Toxoplasma gondii seroprevalence in the Portuguese population: comparison of three cross-sectional studies spanning three decades

Anti-Toxoplasma gondii Antibodies in European Residents: A Systematic Review and Meta-Analysis of Studies Published between 2000 and 2020

Toxoplasmosis has a major impact on animal and public health. Information regarding the seroprevalence of human Toxoplasma gondii infections from a European perspective has not yet been compiled to date. Thus, the present review summarized available resident data from the period 2000-2020. The overall seroprevalence of anti-T. gondii IgG was 32.1%, with great variability between countries (n = 30). The subgroup analysis identified different pooled prevalence data depending on the geographic area (p < 0.0001), target population (p = 0.0147), and serological diagnosis assays used (p = 0.0059). A high heterogeneity (I2 = 100%, p < 0.001; Q = 3.5e+05, d.f. = 135, p < 0.001) and degree of publication bias (Egger's test = 6.14, p < 0.001) were observed among the 134 studies considered. The occurrence of anti-T. gondii IgM, which was reported in 64.7% of studies, reached a pooled seroprevalence of 0.6%. In addition, among the eight main risk factors identified, "contact with soil", "consumption of undercooked beef", and "intake of unwashed vegetables" were the most significantly associated with infections. The fact that one-third of the European population has been exposed to T. gondii justifies extra efforts to harmonize surveillance systems and develop additional risk-factor analyses based on detailed source attribution assessment.

Past and present seroprevalence and disease burden estimates of Toxoplasma gondii infections in Germany: An appreciation of the role of serodiagnostics

Toxoplasmosis is one of the major foodborne parasitic diseases in Germany, with 49% of its population chronically infected with its causative agent, Toxoplasma gondii. Although the acute disease is usually benign in immunocompetent individuals, it is a threat for immunocompromised patients as well as for fetuses of seronegative mothers. As a result of infection, congenital and ocular toxoplasmosis can have serious lifelong consequences. Here I will highlight the epidemiologic situation, from its past in the two separate parts of Germany, to its unification 30 years ago and up to the present day. The main identified risk factor for infection in Germany is thought to be the consumption of undercooked or raw meat or sausages. However, the relative impact of this risky eating habit as well as that of other risk factors are changing and are discussed and compared to the situation in the Netherlands. Finally, the importance of robust and efficient high-throughput serological assays for obtaining reliable epidemiological data, on which public health decisions can be made, is highlighted. The potential of bead-based multiplex assays, which allow the incorporation of multiple antigens with different analytical properties and thus yield additional information, are described in this context. It illustrates the interdependence of new analytic assay developments and sound epidemiology, a foundation that decades-old data from Germany did not have.

Seroprevalence of Toxoplasma gondii and associated risk factors for infection in the Netherlands: third cross-sectional national study

A third nationally representative serosurvey was performed to study the changes in Toxoplasma gondii (T. gondii) seroprevalence in the Netherlands over a 20-year time span and to identify and confirm risk factors for acquired toxoplasmosis. This cross-sectional study (conducted in 2016/2017) was designed similarly to the previous two studies (1995/1996 and 2006/2007) and included a questionnaire and serum sampling among Dutch residents. Factors associated with seropositivity for T. gondii were determined using multivariable analysis of the questionnaire-derived data. The earlier observed decrease in T. gondii seroprevalence between 1995/1996 and 2006/2007 (from 40.5% to 26.0%) did not continue into 2016/2017 (29.9%). Similarly to the previous studies, the seroprevalence increased with age and varied among regions. In all studies, higher T. gondii seropositivity was associated with increasing age, lower educational level, not living in the Southeast, and eating raw or semi-cooked pork. The incidence of congenital toxoplasmosis was estimated at 1.3/1000 (95% CI 0.9-1.8) live-born children in 2017. As the seroprevalence of T. gondii in the Netherlands did not decrease over the last decade, an increase in public health awareness is needed and prevention measures may need to be taken to achieve a further reduction in T. gondii infections in the Netherlands.

Screening for the Detection of Toxoplasma gondii IgG, IgM and IgA in Females of Reproductive Age from Western Romania

Toxoplasma gondii, a zoonotic protozoan parasite, has the capacity to infect the fetus if the pregnant woman primarily acquires the infection during pregnancy. We evaluated the prevalence of T. gondii IgG, IgM and IgA antibodies in women of reproductive age residing in Western Romania. We also assessed the value of adding a T. gondii IgA test to the serologic panel for the diagnosis of toxoplasmosis, including the detection of a recently acquired infection. Serologic testing to demonstrate the presence of T. gondii IgG antibodies was conducted in 1317 females aged 15−45 years. T. gondii IgM and IgA antibody tests were performed in those with detectable IgG antibodies and IgG avidity test was performed if IgM and/or IgA screening test results were positive. T. gondii IgG were detected in 607 (46.09%; 95%CI: 43.41−48.79) of 1317 study participants and IgG seroprevalence tended to increase with age from 35.44% (95%CI: 29.89−41.30) in age group 15−24 years to 62.85% (95%CI: 56.57−68.82) in age group 35−45 years, showing a significant age-associated increase (p < 0.001). Of the 607 persons with detectable T. gondii IgG antibodies, T. gondii IgM antibodies were demonstrated in 8.90% (95%CI: 6.88−11.43), T. gondii IgA in 1.65% (95%CI: 0.90−3.01) and both T. gondii IgM and IgA in 0.99% (95%CI: 0.45−2.14). The prevalence of IgA antibodies tended to decrease with increasing avidity, from 75% (95%CI: 19.41−99.37) in samples with low avidity to 11.76% (95%CI: 4.44−23.87) in those with high avidity (p = 0.01). Of the study participants who were positive for both T. gondii IgM and IgA antibodies, 66.67% had low or equivocal IgG avidity test results compared to 6.25% who tested positive for IgM, were negative for IgA and in whom low or equivocal IgG avidity test results were noted (p = 0.001). This study indicates that in Western Romania, T. gondii IgG seroprevalence is high in females of reproductive age and T. gondii IgA antibodies may be rarely detected during a serologic screening. However, in individuals with demonstrable T. gondii IgG and IgM antibodies, testing for T. gondii IgA may improve the rate for the detection of a recently acquired toxoplasmosis.

Seroprevalence and Risk Factors for Toxoplasma gondii and Neospora caninum in Cattle in Portugal

Simple Summary

Neospora caninum and Toxoplasma gondii are apicomplexan parasites with a worldwide distribution and both infect cattle. While the importance of N. caninum is mainly linked to reproductive losses, concern has been raised about the role of beef as a source of food-borne toxoplasmosis in humans. Little is known about the prevalence of these parasites in cattle in Portugal. This study aimed to evaluate the seroprevalence and risk factors for N. caninum and T. gondii in naturally exposed cattle from different geographical areas in the country. Results point to a low but widespread seroprevalence of T. gondii, while that of N. caninum was found to be in the same range as reported in other Mediterranean countries. Distribution of both parasites may be explained by common climate factors and management practices identified as significant predictors of infection in the study.

Abstract

Neospora caninum has a worldwide economic impact as an important cause of abortion in cattle, while Toxoplasma gondii, another abortifacient pathogen, is globally a major foodborne zoonotic threat. The study aimed to evaluate the seroprevalence and risk factors for the two parasites in cattle in Portugal. A total of 612 sera from 35 farms were tested by an in-house p30 ELISA for T. gondii and p38 ELISA for N. caninum. T. gondii positive and suspicious sera were confirmed by p30 Western blot or IFAT. T. gondii and N. caninum animal seroprevalence was 9.2% (95%CI 7.1–11.7) and 17.2% (95% CI 14.4–20.4) and herd seroprevalence was 51.4% (95% CI 35.6–67.0) and 68.6% (95% CI 52.0–81.5), respectively. At the univariable level, climate area and precipitation of wettest month, driest month, driest quarter, and warmest quarter were significant predictors of seropositivity for both. N. caninum seropositivity was more likely in the region Norte, densely populated areas, and intensive production, and the probability of T. gondii seropositivity decreased with herd size. Results confirm the need to consider neosporosis in the differential diagnosis of cattle reproductive disorders in Portugal and may be valuable to inform source attribution models for human toxoplasmosis.

A Cross-Sectional Study of Knowledge on Ownership, Zoonoses and Practices among Pet Owners in Northern Portugal

Simple Summary

Pet ownership is common in most countries, but few published studies have addressed pet owners’ knowledge of zoonoses, pet contact practices, or awareness of zoonotic disease risks posed by pets. The aim of this study was to assess household knowledge, attitudes, and risks related to pet ownership and zoonoses in northern Portugal. A questionnaire was developed to gather information regarding participants’ demographic characteristics; household pet types and their importance to the family; pet contact-related attitudes; knowledge of zoonoses, high-risk groups, disease transmission pathways, and disease protection measures. It was observed that most participants considered pets an important part of the family. Nevertheless, high-risk practices were recurrent and pet owners’ knowledge was limited. These results reinforce the importance of further studies to better understand the existing gaps in knowledge of pet ownership and zoonoses and strengthens the need to adopt the One Health concept.

Abstract

Pet ownership is common in modern society. In Portugal, 38% and 31% of all households own at least one dog or cat, respectively. Few studies have ascertained the knowledge of pet owners on pet ownership and zoonoses, and none have been carried out in Portugal. The aim of the present study was to assess household knowledge and practices related to pet ownership and zoonoses in northern Portugal. A face-to-face questionnaire was completed by 424 pet owners, from November 2019 to February 2020. Most respondents (97.2%) considered pets as an important part of the family, especially women (p = 0.036); 73.1% allowed their pets to live an indoor/outdoor life; 41.3% denied sharing the bed with their pets while 29% assumed they did it daily; 20.3% reported never kissing their pets/pets licking their faces. Furthermore, 73.6% considered animals as potential sources of human diseases, but only 25.9% reported knowing the definition of zoonoses; 96.9% considered the role of veterinarians important in protecting public health. The low level of knowledge of pet owners and the occurrence of high-risk behaviors indicates a need to strengthen communication between veterinarians, physicians, pet owners, and the general public towards reduce the risk of acquisition and transmission of zoonoses.

Prevalence of Antibodies to Toxoplasma gondii in Different Wild Bird Species Admitted to Rehabilitation Centres in Portugal

Toxoplasma gondii is a worldwide zoonotic parasite. According to the “One Health” approach, studies on toxoplasmosis are essential since it affects humans and domestic and wild animals. In the present study, antibodies to T. gondii were determined in serum samples from 263 wild birds located in five wildlife rehabilitation centres in mainland Portugal by using the modified agglutination test (MAT) with a cut-off titre of 20. An overall seroprevalence of 36.5% (95% confidence interval [CI]: 30.7–42.6) was observed. For the first time, antibodies to T. gondii were detected in some avian species, including pallid swift (Apus pallidus) (33.3%), black-backed gull (Larus fuscus) (39.3%), European turtle-dove (Streptopelia turtur) (100%), bee-eater (Merops apiaster) (50.0%), carrion crow (Corvus corone) (33.3%), and Egyptian vulture (Neophron percnopterus) (100%), which expands the list of intermediate hosts of T. gondii. A lower seroprevalence was found in juvenile birds (31.9%) compared to adults (48.7%) (p = 0.016). The central region of Portugal was considered a risk factor for T. gondii infection in wild birds (odds ratio: 3.61; 95% CI: 1.09–11.91). This pioneer study calls attention to the need for further studies, to provide a clearer understanding of T. gondii epidemiology in Portugal, because it reflects wide dispersion of T. gondii oocysts in the environment.

National perinatal survey demonstrates a decreasing seroprevalence of Toxoplasma gondii infection among pregnant women in France, 1995 to 2016: impact for screening policy

Background

Toxoplasmosis during pregnancy can result in congenital anomalies or fetal death. Universal antenatal screening is recommended in France, a strategy in place since the 1970s.

Aim

We determined the seroprevalence of toxoplasmosis among pregnant women participating in the 2016 national perinatal survey (ENP), compared results with previous ENPs, and investigated factors associated with Toxoplasma gondii infection.

Methods

Using the 2016 ENP data, which contain sociodemographic and clinical information from all women giving birth during a one week period, we calculated adjusted prevalence ratios (aPR) by sociodemographic factors. Using available data from prior ENPs (1995, 2003 and 2010), we calculated age-standardised seroprevalences and aPRs for French women.

Results

In 2016, seroprevalence was 31.3% overall. Among French women, associations with increasing age (aPR: 1.54; 95% CI: 1.39–1.70), residence in Paris (aPR: 1.19; 95% CI: 1.08–1.31) or south-western regions (aPR: 1.19; 95% CI: 1.08–1.31), and higher professional status (aPR: 1.12; 95%CI 1.04–1.21) were observed. An association with increasing age was also evident among women from North Africa and sub-Saharan Africa. Age-standardised seroprevalence decreased from 55.0% in 1995 to 33.7% in 2016. Among French women, significant associations with age, Paris and south-west regions persisted across all ENPs.

Conclusion

Higher prevalences in older women may reflect a higher past risk of exposure while persistent geographical differences may reflect dietary or environmental differences. Toxoplasma seroprevalence among pregnant women continues to fall and will impact screening effectiveness. This warrants a comprehensive review to determine the appropriate future of prevention in France.

Seroprevalence of Toxoplasma gondii infection among women of childbearing age in an endemic region of Romania, 2016-2018

Toxoplasmosis is an important worldwide zoonosis caused by the protozoan parasite Toxoplasma gondii. This parasitic infection is often asymptomatic in immunocompetent people. However, if the infection occurs in pregnant women, it can have serious consequences for the foetus. In this study, we evaluated the seroprevalence of T. gondii in women of childbearing age in Arad County, Western Romania. Serum samples from 2626 women were analysed using a Siemens ADVIA Centaur XP Immunoassay System. Toxoplasma gondii IgG antibodies were demonstrated in 1081 women (41%) and prevalence tended to increase with age, from 32% in women aged 15–19 years to 62% in women aged 40–45 years. There was a higher prevalence in rural areas (46%) than in urban areas (36%). This study provides new data on T. gondii seroprevalence in women of childbearing age from Western Romania.

Toxoplasmosis and the Heart

Toxoplasmosis is a common disease caused by Toxoplasma gondii, a parasite with high prevalence in tropical regions. Most infections show minimal symptoms, but immunocompromised patients tend to have a poor prognosis. Cardiovascular manifestations in toxoplasmosis are rare and reported in a limited number of patients. As part of the "Neglected Tropical Diseases and Other Infectious Diseases Affecting the Heart" (NET-Heart) project, this paper aims to systematically review all available information regarding the cardiovascular implications of toxoplasmosis. Relevant studies were identified in the MEDLINE and/or PubMed database, and 48 articles were ultimately included. This was completed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Cardiac compromise in toxoplasmosis mainly involves myocarditis, and complications vary widely in severity. Toxoplasmic myocarditis is challenging to diagnose, as endomyocardial biopsy is usually required. This article provides a summary of cardiac toxoplasmosis, including an original algorithm facilitating diagnosis and treatment.

Catastrophic consequences: can the feline parasite Toxoplasma gondii prompt the purrfect neuroinflammatory storm following traumatic brain injury?

Traumatic brain injury (TBI) is one of the leading causes of morbidity and mortality worldwide; however, treatment development is hindered by the heterogenous nature of TBI presentation and pathophysiology. In particular, the degree of neuroinflammation after TBI varies between individuals and may be modified by other factors such as infection. Toxoplasma gondii, a parasite that infects approximately one-third of the world’s population, has a tropism for brain tissue and can persist as a life-long infection. Importantly, there is notable overlap in the pathophysiology between TBI and T. gondii infection, including neuroinflammation. This paper will review current understandings of the clinical problems, pathophysiological mechanisms, and functional outcomes of TBI and T. gondii, before considering the potential synergy between the two conditions. In particular, the discussion will focus on neuroinflammatory processes such as microglial activation, inflammatory cytokines, and peripheral immune cell recruitment that occur during T. gondii infection and after TBI. We will present the notion that these overlapping pathologies in TBI individuals with a chronic T. gondii infection have the strong potential to exacerbate neuroinflammation and related brain damage, leading to amplified functional deficits. The impact of chronic T. gondii infection on TBI should therefore be investigated in both preclinical and clinical studies as the possible interplay could influence treatment strategies.

Seroepidemiology of Toxoplasma gondii in blood donors in Portugal

Infection with the protozoan parasite Toxoplasma gondii is prevalent in animals and humans worldwide. The present study aimed to evaluate the prevalence of antibodies to T. gondii and associated risk factors among blood donors in Portugal. Serum samples were tested for the presence of anti-T. gondii immunoglobulin (Ig) G by a modified agglutination test (MAT). A written standardized questionnaire was used to collect sociodemographic and behavioural data from the blood donors. Out of 520 participants (median age: 39.5 years; interquartile range: 29.0-47.0), who attended blood collection sessions promoted by the Portuguese Institute for Blood and Transplantation (IPST), 198 (38.1%) were positive for anti-T. gondii IgG (95% confidence interval [CI]: 33.9-42.4%). Multiple logistic regression analysis revealed that ages of 46-55 years (odds ratio [OR] = 6.72; 95% CI = 3.40-13.28), and of 56-65 years (OR = 4.34; 95% CI = 1.73-10.86), having a lower education level (OR = 2.55; 95% CI = 1.45-4.49), living in the North (OR = 2.14; 95% CI = 1.25-3.65) and in the Centre regions (OR = 2.54; 95% CI = 1.36-4.76) of Portugal, and drinking water from untreated sources (OR = 2.46; 95% CI = 1.12-5.39) were risk factors for seropositivity to T. gondii. This study provides the first data on the seroprevalence of T. gondii in blood donors in Portugal, as well insights to sociodemographic and behavioural risk factors as the basis for future prevention programs.

Seroprevalence of Toxoplasmosis at a Tertiary Care Centre in North India from 2004 to 2014

Purpose

This study was carried out to determine the seroprevalence of anti-Toxoplasma gondii antibodies in different groups of patients at a tertiary care hospital in North India.

Materials and Methods

Clinical and demographic data such as age and gender of patients who had undergone testing for the presence of anti-T. gondii IgG and IgM antibodies between January 2004 and October 2014 were retrospectively analysed.

Results

Amongst the 8397 serum samples, an overall seropositivity of 21% (n = 1763) and IgG and IgM seropositivity of 5.7% (n = 481) and 15.3% (n = 1282) were respectively observed. Compared to the period of 2004-2012 (median seroprevalence: 23.6%), a decline in seropositivity to 9.7% in 2013 and 8.1% in 2014 was noted. A rising seroprevalence with age and a higher seroprevalence in females versus males (29.5%, n = 1179 vs. 13.3%, n = 584) were recorded. The highest seroprevalence was observed in suspected ocular toxoplasmosis (47.2%, n = 47), followed by neurological (26.8%, n = 77), human immunodeficiency virus/acquired immunodeficiency syndrome (18.9%, n = 267), post-transplant (17.1%, n = 12) and congenital (7.2%, n = 144) toxoplasmosis. In patients screened for Toxoplasma exposure, the seropositivity was 47.8% (n = 11) in transplant screening and 44.9% (n = 781) in antenatal screening.

Conclusion

Toxoplasma infection is highly prevalent in the population of North India across various clinical categories of patients. Future studies focusing on continuous monitoring of seroprevalence trends and elucidation of the risk factors associated with seropositivity in more defined groups of patients are needed.

Seroepidemiological map of Toxoplasma gondii infection and associated risk factors in preconception period in China: A nationwide cross-sectional study

AIM

The aims of this study were to investigate the regional differences in seroepidemiology of toxoplasmosis in preconception period among Chinese women of reproductive age and to evaluate associated risk factors.

METHODS

This national, population-based, cross-sectional serosurvey covered all 31 provinces and province-level municipalities in Mainland China. Married women intending to get pregnant within 6 months between 2010 and 2012 were recruited. Information on demographic characteristics (age, place of residence, occupation, dietary habits and exposure to cat) was obtained using interviews, and venous blood samples were collected to screen for Toxoplasma gondii infection.

RESULTS

Of 2 008 561 women recruited to the study, 45 405 (2.3%) were Toxoplasma gondii IgG positive, and 6884 (0.3%) were IgM positive. Geographical variation for seropositivity ranged from 0.2% in Heilongjiang to 11.2% in Tianjing for IgG and from 0% in Tibet to 0.9% in Anhui for IgM. Advanced maternal age, occupation of a farmer, vegetarian diet and exposure to cat was significantly associated with Toxoplasma gondii IgM seropositivity, and its association with occupation of farmer and exposure to cat was significant after adjusting for province of residence (P < 0.05).

CONCLUSION

There were significant regional variations in Toxoplasma gondii seropositivity and associated risk factors among Chinese women of reproductive age during preconception period. This calls for a targeted primary prevention strategy. Screening and treatment before conception and preconception health education may have potential for reducing congenital Toxoplasmosis in China.