High prevalence and abundant atypical genotypes of Toxoplasma gondii isolated from lambs destined for human consumption in the USA

Dubey, J. P.; Natarajan, Sundar; Hill, Dolores E.; Velmurugan, G. V.; Bandini, Luciana Ahlf; Kwok, O. C. H.; Majumdar, D.; Su, Chunlei

doi:10.1016/j.ijpara.2007.11.012

Cited by 171 publications

(76 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…#9 (n = 1) u -1 II II III III II II III II II I TgWolfAK1 This study. Also identified from a sheep in USA (Dubey et al, 2008c In the present study, T. gondii was isolated from a single seropositive opossum from Georgia, USA. Smith and Frenkel (1995) isolated T. gondii from one of three dye test positive opossums from Kansas, and to our knowledge this isolate was not genotyped.…”

Section: Genetic Typingmentioning

confidence: 75%

“…Dubey et al (2007c) a Also identified from sheep (Dubey et al, 2008c) and pigs III III III I III I III III III III TgFsUS1 This study. #9 (n = 1) u -1 II II III III II II III II II I TgWolfAK1 This study.…”

Section: Genetic Typingmentioning

confidence: 99%

“…Tissues were homogenised, digested in acidic pepsin, washed and aliquots of homogenates were inoculated s.c. into two to five outbred Swiss Webster (SW) mice ) and/or two knockout (KO) mice (Dubey et al, 2008c). Tissue imprints of lungs and brains of inoculated mice that died were examined for T. gondii tachyzoites or tissue cysts.…”

Section: Bioassay In Micementioning

confidence: 99%

See 2 more Smart Citations

Genetic characterisation of Toxoplasma gondii in wildlife from North America revealed widespread and high prevalence of the fourth clonal type

Dubey

Velmurugan

Rajendran

et al. 2011

International Journal for Parasitology

Self Cite

162

View full text Add to dashboard Cite

a b s t r a c tLittle is known of the genetic diversity of Toxoplasma gondii circulating in wildlife. In the present study wild animals, from the USA were examined for T. gondii infection. Tissues of naturally exposed animals were bioassayed in mice for isolation of viable parasites. Viable T. gondii was isolated from 31 animals including, to our knowledge for the first time, from a bald eagle (Haliaeetus leucocephalus), five gray wolves (Canis lupus), a woodrat (Neotoma micropus), and five Arctic foxes (Alopex lagopus). Additionally, 66 T. gondii isolates obtained previously, but not genetically characterised, were revived in mice. Toxoplasma gondii DNA isolated from these 97 samples (31 + 66) was characterised using 11 PCR-restriction fragment length polymorphism (RFLP) markers (SAG1, 5 0 -and 3 0 -SAG2, alt.SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 and Apico). A total of 95 isolates were successfully genotyped. In addition to clonal Types II, and III, 12 different genotypes were found. These genotype data were combined with 74 T. gondii isolates previously characterised from wildlife from North America and a composite data set of 169 isolates comprised 22 genotypes, including clonal Types II, III and 20 atypical genotypes. Phylogenetic network analysis showed limited diversity with dominance of a recently designated fourth clonal type (Type 12) in North America, followed by the Type II and III lineages. These three major lineages together accounted for 85% of strains in North America. The Type 12 lineage includes previously identified Type A and X strains from sea otters. This study revealed that the Type 12 lineage accounts for 46.7% (79/169) of isolates and is dominant in wildlife of North America. No clonal Type I strain was identified among these wildlife isolates. These results suggest that T. gondii strains in wildlife from North America have limited diversity, with the occurrence of only a few major clonal types. Ó

show abstract

Section: Genetic Typingmentioning

confidence: 75%

Section: Genetic Typingmentioning

confidence: 99%

See 1 more Smart Citation

Genetic characterisation of Toxoplasma gondii in wildlife from North America revealed widespread and high prevalence of the fourth clonal type

Dubey

Velmurugan

Rajendran

et al. 2011

International Journal for Parasitology

Self Cite

162

View full text Add to dashboard Cite

show abstract

“…Avirulent Toxoplasma strains, particularly the type II archetype and its ancestral derivatives such as haplogroup 12 (33), are dominant in infections of humans and their domesticated animals in Europe and North America (34)(35)(36)(37). However, the infections caused by virulent type I strains are rare (19).…”

Section: Discussionmentioning

confidence: 99%

Avirulent strains of Toxoplasma gondii infect macrophages by active invasion from the phagosome

Zhao

Marple

Ferguson

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Unlike most intracellular pathogens that gain access into host cells through endocytic pathways, Toxoplasma gondii initiates infection at the cell surface by active penetration through a moving junction and subsequent formation of a parasitophorous vacuole. Here, we describe a noncanonical pathway for T. gondii infection of macrophages, in which parasites are initially internalized through phagocytosis, and then actively invade from within a phagosomal compartment to form a parasitophorous vacuole. This phagosome to vacuole invasion (PTVI) pathway may represent an intermediary link between the endocytic and the penetrative routes for host cell entry by intracellular pathogens. The PTVI pathway is preferentially used by avirulent strains of T. gondii and confers an infectious advantage over virulent strains for macrophage tropism.virulence | Trojan horse | apicomplexa | phagocytes P hagocytosis is one of the most ancient defense mechanisms for the host to destroy invasive pathogens. However, most intracellular pathogens exploit this very pathway for internalization and survival in phagocytes (1). A notable exception to this paradigm is the infection pathway used by apicomplexan parasites-exemplified by Toxoplasma gondii. The current consensus model of T. gondii infection suggests that the parasite actively invades host cells by forming a moving junction (MJ) at the host cell surface (2). Penetration of T. gondii through this junction is largely driven by its own actin motor complex (3). The parasitophorous vacuoles formed by this pathway are nonfusogenic with the host endocytic system, thus evading lysosome-mediated destruction (4-6). However, recent reports including the findings that host F-actin participates in entry by T. gondii (7), and that the parasite is still able to infect cells, albeit much less efficiently, even without some key components of the invasion machinery (8), suggest the existence of alternative infection pathways for Toxoplasma. The active penetration model was defined largely by using nonphagocytic host cells and hypervirulent strains of the parasite. Unlike their virulent counterparts, the interaction of avirulent Toxoplasma strains with macrophage and dendritic cell results in heightened innate cytokine and chemokine production (9) and the development of a "hypermotile" host cellular phenotype (10), which promotes the control of acute infection and mediates dissemination into sites of parasite latency (11,12). Here, we investigated whether avirulent parasites interact with phagocytic host cells in a fundamentally different way from the outset. We found that the avirulent Toxoplasma strains infect macrophages initially via phagocytosis and subsequent active penetration from within the phagosome to form a parasitophorous vacuole. This hybrid invasion pathway may represent an intermediary link between the endocytic and the penetrative routes for host cell entry by intracellular pathogens. ResultsTo investigate whether avirulent Toxoplasma (PTG, type II strain) uses the active penetration p...

show abstract

“…26 The possible mechanism leading to the observed mixed infection is the ingestion of tissue cysts from infected meat. 27 Mutton is the meat most commonly incriminated in the transmission of toxoplasmosis in Tunisia, and it could be seen as a real source of contamination. 28 Genotypic characterization of T. gondii in sheep in Tunisia could help to establish correlation between mixed infections in humans in Tunisia and contaminated mutton.…”

Section: Discussionmentioning

confidence: 99%

Direct Genotypic Characterization of Toxoplasma gondii Strains Associated with Congenital Toxoplasmosis in Tunisia (North Africa)

Boughattas¹,

Ben-Abdallah²,

Siala³

et al. 2010

The American Society of Tropical Medicine and Hygiene

View full text Add to dashboard Cite

Here, we determined the Toxoplasma gondii genotype in amniotic fluid, placenta, and cerebrospinal fluid samples from 14 congenital toxoplasmosis cases in Tunisia, North Africa. Direct genotypic characterization of T. gondii strains was performed by polymerase chain reaction (PCR) amplification of six genetic markers (3'SAG2, 5' SAG2, SAG3, BTUB, GRA6, and APICO) and thereafter, was analyzed by restriction fragment-length polymorphism (RFLP). Samples were sequenced to resolve strain type whenever there were unclear enzyme digestion results. Multilocus analysis revealed that only one specimen harbored the type I allele in all studied loci, whereas the 13 others gave mixed genotype results with different alleles at different markers. Seven specimens produced RFLP profile of the recombinant strains I/III, and three produced a profile of I/II recombinant strains. The last three specimens produced complex digestion patterns. In these cases, sequence analysis revealed double peaks at known polymorphic sites, indicating the presence of multiple alleles.

show abstract

High prevalence and abundant atypical genotypes of Toxoplasma gondii isolated from lambs destined for human consumption in the USA

Cited by 171 publications

References 40 publications

Genetic characterisation of Toxoplasma gondii in wildlife from North America revealed widespread and high prevalence of the fourth clonal type

Genetic characterisation of Toxoplasma gondii in wildlife from North America revealed widespread and high prevalence of the fourth clonal type

Avirulent strains of Toxoplasma gondii infect macrophages by active invasion from the phagosome

Direct Genotypic Characterization of Toxoplasma gondii Strains Associated with Congenital Toxoplasmosis in Tunisia (North Africa)

Contact Info

Product

Resources

About