Polymerase chain reaction (PCR) in ocular and ganglionar toxoplasmosis and the effect of therapeutics for prevention of ocular involvement in South American setting

Marín, Jorge Enrique Gómez; Zuluaga, Juan David; Campo, Eunice Julied Pechené; Triviño, Jessica; de-la-Torre, Alejandra

doi:10.1016/j.actatropica.2018.01.013

Cited by 21 publications

(9 citation statements)

References 25 publications

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“…A high prevalence of retinochoroidal scars (6%) was previously observed in a population of young university students in Colombia [18]. Notably, 10%-20% of T. gondii infections in immune-competent adults and children are symptomatic [23]. Ocular symptoms in acquired OT include blurred vision, scotoma, ocular pain, photophobia, epiphora, or loss of central vision; such symptoms may be easily distinguishable when they first occur [8,24].…”

Section: Discussionmentioning

confidence: 98%

High frequency of ocular toxoplasmosis in Quindío, Colombia and risk factors related to the infection

Gómez‐Marín

Muñoz-Ortíz

Mejía-Oquendo

et al. 2021

Heliyon

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Objectives To determine the frequency of retinochoroidal lesions by ocular toxoplasmosis and their relationships with risk factors, in residents of two districts with high exposure to Toxoplasma, in Armenia-Quindío, Colombia. Methods Cross-sectional analyses of fundoscopy screening, serological tests, and questionnaires were performed to determine risk factors associated with ocular toxoplasmosis retinochoroidal lesions. Differences in proportions were analyzed using the chi-squared test. Results Of 161 individuals examined, 17 (10.5%) exhibited retinochoroidal scars suggestive of old inactive Toxoplasma gondii infection. All 17 individuals were seropositive for T. gondii antibodies. Consumption of bottled water was protective against T. gondii infection among individuals in this study. There were no specific epidemiological risk factors associated with ocular toxoplasmosis retinochoroidal lesions. Conclusion Ocular toxoplasmosis is an important cause of visual impairment in Armenia-Quindío, Colombia. The consumption of boiled or bottled water is a major preventive public health measure to reduce infection by T. gondii and the subsequent onset of OT.

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Section: Discussionmentioning

confidence: 98%

High frequency of ocular toxoplasmosis in Quindío, Colombia and risk factors related to the infection

Gómez‐Marín

Muñoz-Ortíz

Mejía-Oquendo

et al. 2021

Heliyon

Self Cite

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“…Although clinical examination is the standard method for the diagnosis of OT in the second and third forms of the disease (old scars and reactivated disease), the first form of disease (active lesions) cannot always be differentiated from other chorioretinal inflammations based on funduscopic appearance alone [ 34 ]. Based on the previous studies, ocular fluid samples are the most sensitive sources for the molecular diagnosis of OT [ 15 , 34 , 35 ]. Molecular examination of the aqueous humor puncture allows identification of coinfections or various etiological agents for the infectious uveitis.…”

Section: Discussionmentioning

confidence: 99%

“…Nested-PCR with REP-529 target included 57 and 100% sensitivity and specificity in diagnosis of recently acquired OT, respectively [ 25 ]. In contrast, studies have revealed that molecular testing on peripheral blood samples is not sufficiently sensitive for the detection of T. gondii in patients with OT [ 35 ]. In a study, Bourdin et al reported 35.9% sensitivity in diagnosis of OT using PCR of peripheral blood samples.…”

Section: Discussionmentioning

confidence: 99%

Utility of blood as the clinical specimen for the diagnosis of ocular toxoplasmosis using uracil DNA glycosylase-supplemented loop-mediated isothermal amplification and real-time polymerase chain reaction assays based on REP-529 sequence and B1 gene

et al. 2022

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Background Ocular infection with Toxoplasma gondii is a major preventable cause of blindness, especially in young people. The aim of the present study was to assess detection rate of T. gondii DNA in blood samples of clinically diagnosed of ocular toxoplasmosis using uracil DNA glycosylase-supplemented loop-mediated isothermal amplification (UDG-LAMP) and real-time quantitative PCR (qPCR) based on REP-529 and B1. Methods One hundred and seventeen patients with clinically diagnosed ocular toxoplasmosis (OT) were participated in the study as well as 200 control patients. Peripheral blood samples were assessed using UDG-LAMP and qPCR techniques targeting REP-529 and B1. Results Detection limits of qPCR using REP-529 and B1 were estimated as 0.1 and 1 fg of T. gondii genomic DNA, respectively. The limits of detection for UDG-LAMP using REP-529 and B1 were 1 and 100 fg, respectively. In this study, 18 and 16 patients were positive in qPCR using REP-529 and B1, respectively. Based on the results of UDG-LAMP, 15 and 14 patients were positive using REP-529 and B1, respectively. Results of the study on patients with active ocular lesion showed that sensitivity of REP-529 and BI targets included 64 and 63%, respectively using qPCR. Sensitivity of 62 and 61%, were concluded from UDG-LAMP using REP-529 and B1 in the blood cases of active ocular lesion. qPCR was more sensitive than UDG-LAMP for the detection of Toxoplasma gondii DNA in peripheral blood samples of patients with clinically diagnosed toxoplasmic chorioretinitis. Furthermore, the REP-529 included a better detection rate for the diagnosis of ocular toxoplasmosis in blood samples, compared to that the B1 gene did. Moreover, the qPCR and UDG-LAMP specificity assessments have demonstrated no amplifications of DNAs extracted from other microorganisms based on REP-529 and B1. Conclusions Data from the current study suggest that qPCR and UDG-LAMP based on the REP-529 are promising diagnostic methods for the diagnosis of ocular toxoplasmosis in blood samples of patients with active chorioretinal lesions.

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“…gondii have reported that 48.6% of IgM seropositive patients were also positive by PCR, falling to 3.6% in IgM negative, IgG positive chronically infected patients [ 39 ]. In a separate study, 31% of asymptomatic chronically infected people tested positive by PCR [ 40 ]. Here, similar levels of detection were reported from IgM and IgG positve women.…”

Section: Discussionmentioning

confidence: 99%

Detection and genetic characterisation of Toxoplasma gondii circulating in free-range chickens, pigs and seropositive pregnant women in Benue state, Nigeria

et al. 2021

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Toxoplasma gondii parasites present strong but geographically varied signatures of population structure. Populations sampled from Europe and North America have commonly been defined by over-representation of a small number of clonal types, in contrast to greater diversity in South America. The occurrence and extent of genetic diversity in African T. gondii populations remains understudied, undermining assessments of risk and transmission. The present study was designed to establish the occurrence, genotype and phylogeny of T. gondii in meat samples collected from livestock produced for human consumption (free-range chickens, n = 173; pigs, n = 211), comparing with T. gondii detected in blood samples collected from seropositive pregnant women (n = 91) in Benue state, Nigeria. The presence of T. gondii DNA was determined using a published nested polymerase chain reaction, targeting the 529 bp multicopy gene element. Samples with the highest parasite load (assessed using quantitative PCR) were selected for PCR-restriction fragment length polymorphism (PCR-RFLP) targeting the surface antigen 3 (SAG3), SAG2 (5’ and 3’), beta-tubulin (BTUB) and dense granule protein 6 (GRA6) loci, and the apicoplast genome (Apico). Toxoplasma gondii DNA was detected in all three of the populations sampled, presenting 30.6, 31.3 and 25.3% occurrence in free-range chickens, pigs and seropositive pregnant women, respectively. Quantitative-PCR indicated low parasite occurrence in most positive samples, limiting some further molecular analyses. PCR-RFLP results suggested that T. gondii circulating in the sampled populations presented with a type II genetic background, although all included a hybrid type I/II or II/III haplotype. Concatenation of aligned RFLP amplicon sequences revealed limited diversity with nine haplotypes and little indication of host species-specific or spatially distributed sub-populations. Samples collected from humans shared haplotypes with free-range chickens and/or pigs. Africa remains under-explored for T. gondii genetic diversity and this study provides the first detailed definition of haplotypes circulating in human and animal populations in Nigeria.

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Polymerase chain reaction (PCR) in ocular and ganglionar toxoplasmosis and the effect of therapeutics for prevention of ocular involvement in South American setting

Cited by 21 publications

References 25 publications

High frequency of ocular toxoplasmosis in Quindío, Colombia and risk factors related to the infection

High frequency of ocular toxoplasmosis in Quindío, Colombia and risk factors related to the infection

Utility of blood as the clinical specimen for the diagnosis of ocular toxoplasmosis using uracil DNA glycosylase-supplemented loop-mediated isothermal amplification and real-time polymerase chain reaction assays based on REP-529 sequence and B1 gene

Detection and genetic characterisation of Toxoplasma gondii circulating in free-range chickens, pigs and seropositive pregnant women in Benue state, Nigeria

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