The effect of water source and soil supplementation on parasite contamination in organic vegetable gardens

Prevalence of Ocular Toxoplasmosis in the General Population and Uveitis Patients: A Systematic Review and Meta-Analysis

PURPOSE

The present study aimed to estimate the global prevalence of ocular toxoplasmosis in the general population and patients with uveitis.

METHODS

Four electronic databases were searched and 130 studies for evaluating the prevalence of OT among the general population and uveitis patients were included.

RESULTS

The pooled prevalence of OT among the general population was estimated at 2% (95% CI, 2-3%; 762/486 051). The highest prevalence rate was observed in America 6% (95% CI, 1-11%). In uveitis patients, a prevalence rate of 9% (95% CI, 8-10%; 5668/88 006) was reported. The countries with a lower middle income had higher prevalence rates. The prevalence of OT in posterior uveitis 33% (95%CI, 24-42%) was substantially higher than in panuveitis 7% (95% CI, 5-8%).

CONCLUSION

Our results provide a new perspective on the prevalence of OT. Knowledge of international and regional patterns of disease is essential for the establishment of precise diagnostic protocols and control programs.

Protozoan parasites and free-living amoebae contamination in organic leafy green vegetables and strawberries from Spain

In this study, the presence of Acanthamoeba spp., Blastocystis sp., Cryptosporidium spp., Cyclospora cayetanensis, Entamoeba histolytica, Giardia sp., Toxoplasma gondii and Vermamoeba vermiformis was assessed in organic leafy green vegetables (lettuce, spinach, cabbage) and fruits (strawberry), which are usually consumed raw. A total of 110 organic samples were collected in Valencia (Spain). Protozoa were concentrated before detection by immunofluorescence (Cryptosporidium spp. and Giardia sp.) or real-time qPCR (Acanthamoeba spp., Blastocystis sp., C. cayetanensis, E. histolytica, T. gondii and V. vermiformis). The most abundant protozoa in organic vegetables and berry fruits were Acanthamoeba (65.5%), followed by T. gondii (37.2%), V. vermiformis (17.3%), C. cayetanensis (12.7%), Cryptosporidium spp. (6.8%), Blastocystis sp. (1.8%) and Giardia sp. (1.7%). E. histolytica was not found in any of the organic samples. Thus, results showed that consumers can be exposed to protozoan parasites by consuming organic vegetables and berry fruits. This is the first report in Spain describing the presence of the protozoan pathogens Acanthamoeba spp., Blastocystis sp., C. cayetanensis, T. gondii and V. vermiformis, Cryptosporidium spp. and Giardia sp. in organic fresh produce. The results of this research will help determine the risk of foodborne protozoan parasites on organic leafy greens and strawberries that are available at local markets.

Exploring genetic variability of Giardia duodenalis and Enterocytozoon bieneusi in raw vegetables and fruits: implications for food safety and public health in Mozambique

Giardia duodenalis and Enterocytozoon bieneusi are etiological agents of enteric diseases characterized by diarrhea that can progress to chronicity in humans, especially in children and in immunocompromised patients. This study aims to assess the genetic pattern of G. duodenalis and E. bieneusi detected in vegetables and fruits commercialized in Maputo markets, Mozambique and determine their public health importance. Eight study points were sampled: a farmer zone, a wholesale, four retail markets, and two supermarkets in Maputo city, where eight types of horticultural products were purchased. Using nested-PCR methods, 2.8% (9/321) and 1.3% (4/321) of samples monitored were positive for G. duodenalis and E. bieneusi, respectively. Based on the analysis of the β-giardin and ITS rRNA sequences of G. duodenalis and E. bieneusi detected, respectively, four different sequences of G. duodenalis (three novel sequences: BgMZ1, BgMZ2, and BgMZ3, and one known sequence) all from assemblage B and three genotypes of E. bieneusi (two novel sequences: EbMZ4 and EbMZ5, and one known sequence: KIN-1) from group 1. These microorganisms were found and characterized for the first time in horticultural products in Maputo markets. All identified G. duodenalis and E. bieneusi display high genetic similarity within their β-giardin and ITS rRNA sequences, respectively, having been clustered into assemblages and genotypes with high zoonotic transmission potential. Our study may represent a relevant step in the understanding of these intestinal pathogens in association with fresh vegetables and fruits for human consumption, for a better and broader "One Health" approach.

Seropositivity of Anti-Toxoplasma gondii Antibodies in Owners and Their Dogs Living on Island and Mainland Seashore Areas of Southern Brazil

Although toxoplasmosis has been considered among the most neglected zoonoses worldwide, no study has focused on the frequency and associated risk factors of owners and their dogs living on an island and mainland seashore areas. Accordingly, anti-Toxoplasma gondii IgG antibodies were screened by indirect fluorescent antibody test (IFAT) in owners and dogs from three oceanic islands and two nearby mainland harbor areas, with associated risk factors for toxoplasmosis assessed by univariable and multivariable logistic regression models. Overall, anti-T. gondii seropositivity was observed in 59/328 (18.0%) owners and 66/283 (23.3%) dogs, with no statistical difference between owners (p = 0.360) and dogs (p = 0.655) from islands and mainland areas. Consumption of local water springs (p = 0.016; OR = 2.11) was an associated risk factor for T. gondii seropositivity, and owners with the habit of spring water intake were twice more likely seropositive (p = 0.014; OR = 2.14). Presence of anti-T. gondii antibodies in dogs was associated with seropositive owners (p = 0.008; OR = 2.81), household consumption of beef meat (p = 0.042; OR = 1.7) and chicken (p = 0.026; OR = 2.9). Despite being lower than the worldwide prevalence, toxoplasmosis seropositivity in owners and their dogs in southern Brazil was influenced by the positive owner, water source, and meat consumption, and not by inhabiting islands or seashore mainland areas, presence of dogs, cats, or both. In addition, drinking water quality should always be considered a critical risk factor for toxoplasmosis on islands.

Detection of Giardia duodenalis and Toxoplasma gondii in soil and water samples in the Quindío River basin, Colombia

Two zoonotic protozoan pathogens, Giardia duodenalis and Toxoplasma gondii, are important causes of waterborne infections in the Quindío region in Colombia. No previous data exist on how contamination occurs at the source for drinking water consumed by the human population in this region. Our aim was to describe the frequency of G. duodenalis and T. gondii DNA in 11 sampling points during a five-month period in water and adjacent soil at the Quindío River basin (Andean region in the central western part of Colombia). The study employed nested PCR for T. gondii, using the B1 gene as the amplification target, and single-round PCR for G. duodenalis assemblage A and assemblage B, amplifying the gdh gene, followed by DNA sequencing. In 50 soil samples, 28% (14/50) were positive for T. gondii. For G. duodenalis, distribution was in equal parts for assemblage A (8%; 4/50) and assemblage B (8%, 4/50). Genotyping of T. gondii sequences showed two soil samples with type I strain, another two samples of soil with type III strain, but most samples were of unidentified strains. In water samples, T. gondii was detected in 9.1% (5/55), G. duodenalis assemblage A in 34.5% (19/55), and G. duodenalis assemblage B in 12.7% (7/55). T. gondii DNA positivity was associated with lower soil temperature (p = 0.0239). Presence of G. duodenalis and T. gondii was evidenced in soil and water samples in the Quindío River basin, indicating soil as the potential source of contamination for the river that it is destined for human consumption. Monitoring these protozoa in drinking water is necessary to prevent public health risks in human populations.

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55 water and 50 soil samples from Colombian Quindio river basin were studied.

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Positive soil: 28% T. gondii, 8% G. intestinalis assemblages A and B.

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Positive water: 9.1% T. gondii, 4.5% G. intestinalis assemblages A and B.

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Soil and water are potential sources of contamination for river water that is destined for human consumption.

Investigation of Toxoplasma gondii in wastewater and surface water in the Qinghai-Tibet Plateau, China using real-time PCR and multilocus genotyping

Toxoplasma gondii is a protozoan parasite, causing one of the most prevalent parasitic infections in the world. In the present study water sources of the Qinghai-Tibet Plateau (QTP), China, where the hygienic infrastructure is still developing, were investigated. A total of 214 water samples of 10 L volume, were collected from wastewater treatment plants (WWTPs), a slaughterhouse and rivers. The samples were filtered and then analysed using real-time PCR and multilocus genotyping. T. gondii DNA was found in four (1.9%) samples representing T. gondii type I; in one of them T. gondii-like oocysts were also confirmed microscopically. The approximate level of contamination of positive samples ranged between 30 and 2300 T. gondii sporozoites. The results of this study confirmed that T. gondii is present in wastewater in the greater metropolitan area of Xining and a neighbouring county. Contamination of wastewater at this level constitutes rather a moderate source of Toxoplasma infections in humans and animals. It suggests, however, a link between environmental exposure of animals, meat processing facilities and WWTPs. To our knowledge, this is the first investigation describing T. gondii detection in wastewater and environmental water samples collected from the territory of P.R. China using sensitive molecular tools.

Molecular detection of Toxoplasma gondii and Neospora caninum in rock pigeons (Columba livia) in Punjab, Pakistan

Rock pigeons are synanthropic birds and live in close association within human settlements. Synanthropic birds are considered potential carriers of diseases and pose a subsequent risk of their transmission to humans. Neospora caninum and Toxoplasma gondii are intracellular protozoans infecting a wide range of hosts, as well as birds. Data related to the incidence of these protozoans in rock pigeons in Pakistan are scant. The aims of the study were to detect T. gondii and N. caninum DNA in tissue samples from rock pigeons (Columba livia) and to identify possible risk factors associated with infection. To accomplish this, pectoral muscle and brain samples were carefully collected from rock pigeons (n = 120) belonging to three zones located in ten districts of Punjab during a 4-month sampling span (July 2018 to October 2018). Data related to sex, age, sampling site, districts, seasonality, and ecological zones were recorded. DNA from brain and pectoral muscle samples was screened for both T. gondii and N. caninum by PCR assays. Chi-square analysis was used to check the association between positive samples and risk factors. The level of significance was p ≤ 0.05. T. gondii was detected in 46 (38.3%) brain samples, while 24 pectoral muscle samples (20%) were positive for N. caninum. Agroecological zones were statistically associated with the detection of N. caninum DNA. The outcomes of this study provide an understanding of the epidemiological pattern of N. caninum and T. gondii infection in rock pigeons in different regions of Punjab, Pakistan.

Contamination of Soil, Water, Fresh Produce, and Bivalve Mollusks with Toxoplasma gondii Oocysts: A Systematic Review

Toxoplasma gondii is a major foodborne pathogen capable of infecting all warm-blooded animals, including humans. Although oocyst-associated toxoplasmosis outbreaks have been documented, the relevance of the environmental transmission route remains poorly investigated. Thus, we carried out an extensive systematic review on T. gondii oocyst contamination of soil, water, fresh produce, and mollusk bivalves, following the PRISMA guidelines. Studies published up to the end of 2020 were searched for in public databases and screened. The reference sections of the selected articles were examined to identify additional studies. A total of 102 out of 3201 articles were selected: 34 articles focused on soil, 40 focused on water, 23 focused on fresh produce (vegetables/fruits), and 21 focused on bivalve mollusks. Toxoplasma gondii oocysts were found in all matrices worldwide, with detection rates ranging from 0.09% (1/1109) to 100% (8/8) using bioassay or PCR-based detection methods. There was a high heterogeneity (I2 = 98.9%), which was influenced by both the sampling strategy (e.g., sampling site and sample type, sample composition, sample origin, season, number of samples, cat presence) and methodology (recovery and detection methods). Harmonized approaches are needed for the detection of T. gondii in different environmental matrices in order to obtain robust and comparable results.

Diverse Genotypes and Species of Cryptosporidium in Wild Rodent Species from the West Coast of the USA and Implications for Raw Produce Safety and Microbial Water Quality

Cryptosporidium spp. are protozoan parasites that infect perhaps all vertebrate animals, with a subset of species and genotypes that function as food- and waterborne pathogens. The objective of this work was to collate the Cryptosporidium species and genotypes from common wild rodents on the west coast of the USA and update the information regarding the zoonotic potential of Cryptosporidium from these ubiquitous wild species. Representative sequences of the 18S rRNA gene for a unique set of Cryptosporidium isolates obtained from deer mice, house mice, mountain beavers, yellow-bellied marmot, long-tailed vole, California ground squirrels, Belding’s ground squirrels, and a golden-mantled ground squirrel in GenBank were selected for phylogenetic analysis. Phylogenetic and BLAST analysis indicated that 4 (18%) of the 22 unique Cryptosporidium sequences from these wild rodent species were 99.75% to 100% identical to known zoonotic species (C. parvum, C. ubiquitum, C. xiaoi), suggesting that a minority of these representative Cryptosporidium isolates could have a public health impact through food and waterborne routes of human exposure. These zoonotic isolates were shed by deer mice and a yellow-bellied marmot from California, and from a mountain beaver trapped in Oregon. In addition, the group of unique Cryptosporidium isolates from deer mice and ground dwelling squirrels exhibited considerable DNA diversity, with multiple isolates appearing to be either host-limited or distributed throughout the various clades within the phylogenetic tree representing the various Cryptosporidium species from host mammals. These results indicate that only a subset of the unique Cryptosporidium genotypes and species obtained from wild rodents on the US west coast are of public health concern; nevertheless, given the geographic ubiquity of many of these host species and often high density at critical locations like municipal watersheds or produce production fields, prudent pest control practices are warranted to minimize the risks of water- and foodborne transmission to humans.

Giardia and Cryptosporidium in Neo-Tropical Rodents and Marsupials: Is There Any Zoonotic Potential?

Cryptosporidiosis and giardiasis have been identified as emerging diseases in both developed and developing countries. Wildlife has been highlighted to play a major role in the spread of these diseases to humans. This review aims to highlight the research findings that relate to Cryptosporidium spp. and Giardia spp., with a focus on (1) parasitism of neo-tropical hystricomorphic rodents and marsupials from the genus Didelphis and (2) prevention and treatment strategies for humans and animals for the neo-tropical region. It was found that there are few studies conducted on neo-tropical rodent and marsupial species, but studies that were found illustrated the potential role these animals may play as zoonotic carriers of these two parasites for the neo-tropical region. Thus, it is recommended that further studies be done to assess the threat of protozoan parasites in neo-tropical wildlife to humans and domestic animals, and to further determine the most effective prophylaxis adapted for the unique conditions of the region.

Multilocus Genotyping of Giardia duodenalis in Mostly Asymptomatic Indigenous People from the Tapirapé Tribe, Brazilian Amazon

Little information is available on the occurrence and genetic variability of the diarrhoea-causing enteric protozoan parasite Giardia duodenalis in indigenous communities in Brazil. This cross-sectional epidemiological survey describes the frequency, genotypes, and risk associations for this pathogen in Tapirapé people (Brazilian Amazon) at four sampling campaigns during 2008–2009. Microscopy was used as a screening test, and molecular (PCR and Sanger sequencing) assays targeting the small subunit ribosomal RNA, the glutamate dehydrogenase, the beta-giardin, and the triosephosphate isomerase genes as confirmatory/genotyping methods. Associations between G. duodenalis and sociodemographic and clinical variables were investigated using Chi-squared test and univariable/multivariable logistic regression models. Overall, 574 individuals belonging to six tribes participated in the study, with G. duodenalis prevalence rates varying from 13.5–21.7%. The infection was positively linked to younger age and tribe. Infected children <15 years old reported more frequent gastrointestinal symptoms compared to adults. Assemblage B accounted for three out of four G. duodenalis infections and showed a high genetic diversity. No association between assemblage and age or occurrence of diarrhoea was demonstrated. These data indicate that the most likely source of infection was anthropic and that different pathways (e.g., drinking water) may be involved in the transmission of the parasite.

Epidemiology of Giardia duodenalis assemblages in Brazil: there is still a long way to go

Giardia duodenalis infection is distributed worldwide and can achieve prevalence around 60%, especially in developing countries. This protozoan is divided into eight assemblages, in which A and B have high zoonotic potential, whereas C to H are host-specific. This scenario is changing as molecular studies progress, highlighting that knowledge on host-specificity still has a long way to go. Understanding the players involved in transmission routes enables rational designs of control strategies. Considering the high prevalence of giardiasis, this review aims to gather together the data on available studies on the distribution of G. duodenalis assemblages in Brazil until September 2020.

Serological prevalence of toxoplasmosis in pregnant women in Luanda (Angola): Geospatial distribution and its association with socio-demographic and clinical-obstetric determinants

We report a study on toxoplasmosis in pregnant women in Luanda, Angola, determining the seroprevalence, geospatial distribution and its association with socio-economic features, dietary habits and hygiene and health conditions. Anti-Toxoplasma gondii IgG and IgM were quantified in serum samples of women attended at the Lucrecia Paim Maternity Hospital between May 2016 and August 2017. The IgG avidity test and qPCR assay were used for dating the primary infection. Data were collected by questionnaire after written consent, and spatial distribution was assessed through a Kernel Density Function. The potential risk factors associated with Toxoplasma infection were evaluated using bivariate and multivariate binomial logistic regression analysis. Anti-T. gondii antibodies were quantified in 878 pregnant women, and 346 (39.4%) samples were IgG positive, 2 (0.2%) positive for IgM and IgG, and 530 (60.4%) negative for both immunoglobulins. The longitudinal study showed that none of the seronegative women seroconverted during the survey. Regarding other infections, 226 (25.7%) were positive for hepatitis B, while 118 (13.4%) were HIV-positive. The seroprevalence of toxoplasmosis was similar in most municipalities: 43.8% in Cazenga (28 of 64); 42.5% in Viana (88 of 207); 42.3% in Cacuaco (22 of 52); and 41.1% in Luanda ((179 of 435). In contrast, the seroprevalence in municipality of Belas was lower (25.8%; 31 of 120) and bivariate and multivariate analysis has shown a lower risk for toxoplasmosis in this area (OR 0.479, CI: 0.305–0.737; OR 0.471, CI: 0.299–0.728). The multivariate analysis has shown a significant increased risk for toxoplasmosis in women in the last trimester of pregnancy (OR 1.457, CI: 1.011–2.102), suffering spontaneous abortion (OR 1.863, CI: 1.014–3.465) and having pets at home (OR 1.658, CI: 1.212–2.269). Also, women who tested positive for hepatitis B (OR 1.375, CI: 1.008–1.874) and HIV (OR 1.833, CI: 1.233–2.730) had a significant increased risk for T. gondii infection. In conclusion, our study showed that a large number of pregnant women are not immunized for toxoplasmosis and identified the risk factors for this infection in Luanda. It is crucial to establish the diagnosis of primary maternal infection as well as the diagnosis of congenital toxoplasmosis. Our results underlined the need for diagnostic and clinical follow-up of toxoplasmosis, HIV and hepatitis B during pregnancy.

Outbreak of Amazonian Toxoplasmosis: A One Health Investigation in a Remote Amerindian Community

Background:Toxoplasma gondii is a parasite of worldwide importance but its burden in indigenous communities remains unclear. In French Guiana, atypical strains of T. gondii originating from a complex rainforest cycle involving wild felids have been linked to severe infections in humans. These cases of Amazonian toxoplasmosis are sporadic and outbreaks are rarely described. We report on the investigation of an outbreak of acute toxoplasmosis in a remote Amerindian village. We discuss the causes and consequences of this emergence.

Methods: In May 2017, during the rainy season and following an episode of flooding, four simultaneous cases of acute toxoplasmosis were serologically confirmed in two families living the village. Other non-diagnosed cases were then actively screened by a medical team along with epidemiological investigations. Inhabitants from nine households were tested for T. gondii antibodies and parasite DNA by PCR when appropriate. Samples of water, cat feces and cat rectal swabs, soil, and meat were tested for T. gondii DNA by PCR. Positive PCR samples with sufficient DNA amounts were genotyped using 15 microsatellite markers.

Results: Between early May and early July 2017, out of 54 tested inhabitants, 20 cases were serologically confirmed. A fetus infected at gestational week 10 died but other cases were mild. Four patients tested positive for parasite DNA and two identical strains belonging to an atypical genotype could be isolated from unrelated patients. While domestic cats had recently appeared in the vicinity, most families drank water from unsafe sources. Parasite DNA was recovered from one water sample and nine soil samples. Three meat samples tested positive, including wild and industrial meat.

Conclusions: The emergence of toxoplasmosis in such a community living in close contact with the Amazon rainforest is probably multifactorial. Sedentary settlements have been built in the last few decades without providing safe water sources, increasing the risk of parasite circulation in cases of dangerous new habits such as cat domestication. Public health actions should be implemented in these communities such as safe water supply, health recommendations, and epidemiological surveillance of acute toxoplasmosis. A “One Health” strategy of research involving medical anthropology, veterinary medicine, and public health needs to be pursued for a better understanding of the transmission routes and the emergence of this zoonosis.

Detection of human intestinal protozoan parasites in vegetables and fruits: a review

Diarrheal diseases caused by intestinal protozoan parasites are a major food-borne public health problem across the world. Vegetables and fruits provide important nutrients and minerals, but are also common sources of some food-borne human pathogenic microorganisms. The contamination of raw vegetables and fruits with human pathogenic parasites are now a global public health threat, despite the health benefits of these foods in non-pharmacological prophylaxes against diseases. A large number of reports have documented the contamination of vegetables or fruits with human pathogenic microorganisms. In this paper, we reviewed the contamination and detection methods of human pathogenic intestinal protozoans that are frequently recovered from raw vegetables and fruits. The protozoan parasites include Cryptosporidium spp., Giardia duodenalis, Cyclospora cayetanensis, Entamoeba spp., Toxoplasma gondii, Balantioides coli, Blastocystis sp., Cystoisospora belli and Enterocytozoon bieneusi. The risk factors involved in the contamination of vegetables and fruits with parasites are also assessed.

Patterns of Transmission and Sources of Infection in Outbreaks of Human Toxoplasmosis

We report on apparent temporal progression of probable sources of infection and transmission routes for global human toxoplasmosis outbreaks as described in published articles. We searched the Scientific Electronic Library Online, Web of Science, PubMed, and Scopus databases for articles on Toxoplasma, toxoplasmosis, and outbreaks. We found that transmission routes for Toxoplasma gondii varied by decade. In the 1960s and 1990s, toxoplasmosis outbreaks mainly occurred through ingestion of cysts in meat and meat derivatives; in the 1980s, through milk contaminated with tachyzoites; in 2000, due to the presence of oocysts in water, sand, and soil; and in 2010, due to oocysts in raw fruits and vegetables. Our study suggests a possible change in the epidemiology of reported toxoplasmosis outbreaks. Because of this change, we suggest that greater attention be paid to the disinfection of vegetables, as well as to the quality of water used for drinking and irrigation.

Detection of Toxoplasma gondii oocysts in fresh vegetables and berry fruits

BACKGROUND

Toxoplasma gondii is the third most important contributor to health burden caused by food-borne illness. Ingestion of tissue cysts from undercooked meat is an important source of horizontal transmission to humans. However, there is an increasing awareness of the consumption of fresh fruit and vegetables, as a possible source for oocyst transmission, since this stage of the parasite can persist and remain infective in soil and water for long time. Herein, we outline findings related with detection of T. gondii oocysts in vegetables and berry fruits, which are usually raw consumed. The procedure includes the estimation of the number of oocysts.

METHODS

Food samples were collected from local producers and supermarket suppliers. Toxoplasma gondii oocysts were concentrated after washing the samples by applying high resolution water filtration and immunomagnetic separation (method 1623.1: EPA 816-R-12-001-Jan 2012), in order to (i) remove potential Cryptosporidium spp. oocysts and Giardia spp. cysts present in the samples; and (ii) select T. gondii oocysts. Toxoplasma gondii oocyst detection and an estimation of their numbers was performed by conventional PCR and real time qPCR, using specific primers for a 183-bp sequence of the T. gondii repetitive DNA region. All PCR-positive DNA samples were purified and sequenced. Restriction enzyme digestion with EcoRV endonuclease confirmed the presence of the T. gondii DNA fragment. In addition, the presence of the parasite was observed by fluorescent microscopy, taking advantage of the oocysts autofluorescence under UV light.

RESULTS

Forty percent of the analysed samples (95% CI: 25.5-56.5%) presented the expected PCR and digested DNA fragments. These fragments were confirmed by sequencing. Microscopic autofluorescence supported the presence of T. gondii-like oocysts. The estimated mean (± SE) oocyst concentration was 23.5 ± 12.1 oocysts/g, with a range of 0.6-179.9 oocysts/g.

CONCLUSIONS

Our findings provide relevant evidence of contamination of fresh vegetables and berry fruits with T. gondii oocysts.

First molecular detection of Toxoplasma gondii in vegetable samples in China using qualitative, quantitative real-time PCR and multilocus genotyping

Toxoplasma gondii infection is becoming increasing problem in China but there is no data concerning contamination of vegetables intended for consumption with this parasite. The aim of the present study was to investigate fresh vegetables originated from open markets located in the Xining City, the Qinghai-Tibet Plateau (QTP), P.R. China for their contamination with T. gondii. A total of 279 fresh vegetable samples were collected and analysed using real-time PCR assay targeting B1 gene and multilocus genotyping. T. gondii DNA was found in 10 (3.6%) samples tested; eight of them represented T. gondii type I and remaining two T. gondii type II. The approximate level of contamination of positive vegetables samples, estimated based on quantitative real-time PCR (qPCR), ranged between less than one and 27000 T. gondii oocysts per sample, with majority not exceeding several oocysts per sample. The results of the study confirmed that T. gondii is present in vegetables offered in open markets in the Qinghai province, P.R. China; eating them unwashed and raw may therefore pose a threat to consumers. This is the first investigation describing T. gondii detection in fresh vegetables intended for consumption collected from the territory of P.R. China using sensitive molecular tools.

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.