Environmental risk factors for Toxoplasma gondii infections and the impact of latent infections on allostatic load in residents of Central North Carolina

Time outdoors and residential greenness are associated with reduced systemic inflammation and allostatic load

Contacts with nature are linked with reduced morbidity and mortality. Hypothesized pathways include relaxation, physical activity, and improved immune function. This cross-sectional study of 320 adults in central North Carolina assessed health benefits of residential greenness using allostatic load (AL) and systemic inflammation (INFL) indices, composite biomarker-based measures of physiological dysregulation and inflammation, respectively. Distance-to-residence weighted tree cover and vegetated land cover measures were estimated within 500 m of each residence; 37 biomarkers of immune, neuroendocrine, cardiovascular, and metabolic functions were dichotomized at distribution or health-based cut-offs. AL was calculated as a sum of potentially unhealthy values of all biomarkers; INFL was based on a subset of 18 immune biomarkers. Regression analysis used generalized additive models for Poisson-distributed outcome. An interquartile range (IQR) increase in tree cover was associated with 0.89 (95 % Confidence Limits 0.82; 0.97) and 0.90 (0.79; 1.03)-fold change in AL and INFL, respectively. Greater daily outdoor time was associated with reduced AL and INFL, while leisure screen time, problems with sleeping, and common chronic infections were linked with increased AL and INFL. Among 138 individuals spending more than 1 h outdoors daily, an IQR increase in tree cover was associated with 0.76 (0.67; 0.86) and 0.81 (0.65; 1.02)-fold changes in AL and INFL, respectively. Among individuals with residential tree cover above the 50th percentile, spending more than 3 h outdoors daily was associated with 0.54 (0.37; 0.78) and 0.28 (0.15; 0.54)-fold changes in AL and INFL, respectively, compared to spending less than 30 min outdoors; there were no significant effects in the low tree cover stratum. Consistent but weaker effects were observed for vegetated land cover. Interaction effects of tree and vegetative cover and time spent outdoors on AL and INFL were statistically significant. This biomarker-based approach can help to assess public health benefits of green spaces.

Detection, fate and transport of the biohazardous agent Toxoplasma gondii in soil water systems: Influence of soil physicochemical properties, water chemistry and surfactant

A series of laboratory experiments were conducted to study the fate and transport of Toxoplasma gondii oocysts in soils as a function of soil physicochemical properties and soil water chemistry properties. Soil columns were homogeneously packed with loamy sand soils (Lewiston and Greenson series) and sandy loam soils (Sparta and Gilford series), and subject to hydrologic conditions characterized by the absence and presence of an anionic surfactant-Aerosol 22 in the artificial rainfall. Quantitative polymerase chain reaction (qPCR) was utilized for the detection and enumeration of oocysts in soil leachates to evaluate their breakthrough and in soil matrices to examine their spatial distribution. Differences in the rate and extent of transport of oocysts were observed as a function of physical and chemical parameters tested. The breakthrough of oocysts was observed for all the soils irrespective of the presence of surfactant. However, in the absence of surfactant, the predominant fate of oocysts in soils subject to simulated rainfall was their retention in the soil profile. The presence of surfactant induced a change in the fate of oocysts in these soils exposed to rainfall simulation as the predominant fate of oocysts was found to be in the soil leachates.

"Whoever takes the dog gets the house": How older adults negotiate, budget, and deploy resources for multispecies family health and well-being

In this study, we interrogate the ways that older adult pet owners exercise their agency within the limits of their social statuses to allocate their resources for the management of the health needs of their multispecies families. Guided by fundamental cause theory, we consider how the participants' memberships in socially constructed categories can impact their experiences with household health management. We conducted focus groups with 30 community-dwelling older adults who owned pets. Using a thematic analytic approach, we found that the participants' bonds with their pets led them to negotiate priorities and make concessions for the benefit of the household.

Seroprevalencia y factores de riesgo asociados a toxoplasmosis gestacional en el Nororiente Colombiano

Highlights: La toxoplasmosis gestacional podría constituir una grave problemática en ascenso en la población atendida en zona fronteriza nororiental de Colombia. La incrementada reactividad IgM específica a T.gondii en mujeres gestantes representa una alarma para la generación de estrategias de impacto en la prevención de esta problemática, como población priorizada. La seronegatividad frente a T.gondii, aún predominante en población gestante evaluada en región nororiental de Colombia, constituye un factor de riesgo relevante de toxoplasmosis gestacional, reflejado en alta susceptibilidad. La considerable exposición a factores de riesgo de toxoplasmosis en el embarazo implica una clara oportunidad de mejora de la calidad del control prenatal, mediante atención integral. Introducción:La toxoplasmosis es una zoonosis prevalente en un tercio de la población mundial, que afecta negativamente la salud materno-fetal causando daños de grado variable al feto. Objetivo: Se propuso evaluar el estado serológico IgG e IgM anti-Toxoplasma gondii y factores de riesgo relacionados, en mujeres gestantes de primer trimestre en Cúcuta, Colombia, en el año 2018. Materiales y métodos: Estudio transversal y correlacional en 111 mujeres participando voluntariamente, a quienes se testeó para IgM e IgG específicas por inmunoensayo LIA. Resultados: Se halló 19,8% y 35,1% de seropositividad total para IgM e IgG, respectivamente, 11,7% lo fue únicamente para IgM y 53,2% corresponde a la frecuencia de seronegatividad global para T.gondii; Se identificaron factores de riesgo (IC=95%) como consumo de carne mal cocida (54,1% de los casos, OR=1,8, p=0,120), de agua del grifo (48,6%, OR=1,4, p=0,421), de leche cruda de cabra o de vaca (39,6%, OR=0,78, p=0,553), además de convivencia con gatos (23,4%), éste último asociado significativamente a seropositividad al parásito (OR=2,8, p=0,025). Discusión y Conclusiones: Nuestros hallazgos revelan un posible riesgo de primo-infección en más de la mitad de la población gestante dada su seronegatividad frente al parásito, pero también una frecuencia considerable de casos con sospecha de infección muy reciente, lo que además de asociarse a un factor de riesgo previamente reconocido, deja entrever otros aspectos de riesgo en torno a la alimentación que deben impactarse mediante estrategias de prevención durante el control prenatal, sugiriendo la necesidad de fortalecer la vigilancia en torno al evento. Como citar este artículo: Cárdenas Sierra Denny Miley, Domínguez Julio Camila, Blanco Oliveros María Ximena, Soto Javier Andrés, Tórres Morales Elizabeth. Seroprevalencia y factores de riesgo asociados a toxoplasmosis gestacional en el Nororiente Colombiano. Revista Cuidarte. 2023;14(1):e2287. http://dx.doi.org/10.15649/cuidarte.2287

Back to the Future: The Role of Infections in Psychopathology. Focus on OCD

OBJECTIVE

Recently, there has been a resurgence of interest in the relationship between infections and psychopathology, given the increasing data on the neurotropism and neurological/psychiatric morbidity of the SARS-COV2 virus, responsible for the current worldwide pandemic. Although the majority of observations were those obtained in mood and schizophrenic disorders, a few data are also available on the presence of bacterial or viral infections in patients suffering from obsessive-compulsive disorder (OCD). Therefore, given the limited information, the present paper aimed at reviewing the most updated evidence of infections in neuropsychiatric disorders and their possible mechanisms of actions, with a narrow focus on microbes in OCD.

METHOD

This paper is a narrative review. The databases of PubMed, Scopus, Embase, PsycINFO and Google Scholar were accessed to research and collect English language papers published between 1 January 1980 and 31 December 2021. The data on PANDAS/PANS and those observed during severe brain infections were excluded.

RESULTS

Several pathogens have been associated with an increased risk to develop a broad spectrum of neuropsychiatric conditions, such as schizophrenia, mood disorders, autism, attention-deficit/hyperactivity disorder, anorexia nervosa, and post-traumatic stress disorder. Some evidence supported a possible role of infections also in the pathophysiology of OCD. Infections from Herpes simplex virus 1, Borna disease virus, Group A-Beta Hemolytic Streptococcus, Borrelia spp., and Toxoplasma gondii were actually found in patients with OCD. Although different mechanisms have been hypothesized, all would converge to trigger functional/structural alterations of specific circuits or immune processes, with cascade dysfunctions of several other systems.

CONCLUSIONS

Based on the current evidence, a possible contribution of different types of microbes has been proposed for different neuropsychiatric disorders including OCD. However, the currently available literature is meager and heterogeneous in terms of sample characteristics and methods used. Therefore, further studies are needed to better understand the impact of infectious agents in neuropsychiatric disorders. Our opinion is that deeper insights in this field might contribute to a better definition of biological underpinnings of specific clinical pictures, as well as to promote psychiatric precision medicine, with treatments based on altered pathological pathways of single patients. This might be particularly relevant in OCD, a disorder with a high proportion of patients who are resistant or do not respond to conventional therapeutic strategies.

Toxoplasma gondii Infection Is Associated with Low Birth Weight: Findings from an Observational Study among Rural Bangladeshi Women

Gestational Toxoplasma gondii (T. gondii) infection may cause substantial adverse effects on developing fetuses, newborns and also mothers. This study aims to estimate the seroprevalence of T. gondii among rural Bangladeshi pregnant women and determine the risk of a low birth weight (LBW). We followed a longitudinal design where 208 pregnant women were followed until the birth of their infants. Levels of IgG and IgM of T. gondii were assessed using chemiluminescent immunoassay. Modified Poisson regression was used to estimate crude and adjusted associations and multiple regression analysis was performed to understand the confounding and modifying effects of the variables. Thirty-nine (19%) children were born with LBW, among whom 15 (39%) mothers were positive for T. gondii IgG during pregnancy. After adjusting for several confounders and modifiers, pregnant women with T. gondii IgG or IgM seropositivity were significantly associated with LBW of infants (aRR: 2.00, 95% CI: 1.17–3.42). The strength of this association increased after adjusting for maternal education (aRR: 4.88, 95% CI: 1.74–13.69). The final model had an AROC of 0.84 with a sensitivity of 36% and specificity of 97%. Although causality is yet to be established, the study observed an association between T. gondii infection during pregnancy among rural Bangladeshi women and LBW of newborns.

Allostatic Load and Its Impact on Health: A Systematic Review

INTRODUCTION

Allostatic load refers to the cumulative burden of chronic stress and life events. It involves the interaction of different physiological systems at varying degrees of activity. When environmental challenges exceed the individual ability to cope, then allostatic overload ensues. Allostatic load is identified by the use of biomarkers and clinical criteria.

OBJECTIVE

To summarize the current knowledge on allostatic load and overload and its clinical implications based on a systematic review of the literature.

METHODS

PubMed, PsycINFO, Web of Science, and the Cochrane Library were searched from inception to December 2019. A manual search of the literature was also performed, and reference lists of the retrieved articles were examined.We considered only studies in which allostatic load or overload were adequately described and assessed in either clinical or non-clinical adult populations.

RESULTS

A total of 267 original investigations were included. They encompassed general population studies, as well as clinical studies on consequences of allostatic load/overload on both physical and mental health across a variety of settings.

CONCLUSIONS

The findings indicate that allostatic load and overload are associated with poorer health outcomes. Assessment of allostatic load provides support to the understanding of psychosocial determinants of health and lifestyle medicine. An integrated approach that includes both biological markers and clinimetric criteria is recommended.

Spatial distribution of anti-Toxoplasma gondii antibody-positive wild boars in Gifu Prefecture, Japan

Toxoplasma gondii is a globally wide-spread parasite that infects almost all species of mammals and birds, including humans. We studied the spatial distribution of individual T. gondii-seropositive wild boar in Gifu Prefecture (10,621 km²), Japan. Altogether, 744 wild boars were captured at 663 points around human settlements in Gifu Prefecture. Serum samples were collected after recording the exact capture locations, along with each wild boar’s body length and sex. We then used a commercial enzyme-linked immunosorbent assay kit for swine to measure anti-T. gondii antibodies in these animals. Among the 744 wild boars, 169 tested positive for T. gondii (22.7%). No significant difference in T. gondii seroprevalence was observed between the mountainous northern region with high winter snow cover and the mild-wintered geographical plain of the southern part of the prefecture. In contrast, 8 of the 11 wild boars that were captured in a public park surrounded by residential areas showed T. gondii seropositivity (72.7%), a value significantly higher than those of the wild boar populations in the other prefecture areas. This in-depth analysis, which spans the big city suburbs and rural areas of a whole prefecture, explains the seroprevalence of zoonotic T. gondii in wild boar and has public health implications.

Synthesis of Two Decades of US EPA's Ecosystem Services Research to Inform Environmental, Community, and Sustainability Decision Making

A conceptual framework is helpful to understand what types of ecosystem services (ES) information is needed to support decision making. Principles of structured decision making are helpful for articulating how ES consideration can influence different elements in a given decision context resulting in changes to the environment, human health, and well-being. This article presents a holistic view of an ES framework, summarizing two decades of the US EPA's ES research, including recent advances in final ES, those ES that provide benefits directly to people. Approximately 150 peer-reviewed publications, technical reports, and book chapters characterize a large ES research portfolio. In introducing framework elements and the suite of relevant US EPA research for each element, both challenges and opportunities are identified. Lessons from research to advance each of the final ES elements can be useful for identifying gaps and future science needs. Ultimately, the goal of this article is to help the reader develop an operational understanding of the final ES conceptual framework, an understanding of the state of science for a number of ES elements, and an introduction to some ES tools, models, and frameworks that may be of use in their case-study applications or decision-making contexts.

Latent Toxoplasma gondii infections are associated with elevated biomarkers of inflammation and vascular injury

BACKGROUND

Toxoplasma gondii is a protozoan parasite that infects cats as definitive hosts and other warm-blooded animals including humans as intermediate hosts. It forms infectious cysts in the brain, muscle and other tissues establishing life-long latent infection. Approximately 10% of the US population is infected. While latent infections are largely asymptomatic, they are associated with neurological deficits and elevated risks of neuropsychiatric diseases.

METHODS

This cross-sectional epidemiological study investigated associations of T. gondii infections with biomarkers of inflammation and vascular injury: soluble intercellular adhesion molecule 1 (ICAM-1), soluble vascular cell adhesion molecule 1 (VCAM-1), C-reactive protein (CRP), and serum amyloid A (SAA). Serum samples from 694 adults in the Raleigh-Durham-Chapel Hill, North Carolina metropolitan area were tested for IgG antibody response to T. gondii, and for the above biomarkers using commercially available assays.

RESULTS

T. gondii seroprevalence rate in this sample was 9.7%. Seropositivity was significantly associated with 11% (95% confidence limits 4, 20%) greater median levels of VCAM-1 (p = 0.003), and marginally significantly with 9% (1, 17%), and 36% (1, 83%) greater median levels of ICAM-1, and CRP, respectively (p = 0.04 for each) after adjusting for sociodemographic and behavioral covariates, while the 23% (- 7, 64%) adjusted effect on SAA was not statistically significant (p = 0.15).

CONCLUSIONS

Latent infections with T. gondii are associated with elevated biomarkers of chronic inflammation and vascular injury that are also known to be affected by ambient air pollution.

Epidemiological Survey of Toxoplasma gondii and Associated Risk Factors in Ruminant Species of the Khyber Pakhtunkhwa Province of Pakistan

Toxoplasma infection is one of the most common human parasitic diseases. During 2018-2020, in the rural areas of three districts of Pakistan, we surveyed a total of 451 animals, belonging to different asymptomatic ruminant species, to determine the prevalence of Toxoplasma gondii antibodies. We used ELISA assay as well as recorded some associated risk factors contributing to its transmission. IgM antibodies were detected in 17% and IgG in 13.4% of ruminant samples with the highest percentage, 10% for IgM and 8.6% for IgG in sheep. A strong significant association was found between antibodies and different species (IgM, ${\chi }^2=29$ .280, $P=.000$ , and IgG, ${\chi }^2=22.580$ , $P=.000$ ), respectively. Infection with T. gondii seems mainly associated with different geographic features and the presence of cats in the environment, low hygiene water systems and livestock that are mostly dependent on outdoor drinking and grazing. There was no significant association between IgM and age grouping ( ${\chi }^2=6.660$ , $P=0.840$ nor for IgG ( ${\chi }^2=8.136$ , $P=0.43$ ). The results of this study may be considered the starting point to promote the awareness about parasitic infections in ruminants in Pakistan in order to prevent this infection from further spreading.

Prevalência de anticorpos IgM e IgG anti-Toxoplasma gondii em universitários do Curso de Ciências Biológicas, Pontal do Triângulo Mineiro

Objetivo: Investigar a presença de IgG e IgM anti-Toxoplasma gondii no soro de estudantes de Ciências Biológicas da Universidade Federal de Uberlândia, campus do Pontal. Métodos: Estudo transversal de prevalência, com coleta de dados realizada entre junho de 2017 e fevereiro de 2018. Foram utilizadas as técnicas de Imunofluorescência Indireta e Ensaio Imunoenzimático (ELISA) e aplicados questionário semiestruturado para avaliação dos conhecimentos prévios sobre a toxoplasmose. Resultados: Participaram do estudo 128 alunos com faixa etária de 18 a 41 anos, sendo 83 (64,4%) do sexo feminino e 45 (35,6%) do sexo masculino. Foram colhidas amostras de sangue de 106 participantes e 13 (12,3%) apresentaram anticorpos anti-T. gondii.  Destes, 3 (2,8%) afirmaram consumir leite bovino não pasteurizado, 3 (2,8%) carne crua ou mal passada e 1 (0,94%) vegetais crus ou não higienizados. Não foi observada associação estatisticamente significativa entre positividade (IgM anti-T. gondii e/ou IgG anti-T. gondii) e as variáveis analisadas no questionário.Conclusão: Neste trabalho foi possível verificar a presença de anticorpos IgM e IgG anti-T. gondii em universitários. Não se observou uma associação entre soropositividade e o hábito alimentar.  Entretanto, a análise das respostas obtidas no questionário mostrou comportamento de risco por parte destes indivíduos, principalmente ao que se refere ao contato frequente com cães e gatos, muitas vezes recolhidos na rua.

Exposure to Toxoplasma gondii Through Consumption of Raw or Undercooked Meat: A Systematic Review and Meta-Analysis

Toxoplasma gondii is a globally distributed protozoan that mainly causes health issues in the fetuses of pregnant women who have never been exposed to this parasite and patients with deficient immune systems. Except in these vulnerable populations, the primary infection generally goes unnoticed in most healthy individuals. Apart from transplant/transfusion, congenital transmission, direct contact with infected cats or their feces, and environmental contamination (i.e., oocysts in food, water, and soil) pathways, humans can acquire the parasite through consumption of animal tissues infected by T. gondii. This meta-analysis estimated the risk of acquiring T. gondii by consuming raw or undercooked meat, regardless of which animal species are eaten. Using a random-effect model, crude and adjusted pooled measures of association (risk and odds ratio) were estimated according to study design (cohort, case-control, and cross-sectional studies). The meta-analysis included measures of heterogeneity as well as quality rating scales for each study design. Our results suggest that individuals who eat raw or undercooked meat have, respectively, 1.2-1.3 times the risk and 1.7-3.0 times the odds of T. gondii infection compared to those who thoroughly cook meat, regardless of the animal species they consume. These results align with the current understanding that adequately cooking meat inactivates the parasite and decreases the risk of transmission. Seroprevalence ranged from 1.3% to 88.6%, while the proportion of individuals eating raw or undercooked meat fluctuated from 0.7% to 98.3% across the studies in the meta-analysis. These numbers reflect various preferences with regard to eating meat (i.e., eating tartar, sausages, or salamis) as well as individual, cultural and religious food habits, and personal awareness.

Human Cytomegalovirus Infections Are Associated With Elevated Biomarkers of Vascular Injury

Background: Human cytomegalovirus (HCMV) infects ~50% of adults in the United States. HCMV infections may cause vascular inflammation leading to cardiovascular disease, but the existing evidence is inconsistent.

Objective: We investigated demographic predictors of HCMV infection and explored associations between HCMV infection status, the intensity of anti-HCMV Immunoglobulin G (IgG) antibody response, and biomarkers of inflammation and endothelial function which are known predictors of cardiovascular disease.

Methods: We conducted a cross-sectional study of 694 adults residing in the Raleigh-Durham-Chapel Hill, NC metropolitan area. Serum samples were tested for IgG antibody response to HCMV, and for biomarkers of vascular injury including soluble intercellular adhesion molecule 1 (sICAM-1), soluble vascular cell adhesion molecule 1 (sVCAM-1), C-reactive protein (CRP), and serum amyloid A (SAA). Associations between HCMV and biomarker levels were analyzed using two approaches with HCMV serostatus modeled as a binary variable and as an ordinal variable with five categories comprised of seronegative individuals and quartiles of anti-HCMV antibody responses in seropositive individuals.

Results: HCMV seroprevalence in the study population was 56%. Increased body mass index, increased age, female gender, racial/ethnic minority status, and current smoking were significantly associated with HCMV seropositivity in a multivariate regression analysis. HCMV seropositivity was also associated with 9% (95% confidence interval 4–15%) and 20% (0.3–44%) increases in median levels of sICAM-1 and CRP, respectively, after adjusting for covariates. The association between HCMV seropositivity and median levels of sVCAM-1 and SAA were positive but not statistically significant. Significant positive associations were observed between the intensity of anti-HCMV IgG responses and levels of sICAM-1 and sVCAM-1 (p-values 0.0008 and 0.04 for linear trend, respectively). To our knowledge, this is the first epidemiological study to show a relationship between anti-HCMV IgG responses and vascular injury biomarkers sICAM-1 and sVCAM-1 in the general population.

Conclusion: HCMV infections are associated with vascular injury and inflammation biomarkers in adult residents of North Carolina.

Greater tree cover near residence is associated with reduced allostatic load in residents of central North Carolina

BACKGROUND

Among urban residents, increased contacts with nature are associated with reduced morbidity and mortality. The concept of allostatic load, a biomarker-based composite measure of physiological dysregulation, can be applied to study subclinical benefits of exposure, and to elucidate pathways leading to improved health.

OBJECTIVE

This research explored associations between residential vegetated land cover and an allostatic load index calculated using the statistical distance measure known as Mahalanobis distance.

METHODS

This cross-sectional population-based study involved 186 adult residents of the Durham-Chapel Hill, North Carolina metropolitan area. Measures of tree and grass cover within 500 m of residence were derived from the U.S. Environmental Protection Agency's EnviroAtlas land cover database. Fifteen biomarkers of immune, neuroendocrine, and metabolic functions were analyzed in serum samples. Regression analysis was conducted using generalized additive models with thin-plate spline functions of geographic coordinates, adjusting for modelled traffic air pollution from local sources and sociodemographic covariates.

RESULTS

The second and third tertiles of distance-weighted tree cover were associated with 14% (95% Confidence Limits 20%; 8%) and 15% (21%; 8%) reduction in adjusted median allostatic load, respectively, compared to the first tertile. The same tertiles of tree cover were also associated with 0.16 (0.03; 0.76) and 0.04 (0.01; 0.35) adjusted odds ratios of having allostatic load index above the 90th percentile of the sample distribution. Grass cover was inversely correlated with tree cover and was not associated with reduced allostatic load.

CONCLUSIONS

Subclinical beneficial health effects of green spaces demonstrated in this study are consistent with reduced susceptibility to acute environmental and social stressors, and reduced risks of morbidity and mortality.

Seroprevalence and Risk Factors of Toxoplasma gondii Infection in Pregnant Women from Western Romania

Seroprevalence and risk factors of Toxoplasma gondii infection were assessed among pregnant women in Western Romania. T. gondii seroprevalence was evaluated in 208 pregnant women by demonstration of serum antibodies using the commercial Vitros anti-Toxoplasma immunoglobulin G (IgG) and IgM assays. A questionnaire was administered to obtain information regarding the risk factors associated with T. gondii seropositivity. Chi-squared tests, Fisher exact test, and Stata 9.2 (Statacorp, Texas) were used to evaluate differences between T. gondii positive and negative women. T. gondii antibodies were demonstrated in 116 (55.8%) of 208 pregnant women. Lower level of education and working with meat were found to be risk factors for T. gondii seropositivity. Pet owners (cats and/or dogs) had a higher T. gondii seroprevalence than those who did not report having any pet (p = 0.032). Women with ≥4 live births were more frequently T. gondii seropositive than those without previous births (p < 0.002). Women with histories of spontaneous abortions were more frequently T. gondii seropositive than those without such a history (p = 0.036). Our results indicate a high prevalence of T. gondii antibodies in pregnant women in Romania. Risk factors for T. gondii past infection were being in the older age group, working with meat, having pets, a lower level of education, higher gravidity, and history of spontaneous abortions. This survey provided the first data regarding risk factors for T. gondii infection in pregnant women from Western Romania.

Molecular identification of Toxoplasma gondii in domesticated and broiler chickens (Gallus domesticus) that possibly augment the pool of human toxoplasmosis

Toxoplasma gondii (T. gondii) is a protozoan parasite that infects all warm-blooded animals including domesticated birds and humans. Birds normally get infected by ground feeding and human beings contract the disease by consumption of undercooked chicken meat. This study aimed to analyze seroprevalence and DNA of T. gondii in chickens (domesticated and broiler) and to assess possible transfer to humans by review of available literature from Pakistan. Blood from and tissues from domesticated and broilers chickens were analyzed for Toxo-IgM/IgG and Toxoplasma DNA through ELISA and PCR respectively. Furthermore, research articles published during 1990-2019 on the prevalence of T. gondii in humans from Pakistan, were analyzed to assess the possible infection burden in the area in connection to transmission from chickens. The overall prevalence of IgM and IgG for T. gondii was 17.83% and 8.8% respectively in the study areas. Significant seroprevalence was found in domesticated chickens than broilers. In domesticated chickens, the prevalence was high in age ≥ 2 years. Toxoplasma DNA was detected in tissues with an overall prevalence of 10.84%. Higher prevalence was observed in liver (10.50%) than heart (9.5%) and muscles (7.11%). Only 4.78% broiler and 2.38% domesticated chickens were positive for both IgM and DNA, 1.2% domesticated and 1.30% broilers were positive for IgG and DNA, while 2.98% domesticated and 2.17% broilers were positive for IgM, IgG, and DNA. Available literature showed that 25.8% of human beings were infected with T. gondii in Pakistan. The prevalence was 20.64% in male and 26.82%in the female. The rate of infections increases with age and high (37.36%) was found in humans of age range 40 to 60 years. A high prevalence of T. gondii is found in both domesticated and broiler chickens in the study area. Moreover, the literature survey indicates that a high seroprevalence of T. gondii is present in human beings of Pakistan. It is concluded that the high prevalence of T. gondii in humans may be associated with the parasite transmission through infected chicken's meat in Pakistan.

Environmental transmission of Toxoplasma gondii: Oocysts in water, soil and food

Toxoplasma gondii is a zoonotic protozoan parasite that can cause morbidity and mortality in humans, domestic animals, and terrestrial and aquatic wildlife. The environmentally robust oocyst stage of T. gondii is fundamentally critical to the parasite's success, both in terms of its worldwide distribution as well as the extensive range of infected intermediate hosts. Despite the limited definitive host species (domestic and wild felids), infections have been reported on every continent, and in terrestrial as well as aquatic environments. The remarkable resistance of the oocyst wall enables dissemination of T. gondii through watersheds and ecosystems, and long-term persistence in diverse foods such as shellfish and fresh produce. Here, we review the key attributes of oocyst biophysical properties that confer their ability to disseminate and survive in the environment, as well as the epidemiological dynamics of oocyst sources including domestic and wild felids. This manuscript further provides a comprehensive review of the pathways by which T. gondii oocysts can infect animals and people through the environment, including in contaminated foods, water or soil. We conclude by identifying critical control points for reducing risk of exposure to oocysts as well as opportunities for future synergies and new directions for research aimed at reducing the burden of oocyst-borne toxoplasmosis in humans, domestic animals, and wildlife.

Socioeconomic vulnerability associated to Toxoplasma gondii exposure in southern Brazil

Human toxoplasmosis, a protozoonosis caused by Toxoplasma gondii, has been described as a worldwide foodborne disease with important public health impact. Despite infection has reportedly varied due to differences in alimentary, cultural and hygienic habits and geographic region, social vulnerability influence on toxoplasmosis distribution remains to be fully established. Accordingly, the present study has aimed to assess T. gondii seroprevalence and factors associated to social vulnerability for infection in households of Ivaiporã, southern Brazil, with 33.6% population making half minimum wage or less, ranked 1,055th in population (31,816 habitants), 1,406th in per capita income (U$ 211.80 per month) and 1,021st in HDI (0.764) out of 5,570 Brazilian cities. Serum samples and epidemiological questionnaires were obtained from citizen volunteers with official City Secretary of Health assistance in 2015 and 2016. In overall, serosurvey has revealed 526/715 (73.57%) positive samples for anti-T. gondii antibodies by Indirect Fluorescent Antibody Test. Logistic regression has shown a significant increase associated to adults (p = 0.021) and elderly (p = 0.014) people, illiterates (p = 0.025), unemployment (p <0.001) and lack of household water tank (p = 0.039). On the other hand, sex (male or female), living area (urban or rural), yard hygiene, meat ingestion, sand or land contact, owning pets (dog, cat or both) were not significant variables of positivity for anti-T. gondii antibodies in the surveyed population. Although no significant spatial cluster was found, high intensity areas of seropositive individuals were located in the Kernel map where the suburban neighborhoods are located. In conclusion, socioeconomic vulnerability determinants may be associated to Toxoplasma gondii exposure. The increased risk due to illiteracy, adult or elderly age, unemployment and lack of household water tank were confirmed by multivariate analysis and the influence of low family income for seropositivity by the spatial analysis.