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Toxoplasmosis, caused by the obligate intracellular protozoan Toxoplasma gondii , is an important zoonosis with medical and veterinary importance worldwide. The disease is mainly contracted by ingesting undercooked or raw meat containing viable tissue cysts, or by ingesting food or water contaminated with oocysts. The diagnosis and genetic characterization of T. gondii infection is crucial for the surveillance, prevention and control of toxoplasmosis. Traditional approaches for the diagnosis of toxoplasmosis include etiological, immunological and imaging techniques. Diagnosis of toxoplasmosis has been improved by the emergence of molecular technologies to amplify parasite nucleic acids. Among these, polymerase chain reaction (PCR)-based molecular techniques have been useful for the genetic characterization of T. gondii . Serotyping methods based on polymorphic polypeptides have the potential to become the choice for typing T. gondii in humans and animals. In this review, we summarize conventional non-DNA-based diagnostic methods, and the DNA-based molecular techniques for the diagnosis and genetic characterization of T. gondii . These techniques have provided foundations for further development of more effective and accurate detection of T. gondii infection. These advances will contribute to an improved understanding of the epidemiology, prevention and control of toxoplasmosis.

Marked phenotypic variation characterizes isolates of Toxoplasma gondii, a ubiquitous zoonotic parasite that serves as an important experimental model for studying apicomplexan parasites. Progress in identifying the heritable basis for clinically and epidemiologically significant differences requires a robust system for describing and interpreting evolutionary subdivisions in this prevalent pathogen. To develop such a system, we have examined more than 950 isolates collected from around the world and genotyped them using three independent sets of polymorphic DNA markers, sampling 30 loci distributed across all nuclear chromosomes as well as the plastid genome. Our studies reveal a biphasic pattern consisting of regions in the Northern Hemisphere where a few, highly clonal and abundant lineages predominate; elsewhere, and especially in portions of South America are characterized by a diverse assemblage of less common genotypes that show greater evidence of recombination. Clustering methods were used to organize the marked genetic diversity of 138 unique genotypes into 15 haplogroups that collectively define six major clades. Analysis of gene flow indicates that a small number of ancestral lineages gave rise to the existing diversity through a process of limited admixture. Identification of reference strains for these major groups should facilitate future studies on comparative genomics and identification of genes that control important biological phenotypes including pathogenesis and transmission.

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.

Fatal infections with the rare COUG strain of the zoonotic parasite Toxoplasma gondii were recently detected for the first time in four southern sea otters ( Enhydra lutris nereis ) exhibiting severe protozoal steatitis. The objectives of this study were to describe new COUG strain infections in sea otters, investigate the potential contributory role of a recently discovered parasite-infecting narnavirus ( Apocryptovirus odysseus ) in these infections, assess the potential contribution of vitamin E deficiency in the development of systemic steatitis, and explore the utility of serotyping for strain-specific diagnosis of T. gondii infections in sea otters. Since initial reporting, six additional sea otters died due to fatal COUG strain T. gondii infections. Five animals exhibited lesion patterns resembling the prior case definition including severe, widespread steatitis. The final case died due to severe T. gondii -associated meningoencephalitis with no grossly or microscopically apparent steatitis. In contrast with a recent report utilizing a cougar-derived parasite isolate, A. odysseus RNA was not detected in sea otter-derived COUG strain isolates, suggesting that this narnavirus is not associated with fatal COUG strain infections in sea otters. Serotyping using dense granule (GRA) peptides to distinguish between T. gondii strains infecting sea otters suggests that Type X, Type II, and COUG strains exhibit different peptide-reactivity profiles that may allow them to be distinguished serologically. COUG strain T. gondii infections are an emerging threat to southern sea otter population health, and this strain has the potential to infect other animal and human hosts that share their environment and food sources with sea otters. Additional studies are needed to clarify the environmental sources, epidemiology, pathophysiology, and premortem serodiagnosis of COUG strain T. gondii infections in southern sea otters and other susceptible hosts.

Toxoplasma gondii infections are common in humans and animals worldwide. Domestic free-range chickens (Gallus domesticus) are excellent sentinels of environmental contamination with T. gondii oocysts because they feed on the ground. Chickens can be easily infected with T. gondii; however, clinical toxoplasmosis is rare in these hosts. Chickens are comparatively inexpensive and thus are good sentinel animals for T. gondii infections on the farms. Here, the authors reviewed prevalence, the persistence of infection, clinical disease, epidemiology and genetic diversity of T. gondii strains isolated from chickens worldwide for the past decade. Data on phenotypic and molecular characteristics of 794 viable T. gondii strains from chickens are discussed, including new data on T. gondii isolates from chickens in Brazil. This paper will be of interest to biologists, epidemiologists, veterinarians and parasitologists.

Toxoplasmosis is a food- and waterborne zoonosis of a great importance, ranked as the fourth most important foodborne parasitosis in the world. The objective of this study was to determine the seroprevalence and molecular prevalence of Toxoplasma gondii in wild boar ( Sus scrofa ) and to identify genotypes circulating in Croatia. A total of 103 wild boars from four hunting areas in Croatia were screened. Cardiac fluid samples were tested for anti- T. gondii antibodies by MAT, while heart samples were tested for T. gondii DNA using qPCR. The seroprevalence in the cardiac fluid reached 54.4%, while 19.4% of the heart samples were positive by qPCR. The highest seroprevalence was detected in the hunting ground Visocica with 95.6%. Partial microsatellite genotyping was achieved for 2/20 qPCR-positive heart samples suggesting type II strain of T. gondii . Relatively high seroprevalence and detection of T. gondii DNA in tested samples highlights the risk of human infection through consumption of undercooked meat. Further studies focusing on parasite detection in wild boar meat, especially across different climates, are needed to understand regional differences. Expanding research to other wildlife species is also important to clarify their role in the spread of T. gondii .

Previous studies have reported high diversity between and within populations of Toxoplasma gondii in South America. In the present study, isolates of T. gondii from chickens were obtained from the Amazon region. Adult free-range chickens were acquired from 29 municipalities in the Brazilian Amazon region that included Acre (n = 9 municipalities), Amapá (n = 6), Amazonas (n = 6), Pará (n = 6), and Roraima (n = 2) states and from two municipalities in Peru, three in Bolivia, one in Guyana, and one in Venezuela. Heart, brain, and blood samples were collected from 401 chickens. Anti- T. gondii serum antibodies were detected in 273 (68.1%) chickens using the Modified Agglutination Test (MAT ≥ 5), and bioassays in mice were performed using 220 birds. Isolates were obtained from 116 (52.7%) chickens with antibody titers ≥ 20. Of these isolates, 93 (84.5%) led to acute sickness in more than 50% of the infected mice within 30 days post-inoculation. The 116 isolates were genotyped using multilocus nested polymerase chain reaction-restriction fragment length polymorphism (Mn-nPCR-RFLP) with 12 markers and 15 microsatellite (MS) markers. PCR-RFLP analysis revealed 42 genotypes from the 116 isolates. Of these, 20 (46.51%) genotypes are described for the first time. The most abundant genotype was ToxoDB PCR-RFLP genotype #7 with 40 isolates. A total of 83 genotypes were observed from the 116 isolates by MS analysis. The phylogenetic network constructed of T. gondii genotypes from current and previously reported isolates, using PCR-RFLP data, revealed five groups with clear indication of geographical separation of T. gondii population in the Amazon region versus the Southeastern region of Brazil. Such spatial diversity was also observed within the Amazon region. This study expands our knowledge of T. gondii population in South America and emphasizes the importance of genetic diversity and high mouse-virulence of the parasite in the Amazon region.

Toxoplasma gondii (T. gondii) affects around 30% of humans worldwide. Recently, it has emerged as a significant opportunistic pathogen to immunocompromised patients. Data available is still lacking about toxoplasmosis in cancer patients in Egypt. This study aimed to reveal the current trend of T. gondii in cancer patients in Sohag, Egypt. Sera from 50 cancer patients and 50 healthy controls were screened for Toxoplasma IgG and IgM. Further, buffy coats from both groups were used for detection of T. gondii B1 and RE genes via conventional and nested PCR, respectively. The overall seroprevalence of T. gondii IgG was high (58%). IgG and IgM were detected in 30% and 9% cancer patients, respectively. Patients with solid cancers exhibited a greater IgG seropositivity compared to those with hematologic tumors (77.27% and 46.43%, respectively) ( P  = 0.03). Concerning the molecular results, only 4 (9%) were positive regarding both PCR assays. In conclusion, T. gondii is highly prevalent in cancer patients in Sohag, Egypt. PCR is strongly recommended to complement serology to diagnose acute or reactivated toxoplasmosis in cancer patients. B1 PCR was found to be equivalent to RE PCR. Nevertheless, thorough large-scale research must be implemented.

Globally, congenital toxoplasmosis remains a significant cause of morbidity and mortality, and outbreaks of infection with T. gondii represent a significant, emerging public health burden, especially in the developing world. This parasite is a threat to public health. Disease often is not recognized and is inadequately managed. Herein, we analyze the status of congenital toxoplasmosis in Morocco, Colombia, the United States, and France. We identify the unique challenges faced by each nation in the implementation of optimal approaches to congenital toxoplasmosis as a public health problem. We suggest that developed and developing countries use a multipronged approach, modeling their public health management protocols after those in France. We conclude that education, screening, appropriate treatment, and the development of novel modalities will be required to intervene successfully in caring for individuals with this infection. Gestational screening has been demonstrated to be cost-effective, morbidity-sparing, and life-saving. Recognition of the value and promise of public health interventions to prevent human suffering from this emerging infection will facilitate better patient and societal outcomes.

The development of simple, sensitive and rapid methods for the detection and identification of Toxoplasma gondii is important for the diagnosis and epidemiological studies of the zoonotic disease toxoplasmosis. In the past 2 decades, molecular methods based on a variety of genetic markers have been developed, each with its advantages and limitations. The application of these methods has generated invaluable information to enhance our understanding of the epidemiology, population genetics and phylogeny of T. gondii. However, since most studies focused solely on the detection but not genetic characterization of T. gondii, the information obtained was limited. In this review, we discuss some widely used molecular methods and propose an integrated approach for the detection and identification of T. gondii, in order to generate maximum information for epidemiological, population and phylogenetic studies of this key pathogen.