Toxoplasma

A special issue of Pathogens (ISSN 2076-0817). This special issue belongs to the section "Parasitic Pathogens".

Deadline for manuscript submissions: closed (31 March 2023) | Viewed by 26151

Special Issue Editor


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Guest Editor
Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
Interests: molecular parasitology; microbial genetics; protease; small nutrients; toxoplasma gondii

Special Issue Information

Dear Colleagues,

Toxoplasma gondii is a significant human protozoan pathogen and has infected almost one-third of the world’s human population. Although the infection only causes flu-like symptoms in immunocompetent people, it can lead to severe, even lethal, situations in the immunocompromised population. As it is an intracellular pathogen, its parasites utilize their unique organelles and virulence factors to penetrate the host cell’s plasma membrane, usurp nutrients from the host cells, and mediate infections across host cells. The parasites also adopt strategies to evade host immunity for intracellular survival. 

This Special Issue will cover novel findings that focus on understanding the molecular mechanisms by which Toxoplasma parasites infect their host cells as well as host–Toxoplasma interaction research. In addition, original research studying the molecular detection of Toxoplasma infection, the phylogenetic evolution of Toxoplasma, and parasite ecology will be welcomed for this Special Issue.

Dr. Zhicheng Dou
Guest Editor

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Published Papers (8 papers)

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Research

8 pages, 267 KiB  
Communication
Prevalence of Toxoplasma gondii Antibodies and Risk Factor Investigation in Portuguese Veterinarians: A Matched Case–Control Study
by Daniela Almeida, Sérgio Santos-Silva, Maria Aires Pereira, Carla Santos, Cristina Mega, Catarina Coelho, Carmen Nóbrega, Fernando Esteves, Rita Cruz, Helena Vala and João R. Mesquita
Pathogens 2022, 11(10), 1217; https://doi.org/10.3390/pathogens11101217 - 21 Oct 2022
Cited by 2 | Viewed by 1807
Abstract
(1) Background: Toxoplasma gondii is a widespread zoonotic agent that greatly impacts Public Health, being responsible for one of the most important parasitic zoonosis worldwide. T. gondii has a heteroxenous life cycle, with cats being the definitive hosts and all warm-blooded animals, including [...] Read more.
(1) Background: Toxoplasma gondii is a widespread zoonotic agent that greatly impacts Public Health, being responsible for one of the most important parasitic zoonosis worldwide. T. gondii has a heteroxenous life cycle, with cats being the definitive hosts and all warm-blooded animals, including humans, being intermediate hosts. Veterinary practitioners (VP) may be at a higher risk than the general population for T. gondii infection, as they have direct and daily contact with many animal species. The aim of the present study was to ascertain if VP were more likely to be anti-T. gondii IgG seropositive than the general population, as well as to understand if age, accidents with blood-contaminated sharps (cross-blood contamination), gender, working years, and geographic regions play a role as risk factors for T. gondii infection. For this purpose, a case–control study using archived samples was performed. (2) Methods: A total of 350 veterinary practitioners were tested using a commercial semiquantitative enzyme immunoassay for anti-T. gondii IgG. From the general population, 175 anonymous volunteers (matched with cases by region, age, and gender) were studied for anti-T. gondii IgG. (3) Results: There was no statistical difference found between the presence of anti-T. gondii IgG in practitioners (26%; CI = 21.40–30.60%) and the general population (33.14%; CI = 26.17–40.12%) (p = 0.108). Univariate and multivariate analysis showed that only age (older groups) was found to be associated with a higher prevalence of anti-T. gondii IgG, with significant p values (p < 0.05) for both univariate and multivariate analysis. (4) Conclusions: To the best of our knowledge, this is the first case–control study fully focused on the prevalence of anti-T. gondii IgG in VP in Portugal, showing that there was no significant risk for T. gondii infection in veterinarians exposed daily and repeatedly to different species of animals. Full article
(This article belongs to the Special Issue Toxoplasma)
9 pages, 1413 KiB  
Article
Toxoplasmosis in Captive Ring-Tailed Lemurs (Lemur catta)
by Guido Rocchigiani, Niccolò Fonti, Simona Nardoni, Paolo Cavicchio, Francesca Mancianti and Alessandro Poli
Pathogens 2022, 11(10), 1142; https://doi.org/10.3390/pathogens11101142 - 3 Oct 2022
Cited by 2 | Viewed by 3883
Abstract
Toxoplasma gondii is one of the most common protozoan parasites and is widely present in all warm-blooded animals. Although clinical disease is uncommon, some species, including ring-tailed lemurs (Lemur catta), have been found to develop acute and lethal toxoplasmosis. The aim [...] Read more.
Toxoplasma gondii is one of the most common protozoan parasites and is widely present in all warm-blooded animals. Although clinical disease is uncommon, some species, including ring-tailed lemurs (Lemur catta), have been found to develop acute and lethal toxoplasmosis. The aim of this study was to describe the pathologic, immunohistochemical, serological, and molecular findings of an outbreak of fatal toxoplasmosis in three captive ring-tailed lemurs in Central Italy in 2009. The animals died acutely within few days. The necropsy was immediately performed; necrotic lesions in the spleen, liver, and kidney, as well as interstitial pneumonia, were found histologically. All animals had high titers of anti–T. gondii-specific antibodies (1:1280 IgM and 1:640 IgG) according to a modified agglutination test (MAT) and immunohistochemistry showed scattered tachyzoites in the target organs. Diagnosis was confirmed by PCR and clonal type II was identified. In addition, the seven co-habiting lemurs were seronegative. This paper reports the first outbreak of acute disseminated toxoplasmosis in captive ring-tailed lemurs in Italy. These findings confirm the high susceptibility of this endangered species to toxoplasma infection, which may be considered a further threat to captive population viability. Full article
(This article belongs to the Special Issue Toxoplasma)
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8 pages, 1041 KiB  
Article
Diagnostic Accuracy of LDBIO-Toxo II IgG and IgM Western Blot in Suspected Seroconversion in Pregnancy: A Multicentre Study
by Valeria Meroni, Francesca Genco, Luigia Scudeller, Marie-Pierre Brenier-Pinchart, Hélène Fricker-Hidalgo, Coralie L’Ollivier, Luc Paris and Hervé Pelloux
Pathogens 2022, 11(6), 665; https://doi.org/10.3390/pathogens11060665 - 8 Jun 2022
Cited by 2 | Viewed by 2355
Abstract
The high sensitivity of the automated tests used for Toxoplasma gondii serology can yield false-positive IgM results due to aspecific reactions. On the other hand, specific therapy can delay IgG production and, therefore, the diagnosis of seroconversion. There is a need for confirmation [...] Read more.
The high sensitivity of the automated tests used for Toxoplasma gondii serology can yield false-positive IgM results due to aspecific reactions. On the other hand, specific therapy can delay IgG production and, therefore, the diagnosis of seroconversion. There is a need for confirmation tests to early detect seroconversions during pregnancy. We conducted a multicentre study to evaluate the diagnostic accuracy of the Toxo II IgG and a new, not yet commercialised Toxo II IgM western blot (WB) (LDBio diagnostics Lyon France) on 229 sera corresponding to 93 patients with seroconversions and 158 sera corresponding to 68 patients with nonspecific IgM. Sensitivity was 97.8% for IgM WB and 98.9% for IgG WB. Specificity was 89.7% and 100%, respectively. The concordance between IgM and IgG Toxo WB with the final diagnosis was very good, K = 0.89 and K = 0.99, respectively. In 5 cases (5.4%), the appearance of IgM, and in 55 cases (59.1%), the appearance of IgG was recorded by WB earlier than by traditional tests. In 10 cases (10.8%), IgM was detected after the traditional tests and in 2 cases (2.2%) for IgG. The association of IgG and IgM WB on the same sample not only detected all seroconversions but also correctly identified most of the false-positive results. Full article
(This article belongs to the Special Issue Toxoplasma)
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10 pages, 1530 KiB  
Article
Molecular Characterization of Toxoplasma gondii in Cats and Its Zoonotic Potential for Public Health Significance
by Mian Abdul Hafeez, Muntazir Mehdi, Faiza Aslam, Kamran Ashraf, Muhammad Tahir Aleem, Abdur Rauf Khalid, Adeel Sattar, Syeda Fakhra Waheed, Abdulaziz Alouffi, Omar Obaid Alharbi, Muhammad Abu Bakr Shabbir, Umer Chaudhry and Mashal M. Almutairi
Pathogens 2022, 11(4), 437; https://doi.org/10.3390/pathogens11040437 - 4 Apr 2022
Cited by 10 | Viewed by 4112
Abstract
Toxoplasmosis is a globally distributed disease of warm-blooded animals. It is caused by the opportunistic parasite Toxoplasma gondii (T. gondii). One-third of the global human population is believed to be infected with T. gondii. Cats serve as final host of [...] Read more.
Toxoplasmosis is a globally distributed disease of warm-blooded animals. It is caused by the opportunistic parasite Toxoplasma gondii (T. gondii). One-third of the global human population is believed to be infected with T. gondii. Cats serve as final host of T. gondii and are the main source of contamination of soil and water. This study aimed to detect genotypes of T. gondii in cats. Fecal samples (n = 400) were collected from districts of South Punjab (Khanewal and Sahiwal), and were processed by polymerase chain reaction (PCR) followed by sequencing and phylogenetic analysis. The obtained oligonucleotide sequences (T. gondii) were submitted to the GenBank database, and the evolutionary tree was constructed using MEGA-X software. Seven fecal samples (3.5%) from cats were positive. Five out of thirteen fecal samples (38.46%) found to be positive for T. gondii with microscopy were confirmed by PCR. After phylogenetic analysis with 3 clonal types and atypical strains, isolates of T. gondii in current study were more closely linked to a typical strain (AF249696). Besides genotyping from cats, seroprevalence from humans and ruminants is still considered to be the best and easiest way to identify the Toxoplasma. Blood samples were collected from sheep and goats (n = 2000 each), and human blood samples (n = 400) were collected from the same vicinity. Seroprevalence was determined using a commercial enzyme-linked immunosorbent assay (ELISA) kit. In Khanewal, the blood samples of 292 goats (29.2%) and 265 sheep (26.5%), and 6 fecal samples from cats (3%) were positive. Out of 200 human blood samples, 52 were positive, with a seroprevalence of 26%. In the Sahiwal district, the blood samples from 49 humans, 235 sheep and 348 goats were positive, with seroprevalence of 24.5%, 23.5% and 34.8%, respectively. The present study revealed the current circulating genotype of T. gondii from cats in the districts Khanewal and Sahiwal and the seroprevalence of the organism in small ruminants and humans living in the same vicinity. Further genotype analyses of the organism from ruminants and humans are needed. Full article
(This article belongs to the Special Issue Toxoplasma)
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11 pages, 655 KiB  
Article
Seroprevalence of Toxoplasma gondii in Pinnipeds under Human Care and in Wild Pinnipeds
by Micaela Martins, Nuno Urbani, Carla Flanagan, Ursula Siebert, Stephanie Gross, Jitender P. Dubey, Luís Cardoso and Ana Patrícia Lopes
Pathogens 2021, 10(11), 1415; https://doi.org/10.3390/pathogens10111415 - 31 Oct 2021
Cited by 2 | Viewed by 2352
Abstract
Toxoplasma gondii infection has been reported in numerous species of marine mammals, some of them with fatal consequences. A serosurvey for T. gondii infection was conducted in pinnipeds from an oceanographic park in Portugal (n = 60); stranded pinnipeds on the Portuguese [...] Read more.
Toxoplasma gondii infection has been reported in numerous species of marine mammals, some of them with fatal consequences. A serosurvey for T. gondii infection was conducted in pinnipeds from an oceanographic park in Portugal (n = 60); stranded pinnipeds on the Portuguese coast (n = 10); and pinnipeds captured in Lorenzensplate, Germany (n = 99). Sera from 169 pinnipeds were tested for the presence of antibodies to T. gondii by the modified agglutination test with a cut-off titre of 25. An overall seroprevalence of 8.9% (95% confidence interval: 5.1–14.2) was observed. Antibody titres of 25, 50, 100, 1600 and ≥3200 were found in five (33.3%), two (13.3%), five (33.3%), one (6.7%) and two (13.3%) animals, respectively. Pinnipeds under human care had a seroprevalence of 20.0% (12/60), in contrast to 2.8% (3/109) in wild pinnipeds (p < 0.001). General results suggest a low exposure of wild pinnipeds to T. gondii, while the seroprevalence found in pinnipeds under human care highlights the importance of carrying out further studies. This is the first serological survey of T. gondii in pinnipeds in Portugal and the first infection report in South African fur seal (Arctocephalus pusillus pusillus). Full article
(This article belongs to the Special Issue Toxoplasma)
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12 pages, 315 KiB  
Article
Prevalence of Antibodies to Toxoplasma gondii in Different Wild Bird Species Admitted to Rehabilitation Centres in Portugal
by Carolina Lopes, Ricardo Brandão, Ana Filipa Lopes, Roberto Sargo, María Casero, Carolina Nunes, Filipe Silva, Jitender P. Dubey, Luís Cardoso and Ana Patrícia Lopes
Pathogens 2021, 10(9), 1144; https://doi.org/10.3390/pathogens10091144 - 5 Sep 2021
Cited by 7 | Viewed by 3219
Abstract
Toxoplasma gondii is a worldwide zoonotic parasite. According to the “One Health” approach, studies on toxoplasmosis are essential since it affects humans and domestic and wild animals. In the present study, antibodies to T. gondii were determined in serum samples from 263 wild [...] Read more.
Toxoplasma gondii is a worldwide zoonotic parasite. According to the “One Health” approach, studies on toxoplasmosis are essential since it affects humans and domestic and wild animals. In the present study, antibodies to T. gondii were determined in serum samples from 263 wild birds located in five wildlife rehabilitation centres in mainland Portugal by using the modified agglutination test (MAT) with a cut-off titre of 20. An overall seroprevalence of 36.5% (95% confidence interval [CI]: 30.7–42.6) was observed. For the first time, antibodies to T. gondii were detected in some avian species, including pallid swift (Apus pallidus) (33.3%), black-backed gull (Larus fuscus) (39.3%), European turtle-dove (Streptopelia turtur) (100%), bee-eater (Merops apiaster) (50.0%), carrion crow (Corvus corone) (33.3%), and Egyptian vulture (Neophron percnopterus) (100%), which expands the list of intermediate hosts of T. gondii. A lower seroprevalence was found in juvenile birds (31.9%) compared to adults (48.7%) (p = 0.016). The central region of Portugal was considered a risk factor for T. gondii infection in wild birds (odds ratio: 3.61; 95% CI: 1.09–11.91). This pioneer study calls attention to the need for further studies, to provide a clearer understanding of T. gondii epidemiology in Portugal, because it reflects wide dispersion of T. gondii oocysts in the environment. Full article
(This article belongs to the Special Issue Toxoplasma)
15 pages, 1996 KiB  
Article
Development of Human Toxo IgG ELISA Kit, and False-Positivity of Latex Agglutination Test for the Diagnosis of Toxoplasmosis
by Sarfraz-ur-Rahman, Haroon Akbar, Muhammad Zubair Shabbir, Ubaid Ullah and Muhammad Imran Rashid
Pathogens 2021, 10(9), 1111; https://doi.org/10.3390/pathogens10091111 - 31 Aug 2021
Cited by 9 | Viewed by 4029
Abstract
Toxoplasma gondii is an intracellular zoonotic parasite that causes infection in a wide range of warm-blooded animals and humans. The main aim of this study was to assess the diagnostic value of the recombinant SAG1 antigen (rSAG1) for T. gondii-IgG screening through [...] Read more.
Toxoplasma gondii is an intracellular zoonotic parasite that causes infection in a wide range of warm-blooded animals and humans. The main aim of this study was to assess the diagnostic value of the recombinant SAG1 antigen (rSAG1) for T. gondii-IgG screening through the Human Toxo IgG ELISA Kit (K). The rSAG1 was expressed in E. coli (DE3), and it was purified through metal-affinity chromatography. The rSAG1 was confirmed by immunoblotting, and it had a band on 35 kDa. Total of 400 human sera were tested by LAT and K. One hundred and twenty-two (30.5%) sera were found positive by LAT and eighty-nine (22.25%) sera were found positive by K. Out of 400 samples, 80 were selected to evaluate the performance of K through commercial Toxoplasma gondii IgG ELISA Kit (C). Out of 80 human sera, 55 (68.75%) were found positive, 25 (31.25%) were found negative by K and C, respectively. The cut-off value for K was 0.398 and it was calculated through the receiver operator characteristic curve. The ELISA plates were coated at optimized concentration of rSAG1 = 0.125 µg/mL, and the test was performed by diluting the sera at 1:50. The sensitivity and specificity of K were observed to be 98.5% and 100%, respectively. The six sera (KL+) were found positive through LAT and these human sera were later evaluated by Western blot analysis. These sera did not produce a band equivalent to 35 kDa on WB analysis thus, LAT produced false-positive results. Full article
(This article belongs to the Special Issue Toxoplasma)
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13 pages, 903 KiB  
Article
Seroprevalence and Epidemiology of Toxoplasma gondii in Animals in the Qinghai-Tibetan Plateau Area, China
by Guojing Li, Wangli Zheng, Jinfang Yang, Tongsheng Qi, Yongcai He, Wangkai Chen, Hejia Ma, Yali Sun, Ying Li, Ming Kang and Jixu Li
Pathogens 2021, 10(4), 432; https://doi.org/10.3390/pathogens10040432 - 6 Apr 2021
Cited by 9 | Viewed by 2659
Abstract
Toxoplasma gondii belongs to the Apicomplexan protozoa—an obligate intracellular parasite—causing toxoplasmosis that has a worldwide distribution and is very harmful to both human health and the livestock industry. However, the information on toxoplasmosis in the Qinghai-Tibetan Plateau Area (QTPA) and the seroprevalence of [...] Read more.
Toxoplasma gondii belongs to the Apicomplexan protozoa—an obligate intracellular parasite—causing toxoplasmosis that has a worldwide distribution and is very harmful to both human health and the livestock industry. However, the information on toxoplasmosis in the Qinghai-Tibetan Plateau Area (QTPA) and the seroprevalence of T. gondii in the food-borne animals in that area has been limited. Therefore, this study focused to T. gondii and toxoplasmosis to perform an indirect ELISA test based on recombinant TgSAG2 protein to establish a comprehensive record of the seroprevalence of T. gondii infections in a wide range of animals, including Tibetan sheep (Ovis aries), yaks (Bos grunniens), cows, chicken, pigs, and horses, in the QTPA. Overall, the seropositive rates of the specific-T. gondii IgG and IgM antibodies in all investigated animals were 44.1% (1179/2673) and 18.0% (469/2612), respectively. The 14.9% (389/2612) sera were determined to be both IgG and IgM positive samples, 30.2% (789/2673) were single-IgG seropositive, and a total of 80 in 2612 animals (3.0%) were single-IgM seropositive. Moreover, for the animal species, the pig was the most prevalent animal (90.2%, 304/337) for IgG positivity, followed by Tibetan sheep (50.7%, 460/907), chickens (45.8%, 229/500), yaks (21.1%, 140/663), cows (18.5%, 38/205) and horses (13.1%, 8/61), respectively. For the IgM antibody positivity, the pig was also the most prevalent animal (41.8%, 141/337), followed by Tibetan sheep (21.2%, 191/907), cows (15.1%, 31/205), chickens (12.4%, 62/500) and yaks (6.6%, 44/663), respectively. The significant differences in the prevalent distribution of T. gondii were found in the different altitudes. In conclusion, this study found the high seroprevalence for T. gondii infections among these animal species in the QTPA, and provides new data to facilitate further research for development of control measures against T. gondii infections in the surveyed locations. Full article
(This article belongs to the Special Issue Toxoplasma)
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