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Toxoplasma gondii is a protozoan parasite that may infect many mammals including humans. Cats are one of the main sources of infection for humans. Therefore, routine screening of cats with tests that are inexpensive, rapid, and do not require sophisticated laboratory equipment is important. In this study, a lateral flow assay (LFA) was designed to rapidly diagnose toxoplasmosis in cats. For this purpose, we selected GRA1 protein of T. gondii due to its high antigenicity in diagnostic and vaccine studies. We further analyzed the immunological properties of GRA1 protein using in silico tools. Then, we expressed and purified recombinant GRA1 (rGRA1) protein and used it during the development of LFA to detect toxoplasmosis in serum samples (n = 40) of cats. According to the results, rGRA1 protein has negative GRAVY value, high aliphatic index, alpha helix, random coil and 12 B cell epitopes. The in silico data supported the high antigenic properties of rGRA1 protein and showed that it can be a good antigen candidate for LFA. Among 30 cat positive serum samples, 27 were found positive by the LFA while seronegative sera (n = 10) were negative by the LFA. The preliminary data showed that the LFA has high sensitivity (90 %) and specificity (100 %). When we used high responsive cat sera (i.e. sera that have optical density > 0.5 with ELISA) the sensitivity value reached 100 %. These results showed that rGRA1 protein is a good candidate to develop a LFA for rapid diagnosis of toxoplasmosis in cats., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Toxoplasma gondii ( T. gondii ) is an obligate intracellular parasite that can infect almost all warm-blooded animals, including humans, and one-third of the global population is thought to be infected with this parasite. Infection can occur through consumption of contaminated food, contact with an infected host, or congenital transmission. While toxoplasmosis is asemptomatic in people with a healthy immune system, it can cause severe infections in people with a suppressed immune system or with immunodeficiency. In addition to causing diseases in humans, it also causes infections in livestock and may result in stillbirth and abortion in sheep and goats. There is no 100% effective medicine or vaccination against the parasite that causes major clinical symptoms and financial losses. There is a need for an effective, safe, and durable vaccine that can provide protective immunity for use in humans and animals. Vaccination studies against toxoplasmosis have gathered speed since the 1990s. Today, studies can be carried out to develop effective and safe vaccines depending on the developments in molecular biology, biotechnology, and immunology. DNA vaccines are a promising vaccine platform against toxoplasmosis because they are easy to produce, they are safe, they do not need a cold chain, and they can stimulate both humoral and cellular immune responses. This review provides an overview of the complex life cycle, pathogenesis, and epidemiology of the parasite; the immune response that develops in the host against the infection it causes; and the DNA vaccines developed against toxoplasmosis and these vaccines.

Toxoplasma gondii is an obligate protozoan parasite that can infect mammals and birds. Cats are the definitive host of T. gondii and have a very important role in transmission of toxoplasmosis due to the shedding of millions of unsporulated oocysts, that become infective in the environment. Since cats play a major key role in the epidemiology of toxoplasmosis, rapid and accurate diagnosis of infected cats has utmost importance. In this study, we developed a novel colorimetric loop mediated isothermal amplification (LAMP) assay detecting T. gondii RE gene and modified a previously developed colorimetric LAMP assay targeting B1 gene to detect T. gondii DNA in cat feces for the first time. The analytical sensitivity of colorimetric LAMP assays was determined using plasmid controls. The clinical sensitivities of both colorimetric LAMPs were determined using cat fecal DNA samples that were confirmed to be positive by two different real-time PCRs in our previous study. According to the results, analytical sensitivities of both assays were 1 copy plasmid/reaction. Using real-time PCR as a reference method, sensitivities of colorimetric LAMP assays targeting RE and B1 genes were 100% and 97.56% whereas specificities of both assays were 100%. Overall, the colorimetric LAMP RE assay developed in this study brings an advantage in the diagnosis of T. gondii in cat fecal samples since it has higher sensitivity, does not need for experienced personnel, and can be applied in basic laboratories or in the field., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Toxoplasma gondii has a very wide host range and infects all warm-blooded animals including humans. The disease causes great economic losses both in animals and humans. Vaccination is the most effective approach to fight against toxoplasmosis however an effective vaccine has not been developed yet. In the present study, GRA8 protein of T. gondii that showed high immunogenicity in our previous microarray screening study was used to develop a DNA vaccine using pcDNA 3.3 vector for the first time. In order to increase the potency of the DNA vaccine, 10 times lower amount of GRA8 DNA vaccine was combined with molecular adjuvant CpG and formulated into a commercial liposome (pcDNA3.3-GRA8+CpG+Escort). Mice were vaccinated intramuscularly two times at three-week intervals and challenged orally with the T. gondii PRU strain tissue cysts. The humoral immune response was determined by Western Blot and ELISA. The cellular immune response was analyzed by flow cytometry, cytokine ELISA and MTT assay. Among the vaccine groups, pcDNA3.3-GRA8 and pcDNA3.3-GRA8+CpG+Escort induced strong IgG response compared to controls (P < 0.001). The IgG1 and IgG2a responses showed a balanced Th1-Th2 polarization. The ratio of CD4 + and CD8 + T lymphocytes secreting IFN-γ increased, and significantly higher extracellular IFN-γ secretion was achieved compared to the controls (P < 0.01). The amount of tissue cysts in the group of mice vaccinated with pcDNA3.3-GRA8 decreased significantly compared to control groups (P < 0.0001). In the group vaccinated with pcDNA3.3-GRA8+CpG+Escort, the amount of tissue cysts also decreased significantly compared to PBS (P = 0.0086) and Empty plasmid+CpG+Escort (P = 0.0007) groups. This study showed for the first time that pcDNA 3.3. vector encoding GRA8 with or without CpG and Liposome can induce strong cellular and humoral immune responses and confer strong protection against mouse model of chronic toxoplasmosis., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Introduction: Toxoplasma gondii is a protozoan parasite that has a widespread distribution among mammalians and birds. One of the reasons for the high prevalence may be due to ingesting oocyst disseminated by stray cats' feces. In Turkey, most of the citizens are closely associated with stray cats and they love to pet and feed them on the streets. In this study, we aimed to determine the prevalence of T. gondii DNA in feces of stray cats living in İzmir, Turkey in order to identify the transmission potential to humans and other animals., Methodology: Feces and blood samples of 465 stray cats were investigated for the presence of T. gondii oocysts by microscopy and for the presence of T. gondii DNA by two real time PCR methods. Furthermore, serum samples were analyzed for anti-T. gondii IgG antibodies using an ELISA., Results: Oocysts were detected in 0.43% of the stray cats by microscopy. T. gondii DNA was detected in 14.37% of the stray cats' feces samples. The seroprevalence rate was 37.84%. In the feces and/or blood PCR positive group, 35.89% of them were seropositive. Among the 176 seropositive cats, T. gondii DNA was detected in feces of 27 cats (15.34%)., Conclusions: This study first time showed the inter relation of T. gondii DNA in feces and blood samples and seropositivity. In sum, over 14% of the stray cats living outdoor may have an important role in transmission of toxoplasmosis to humans in İzmir as well as to other animals., Competing Interests: No Conflict of Interest is declared, (Copyright (c) 2021 Muhammet Karakavuk, Huseyin Can, Nebahat Selim, Berna Yesilsiraz, Evren Atli, Esra Atalay Sahar, Ferda Demir, Aytul Gul, Huseyin Gokhan Ozdemir, Nuray Alan, Mustafa Yalcin, Onur Ozkurt, Murat Aras, Tuncel Celik, Sengul Can, Aysu Degirmenci Doskaya, Adnan Yuksel Guruz, Mert Doskaya.)

Toxoplasma gondii is an obligatory intracellular protozoon parasite that causes toxoplasmosis in humans and all warm-blooded animals. In this study, we aimed to investigate the presence of T. gondii DNA in a Eurasian badger (Meles meles) that was found dead in the wildlife area of Izmir. According to the results of real time polymerase chain reaction, T. gondii REP gene was found to be positive in the Eurasian badger brain homogenate. In conclusion, Eurasian badger, a known carnivore, can be a potential source of toxoplasmosis in the natural settings of İzmir, Turkey.

Toxoplasma gondii is a protozoon parasite that causes congenital toxoplasmosis, as well as other serious clinical presentations, in immune compromised humans. Analyses of the prevalence and genotyping of strains from the definitive host and intermediate hosts will help to understanding the circulation of the different strains and elucidating the role of the genotype(s) in human toxoplasmosis. Turkey has a specific geographic location bridging Africa, Europe, and Asia. We hypothesized that T. gondii strains may have been transferred to Turkey from these continents via migratory birds or vice versa. The present study aimed to assess the prevalence of toxoplasmosis in wild birds of prey of İzmir and Manisa provinces as well as genetically characterize T. gondii strains from these wild birds to show the relation between bird strains and neighboring stray cats as well as human strains previously isolated in Turkey. Tissues obtained from 48 wild birds were investigated for the presence of T. gondii DNA and then bioassayed in mouse. Isolated strains were genotyped using 15 microsatellite markers. The prevalence of T. gondii DNA was found to be 89.6% (n: 43/48) in wild birds. Out of 43 positive samples, a total of 14 strains were genotyped by 15 microsatellite markers. Among them, eight were type II, three were type III and three were mixture of genotypes (two type II/II and one was II/III). These are the first data that showed the presence of T. gondii and types II and III genotypes in wild birds of Turkey. Moreover, Africa 1 was not detected. In addition, cluster analysis showed that T. gondii strains within type II and III lineage have close relation with strains previously isolated from stray cats in İzmir. Further studies are required to isolate more strains from human cases, other intermediate hosts, and water sources to reveal this relation.