HDIs and high income levels usually had low T-seroprevalence rates. Our findings also showed that T-seroprevalence varies markedly among countries, according to geographical location (coordinates) and climatic features. Evidence from this study indicates that human toxocariasis is a prevalent, neglected tropical disease and potentially one of major importance to global public health. Our study emphasizes the need for governmental authorities to pay increased attention to the risks and socioeconomic impact of HT in many countries around the world, and for them to design and implement HT prevention or control programs, considering risk predictors identified here.

Associations of mental disorders and neurotropic parasitic diseases: a meta-analysis in developing and emerging countries

BACKGROUND

Although they are declining worldwide, neurotropic parasitic diseases are still common in developing and emerging countries. The aim of this study was to estimate the pooled prevalence and pooled association measures of comorbidities between mental disorders (anxiety, depression, bipolar disorder, and schizophrenia) and neurotropic parasitic diseases (malaria, cysticercosis, toxoplasmosis, human African trypanosomiasis, Chagas disease, and human toxocariasis) in developing and emerging countries.

METHODS

As the first meta-analysis on this topic, this study was performed in accordance with PRISMA guidelines. The protocol was registered in PROSPERO (N°CRD42017056521). The Medline, Embase, Lilacs, and Institute of Epidemiology and Tropical Neurology databases were used to search for articles without any restriction in language or date. We evaluated the quality of studies independently by two investigators using the Downs and Black assessment grid and pooled estimates using the random-effects method from CMA (Comprehensive Meta Analysis) Version 3.0.

RESULTS

In total, 18 studies published between 1997 and 2016 met our inclusion criteria. We found that the prevalence of anxiety and depression in people suffering from Chagas disease and/or neurocysticercosis was 44.9% (95% CI, 34.4-55.9). In 16 pooled studies that included 1782 people with mental disorders and 1776 controls, toxoplasmosis and/or toxocariasis were associated with increased risk of schizophrenia and/or bipolar disorders (odds ratio = 2.3; 95% CI, 1.7-3.2). Finally, toxocariasis and/or toxoplasmosis were associated with an increased risk of the onset of schizophrenia (odds ratio = 2.4; 95% CI, 1.7-3.4).

CONCLUSION

Our pooled estimates show that the associations between diseases studied are relatively high in developing and emerging countries. This meta-analysis supports the hypothesis that toxoplasmosis could be the cause of schizophrenia. These findings could prove useful to researchers who want to further explore and understand the associations studied.

Cerebral Toxocariasis: Silent Progression to Neurodegenerative Disorders?

Toxocara canis and T. cati are highly prevalent nematode infections of the intestines of dogs and cats. In paratenic hosts, larvae do not mature in the intestine but instead migrate through the somatic tissues and organs of the body. The presence of these migrating larvae can contribute to pathology. Toxocara larvae can invade the brains of humans, and while case descriptions of cerebral toxocariasis are historically rare, improved diagnosis and greater awareness have contributed to increased detection. Despite this, cerebral or neurological toxocariasis (NT) remains a poorly understood phenomenon. Furthermore, our understanding of cognitive deficits due to toxocariasis in human populations remains particularly deficient. Recent data describe an enhanced expression of biomarkers associated with brain injury, such as GFAP, AβPP, transforming growth factor β1 (TGF-β1), NF-L, S100B, tTG, and p-tau, in mice receiving even low doses of Toxocara ova. Finally, this review outlines a hypothesis to explore the relationship between the presence of T. canis larvae in the brain and the progression of Alzheimer's disease (AD) due to enhanced AD-associated neurodegenerative biomarker expression.

Seroprevalence and risk factors of Toxocara infection among children in Shandong and Jilin provinces, China

This cross-sectional study was aimed to investigate the Toxocara serology in children in Shandong and Jilin provinces, China using an enzyme-linked immunosorbent assay (ELISA). The overall Toxocara seroprevalence among the study population (n=1458) was 19.3%, sick children (26.4%) had significantly higher seroprevalence than clinically healthy children (14.4%) (P<0.05), and the highest Toxocara seroprevalence was found in children suffering from chronic cough (40.6%), followed by recurrent abdominal pain (40.0%), recurrent headache (38.1%), slight fever (36.2%), and recurrent vomiting (31.6%). Place of residence, education level, type of school, keeping dogs at home, contact with dogs and cats and exposure with soil were found to be associated with Toxocara infection. Our findings show that children infection with Toxocara is common in Shandong and Jilin provinces, eastern and northeastern China, indicating an immediate need for implementing strategies and measures to prevent and control Toxocara infection in children in China.

Lack of Association between Toxocara Exposure and Suicide Attempts in Psychiatric Patients

Infection with Toxocara may affect the central nervous system. A high seroprevalence of Toxocara infection has been reported in psychiatric patients. To the best of our knowledge, there is no previous report about an association of Toxocara infection with suicide attempts. Therefore, we sought to determine whether Toxocara exposure is associated with suicide attempts in psychiatric patients. We studied 282 psychiatric outpatients (156 with suicide attempts and 126 without suicide attempts). Sera of patients were analyzed for the presence of anti-Toxocara IgG antibodies by using a commercially available enzyme immunoassay. One of the 156 (0.6%) suicide attempters and 1 (0.8%) of the 126 controls were positive for anti-Toxocara IgG antibodies (OR = 0.80; 95% CI: 0.04–13.02; P = 1.00). Toxocara seropositivity was significantly higher (P = 0.01) in male patients with consumption of raw dried goat meat than male patients without this consumption. Results suggest that Toxocara exposure is not associated with suicide attempts in psychiatric outpatients in Durango City, Mexico. However, further studies with larger samples sizes to confirm our results should be conducted. Too few patients were seropositive to assess further associations of Toxocara exposure with sociodemographic, clinical, and behavioral characteristics of the psychiatric patients.

Detection of IgG against Toxocara in Sera of Employees of Meat Industry

Contact with raw meat could represent a risk for Toxocara infection. We assessed the association of Toxocara infection with an occupation of meat worker though a case-control seroprevalence study of 124 meat workers and 248 subjects without this occupation. Sera of participants was analyzed for the presence of anti-Toxocara IgG antibodies. One (0.8%) of the 124 meat workers, and 5 (2.0%) of the 248 controls were positive for anti-Toxocara IgG antibodies (OR=0.39; 95% CI: 0.04-3.41; P=0.66). The seropositive meat worker was a male aged 28 years old, without vision impairment. None of the work characteristics i.e. frequency of contact with raw meat, use of safety practices, history of splashes at face with blood or raw meat, and injuries with sharp material at work was associated with Toxocara exposure. Seroprevalence of Toxocara infection was significantly higher (P=0.04) in meat workers with consumption of boar meat (1/6: 16.7%) than in those without this consumption (0/117: 0%). We conclude that meat workers do not have a higher risk for Toxocara infection than subjects without this occupation do. The 2% seroprevalence of Toxocara infection found in control subjects might suggest a low seroprevalence of this infection among people with other occupations in Durango City. However, additional case-control studies with larger sample sizes to confirm our results are needed.

Microarray gene expression analysis reveals major differences between Toxocara canis and Toxocara cati neurotoxocarosis and involvement of T. canis in lipid biosynthetic processes

Toxocara canis and Toxocara cati are globally occurring intestinal nematodes of dogs and cats with a high zoonotic potential. Migrating larvae in the CNS of paratenic hosts, including humans, may cause neurotoxocarosis resulting in a variety of neurological symptoms. Toxocara canis exhibits a stronger affinity to the CNS than T. cati, causing more severe neurological symptoms in the mouse model. Pathomechanisms of neurotoxocarosis as well as host responses towards the respective parasite are mostly unknown. Therefore, the aim of this study was to characterise the pathogenesis at a transcriptional level using whole genome microarray expression analysis and identify differences and similarities between T. canis- and T. cati-infected brains. Microarray analysis was conducted in cerebra and cerebella of infected C57Bl/6J mice 42daysp.i. revealing more differentially transcribed genes for T. canis- than T. cati-infected brains. In cerebra and cerebella of T. canis-infected mice, a total of 2304 and 1954 differentially transcribed genes, respectively, were identified whereas 113 and 760 differentially transcribed genes were determined in cerebra and cerebella of T. cati-infected mice. Functional annotation analysis revealed major differences in host responses in terms of significantly enriched biological modules. Up-regulated genes were mainly associated with the terms "immune and defence response", "sensory perception" as well as "behaviour/taxis" retrieved from the Gene Ontology database. These observations indicate a strong immune response in both infection groups with T. cati-infected brains revealing less severe reactions. Down-regulated genes in T. canis-infected cerebra and cerebella revealed a significant enrichment for the Gene Ontology term "lipid/cholesterol biosynthetic process". Cholesterol is a highly abundant and important component in the brain, representing several functions. Disturbances of synthesis as well as concentration changes may lead to dysfunction in signal transduction and neurodegenerative disease. Overall, only a minor overlap of differentially transcribed genes was observed between the two infection groups in both brain parts. Most genes are regulated individually in each infection group, supporting the evident differences of both roundworm species observed in the paratenic host in previous studies. In summary the present study underlines the differences in pathogenicity of T. canis and T. cati. It furthermore provides a comprehensive basis for future analyses over the course of infection as well as functional tests to identify gene regulatory circuits that are crucial for pathogenesis of neurotoxocarosis. The results of this study provide a promising foundation for further specific research to evaluate the particular pathogenetic mechanisms and to identify possible therapeutic targets.

Seroepidemiology of Toxocara infection in patients with vision impairment and blindness in durango, Mexico

Background

Toxocara infection is a cause of vision impairment and blindness. We aimed to determine the seroprevalence and correlates of Toxocara infection in patients suffering from vision impairment and blindness in Durango City, Mexico.

Methods

Through a cross-sectional seroprevalence study, 204 patients with vision impairment and 19 blind patients were studied for the presence of anti-Toxocara IgG antibodies in Durango City, Mexico. Seroprevalence association with socio-demographic, housing, clinical, and behavioral characteristics of participants was also investigated.

Results

Five (2.5%) of the 204 patients with vision impairment, and none of the 19 patients with blindness were positive for anti-Toxocara IgG antibodies. In total, five of the 223 (2.2%) patients were positive for anti-Toxocara IgG antibodies. Seropositivity to Toxocara was not associated with age, sex, educational level, socio-economic status, presence of underlying diseases or behavioral characteristics of the patients. In contrast, multivariate analysis showed that Toxocara seropositivity was associated with living in a house with soil floor (odds ratio (OR) = 11.14; 95% confidence interval (CI): 1.57 - 78.74; P = 0.01).

Conclusions

This is the first report of Toxocara exposure in patients with vision impairment and blindness in Mexico, and of an association of Toxocara exposure with living in a house with soil floors. Results suggest a low Toxocara exposure in these patients in Durango, Mexico. The risk factor associated with Toxocara exposure identified in this study warrants for further investigation.

Low seroprevalence of Toxocara infection in schizophrenic inpatients in durango, Mexico: a case control study

Psychiatric patients have a higher seroprevalence of toxocariasis than general population. However, there is poor knowledge about any specific psychiatric diagnosis associated with toxocariasis. The aim of the study was to determine whether seropositivity to Toxocara was associated with schizophrenia. Through an age and gender-matched case-control seroprevalence study in Durango City, Mexico, 50 schizophrenic inpatients in a public psychiatric hospital and 100 control subjects of the general population were compared for the presence of anti-Toxocara IgG antibodies. One of the 50 (2%) schizophrenic inpatients, and 3 (3%) of the 100 controls were positive for anti-Toxocara IgG antibodies. No statistically significant difference in Toxocara seroprevalence among cases and controls was found (P=0.59). The Toxocara positive schizophrenic patient suffered from paranoid schizophrenia (F20.0) and had a number of putative risk factors for Toxocara exposure including contact with cats, dogs and other animals, worked in agriculture, and consumed undercooked meat, unwashed fruits and vegetables, and untreated water. Results suggest that seroprevalence of Toxocara infection was low and not associated with schizophrenia in psychiatric inpatients in Durango, Mexico. However, further studies to elucidate the association of toxocariasis with schizophrenia are needed.

Toxocariasis in North America: a systematic review

Toxocariasis is an important neglected tropical disease that can manifest as visceral or ocular larva migrans, or covert toxocariasis. All three forms pose a public health problem and cause significant morbidity in areas of high prevalence. To determine the burden of toxocariasis in North America, we conducted a systematic review of the literature following PRISMA guidelines. We found 18 articles with original prevalence, incidence, or case data for toxocariasis. Prevalence estimates ranged from 0.6% in a Canadian Inuit community to 30.8% in Mexican children with asthma. Commonly cited risk factors included: African-American race, poverty, male sex, and pet ownership or environmental contamination by animal feces. Increased prevalence of Toxocara spp. infection was linked in a group of case control studies conducted in Mexico to several high risk groups including waste pickers, asthmatic children, and inpatient psychiatry patients. Further research is needed to determine the true current burden of toxocariasis in North America; however the prevalence estimates gathered in this review suggest that the burden of disease is significant.

Toxocara seroprevalence among clinically healthy individuals, pregnant women and psychiatric patients and associated risk factors in Shandong Province, Eastern China

BACKGROUND

Toxocarosis is a widespread zoonosis caused by the ascarid nematodes Toxocara canis and Toxocara cati, which primarily infect dogs and cats, respectively. Most human infections with Toxocara are asymptomatic; however, some infected individuals may develop a serious illness and even death. Nevertheless, epidemiological knowledge regarding the prevalence and risks associated with Toxocara infection is limited in China. Therefore, we performed a cross-sectional pilot study and estimated the seroprevalence of Toxocara infection in humans in Shandong Province, eastern China for the first time, from June 2011 to July 2013, involving clinically healthy individuals, pregnant women and psychiatric patients, aiming to attract public attention to Toxocara infection.

METHODOLOGY/PRINCIPLE FINDINGS

Seroprevalence of Toxocara was determined using an enzyme-linked immunosorbent assay based on a cross-sectional study conducted in Qingdao and Weihai, Shandong Province, eastern China. Factors potentially associated with Toxocara infection were identified by logistic regression analysis. The overall Toxocara seroprevalence among the study population (n = 2866) was 12.25%, and a significantly higher seroprevalence in psychiatric patients (16.40%, 73/445) than that in clinically healthy individuals (13.07%, 187/1431) and pregnant women (9.19%, 91/990) was revealed. Univariate analyses suggested that keeping dogs at home (OR = 0.06, 95% CI 0.05-0.08, P<0.001), contact with cats and dogs (OR = 0.42, 95% CI 0.33-0.53, P<0.001) and exposure with soil (OR = 0.37, 95% CI 0.28-0.49, P<0.001) were risk factors associated with Toxocara infection.

CONCLUSIONS/SIGNIFICANCE

The present study revealed, for the first time, that human infection with Toxocara is common in eastern China, posing a significant public health concern. Increasing human and dog populations, population movements and climate change all will serve to increase the importance of this zoonosis. Further studies under controlled conditions are necessary to define potential morbidity associated with Toxocara infection.

Investigation of anti-Toxocara and anti-toxoplasma antibodies in patients with schizophrenia disorder

Objective. The aim of the present study was to examine the relationship between Toxoplasma gondii and Toxocara spp. infections in patients with schizophrenia disorder. Method. A total of 100 patients with schizophrenia disorder and 95 healthy individuals participated in the study. Participants were tested for the presence of anti-T. gondii and anti-Toxocara spp. antibodies by ELISA and Western blotting. Data were analyzed using Chi-square test and Fisher 9 s exact test. Results. There were no differences in T. gondii IgG seroprevalence between patients with schizophrenia and healthy individuals (P = 0.1), but there were differences in seroprevalence between males and females with schizophrenia (P = 0.009). In contrast, Toxocara spp. IgG seroprevalence was greater in patients with schizophrenia disorder than in healthy individuals (P = 0.02), but there were no differences in seroprevalence between men and women with schizophrenia (P = 0.5). Finally, there were no differences in seroprevalence of T. gondii or Toxocara spp. IgG among different subtypes of schizophrenia, various age groups, residential area, or clinical course of treatment (P > 0.05). Conclusion. The present study suggests that patients with schizophrenia disorder are at elevated risk of Toxocara spp. infection. Moreover, contamination with T. gondii is a risk factor for schizophrenia in women.