Toxoplasmic Retinochoroiditis: Clinical Characteristics and Visual Outcome in a Prospective Study

Clinical characteristics, visual acuity outcomes, and factors associated with loss of vision among patients with active ocular toxoplasmosis: A retrospective study in a Thai tertiary center

BACKGROUND

Ocular toxoplasmosis (OT) is the most common cause of infectious uveitis worldwide, including Thailand. This study describes the clinical presentation, visual acuity (VA) outcomes, and factors associated with VA loss in patients with active OT following antiparasitic treatment.

METHODOLOGY/PRINCIPAL FINDINGS

A retrospective chart review of patients with active OT treated with antiparasitic drugs between 2010 and 2020 was performed. Outcome measures included clinical characteristics, interval VA, and predictive factors associated with loss of VA ≤ 20/50 at 6 months post-treatment. Ninety-two patients (95 eyes) were enrolled. The median follow-up time was 10.9 months (IQR 4.9-31.8 months). The median age at presentation was 35.9 years, 51% were male, and 92.4% had unilateral OT. Eleven patients (12%) were immunocompromised (HIV infection, eight patients; receiving immunosuppressive agents, three patients). Patients mainly presented with primary retinitis without previous scar (62%), posterior pole lesion (56%), and lesion size of ≤ 2-disc area (75%). Immunocompromised patients showed a significantly larger size of retinitis than immunocompetent patients. Oral trimethoprim/sulfamethoxazole monotherapy was the primary short-term antiparasitic drug prescribed (85%). At the final visit, 21% of all affected eyes suffered VA ≤ 20/200. The cumulative incidence of recurrent OT at three years was 33.9% (95% CI, 19.7%-54.2%). Immunocompromised patients [adjusted odds ratio (aOR) 4.9, p = 0.041], macular lesion (aOR 5.4, p = 0.032), and initial VA ≤ 20/200 (aOR 9.1, p = 0.014) were predictive of having VA ≤ 20/50 at 6 months post-treatment.

CONCLUSIONS

Ocular toxoplasmosis mainly presents as unilateral primary retinitis within the posterior pole. Severe VA loss was observed in one-fifth of eyes following treatment with lesion resolution. Immunocompromised patients, eyes with macular lesions, and poor initial VA were associated with poor VA outcomes.

Proline Isomerization and Molten Globular Property of TgPDCD5 Secreted from Toxoplasma gondii Confers Its Regulation of Heparin Sulfate Binding

Toxoplasmosis, caused by Toxoplasma gondii, poses risks to vulnerable populations. TgPDCD5, a secreted protein of T. gondii, induces apoptosis through heparan sulfate-mediated endocytosis. The entry mechanism of TgPDCD5 has remained elusive. Here, we present the solution structure of TgPDCD5 as a helical bundle with an extended N-terminal helix, exhibiting molten globule characteristics. NMR perturbation studies reveal heparin/heparan sulfate binding involving the heparan sulfate/heparin proteoglycans-binding motif and the core region, influenced by proline isomerization of P107 residue. The heterogeneous proline recruits a cyclophilin TgCyp18, accelerating interconversion between conformers and regulating heparan/heparin binding. These atomic-level insights elucidate the binary switch's functionality, expose novel heparan sulfate-binding surfaces, and illuminate the unconventional cellular entry of pathogenic TgPDCD5.

Impact of gender on clinical features and outcomes of ocular toxoplasmosis

AIM

To investigate the effect of gender on the clinical features and outcomes of ocular toxoplasmosis.

METHODS

262 patients (139 women and 123 men) presenting to a tertiary referral uveitis service in Ribeirão Preto, Brazil, with serological and clinical evidence of ocular toxoplasmosis were prospectively enrolled in an observational study. Predefined data items including demographics, descriptors of uveitis and ocular toxoplasmosis, best-corrected visual acuity and ocular complications were disaggregated by gender and compared statistically.

RESULTS

Approximately equal numbers of women and men had active versus inactive ocular toxoplasmosis. In both women and men, most infections were remotely acquired. Men were significantly more likely to present with primary active disease than women (24.4% vs 12.9%); conversely, women were significantly more likely to present with recurrent active disease than men (36.0% vs 28.5%). One toxoplasmic retinal lesion was observed in more eyes of men than eyes of women (50.4% vs 35.3%), while women's eyes were more likely to have multiple lesions than men's eyes (54.7% vs 39.8%). Lesions in women's eyes were significantly more likely to occur at the posterior pole compared with those in men's eyes (56.1% vs 39.8%). Measures of vision were similar for women and men. There were no significant differences in measures of visual acuity, ocular complications, and occurrence and timing of reactivations between the genders.

CONCLUSION

Ocular toxoplasmosis has equivalent outcomes in women and men, with clinical differences in the form and type of disease, as well as characteristics of the retinal lesion.

OUTCOMES OF INFECTIOUS PANUVEITIS ASSOCIATED WITH SIMULTANEOUS MULTI-POSITIVE OCULAR FLUID POLYMERASE CHAIN REACTION

PURPOSE

To evaluate features of infectious panuveitis associated with multiple pathogens detected by ocular fluid sampling.

METHODS

Single-center, retrospective, consecutive case series of patients with aqueous/vitreous polymerase chain reaction testing with >1 positive result in a single sample from 2001 to 2021.

RESULTS

Of 1,588 polymerase chain reaction samples, 28 (1.76%) were positive for two pathogens. Most common pathogens were cytomegalovirus (n = 16, 57.1%) and Epstein-Barr virus (n = 13, 46.4%), followed by varicella zoster virus (n = 8, 28.6%), Toxoplasma gondii (n = 6, 21.4%), herpes simplex virus 2 (n = 6, 21.4%), herpes simplex virus 1 (n = 6, 21.4%), and Toxocara (n = 1, 3.6%). Mean initial and final visual acuity (logarithm of the minimum angle of resolution) were 1.3 ± 0.9 (Snellen ∼20/400) and 1.3 ± 1.1 (Snellen ∼20/400), respectively. Cytomegalovirus-positive eyes (n = 16, 61.5%) had a mean final visual acuity of 0.94 ± 1.1 (Snellen ∼20/175), whereas cytomegalovirus-negative eyes (n = 10, 38%) had a final visual acuity of 1.82 ± 1.0 (Snellen ∼20/1,320) ( P < 0.05). Main clinical features included intraocular inflammation (100%), retinal whitening (84.6%), immunosuppression (65.4%), retinal hemorrhage (38.5%), and retinal detachment (34.6%).

CONCLUSION

Cytomegalovirus or Epstein-Barr virus were common unique pathogens identified in multi-PCR-positive samples. Most patients with co-infection were immunosuppressed with a high rate of retinal detachment and poor final visual acuity. Cytomegalovirus-positive eyes had better visual outcomes compared with cytomegalovirus-negative eyes.

Gender differences in retinal diseases: A review

Gender medicine is a medical specialty that addresses gender differences in health and disease. Traditionally, medical research and clinical practice have often been focused on male subjects and patients. As a result, gender differences in medicine have been overlooked. Gender medicine considers the biological, psychological, and social differences between the genders and how these differences affect the development, diagnosis, treatment, and prevention of disease. For ophthalmological diseases epidemiological differences are known. However, there are not yet any gender-based ophthalmic treatment approaches for women and men. This review provides an overview of gender differences in retinal diseases. It is intended to make ophthalmologists, especially retinologists, more sensitive to the topic of gender medicine. The goal is to enhance comprehension of these aspects by highlighting fundamental gender differences. Integrating gender medicine into ophthalmological practice helps promote personalized and gender-responsive health care and makes medical research more accurate and relevant to the entire population.

The role of age in ocular toxoplasmosis: clinical signs of immunosenescence and inflammaging

Purpose

This study aimed to investigate the association between age, immune response, and clinical presentation of ocular toxoplasmosis (OT).

Design

This was a monocentric, retrospective, observational cohort study.

Methods

A review of the medical records of patients with active OT at the Uveitis Center, Charité Universitätsmedizin, was conducted. Baseline parameters included age at presentation, visual acuity, intraocular pressure (IOP), size and location of active lesions, inflammatory activity, antibody index (AI), and complications of intraocular inflammation. The data were presented as the mean ± standard deviation (SD). The level of significance was set at a p-value of <0.05.

Results

Between 1998 and 2019, 290 patients with active OT were diagnosed at our tertiary reference center. The mean age of the participants was 37.7 ± 17.1 years, 53.8% of them were female individuals, and 195 patients (70.9%) showed recurrent disease. Older age was associated with lower baseline visual acuity (p = 0.043), poor visual outcome (p = 0.019), increased inflammatory activity (p < 0.005), and larger retinal lesions (p < 0.005). Older patients presented a lower AI (<35 years: 45.1 ± 82.7, median: 12.1; ≥35 years: 18.6 ± 50.5, median: 5.8; p = 0.046), confirmed by a decrease in AI with increasing age (R2 = 0.045; p = 0.024). Finally, AI was correlated with lesion size (multiple linear regression analysis: p = 0.043). Macular involvement (24.3% of patients) was positively correlated with complications (macular/peripapillary edema and retinal detachment, p < 0.005) and poor visual outcome (p < 0.005) and was negatively correlated with inflammatory activity (p < 0.005).

Conclusion

We found a strong and clinically relevant impact of age on the clinical presentation and course of OT. While an unspecific inflammatory response increased with age, the specific, local humoral immune response declined. These findings are well in line with the concept of immunosenescence and inflammaging in uveitis.

Anti-Toxoplasma gondii effect of tylosin in vitro and in vivo

BACKGROUND

Toxoplasma gondii is an important protozoan pathogen with medical and veterinary importance worldwide. Drugs currently used for treatment of toxoplasmosis are less effective and sometimes cause serious side effects. There is an urgent need for the development of more effective drugs with relatively low toxicity.

METHODS

The effect of tylosin on the viability of host cells was measured using CCK8 assays. To assess the inhibition of tylosin on T. gondii proliferation, a real-time PCR targeting the B1 gene was developed for T. gondii detection and quantification. Total RNA was extracted from parasites treated with tylosin and then subjected to transcriptome analysis by RNA sequencing (RNA-seq). Finally, murine infection models of toxoplasmosis were used to evaluate the protective efficacy of tylosin against T. gondii virulent RH strain or avirulent ME49 strain.

RESULTS

We found that tylosin displayed low host toxicity, and its 50% inhibitory concentration was 175.3 μM. Tylsoin also inhibited intracellular T. gondii tachyzoite proliferation, with a 50% effective concentration of 9.759 μM. Transcriptome analysis showed that tylosin remarkably perturbed the gene expression of T. gondii, and genes involved in "ribosome biogenesis (GO:0042254)" and "ribosome (GO:0005840)" were significantly dys-regulated. In a murine model, tylosin treatment alone (100 mg/kg, i.p.) or in combination with sulfadiazine sodium (200 mg/kg, i.g.) significantly prolonged the survival time and raised the survival rate of animals infected with T. gondii virulent RH or avirulent ME49 strain. Meanwhile, treatment with tylosin significantly decreased the parasite burdens in multiple organs and decreased the spleen index of mice with acute toxoplasmosis.

CONCLUSIONS

Our findings suggest that tylosin exhibited potency against T. gondii both in vitro and in vivo, which offers promise for treatment of human toxoplasmosis.

Comparison of immunological and molecular methods for laboratory diagnosis of ocular toxoplasmosis in blood, serum and tears in Brazil

Ocular toxoplasmosis (OT) is caused by protozoan T. gondii. Ophthalmological examination is considered the gold standard for OT diagnosis, and laboratory tests are used for diagnostic confirmation. However, these tests can present different results, which change depending on their basis, on sample type and on patients' clinical alteration. Thus, the aim of the present study is to assess immunodiagnostic and molecular techniques applied in blood, serum and tear fluid to diagnose T. gondii infection in patients seen at an Ophthalmology Clinic. In total, 160 patients were included in the study, 40 of them had OT with active lesions (G1); 40 had OT with healed lesions (G2), 40 had non-toxoplasmic uveitis (G3) and 40 had no ocular alterations (G4). Serum samples were subjected to Immunoenzymatic Assay (ELISA) and to Indirect Immunofluorescence Reaction (IFAT) to search for anti-T. gondii IgM and IgG. Tear fluid samples were analyzed through ELISA for IgA research. All blood and tear fluid samples were subjected to conventional polymerase chain reaction (cPCR) and in a Nested PCR model for T. gondii DNA amplification with targets B1, GRA7 and REP 529. IgG and IgM anti-T. gondii was detected in serum samples from 106 and 15 patients, respectively, when combining ELISA and IFAT results. Anti-T.gondii IgA antibodies were detected in 9.2% of the tear material. Nested PCR with GRA7 target showed higher positivity in blood samples (24.4%); Nested PCR with B1 target showed a higher frequency of positivity in tears (15%). Biological samples of patients with active lesions showed the highest positivity frequencies in all immunodiagnostic assays, as well as in most PCR models. The present results highlighted the need of associating techniques with different fundamentals to confirm OT diagnosis. Furthermore, further tear fluid analyses should be performed to validate this biological material as lesser invasive alternative for the more accurate OT diagnosis.

Atypical Ocular Toxoplasmosis With Remote Vasculitis and Kyrieleis Plaques

Retinal vasculitis is common in ocular toxoplasmosis (OT) and typically occurs in the same quadrant as retinochoroiditis. This is a case of atypical ocular toxoplasmosis with remote vasculitis distant from the retinochoroiditis lesion. Examination of the left fundus showed the classic posterior segment finding of "headlight in the fog" in the absence of a chorioretinal scar. Retinal vasculitis was noted in all four quadrants at the periphery far from the retinitis area. A presumptive diagnosis of acute panuveitis secondary to ocular toxoplasmosis was made despite the enzyme-linked immunosorbent assay (ELISA) for Toxoplasmosis antibody being pending. The patient was treated empirically with oral sulfamethoxazole-trimethoprim for eight weeks and received both oral and topical corticosteroids. His symptoms and ocular signs have significantly improved. This case report highlights an atypical remote localization of vasculitis with the classic appearance of retinochoroiditis and vitritis, which is highly due to toxoplasmosis. Early initiation of antibiotic therapy is recommended despite pending serology to ensure a good final visual and ocular outcome.

Outcomes of trimethoprim/ sulfamethoxazole treatment for ocular toxoplasmosis in Congolese patients

BACKGROUND

Ocular toxoplasmosis (OT) is the leading cause of infectious posterior uveitis in several areas worldwide. The combination of Trimethoprim/Sulfamethoxazole (TMP/SMX) has been presented as an attractive alternative to the "classic' treatment therapy (Pyrimethamine/Sulfadiazine).

METHODS

A prospective study was carried out between February 2020 and September 2021 in 2 ophthalmic centers in Kinshasa. This study aimed to describe TMP/SMX treatment outcomes for OT in a cohort of immunocompetent Congolese patients.

RESULTS

54 patients were included, with a mean age at presentation of 37.5 ± 13.6 years old and a Male-Female ratio of 1.45:1. Three patients (5.6%) presented a recurrence during the follow-up period. At the end of the follow-up, improvement in VA and resolution of inflammation concerned 75.9% and 77.5% of patients, respectively. Cataracts (3.7%), macular scars (3.7%), and vitreous opacities (3.7%) were the principal causes of non-improvement in VA. Treatment-related adverse events were present in 10 patients (18.5%); gastrointestinal (14.8%) and dermatological (3.7%) adverse events were the most frequent. Dermatological adverse events led to discontinuation of treatment.

CONCLUSION

TMP/SMX regimen appears to be a safe and effective treatment for OT in Congolese patients. The low cost and the accessibility of the molecules make this regimen an option for treating OT in resource-limited countries.

Clinical and Serological Characteristics of Ocular Toxoplasmosis in the Democratic Republic of Congo

PURPOSE

To describe demographic data, clinical features, and serological profiles in a cohort of Congolese patients with ocular toxoplasmosis (OT).

METHOD

Cross-sectional study, carried out between March 2020 and July 2021 in two ophthalmic clinics in Kinshasa.

RESULTS

The study comprised 95 participants with OT. Fifty-three patients were male (55.8%). The mean age at presentation was 35.6 ± 14.1 years (range 8-69 years); 71 had active OT (74.7%), among them, 33 had primary OT (46.5%), and 38 had recurrences (53.5%). At presentation, 51 patients (53.7%) had visual impairment (VA < 6/18). Retinochoroidal lesions were located in the central retina in 60 patients (63.1%). Patients with primary OT tend to have higher IgG levels than those with recurrent OT (P = .01).

CONCLUSION

We report the largest cohort of patients with OT in sub-Saharan Africa. In our setting, most patients had recurrent OT with multiple, extensive, and central retinochoroidal lesions.

Current practice in the management of ocular toxoplasmosis

BACKGROUND

Ocular toxoplasmosis is common across all regions of the world. Understanding of the epidemiology and approach to diagnosis and treatment have evolved recently. In November 2020, an international group of uveitis-specialised ophthalmologists formed the International Ocular Toxoplasmosis Study Group to define current practice.

METHODS

192 Study Group members from 48 countries completed a 36-item survey on clinical features, use of investigations, indications for treatment, systemic and intravitreal treatment with antiparasitic drugs and corticosteroids, and approach to follow-up and preventive therapy.

RESULTS

For 77.1% of members, unilateral retinochoroiditis adjacent to a pigmented scar accounted for over 60% of presentations, but diverse atypical presentations were also reported. Common complications included persistent vitreous opacities, epiretinal membrane, cataract, and ocular hypertension or glaucoma. Most members used clinical examination with (56.8%) or without (35.9%) serology to diagnose typical disease but relied on intraocular fluid testing-usually PCR-in atypical cases (68.8%). 66.1% of members treated all non-pregnant patients, while 33.9% treated selected patients. Oral trimethoprim-sulfamethoxazole was first-line therapy for 66.7% of members, and 60.9% had experience using intravitreal clindamycin. Corticosteroid drugs were administered systemically by 97.4%; 24.7% also injected corticosteroid intravitreally, almost always in combination with an antimicrobial drug (72.3%). The majority of members followed up all (60.4%) or selected (35.9%) patients after resolution of acute disease, and prophylaxis against recurrence with trimethoprim-sulfamethoxazole was prescribed to selected patients by 69.8%.

CONCLUSION

Our report presents a current management approach for ocular toxoplasmosis, as practised by a large international group of uveitis-specialised ophthalmologists.

Influence of killer immunoglobulin-like receptors genes on the recurrence rate of ocular toxoplasmosis in Brazil

BACKGROUND

Recurrence is a hallmark of ocular toxoplasmosis (OT), and conditions that influence its occurrence remain a challenge. Natural killer cells (NK) are effectors cells whose primary is cytotoxic function against many parasites, including Toxoplasma gondii. Among the NK cell receptors, immunoglobulin-like receptors (KIR) deserve attention due to their high polymorphism.

OBJECTIVES

This study aimed to analyse the influence of KIR gene polymorphism in the course of OT infection and its association with recurrences after an active episode.

METHODS

Ninety-six patients from the Ophthalmologic Clinic of the National Institute of Infectology Evandro Chagas were followed for up to five years. After DNA extraction, genotyping of the patients was performed by polymerase chain reaction sequence-specific oligonucleotide (PCR-SSO) utilising Luminex equipment for reading. During follow-up, 60.4% had a recurrence.

FINDINGS

We identified 25 KIR genotypes and found a higher frequency of genotype 1 (31.7%) with worldwide distribution. We note that the KIR2DL2 inhibitor gene and the gene activator KIR2DS2 were more frequent in patients without recurrence. Additionally, we observed that individuals who carry these genes progressed recurrence episodes slowly compared to individuals who do not carry these genes.

MAIN CONCLUSIONS

The KIR2DL2 and KIR2DS2 are associated as possible protection markers against ocular toxoplasmosis recurrence (OTR).

Risk factors for recurrences and visual impairment in patients with ocular toxoplasmosis: A systematic review and meta-analysis

BACKGROUND

Ocular toxoplasmosis (OT) is caused by the parasite Toxoplasma gondii. OT is the leading cause of posterior uveitis globally; it is a recurrent disease that may result in visual impairment and blindness. This systematic review and meta-analysis aim to summarize and evaluate the risk factors for recurrences, visual impairment, and blindness described in the literature worldwide.

METHODS AND FINDINGS

We performed a systematic literature search in PubMed, Embase, VHL, Cochrane Library, Scopus, and DANS EASY Archive. All studies reporting patients with clinically and serologically confirmed OT presenting any clinical or paraclinical factor influencing recurrences, visual impairment, and blindness were included. Studies presenting secondary data, case reports, and case series were excluded. An initial selection was made by title and abstract, and then the studies were reviewed by full text where the eligible studies were selected. Then, the risk of bias was assessed through validated tools. Data were extracted using a validated extraction format. Qualitative synthesis and quantitative analysis were done. This study was registered on PROSPERO (CRD42022327836).

RESULTS

Seventy two studies met the inclusion criteria. Fifty-three were summarized in the qualitative synthesis in three sections: clinical and environmental factors, parasite and host factors, and treatment-related factors. Of the 72 articles, 39 were included in the meta-analysis, of which 14 were conducted in South America, 13 in Europe, four in Asia, three multinational, two in North America and Central America, respectively, and only one in Africa. A total of 4,200 patients with OT were analyzed, mean age ranged from 7.3 to 65.1 year of age, with similar distribution by sex. The frequency of recurrences in patients with OT was 49% (95% CI 40%-58%), being more frequent in the South American population than in Europeans. Additionally, visual impairment was presented in 35% (95% CI 25%-48%) and blindness in 20% (95% CI 13%-30%) of eyes, with a similar predominance in South Americans than in Europeans. On the other hand, having lesions near the macula or adjacent to the optic nerve had an OR of 4.83 (95% CI; 2.72-8.59) for blindness, similar to having more than one recurrence that had an OR of 3.18 (95% CI; 1.59-6.38). Finally, the prophylactic therapy with Trimethoprim/Sulfamethoxazole versus the placebo showed a protective factor of 83% during the first year and 87% in the second year after treatment.

CONCLUSION

Our Systematic Review showed that clinical factors such as being older than 40 years, patients with de novo OT lesions or with less than one year after the first episode, macular area involvement, lesions greater than 1 disc diameter, congenital toxoplasmosis, and bilateral compromise had more risk of recurrences. Also, environmental and parasite factors such as precipitations, geographical region where the infection is acquired, and more virulent strains confer greater risk of recurrences. Therefore, patients with the above mentioned clinical, environmental, and parasite factors could benefit from using prophylactic therapy.

Risk factors for ocular toxoplasmosis among uveitis patients in Kinshasa, DR Congo

Objective

To identify the risk factors associated with ocular toxoplasmosis (OT) in a cohort of Congolese patients with uveitis.

Methods and analysis

A cross-sectional study was conducted between March 2020 and July 2021 in two ophthalmic clinics in Kinshasa. Patients with a diagnosis of uveitis were enrolled in the study. Each patient underwent an interview, an ophthalmological examination and serology testing. Logistic regression was performed to identify risk factors for OT.

Results

212 patients were included in the study with a mean age at presentation of 42.1±15.9 years (limits: 8–74 years) and a sex ratio of 1.1:1. OT concerned 96 patients (45.3%). The age of the patients below 60 years (p=0.001, OR=9.75 CI 95% 2.51 to37.80)), the consumption of cat meat (p=0.01, OR=2.65 CI 95% 1.18 to 5.96)) and undercooked meat (p=0.044, OR=2.30 CI 95% 1.02 to 5.21)) and living in rural area (p=0.021, OR=11.4 (CI 95% 1.45 to 89.84])) were identified as risk factors for OT.

Conclusion

OT affects more young people. It is associated with dietary habits. Informing and educating the population is necessary to avoid infection.

Prevalence of Toxoplasmic Retinochoroiditis in an Australian Adult Population: a Community-Based Study

OBJECTIVE

Toxoplasmic retinochoroiditis is the most common clinical manifestation of an infection with the protozoan parasite, Toxoplasma gondii. Up to 50% of the human population is estimated to be infected with T. gondii. However, the epidemiology of toxoplasmic retinochoroiditis is not widely reported. We sought to estimate the prevalence of toxoplasmic retinochoroiditis in Australia using data collected as part of the Busselton Healthy Ageing Study.

DESIGN

Cross-sectional, community-based, prospective cohort study.

PARTICIPANTS

5,020 Australian adults (2,264 men and 2,756 women; age range of 45-69 years and median age of 58 years).

METHODS

Retinal color photographs centered on the optic disc and macula were captured on a digital retinal camera following dilation of the pupils. Three uveitis-subspecialized ophthalmologists assessed each pigmented retinal lesion, and complete concordance of opinion was required to assign a toxoplasmic etiology. Serum T. gondii immunoglobulin (Ig)G levels were measured for those participants with retinal lesions judged to be toxoplasmic retinochoroiditis.

MAIN OUTCOME MEASURES

Prevalence of toxoplasmic retinochoroiditis.

RESULTS

Eight participants (0.16%) had retinal lesions that were considered to have the characteristic appearance of toxoplasmic retinochoroiditis, plus detectable serum T. gondii IgG, consistent with the diagnosis of toxoplasmic retinochoroiditis. On the assumption that 23.81% of retinal lesions occur at the posterior pole, as reported in a community-based survey conducted in Brazil (Sci Rep. 2021;11:3420), the prevalence of toxoplasmic retinochoroiditis was estimated at 0.67% or 1 per 149 persons.

CONCLUSIONS

Toxoplasmic retinochoroiditis is common in Australian adults. Efforts to quantify and address risk factors for human infection with T. gondii are justified.

Vitreoretinal interface anomalies in patients with a history of toxoplasmosis retinochoroiditis

PURPOSE

To evaluate vitreoretinal interface anomalies over time in patients diagnosed with toxoplasmosis retinochoroiditis (TRC) and progression of the chronic disease.

STUDY DESIGN

Retrospective clinical study.

METHODS

The clinical records of 36 patients with TRC were studied retrospectively. All patients underwent standard ophthalmological examinations and optical coherence tomography (optical coherence tomography: OCT). Vitreoretinal interface changes and retinal layers in the macula and lesion area were evaluated.

RESULTS

The fovea was involved in 9 (25%) patients. OCT of the scar region showed retinal layer thinning and disorganization in all cases. Complete posterior vitreous detachment (PVD) was detected in 9 (25%) cases, incomplete PVD in 22 (61%) cases and no PVD in 5 (13.8%) cases. In 23 (63%) of the 36 patients with inactive TRC lesions, an epiretinal membrane (ERM) was detected by follow-up OCT, i.e., in 14 (60%) patients with incomplete PVD, 8 (34.7%) with complete PVD, and 1 (4%) with no PVD. Vitreoschisis was found in 5 of 22 patients with incomplete PVD; an ERM developed in 4 of these 5 patients. No ERM developed only in the macula, i.e., independent of the TRC scar region.

CONCLUSIONS

Vitreoretinal interface anomalies are common in patients diagnosed with TRC, including those with incomplete PVD. We observed no progression of vitreoretinal interface anomalies during the follow-up of patients diagnosed with TRC.

Treatment of a full-thickness macular hole and retinal detachment secondary to toxoplasma chorioretinitis that developed shortly after COVID-19: A case report

Although ocular toxoplasmosis is usually a self-limiting infection, it can lead to severe reduction in visual acuity due to intense vitreous inflammation or involvement of posterior segment structures. Depending on the severity of intraocular inflammation, serious complications, including epiretinal membrane or retinal detachment may develop. In this paper, we aim to present a case that complicated by both a full-thickness macular hole and retinal detachment secondary to toxoplasmosis chorioretinitis that developed shortly after the novel coronavirus disease (COVID-19) and discuss our treatment approach. After the patient was diagnosed based on a routine ophthalmological examination, fundus imaging, and serological examination, functional and anatomical recovery was achieved through systemic antibiotherapy and vitreoretinal surgery. Full-thickness macular hole and retinal detachment are rare complications of ocular toxoplasmosis. However, there are only few publications in the literature concerning these complications and their surgical treatment. In this case report, we demonstrated the success of vitreoretinal surgery combined with antibiotic therapy on the posterior segment complications of ocular toxoplasmosis.

In vitro activity of N-phenyl-1,10-phenanthroline-2-amines against tachyzoites and bradyzoites of Toxoplasma gondii

Toxoplasma gondiiis an apicomplexan parasite, the causative agent of toxoplasmosis, a common disease in the world. Toxoplasmosis could be severe, especially in immunocompromised patients. The current therapy is limited, where pyrimethamine and sulfadiazine are the best choices despite being associated with side effects and ineffective against the bradyzoites, the parasitic form present during the chronic phase of the infection. Thus, new therapies against both tachyzoites and bradyzoites from T. gondii are urgent. Herein, we present the anti-T. gondii effect of 1,10-phenanthroline and its N-phenyl-1,10-phenanthroline-2-amine derivatives. The chemical modification of 1,10-phenanthroline tonew derivatives improved the anti-T. gondiiactivity 3.4 fold. The most active derivative presented ED₅₀in the nanomolar range, the smallest value found was for Ph8, 0.1 µM for 96 h of treatment. The host cell viability was maintained after the treatment with the compounds, which were found to be highly selective presenting large selectivity indexes. Treatment with derivatives for 96 h was able to eliminate the T. gondii infection irreversibly. The ultrastructural alterations caused after the treatment with the most effective derivative (Ph8) included signs of cell death, specifically revealed by the Tunel assay for detection of DNA fragmentation. The Phen derivatives were also able to control the growth of the in vitro-derived bradyzoite forms of T. gondii EGS strain, causing its lysis and death. These findings promote the 1,10-phenanthroline derivatives as potential lead compounds for the development of a treatment for acute and chronic phases of toxoplasmosis.

Ocular toxoplasmosis in immunocompetent adults: current cost-effectiveness of four treatment regimens in Colombia

BACKGROUND

Ocular toxoplasmosis is an infection caused by Toxoplasma gondii. In South America, the clinical course of ocular toxoplasmosis is more severe than in Europe and North America because virulent strains of the parasite are present. Ocular toxoplasmosis is the leading cause of posterior uveitis and retinochoroiditis in Colombia, requiring timely and appropriate treatment. However, there is no standardized therapy protocol based on economic studies for the country.

PURPOSE

To compare the cost-effectiveness of four first-line treatment regimens for active ocular toxoplasmosis in immunocompetent adults in Colombia, using the number of averted therapeutic failures as the outcome.

METHODS

We performed an economic and cost-effectiveness analysis to compare four first-line treatment regimens for ocular toxoplasmosis from the perspective of a third-party payer (Colombian General System of Social Security in Health). A decision analysis tree was used over a 24-week time horizon, considering only direct costs. Additionally, we performed a discrete sensitivity analysis and a probabilistic sensitivity analysis with 10,000 iterations in the Monte Carlo simulation.

RESULTS

For the base case, trimethoprim/sulfamethoxazole showed 86% effectiveness at a cost of <57 United States Dollars, resulting in the most cost-effective first-line alternative. When performing the probabilistic sensitivity analysis and maintaining the willingness to pay 466.00 United States Dollars, the trimethoprim/sulfamethoxazole regimen remained the most cost-effective alternative.

CONCLUSION

Ocular toxoplasmosis is a public health issue in Latin America. Despite severe visual consequences for affected patients, there are no standardized treatment guidelines in countries such as Colombia. Our evidence supports the use of trimethoprim/sulfamethoxazole as first-line treatment in Colombia because of its availability and optimal cost-effectiveness performance; it reduces recurrences and complications, while averting therapeutic failure. Furthermore, our evidence can be generalized to other Latin American countries with similar frequencies and severities of Toxoplasma gondii ocular infection and health systems similar to the Colombian system.

Punctate Inner Retinal Toxoplasmosis: Case Series and Review of Literature

PURPOSE

To describe clinical and multimodal imaging characteristics of punctate inner retinal toxoplasmosis (PIRT) as an atypical presentation of ocular toxoplasmosis (OT).

METHODS

Retrospective review of OT cases with PIRT lesions and review of the literature. We describe five cases (6 eyes).

RESULTS

PIRT lesions were seen adjacent to active/healed toxoplasma retinochoroiditis. The appearance of PIRT was creamy yellowish-white, inner retinal, punctate, and sub-centimetric lesions. The depth of these lesions on optical coherence tomography was till the outer plexiform layer. Co-existing punctate outer retinal toxoplasmosis (PORT) was found in three eyes and recurrent retinochoroiditis in three. The fate of PIRT was resolution with minimal retinal thinning or progression to a full-thickness retinochoroiditis.

CONCLUSION

PIRT was noted in association with typical toxoplasma retinochoroiditis and PORT lesions, and had equal chances of resolution or progression to full-thickness lesions.

Comparison between the areas of scarred and active toxoplasmic retinochoroiditis

BACKGROUND/OBJECTIVES

To assess the ratio of scarred/active areas of fundus lesions in patients with presumed ocular toxoplasmosis.

SUBJECTS/METHODS

Retrospective monocentric study of patients with presumed ocular toxoplasmosis seen between May 2004 and February 2018. Patients with a positive anti-Toxoplasma serology presenting characteristic fundus lesions. Cases with images of both baseline active and scarred lesions of the fundus were included. The borders of each active or scarred lesion were delineated on colour photographs by two independent observers and the area of the lesions was calculated using Digimizer 4.2.2 (MedCalc Software, Ostend, Belgium). The interobserver variability of the measures was recorded and their means were used for further calculations. To study the ratio of the area of scarred retinochoroiditis over the area of the baseline active lesion (R).

RESULTS

A total of 171 cases (83 males, 88 females) with a mean age of 31.6 ± 13.8 years were included. The average areas of active and scarred retinochoroiditis were, respectively, 1.32 ± 1.59 and 1.79 ± 2.36 optic disc area. The average ratio between scarred and active areas of retinochoroiditis was 1.36 [range 0.54-2.18]. The administration of a systemic treatment [R = 1.25, p = 0.003], the absence of a pre-existing scar [R = 1.05, p < 0.001] and a peripapillary location of the lesion [R = 0.85, p < 0.001] were each significantly associated with smaller scarred/active area ratios.

CONCLUSIONS

We assessed in a standardized manner the ratio of scarred/active areas of toxoplasmic lesions and showed that the area of scarred lesions was on average slightly larger than the area of active retinochoroiditis.

Optical coherence tomography findings in toxoplasma retinochoroiditis

Purpose:

This study aimed to evaluate the optic coherence tomography (OCT) findings in patients with toxoplasmic retinochoroiditis (TRC).

Methods:

A total of 12 eyes of 12 patients with active TRC were included in the study. At baseline, at the first-month follow-up, at the sixth-month follow-up and at the 1-year follow-up, the TRC lesion OCT and macula OCT were evaluated.

Results:

Hyperreflectivity of the inner retinal layers and an increase in retinal thickness were observed on the OCT examinations of all the patients with an active TRC lesion. The retinal thickness decreased and the reflectivity of retinal layers was disorganized in the OCT images obtained in the follow-up period. Partial posterior hyaloid detachment (PHD) and no PHD were detected in 11 cases and 1 case, respectively. Epiretinal membrane (ERM) had developed in the adjacent region of the scar in 7 patients. With the regression of the lesion, the disruption of the ellipsoid zone (EZ), retinal pigment epithelium (RPE) and external limiting membrane (ELM) improved in the adjacent areas. In all the eyes, ERM and the PHD configuration did progress during the follow-up period. Vitreoschisis was found in 4 of the 11 patients with partial PHD. It was observed that ERM developed in all the patients with vitreoschisis.

Conclusion:

ERM and partial PHD were common in the TRC patients, and there was no progression during the follow-up period. Regeneration of the EZ, RPE and ELM was observed in the follow-up period.

Case of Macular Hole Secondary to Ocular Toxoplasmosis Treated Successfully by Vitrectomy with Inverted Internal Limiting Membrane Flap

We report a case of ocular toxoplasmosis that developed a full-thickness macular hole (FTMH) which was successfully treated by pars plana vitrectomy combined with an inverted internal limiting membrane (ILM) flap. A 49-years-old Japanese man was aware of blurred vision in his right eye. Slit-lamp biomicroscopy, ophthalmoscopy, and optical coherence tomography (OCT) of the right eye showed that there was a grayish-white subretinal lesion at the macula accompanied by retinal exudation and mild vitreous flare and iritis. An increase in the level of serum IgM for toxoplasma led to a diagnosis of ocular toxoplasmosis. He developed a FTMH adjacent to the lesion 2 weeks after administering sulfamethoxazole/trimethoprim, and his decimal visual acuity was 0.15. Because the FTMH remained 3 months after the resolution of inflammation and his metamorphopsia persisted, vitrectomy with an inverted ILM flap was performed. After the surgery, the visual acuity improved to 0.2 with the closure of the FTMH confirmed by OCT. A FTMH in an eye with ocular toxoplasmosis was successfully closed by vitrectomy with an inverted ILM flap.

Frequency and visual outcomes of ocular toxoplasmosis in an adult Brazilian population

Although ocular toxoplasmosis is a leading cause of posterior uveitis worldwide, there is scarce information about the real-life frequency of ocular lesions, visual outcomes, and risk factors for poor prognosis. We conducted a community-based cross-sectional study with 721 adults living in Cássia dos Coqueiros, Southeast Brazil, consisted of visual acuity measurement, dilated ocular examination, a risk-factor questionnaire, and peripheral blood collection for anti-T. gondii serology. Presumed toxoplasmic lesions were recorded on video and analyzed by experienced and masked ophthalmologists. Ocular toxoplasmosis was determined if at least one suspected lesion was appointed by two graders in the presence of positive anti-T. gondii serology. Forty-eight eyes (n = 42 participants; 6.7% among those with positive anti-T. gondii serology) with ocular toxoplasmosis were found. Most lesions were single (n = 28; 58.3%), peripheral (n = 34; 77.1%) and unilateral (85.7% of participants); no active lesions were found. Older age was associated with lesions larger than one-disc diameter (p = 0.047), and lower social stratum (OR: 2.89; CI 1.2-6.97; p = 0.018) was associated with the presence of toxoplasmic lesions. Although there were no differences in visual acuity between participants and eyes with or without ocular lesions (p > 0.05), unilateral blindness associated with ocular toxoplasmosis was identified in a reduced number of individuals.

Clinical manifestations and visual outcomes associated with ocular toxoplasmosis in a Brazilian population

Ocular toxoplasmosis is the leading cause of posterior uveitis worldwide. We conducted an observational study of 262 consecutive individuals (n = 344 eyes) with ocular toxoplasmosis who were followed over a 34-month period. Most subjects were T. gondii IgG + /IgM- (n = 242; 92.4%; 317 eyes), and 140 eyes (40.7%) had active lesions. For eyes in which retinal lesions were active at recruitment and best-corrected visual acuity (BCVA) could be measured (n = 133), 21.0% (n = 28) remained blind (BCVA below 20/400) after inflammation resolved. In these eyes, atypical ocular toxoplasmosis (OR 4.99; 95% CI 1.14–22.85; p = 0.0330), macular lesion (OR 9.95; 95% CI 2.45–47.15; p = 0.0019) and any complication (OR 10.26; 95% CI 3.82–30.67; p < 0.0001) were associated with BCVA below 20/200. For eyes with only inactive lesions at recruitment and BCVA measured (n = 178), 28.1% (n = 50) were blind. In these eyes, having at least one lesion larger than one disc-diameter (OR 6.30; 95% CI 2.28–22.46; p = 0.0013) and macular lesion (OR 5.69; 95% CI 2.53–13.54; p < 0.0001) were associated with BCVA below 20/200. Older age (OR 1.02; 95% CI 1.00–1.05; p = 0.0493) and active disease at presentation (OR 4.74; 95% CI 1.95–12.91; p = 0.0011) were associated with recurrences. Additional clinical attention should be directed towards patients with risk factors for poor visual outcome.

Ocular toxoplasmosis: phenotype differences between toxoplasma IgM positive and IgM negative patients in a large cohort

PURPOSE

To investigate the differences in demographics and clinical characteristics of patients diagnosed with ocular toxoplasmosis according to their IgM status.

METHODS

Retrospective case note analysis was carried out on patients who tested positive for serum Toxoplasma gondii-specific IgM antibodies (IgM+) as well as a comparator group who tested negative for serum IgM (IgM-), but positive for serum IgG. Patient demographics and clinical features were compared between the two groups to evaluate for any significant differences.

RESULTS

One hundred and six patients were included in the study between March 2011 and June 2018, consisting of 37 in the IgM +group and 69 in the IgM- group. Patients in the IgM +group were significantly older (51.1 vs 34.1 years, p<0.0001), more likely to present with central macular lesions (32% vs 12%, p=0.012), and more likely to develop rhegmatogenous retinal detachment (11% vs 1%, p=0.049). In contrast, patients in the IgM- group were more likely present with pain (20% vs 3%, 0.017) and exhibit more severe inflammation of the anterior chamber and vitreous (p<0.05). Overall, retinal lesions were more likely to be superotemporal (55%) and superonasal (31%). Furthermore, age was associated with larger (p=0.003) and more peripheral lesions (p=0.007).

CONCLUSIONS

This study demonstrated significant differences in clinical characteristics of ocular toxoplasmosis according to serum IgM status. IgM+ patients were older, less likely to report pain, had lower levels of intraocular inflammation, but were more likely to have macular involvement. We also found age to be correlated with larger and more peripheral lesions.

NMR resonance assignments of the programmed cell death protein 5 (PDCD5) from Toxoplasma gondii

Toxoplasmosis is a systematic protozoan disease caused by a tiny parasite Toxoplasma gondii. The infection can be dangerous for pregnant woman and people with weak immune systems. The secreted protein named TgPDCD5 (Programmed cell death protein 5 from Toxoplasma gondii) plays an important role in apoptosis-inducing effect on host cells. Here, we report the ¹H, ¹³C, and ¹⁵N resonance assignments of TgPDCD5. This work provides the ground for further structural elucidate and biophysical investigation about protein function.

Pathogenesis of ocular toxoplasmosis

Ocular toxoplasmosis is a retinitis -almost always accompanied by vitritis and choroiditis- caused by intraocular infection with Toxoplasma gondii. Depending on retinal location, this condition may cause substantial vision impairment. T. gondii is an obligate intracellular protozoan parasite, with both sexual and asexual life cycles, and infection is typically contracted orally by consuming encysted bradyzoites in undercooked meat, or oocysts on unwashed garden produce or in contaminated water. Presently available anti-parasitic drugs cannot eliminate T. gondii from the body. In vitro studies using T. gondii tachyzoites, and human retinal cells and tissue have provided important insights into the pathogenesis of ocular toxoplasmosis. T. gondii may cross the vascular endothelium to access human retina by at least three routes: in leukocyte taxis; as a transmigrating tachyzoite; and after infecting endothelial cells. The parasite is capable of navigating the human neuroretina, gaining access to a range of cell populations. Retinal Müller glial cells are preferred initial host cells. T. gondii infection of the retinal pigment epithelial cells alters the secretion of growth factors and induces proliferation of adjacent uninfected epithelial cells. This increases susceptibility of the cells to parasite infection, and may be the basis of the characteristic hyperpigmented toxoplasmic retinal lesion. Infected epithelial cells also generate a vigorous immunologic response, and influence the activity of leukocytes that infiltrate the retina. A range of T. gondii genotypes are associated with human ocular toxoplasmosis, and individual immunogenetics -including polymorphisms in genes encoding innate immune receptors, human leukocyte antigens and cytokines- impacts the clinical manifestations. Research into basic pathogenic mechanisms of ocular toxoplasmosis highlights the importance of prevention and suggests new biological drug targets for established disease.

Optical coherence tomography angiography findings in macular toxoplasma retinochoroiditis: A case report

Purpose

To report the optical coherence tomography angiography (OCT-A) findings in a patient with macular toxoplasma retinochoroiditis (TRC).

Observations

A 14-year old female presented with a 2-week history of decreased vision of her right eye. Upon presentation, on the right eye, visual acuity was 20/200 and the fundus revealed 2+ vitritis and an active parafoveal area of retinitis superotemporally. Toxoplasma serology revealed positive IgG and negative IgM. Initial treatment consisted of intravitreal clindamycin (1.0mg in 0.1 mL) with dexamethasone (1.0 mg in 0.1 mL) along with oral trimethoprim/sulfamethoxazole, azithromycin and prednisone; of which the trimethoprim/sulfamethoxazole was discontinued 4 days into therapy due to a pruritic rash. Six-weeks after the presentation, the oral prednisone had been tapered off, and all therapy discontinued. The patient had complete resolution of TRC and recovered 20/20 vision. OCT-A analysis of the right macula, performed after completion of treatment, revealed preservation of foveal perfusion along a parafoveal area of ischemia, superotemporally, at the superficial and deep retinal vascular complexes, including the choriocapillaris.

Conclusion and Importance

In macular TRC, OCT-A may help to assess therapeutic outcomes from a vascular perspective. To our knowledge, our case represents the first description in the medical literature of OCT-A findings in macular TRC.

Adverse Reactions in Antifolate-Treated Toxoplasmic Retinochoroiditis

This study seeks to define factors affecting the development of adverse reactions to intensive therapy of toxoplasmic retinochoroiditis with antifolate agents (pyrimethamine/sulfadoxine) and antibiotics followed by secondary antifolate prophylaxis. The study was of retrospective and observational nature. Medical files were reviewed of 551 patients suffering from ocular toxoplasmosis during 1994-2013. All patients were treated with the same protocol: 3-week intensive pyrimethamine/sulfadoxine plus antibiotic/steroid therapy. Three hundred and fourteen out of the 551 patients qualified for the subsequent 6-month long secondary antifolate prophylaxis. The type and occurrence rate of adverse reactions were taken into account. The probability of an adverse reaction during the intensive therapy phase was 33.4%. Hypertransaminasemia was the most common event observed in 24.6% of the patients, but it assumed a severe character in just 0.9%, with male gender and age over 25 years being the predisposing factors. Less common adverse effects included thrombocytopenia (8.3%), hypersensitivity skin reactions (3.0%), and abdominal pain (1.4%). The adverse effects of secondary antifolate prophylaxis, most commonly hypersensitivity skin reactions and hypertransaminasemia, followed by thrombocytopenia and abdominal pain, were observed in 4.9% of the patients. Ten of them (2.7%) had to discontinue the treatment while eight others continued with pyrimethamine alone without further adverse effects, which suggests that discontinuation of the sulfonamide decreased the propensity for adverse reactions. The treatment strategy in these patients differed from previous reports in that it used lower doses of pyrimethamine/sulfonamide, with no folinic acid supplementation. Nonetheless, the rate and severity of adverse events were no greater than those noticed with traditional regimens, with higher antifolate doses and folinic acid supplementation. We conclude that the dose and drug-mitigated treatment strategy we employed deserves consideration as a promising alternative to traditional treatments for ocular toxoplasmosis.

[Epidemiology and clinical pattern of ocular toxoplasmosis in Kinshasa]

PURPOSE

To determine the epidemiology and clinical pattern of Congolese patients with ocular toxoplasmosis.

PATIENTS AND METHODS

A retrospective study was conducted on records of patients with ocular toxoplasmosis examined in the Teaching Hospital of Kinshasa (DR Congo) from 2010 to 2012. Each patient underwent a complete ophthalmic examination. Sociodemographic data, clinical symptoms and signs, visual outcome, modality of treatment and type of complications were studied.

RESULTS

Thirty-five cases of ocular toxoplasmosis were diagnosed out of 18,144 patients, giving a frequency of 0.2 %. Eighteen men (51.4 %) were affected, with a sex ratio of 1.05. The mean age of the patients was 40.9±20 years (range: 10-72 years). The mean time until consultation was 10 months (range: 2 days-84 months). Ocular involvement was unilateral for 65.7 % of patients. Decreased visual acuity (77.1 %) and pain (7.1 %) were the main ocular complains. Chorioretinal lesions involved the central retina in 26 patients (74.3 %). Five patients (14.2 %) developed recurrences during follow-up. Complications affected 17 patients (48.6 %), with macular scarring (34.3 %) and cataract (17.1 %) being the most common. At the first consultation, 61.7 % of the affected eyes had visual impairment (VA<0.3). Visual impairment was associated with macular lesions (P<0.001, OR=3 [1.4-6.1]) and age greater than 45 years (P=0.002, OR=11 [2.2-53.6]).

CONCLUSION

In our context, complications are common with ocular toxoplasmosis,s and they lead to visual impairment in the majority of patients.

de Oliveira R, Cavalcanti Albuquerque M, Biancardi AL, Land Curi AL, Israel Benchimol E, Reis Amendoeira MR. Toxoplasmic retinochoroiditis: The influence of age, number of retinochoroidal lesions and genetic polymorphism for IFN-γ +874 T/A as risk factors for recurrence in a survival analysis

Purpose

To analyze risk factors for recurrent toxoplasmic retinochoroiditis.

Design

Single center prospective case series.

Population and Methods

A total of 230 patients with toxoplasmic retinochoroiditis were prospectively followed to assess recurrences. All patients were treated with a specific drug regime for toxoplasmosis in each episode of active retinochoroiditis. Individuals with chronic diseases and pregnant women were excluded. Survival analysis by extended Cox regression model (Prentice-Williams-Peterson counting process model) was performed to evaluate the time between recurrences according to some potential risk factors: age, number of retinochoroidal lesions at initial evaluation, sex and interferon gamma +874 T/A gene polymorphism. Hazard Ratios (HR) and 95% confidence intervals (CI) were provided to interpret the risk effects.

Results

One hundred sixty-two recurrence episodes were observed in 104 (45.2%) patients during follow-up that lasted from 269 to 1976 days. Mean age at presentation was 32.8 years (Standard deviation = 11.38). The risk of recurrence during follow up was influenced by age (HR = 1.02, 95% CI = 1.01–1.04) and number of retinochoroidal lesions at the beginning of the study (HR = 1.60, 95% CI = 1.07–2.40). Heterozygosis for IFN-γ gene polymorphism at position +874 T/A was also associated with recurrence (HR = 1.49, 95% CI = 1.04–2.14).

Conclusion

The risk of ocular toxoplasmosis recurrence after an active episode increased with age and was significantly higher in individuals with primary lesions, which suggests that individuals with this characteristic and the elderly could benefit from recurrence prophylactic strategies with antimicrobials. Results suggest an association between IFN-γ gene polymorphism at position +874T/A and recurrence.

Primary Acquired Toxoplasma Retinochoroiditis: Choroidal Neovascular Membrane as an Early Complication

Ocular toxoplasmosis occurs subsequently after systemic infection with the protozoan parasite, Toxoplasma gondii (T. gondii). The parasite has a high affinity for retinal microvascular endothelium with the retina being the primary site of infection in the eye. Choroidal neovascular membrane (CNVM) is a late complication of ocular toxoplasmosis, mostly occurring in healed, inactive lesions and may be a cause of sudden loss of vision, especially in young patients. However, we report a case of a 22-year-old female who presented to our clinic with CNVM as an early complication. She complained of metamorphopsia and diminished vision in her right eye. Ocular examination, serological investigation and fundoscopy, fundus fluorescein angiography (FFA), axial optical coherence tomography (OCT), and optical coherence tomography angiography (OCTA) were carried out and a diagnosis of primary acquired Toxoplasma retinochoroiditis with active CNVM was made. Treatment was commenced with sulfamethoxazole and trimethoprim. Oral prednisolone and intravitreal injection of the anti-vascular endothelial growth factor (anti-VEGF), bevacizumab, were also given. This report describes the rare presentation of ocular toxoplasmosis as a primary lesion in which adjacent pre-existing fundal scarring was absent. The lesion had an acquired etiology in an immunocompetent patient and was complicated early by CNVM.

Protective Efficacy Against Acute and Chronic Toxoplasma gondii Infection Induced by Immunization With the DNA Vaccine TgDOC2C

Toxoplasma gondii is a ubiquitous intracellular apicomplexan parasite that can cause zoonotic toxoplasmosis. Effective vaccines against T. gondii infection are necessary to prevent and control the spread of toxoplasmosis. The present study analyzed the B-linear epitopes of T. gondii DOC2 (TgDOC2) protein and then cloned the C-terminus of the TgDOC2 gene (TgDOC2C) to construct the pVAX-TgDOC2C eukaryotic vector. After intramuscular injection of pVAX-TgDOC2C, immune responses were monitored. Two weeks after the last immunization, the protective effects of pVAX-TgDOC2C against acute and chronic toxoplasmosis were evaluated by challenges with T. gondii RH tachyzoites (genotype I) and PRU cysts (genotype II). The DNA vaccine elicited strong humoral and cellular immune responses with high levels of IgG antibody, IL-2 and IFN-γ production compared to those of the controls. The percentage of CD4+ and CD8+ T cells in mice immunized with pVAX-TgDOC2C was significantly increased compared to that of mice injected with empty pVAX I or PBS. After acute infection with 10³ lethal tachyzoites, mice immunized with pVAX-TgDOC2C survived longer (12.5 days) than mice treated with pVAX I (8 days) and PBS (7.5 days). Mice immunized with pVAX-TgDOC2C had significantly less brain cysts (1600.83 ± 284.61) compared to mice immunized with pVAX I (3016.67 ± 153.84) or PBS (3100 ± 246.98). Together, these results demonstrated that TgDOC2C confers protective immunity against T. gondii infection and may be a promising candidate antigen for further development of an effective multicomponent vaccine for veterinary use against toxoplasmosis in livestock animals.

Toxoplasma gondii Infection and Headache: A Matched Case-Control Study in a Public Hospital in Durango City, Mexico

Background

Toxoplasma gondii (T. gondii) can disseminate to brain in infected hosts. Little is known about the magnitude of the association between this infection and headache. Therefore, we sought to determine the association of T. gondii seropositivity and headache in patients attending neurological consultations in a public hospital in Durango City, Mexico.

Methods

Through an age- and gender-matched case-control study, 105 patients suffering from headache and 105 subjects without headache were examined for anti-T. gondii IgG and IgM antibodies using commercially available enzyme-linked immunoassays. Seropositive cases were analyzed for detection of T. gondii DNA by polymerase chain reaction.

Results

Anti-T. gondii IgG antibodies were found in five (4.8%) of the 105 cases and in seven (6.7%) of the 105 controls (odds ratio (OR) = 0.70; 95% confidence interval (CI): 0.21 - 2.28; P = 0.76). The frequency of high (> 150 IU/mL) levels of anti-T. gondii IgG antibodies among anti-T. gondii IgG positive individuals was significantly (P = 0.01) higher in cases (5/5) than in controls (1/7). Anti-T. gondii IgM antibodies were found in one (20.0%) of the five IgG seropositive cases, and in three (42.9%) of the seven IgG seropositive controls (P = 0.60). T. gondii DNA was not detected in any of the five anti-T. gondii IgG positive cases. No association between T. gondii infection and specific headache types was found.

Conclusions

This is the first matched case-control study on the association between T. gondii infection and headache. Results suggest that high anti-T. gondii IgG antibody levels, but not T. gondii seropositivity, were associated with headache in the population studied.

Ocular toxoplasmosis: susceptibility in respect to the genes encoding the KIR receptors and their HLA class I ligands

The objective of this study was to investigate the influence of the genes encoding the KIR receptors and their HLA ligands in the susceptibility of ocular toxoplasmosis. A total of 297 patients serologically-diagnosed with toxoplasmosis were selected and stratified according to the presence (n = 148) or absence (n = 149) of ocular scars/lesions due to toxoplasmosis. The group of patients with scars/lesions was further subdivided into two groups according to the type of ocular manifestation observed: primary (n = 120) or recurrent (n = 28). Genotyping was performed by PCR-SSOP. Statistical analyses were conducted using the Chi-square test, and odds ratio with a 95% confidence interval was also calculated to evaluate the risk association. The activating KIR3DS1 gene was associated with increased susceptibility for ocular toxoplasmosis. The activating KIR together with their HLA ligands (KIR3DS1-Bw4-80Ile and KIR2DS1⁺/C2⁺⁺ KIR3DS1⁺/Bw4-80Ile⁺) were associated with increased susceptibility for ocular toxoplasmosis and its clinical manifestations. KIR-HLA inhibitory pairs -KIR2DL3/2DL3-C1/C1 and KIR2DL3/2DL3-C1- were associated with decreased susceptibility for ocular toxoplasmosis and its clinical forms, while the KIR3DS1⁻/KIR3DL1⁺/Bw4-80Ile⁺ combination was associated as a protective factor against the development of ocular toxoplasmosis and, in particular, against recurrent manifestations. Our data demonstrate that activating and inhibitory KIR genes may influence the development of ocular toxoplasmosis.