Screening by ophthalmoscopy for Toxoplasma retinochoroiditis in Colombia

Variation in CD8 T cell IFNγ differentiation to strains of Toxoplasma gondii is characterized by small effect QTLs with contribution from ROP16

Introduction

Toxoplasma gondii induces a strong CD8 T cell response characterized by the secretion of IFNγ that promotes host survival during infection. The initiation of CD8 T cell IFNγ responses in vitro differs widely between clonal lineage strains of T. gondii, in which type I strains are low inducers, while types II and III strains are high inducers. We hypothesized this phenotype is due to a polymorphic "Regulator Of CD8 T cell Response" (ROCTR).

Methods

Therefore, we screened F1 progeny from genetic crosses between the clonal lineage strains to identify ROCTR. Naïve antigen-specific CD8 T cells (T57) isolated from transnuclear mice, which are specific for the endogenous and vacuolar TGD057 antigen, were measured for their ability to become activated, transcribe Ifng and produce IFNγ in response to T. gondii infected macrophages.

Results

Genetic mapping returned four non-interacting quantitative trait loci (QTL) with small effect on T. gondii chromosomes (chr) VIIb-VIII, X and XII. These loci encompass multiple gene candidates highlighted by ROP16 (chrVIIb-VIII), GRA35 (chrX), TgNSM (chrX), and a pair of uncharacterized NTPases (chrXII), whose locus we report to be significantly truncated in the type I RH background. Although none of the chromosome X and XII candidates bore evidence for regulating CD8 T cell IFNγ responses, type I variants of ROP16 lowered Ifng transcription early after T cell activation. During our search for ROCTR, we also noted the parasitophorous vacuole membrane (PVM) targeting factor for dense granules (GRAs), GRA43, repressed the response suggesting PVM-associated GRAs are important for CD8 T cell activation. Furthermore, RIPK3 expression in macrophages was an absolute requirement for CD8 T cell IFNγ differentiation implicating the necroptosis pathway in T cell immunity to T. gondii.

Discussion

Collectively, our data suggest that while CD8 T cell IFNγ production to T. gondii strains vary dramatically, it is not controlled by a single polymorphism with strong effect. However, early in the differentiation process, polymorphisms in ROP16 can regulate commitment of responding CD8 T cells to IFNγ production which may have bearing on immunity to T. gondii.

A new look into uveitis in Colombia: changes in distribution patterns and clinical characteristics over the last 25 years

PURPOSE

To describe the distribution patterns and clinical characteristics of patients diagnosed with uveitis at a specialized uveitis center in Bogotá, Colombia, from 2013 to 2021 and compare these patterns with the previously reported between 1996 and 2006.

METHODS

We performed an observational descriptive cross-sectional study systematically reviewing clinical records of patients attending between 2013 and 2021. Data were analyzed and compared with previous reports.

RESULTS

Of the 489 patients with uveitis, 310 were females (63.4%). The mean age of onset was 38.7, with a range between 1 and 83 years. Bilateral (52.8%), anterior (45.8%), non-granulomatous (90.8%), and recurrent (47.6%) were the most common types of uveitis found in our population sample. The most common cause of uveitis in this study was idiopathic, followed by toxoplasmosis and HLA-B27 + associated uveitis, which differs from the previous Colombian study where ocular toxoplasmosis was the most frequent cause. This highlights a significant shift from infectious etiologies to more immune-mediated processes as the cause of uveitis in Colombia nowadays.

CONCLUSION

The results of this study provide a comparison between the clinical patterns of presentation of uveitis from 1996 to 2006 and the patterns observed from 2013 to 2021, enhancing awareness about the changing dynamics of uveitis in Colombia to guide a better understanding of the diagnosis, classification, and correlation with other systemic conditions of the disease.

Exploring the association between precipitation and population cases of ocular toxoplasmosis in Colombia

BACKGROUND

Previous studies suggest a relationship between precipitation and ocular toxoplasmosis (OT) reactivation and congenital toxoplasmosis infection. We aimed to investigate the relationship between precipitation and the frequency of new OT cases in Colombia from 2015 to 2019.

METHODOLOGY

This retrospective cohort study analyzed data obtained from a claims-based database created by the Colombian Ministry of Health and national registries of precipitation of the Institute of Hydrology, Meteorology, and Environmental Studies. We estimated the daily number of OT cases, interpolating data from the average number of annual cases from 2015 to 2019. Then, we compared exposures (mean daily precipitation) in the case period in which the events (interpolated OT new cases) occurred by a quasi-Poisson regression, combined with a distributed lag non-linear model to estimate the non-linear and lag-response curve.

PRINCIPAL FINDINGS

In the 5-year analysis, there were 1,741 new OT cases. Most of the cases occurred in 2019, followed by 2015 and 2018. New OT cases among departments were significantly different (P< 0.01). The cumulative exposure-response curve was decreasing for most departments. Nevertheless, in Chocó, Bogotá, Cesar, Cauca, and Guajira, when a certain amount of precipitation accumulates, the relative risk (RR) increases, which was contrary to the pattern observed in the other regions. The response curves to the one-day lag showed that precipitation influences the RR; however, the trends vary by department. Finally, an increasing trend in the number of cases was directly proportional to precipitation in Guajira, Atlántico, Norte de Santander, Santander, Caquetá and Quindío (r = 0.84; P< 0.05).

CONCLUSIONS

Precipitation influenced the RR for new OT cases. However, varying trends among geographical regions (departments) lead us to hypothesize that other sociodemographic, behavioral, and environmental variables, such as wind and water contamination, could influence the RR.

Toxoplasma gondii Serotypes in Italian and Foreign Populations: A Cross-Sectional Study Using a Homemade ELISA Test

Toxoplasma gondii is a protozoan parasite responsible for human toxoplasmosis. The three major clonal lineages and different recombinant strains of T. gondii have a varied global distribution. This study aimed at evaluating the epidemiological distribution of types II and I–III and recombinant or mixed T. gondii in Italians and foreigners residing in Italy, establishing an association between serotypes and demographic characteristics. We collected the sera of 188 subjects who had tested positive for specific T. gondii antibodies. The population was differentiated into groups based on sex, nationality, and place of birth (Italy, Africa, South America, Asia, or Europe (except Italy)). We then performed a homemade ELISA test that detected both the antibodies against the amino acid sequences of the three main genotype antigens (I–III) in human sera and discerned the T. gondii strains. Serotype II of T. gondii was the most prevalent in the Italian population, whereas type I–III was the most prevalent in the foreign group. Surprisingly, we observed a notable amount of recombinant or mixed serotypes in European and Italian subjects. Moreover, we showed a significant difference in the prevalence of T. gondii serotypes between men and women, Italians, and foreigners. This descriptive study is the first to investigate the epidemiological distribution of T. gondii serotypes in humans in Italy using a homemade ELISA. We considered this technique suitable for discriminating between serotypes II and I–III and, consequently, for an epidemiological study focusing on the observation of circulating T. gondii strains and clinical correlations.

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.

Ocular toxoplasmosis, an overview focusing on clinical aspects

Toxoplasma gondii is a widespread protozoan parasite infecting approximately one third of the world population. After proliferation of tachyzoites during the acute stage, the parasite forms tissue cysts in various anatomical sites and establishes chronic infection. Nowadays the nature of the interplay between the protozoan and its human host remains elusive. This is clearly evident in ocular toxoplasmosis, in which the parasite establishes an ambivalent relationship with the eye, manipulating the immune response and inducing variable initial lesions and further relapses. This review will focus on epidemiology and environmental, parasite and host related risk factors, clinical manifestations and laboratory findings, treatment and prophylaxis approaches in ocular toxoplasmosis. An image collection of patients referred to the Unit of Ophthalmology of Pisa's Hospital will be presented, too.

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

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.

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.

Toxoplasma gondii infection in Colombia with a review of hosts and their ecogeographic distribution

Toxoplasma gondii is one of the most prevalent zoonotic protozoan parasites among warm-blooded animal populations (humans included) around the world, causing multiple clinic manifestations including death in the most severe cases of infection. Due to the versatile life cycle of T. gondii and its diversity of potential hosts, there is a common perception that natural areas and wildlife are highly prevalent reservoirs for the parasite; however, information and reports of the parasite on wildlife populations in Colombia are scarce. Using PRC-based detection analyses of the B1 gene, we evaluated the presence of T. gondii in 49 native small mammal species (10% of the mammal species of Colombia) from 4 different undisturbed natural habitats. Additionally, to understand the ecogeographical distribution of the parasite in Colombia, we developed a literature search of infection reports including information on the host species, density of records and occurrence patterns (using landcover and ecoregions) in natural, rural and urban areas. Our literature review showed a total of 8,103 reports of T. gondii for Colombia of which 86% were related to humans, and 14% to non-human mammals and other categories, with just a single report associated to wildlife; additionally, 82% of all reports were associated to urban areas whereas only 18% to rural sites. Based on the negative results for the presence of T. gondii in our PCR-based analyses and our literature search, we suggest that T. gondii has a synanthropic distribution in Colombia occurring in ecoregions as variable as the xeric scrubs in the northern lowlands and humid montane Andean forests, also we show a lack of information on the parasite relationship with wildlife, a concerning fact given that zoonoses are the leading mechanism for the emergence of infectious diseases.

Ocular Toxoplasmosis in Africa: A Narrative Review of the Literature

PURPOSE

To present a narrative review about ocular toxoplasmosis epidemiology, disease burden and prevalent African parasitic strains.

METHODS

An initial search for MeSH terms was conducted with a posterior advanced search in two electronic databases. Full text reading was performed.

RESULTS

Animal African studies have identified Toxoplasma gondii type II, type III, Africa 1, and Africa 3 strains. Seroprevalence varies from 6.4% to 74.5%. Nevertheless, there is a scarcity of epidemiology and serotyping information about ocular toxoplasmosis. African studies have demonstrated that uveitis patients present high frequencies of ocular toxoplasmosis. There is a lack of studies describing specific clinical characteristics, which can be related, to environmental and socioeconomic factors, parasite serotype and genotype, and genetic susceptibility of the host.

CONCLUSION

As Toxoplasma gondii has more virulent strains in the Southern hemisphere, it is relevant to determine African strain types and the correlation between the infecting strains and the clinical manifestations.

Interferon-γ and IL-10 Release Assay for Patients with Ocular Toxoplasmosis

Peripheral blood mononuclear cells (PBMC) from patients with ocular toxoplasmosis were challenged with total antigens from Toxoplasma gondii lysate (TATL) in a cytokine release assay (CRA), run during the inactive period of the disease. Increased interferon gamma (IFN-γ) levels were detected after PBMC stimulation with either ME49 reference strain (P = 0.0015) or local TgCkAr-11-9 isolate (P = 0.0012), as compared with those recorded under basal conditions. TATL from TgCkAr11-9 isolate induced a higher release of IFN-γ than ME49 strain in CRA from all tested patients (P = 0.02). The median value of IFN-γ release on TgCkAr-11-9 stimulation (26.03 pg/mL) allowed the classification of patients into high- or low-/non-IFN-γ releasers. Clinical correlations were established with both groups. The results obtained in this study suggest the need to include local strains when performing CRA with TATL.

Approach to ocular toxoplasmosis including pregnant women

PURPOSE OF REVIEW

To discuss available information on the effectiveness of anti-toxoplasma therapy for ocular toxoplasmosis and to provide clinicians with a practical approach to the disease.

RECENT FINDINGS

Only eleven randomized studies were identified. In the three studies for acute retinitis, there was a clear trend in favor of treatment. In the two studies for the prevention of recurrences, trimethoprim-sulfamethoxazole prophylaxis was superior to placebo. In the six studies comparing different regimens, there was no statistically significant difference between the regimens. In the setting of acute posterior uveitis suspected to be caused by toxoplasma, serological testing should always be obtained, and anti-toxoplasma drug treatment, and corticosteroids should be instituted for at least 6 weeks. Toxoplasmic chorioretinitis during pregnancy represents a particular challenge.

SUMMARY

Treatment with at least two drugs and corticosteroids should be offered to patients with active toxoplasmic chorioretinitis. Pregnant women with confirmed acute infection and concomitant acute retinitis should be treated for the ocular lesion(s) and to prevent vertical transmission. Pregnant women with chronic Toxoplasma infection acquired prior to gestation and concomitant retinitis by reactivation should be treated for the retinitis and monitored for vertical transmission.

Enzyme-Linked Aptamer Assay (ELAA) for Detection of Toxoplasma ROP18 Protein in Human Serum

Toxoplasma gondii engenders the common parasitic disease toxoplasmosis in almost all warm-blooded animals. Being a critical secretory protein, ROP18 is a major virulence factor of Toxoplasma. There are no reports about ROP18 detection in human serum samples with different clinical manifestations. New aptamers against ROP18 protein were developed through Systematic Evolution of Ligands by Exponential enrichment (SELEX). An Enzyme-Linked Aptamer Assay (ELAA) platform was developed using SELEX-derived aptamers, namely AP001 and AP002. The ELAA was used to evaluate total antigen from T. gondii RH strain (RH Ag) and recombinant protein of ROP18 (rROP18). The results showed that the ELAA presented higher affinity and specificity to RH Ag and rROP18, compared to negative controls. Detection limit of rROP18 protein in serum samples was measured by standard addition method, achieving a lower concentration of 1.56 μg/mL. Moreover, 62 seropositive samples with different clinical manifestations of toxoplasmosis and 20 seronegative samples were tested. A significant association between ELAA test positive for human serum samples and severe congenital toxoplasmosis was found (p = 0.006). Development and testing of aptamers-based assays opens a window for low-cost and rapid tests looking for biomarkers and improves our understanding about the role of ROP18 protein on the pathogenesis of human toxoplasmosis.

Expression of Long Non-Coding RNAs by Human Retinal Müller Glial Cells Infected with Clonal and Exotic Virulent Toxoplasma gondii

Retinal infection with Toxoplasma gondii-ocular toxoplasmosis-is a common cause of vision impairment worldwide. Pathology combines parasite-induced retinal cell death and reactive intraocular inflammation. Müller glial cells, which represent the supporting cell population of the retina, are relatively susceptible to infection with T. gondii. We investigated expression of long non-coding RNAs (lncRNAs) with immunologic regulatory activity in Müller cells infected with virulent T. gondii strains-GT1 (haplogroup 1, type I) and GPHT (haplogroup 6). We first confirmed expression of 33 lncRNA in primary cell isolates. MIO-M1 human retinal Müller cell monolayers were infected with T. gondii tachyzoites (multiplicity of infection = 5) and harvested at 4, 12, 24, and 36 h post-infection, with infection being tracked by the expression of parasite surface antigen 1 (SAG1). Significant fold-changes were observed for 31 lncRNAs at one or more time intervals. Similar changes between strains were measured for BANCR, CYTOR, FOXD3-AS1, GAS5, GSTT1-AS1, LINC-ROR, LUCAT1, MALAT1, MIR22HG, MIR143HG, PVT1, RMRP, SNHG15, and SOCS2-AS1. Changes differing between strains were measured for APTR, FIRRE, HOTAIR, HOXD-AS1, KCNQ1OT1, LINC00968, LINC01105, lnc-SGK1, MEG3, MHRT, MIAT, MIR17HG, MIR155HG, NEAT1, NeST, NRON, and PACER. Our findings suggest roles for lncRNAs in regulating retinal Müller cell immune responses to T. gondii, and encourage future studies on lncRNA as biomarkers and/or drug targets in ocular toxoplasmosis.

Coinfections and differential diagnosis in immunocompetent patients with uveitis of infectious origin

BACKGROUND

Making a definite diagnosis of infectious uveitis is a challenging task because many other infectious, and non-infectious uveitis, may have similar non-specific symptoms and overlapping clinical appearances. Co-infections in immunocompetent patients are not frequently proved with traditional serologic-diagnostic tools.

METHODS

Descriptive transversal study, in a Uveitis Service of an Ophthalmology Reference Center, in Bogotá, Colombia, from July 2014 to February 2016. Aqueous humor (AH) and/or vitreous fluid, blood and serum samples were collected from consecutive patients suspected of having infectious uveitis. The diagnosis of ocular toxoplasmosis (OT) was confirmed by the Goldmann-Witmer coefficient (GWC) and by polymerase chain reaction (PCR). Differential diagnosis by PCR in AH was done for viral origin such as Cytomegalovirus (CMV), Herpes simplex virus type 1 (HSV1), Herpes simplex virus type 2 (HSV2), Varicella zoster virus (VZV), Epstein-Barr virus (EBV) and Mycobacterium tuberculosis.

RESULTS

In 66 Colombian patients with uveitis of presumed infectious origin: 22 (33.3%) were confirmed as OT, 16 (24.2%) as undetermined OT, five (7.5%) as co-infections and 23 (34.8%) as other uveitis. Toxoplasma coinfection with M. tuberculosis was identified in one case by PCR and in four cases with HSV by GWC. The initial clinical diagnosis changed, after laboratory examination, in 21 cases (31.8%).

CONCLUSIONS

Clinical diagnosis can be changed by laboratory examination in a significant proportion of cases of uveitis. Diagnosis of OT should combine the use of PCR and GWC to reach the maximum of confirmation of cases. The use of multiple laboratory methods is necessary to identify co-infections and viral infections that can mimic OT in immunocompetent patients.

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

INTRODUCTION

Cases of toxoplasmosis present in South America tend to be more severe than that found in other continents. Here, we present our clinical experience of ocular and ganglionar toxoplasmosis in the use of PCR, and of the treatment to prevent ocular involvement.

METHODOLOGY

Retrospective analysis of clinical charts of patients with ocular and lymphadenitic toxoplasmosis at the parasitology and tropical medicine consultation in the "Universidad del Quindio" in Colombia. In total, 91 records of cases with ocular toxoplasmosis and 17 with lymphadenitis that underwent PCR analysis for B1 repeated sequence in blood, were compared to the results of 104 people with chronic asymptomatic toxoplasmosis. In addition, 41 clinical records were included from patients with confirmed toxoplasmic lymphadenitis: 10 untreated, 6 that begun treatment after four months of symptoms, and 25 that were treated during the first four months of symptoms and had a follow-up during at least one year.

RESULTS

Patients with ocular toxoplasmosis or lymphadenitis had a higher probability of PCR positivity in peripheral blood than chronic asymptomatic people. There were no cases of retinochoroiditis in 25 patients with toxoplasmic lymphadenitis treated before 4 months of symptoms and followed during at least 12 months. In four out of ten untreated cases, new lesions of retinochoroiditis presented after the symptoms of lymphadenitis.

CONCLUSIONS

Toxoplasmosisin South America exhibits different clinical behavior and this influences the laboratory results as well as the need for treatment in the case of lymphadenitis. Clinicians should be aware of the geographical origin of the infection in order to adopt different therapeutic and diagnostic approaches.

Genetic Polymorphisms in Cytokine Genes in Colombian Patients with Ocular Toxoplasmosis

Toxoplasmosis is caused by infection with the protozoan parasite Toxoplasma gondii, which has the capacity to infect all warm-blooded animals worldwide. Toxoplasmosis is a major cause of visual defects in the Colombian population; however, the association between genetic polymorphisms in cytokine genes and susceptibility to ocular toxoplasmosis has not been studied in this population. This work evaluates the associations between polymorphisms in genes coding for the cytokines tumor necrosis factor alpha (TNF-α) (rs1799964, rs1800629, rs1799724, rs1800630, and rs361525), interleukin 1β (IL-1β) (rs16944, rs1143634, and rs1143627), IL-1α (rs1800587), gamma interferon (IFN-γ) (rs2430561), and IL-10 (rs1800896 and rs1800871) and the presence of ocular toxoplasmosis (OT) in a sample of a Colombian population (61 patients with OT and 116 healthy controls). Genotyping was performed with the "dideoxynucleotide (ddNTP) primer extension" technique. Functional-effect predictions of single nucleotide polymorphisms (SNPs) were done by using FuncPred. A polymorphism in the IL-10 gene promoter (-1082G/A) was significantly more prevalent in OT patients than in controls (P = 1.93e-08; odds ratio [OR] = 5.27e+03; 95% confidence interval [CI] = 3.18 to 8.739; Bonferroni correction [BONF] = 3.48e-07). In contrast, haplotype "AG" of the IL-10 gene promoter polymorphisms (rs1800896 and rs1800871) was present at a lower frequency in OT patients (P = 7e-04; OR = 0.10; 95% CI = 0.03 to 0.35). The +874A/T polymorphism of IFN-γ was associated with OT (P = 3.37e-05; OR = 4.2; 95% CI = 2.478 to 7.12; BONF = 6.07e-04). Haplotype "GAG" of the IL-1β gene promoter polymorphisms (rs1143634, rs1143627, and rs16944) appeared to be significantly associated with OT (P = 0.0494). The IL-10, IFN-γ, and IL-1β polymorphisms influence the development of OT in the Colombian population.

CCR5 chemokine receptor gene polymorphisms in ocular toxoplasmosis

CC chemokine receptor type 5 (CCR5) is a chemokine receptor that influences the immune response to infectious and parasitic diseases. This study aimed to determine whether the CCR5Δ32 and CCR5 59029 A/G polymorphisms are associated with the development of ocular toxoplasmosis in humans. Patients with positive serology for Toxoplasma gondii were analyzed and grouped as 'with ocular toxoplasmosis' (G1: n=160) or 'without ocular toxoplasmosis' (G2: n=160). A control group (G3) consisted of 160 individuals with negative serology. The characterization of the CCR5Δ32 and CCR5 59029 A/G polymorphisms was by PCR and by PCR-RFLP, respectively. The difference between the groups with respect to the mean age (G1: mean age: 47.3, SD±19.3, median: 46 [range: 18-95]; G2: mean age: 61.3, SD±13.7, median: 61 [range: 21-87]; G3: mean age: 38.8, SD±17.9, median: 34 [range: 18-80]) was statistically significant (G1 vs.G2: p-value <0.0001; t=7.21; DF=318; G1 vs.G3: p-value <0.0001; t=4.32; DF=318; G2 vs. G3: p-value <0.0001; t=9.62; DF=318). The Nagelkerke r² value was 0.040. There were statistically significant differences for the CCR5/CCR5 (p-value=0.008; OR=0.261), AA (p-value=0.007; OR=2.974) and AG genotypes (p-value=0.018; OR=2.447) between G1 and G2. Individuals with the CCR5/CCR5 genotype and simultaneously the CCR5-59029 AA or AG genotypes have a greater risk of developing ocular toxoplasmosis (4% greater), which may be associated with a strong and persistent inflammatory response in ocular tissue.

Ocular Toxoplasmosis in Tropical Areas: Analysis and Outcome of 190 Patients from a Multicenter Collaborative Study

PURPOSE

To describe clinical findings and outcomes for ocular toxoplasmosis in an international multicenter collaborative study.

METHODS

Retrospective analysis of 190 patients diagnosed with ocular toxoplasmosis from three study sites (Brazil, India, and Singapore).

RESULTS

There were 93 (48.9%) females with a mean age of 32.8 years. The most common symptoms were isolated blurring of vision (36.8%), followed by blurring of vision with floaters (21.1%). Treatment regimens varied largely from monotherapy to multiple combination therapies. Final visual acuity of ≥20/40 was achieved in 106 (74.2%) patients. In a median follow-up period of 31 weeks (range 12-749 weeks), 83/190 (43.7%) patients suffered a relapse.

CONCLUSIONS

There appears to be geographical variation in the presentation of ocular toxoplasmosis. Compared to previous studies, we did not observe the '"dual peak" phenomenon of chronic and active disease based on age at presentation, and there was less bilateral and macular involvement (but more peripheral involvement).

[Effect of antenatal spiramycin treatment on the frequency of retinochoroiditis due to congenital toxoplasmosis in a Colombian cohort]

INTRODUCTION

Gestational toxoplasmosis is frequent and severe. There is still debate about the benefits of treatment against ocular manifestations in the newborn. Spiramycin treatment is used for this purpose, unfortunately prenatal diagnosis is sometimes delayed and pregnant women are not treated.

OBJECTIVE

To describe the relationship between treatment with spiramycin during pregnancy in mothers with gestational toxoplasmosis and development of ocular toxoplasmosis in newborns.

MATERIALS AND METHODS

We conducted a descriptive study of a case series. We evaluated a prospective cohort of patients diagnosed with gestational toxoplasmosis during three years at the Retinology Service at the Clínica Universitaria Bolivariana in Medellín.

RESULTS

Gestational toxoplasmosis was found in 23 mothers; 15 (65%) were treated during pregnancy with 3 g per day of spiramycin, eight (35%) patients were untreated. In the treated group just one newborn developed ocular toxoplasmosis (6.6%), in contrast with five (62.5%) of the eight patients who did not receive treatment. These results suggest that pregnancy treatment reduces the relative risk of ocular toxoplasmosis in the newborn by 96% (95% CI: 33 - 100%). Only two (14%) of the patients who were evaluated, had nervous system involvement related to toxoplasmosis in CT scan or cerebral ultrasound. These two patients also developed ocular pathology and were diagnosed at the time of birth, so they did not received antenatal treatment.

CONCLUSIONS

A protective effect was found against the ocular involvement in patients whose mother received treatment with spiramycin (OR=0.04;95% CI: 0.00-0.67), p<0.01 (Fisher's Exact Test).

Recent Developments in the Diagnosis and Treatment of Ocular Toxoplasmosis

Ocular toxoplasmosis, a chorioretinal infection with Toxoplasma gondii, is the most common etiology of posterior uveitis in many countries. Accurate diagnosis depends heavily on the characteristic clinical features of this disease, but atypical presentations, especially in immunocompromised patients, may create diagnostic challenges and lead to misdiagnosis and inappropriate treatment. Molecular biology techniques to diagnose ocular toxoplasmosis have been available for many years and are now accessible as standard laboratory tests in many countries. Aqueous humor or vitreous evaluation to detect parasite DNA by polymerase chain reaction or specific antibody may provide definitive evidence for rapid diagnosis. Oral pyrimethamine and sulfadiazine plus systemic corticosteroids are an effective therapy for ocular toxoplasmosis. Recent data supports the use of other treatment approaches, including intravitreal antibiotics. The aim of the present review is to discuss briefly the new diagnostic tools and treatment options for ocular toxoplasmosis.

Striking Divergence in Toxoplasma ROP16 Nucleotide Sequences From Human and Meat Samples

BACKGROUND

ROP16 is a protein kinase of Toxoplasma gondii identified in the mouse model as a virulent marker, but it is unknown whether this finding is relevant in human toxoplasmosis.

METHODS

We obtained the Toxoplasma ROP16 locus DNA sequence in samples from 12 patients with ocular toxoplasmosis, 1 sample from a patient with congenital toxoplasmosis, 22 samples from soldiers operating in the jungle, 2 samples from urban soldiers, and 10 samples from meat for human consumption. An enzyme-linked immunosorbent assay specific for antibodies against the ROP16 mouse-virulent peptide was performed in 46 serum specimens from patients with ocular toxoplasmosis and in 28 serum specimens from patients with chronic asymptomatic infection, of whom 19 had congenital infection and 11 had toxoplasmic lymphadenitis.

RESULTS

We found a striking divergence of the ROP16 nucleotide sequences. Ten of 12 sequences (83.3%) from patients with ocular toxoplasmosis clustered with those of mouse-virulent strains, whereas 7 of 7 ROP16 sequences (100%) from meat were clustered with those of mouse-avirulent strains. Only 11 of 104 serum specimens (10.5%) had specific antibodies against the mouse-virulent peptide, and there was no association between clinical forms and positive results of serological assays.

CONCLUSIONS

The majority of ROP16 nucleotide sequences from Colombian patients with ocular toxoplasmosis belonged to the group of mouse-virulent strains.

Cuban Ocular Toxoplasmosis Epidemiology Study (COTES): incidence and prevalence of ocular toxoplasmosis in Central Cuba

BACKGROUND

Serological studies indicate that rates of ocular toxoplasmosis (OT) vary geographically, with higher rates in tropical regions. Little is known about population-based rates of active OT. We aimed to describe the epidemiology of OT in Central Cuba.

METHODS

This large-population, cross-sectional cohort study used a prospective database at a large regional referral centre in Central Cuba. The patient database was searched for all patients who presented with OT during the 12-month study period from 1 April 2011 to 31 March 2012. Inclusion criteria were the clinical diagnosis of OT, characterised by focal retinochoroidal inflammation and a response to therapy as expected. Gender-stratified and age-stratified study population data from the 2012 Cuban Census were used to calculate incidence rates and prevalence ratios.

RESULTS

Among 279 identified patients with OT, 158 presented with active OT. Of these, 122 new-onset and 36 prior-onset cases were confirmed. Based on the total population in the Sancti Spiritus province (466,106 persons), the overall incidence of active OT was 26.2 per 100,000 person-years (95% CI 21.7 to 31.3) with an annual prevalence ratio of 33.9 per 100,000 persons (95% CI 28.8 to 39.6). The incidence of active OT was lowest in the oldest age group and highest in patients aged 25-44 years (4.5 and 42.1 per 100,000 person-years, respectively).

CONCLUSIONS

This first report describing population-based rates of OT in the Cuban population highlights the importance of patient age as a likely risk factor for OT. Disease rates were found to be highest in females and young to middle-aged adults.

An overview of seventy years of research (1944-2014) on toxoplasmosis in Colombia, South America

This paper summarizes prevalence of Toxoplasma gondii in humans and animals and associated correlates of infection, clinical spectrum of disease in humans, and genetic diversity of T. gondii isolates from Colombia. Recent studies, especially in the states of Antioquia, Quindío and Cundinamarca, indicate that toxoplasmosis is a major public health problem. Approximately half of the women of child bearing age have T. gondii antibodies, and the clinical disease in congenitally infected children is more severe than in Europe. Limited studies indicate that the strains of T. gondii from Colombia are genetically and phenotypically different than in Europe and North America. However, epidemiological factors, such as the involvement of domestic and/or wild animals in transmission, the distribution of strain diversity by natural geographic regions, and the variation in risk factors between regions that are associated with human infection in Colombia, remain unknown. Areas of research for the future are outlined. This review should be of interest to biologists, veterinarians, physicians, and parasitologists.

Severe South American ocular toxoplasmosis is associated with decreased Ifn-γ/Il-17a and increased Il-6/Il-13 intraocular levels

In a cross sectional study, 19 French and 23 Colombian cases of confirmed active ocular toxoplasmosis (OT) were evaluated. The objective was to compare clinical, parasitological and immunological responses and relate them to the infecting strains. A complete ocular examination was performed in each patient. The infecting strain was characterized by genotyping when intraocular Toxoplasma DNA was detectable, as well as by peptide-specific serotyping for each patient. To characterize the immune response, we assessed Toxoplasma protein recognition patterns by intraocular antibodies and the intraocular profile of cytokines, chemokines and growth factors. Significant differences were found for size of active lesions, unilateral macular involvement, unilateral visual impairment, vitreous inflammation, synechiae, and vasculitis, with higher values observed throughout for Colombian patients. Multilocus PCR-DNA sequence genotyping was only successful in three Colombian patients revealing one type I and two atypical strains. The Colombian OT patients possessed heterogeneous atypical serotypes whereas the French were uniformly reactive to type II strain peptides. The protein patterns recognized by intraocular antibodies and the cytokine patterns were strikingly different between the two populations. Intraocular IFN-γ and IL-17 expression was lower, while higher levels of IL-13 and IL-6 were detected in aqueous humor of Colombian patients. Our results are consistent with the hypothesis that South American strains may cause more severe OT due to an inhibition of the protective effect of IFN-γ.

Epidemiology of and diagnostic strategies for toxoplasmosis

The apicomplexan parasite Toxoplasma gondii was discovered a little over 100 years ago, but knowledge of its biological life cycle and its medical importance has grown in the last 40 years. This obligate intracellular parasite was identified early as a pathogen responsible for congenital infection, but its clinical expression and the importance of reactivations of infections in immunocompromised patients were recognized later, in the era of organ transplantation and HIV infection. Recent knowledge of host cell-parasite interactions and of parasite virulence has brought new insights into the comprehension of the pathophysiology of infection. In this review, we focus on epidemiological and diagnostic aspects, putting them in perspective with current knowledge of parasite genotypes. In particular, we provide critical information on diagnostic methods according to the patient's background and discuss the implementation of screening tools for congenital toxoplasmosis according to health policies.

Toxoplasmosis in military personnel involved in jungle operations

Tropical diseases, mainly leishmaniasis and malaria, increased among Colombian military personnel due to intensive operations in the jungle in the last ten years; as a result the Colombian army developed important preventive strategies for malaria and leishmaniasis. However, no knowledge exists about toxoplasmosis, an emergent disease in military personnel. We compared the prevalence of IgG anti-Toxoplasma antibodies by ELISA and of parasitaemia by a real time PCR assay, in 500 professional soldiers that operated in the jungle with a group of 501 soldiers working in an urban zone (Bogotá). We found that the prevalence was significantly different between both groups of soldiers (80% in soldiers operating in jungle vs. 45% in urban soldiers, adjusted OR 11.4; CI 95%: 3.8-34; p<0.0001). All soldiers operating in the jungle drink unboiled and chlorine untreated lake or river water. In urban soldiers, these risk factors along with eating wild animal meat or eating tigrillo (little spotted cat) were significantly associated with a higher prevalence. Characteristic toxoplasmic choriorretinal lesions were found in 4 soldiers that operated in the jungle (0.8%) and in one urban soldier (0.19%). All soldiers before being deployed in jungle operations should be tested for Toxoplasma antibodies and to receive adequate health information about the routine use of personnel filters to purify their water for consumption.

Review of the series "Disease of the year 2011: toxoplasmosis" pathophysiology of toxoplasmosis

Toxoplasma gondii is a major cause of chronic parasitic infection in the world. This protozoan can cause retino-choroiditis in newborns and in adults, both immunocompetent and immunodeficient. This disease tends to be recurrent and can lead to severe visual impairment. The authors review current knowledge on the role of parasite genetics in influencing susceptibility to ocular toxoplasmosis and on the immuno-pathogenesis of this disease.

Causes of blindness and visual impairment in Latin America

We review what is known in each country of the Latin American region with regards to blindness and visual impairment and make some comparisons to Hispanic populations in the United States. Prevalence of blindness varied from 1.1% in Argentina to 4.1% in Guatemala in people 50 years of age and older, with the major cause being cataract. Diabetic retinopathy and glaucoma are starting to make serious inroads, although epidemiological data are limited, and age-related macular degeneration is now a concern in some populations. Infectious diseases such as trachoma and onchocerciasis are quickly diminishing. Although progress has been made, retinopathy of prematurity remains the major cause of childhood blindness. If VISION 2020 is to succeed, many more epidemiological studies will be needed to set priorities, although some can be of the Rapid Assessment of Avoidable Blindness design. Developing the infrastructure for screening and treatment of ophthalmic disease in Latin America continues to be a challenge.

Maternal serologic screening to prevent congenital toxoplasmosis: a decision-analytic economic model

OBJECTIVE

To determine a cost-minimizing option for congenital toxoplasmosis in the United States.

METHODOLOGY/PRINCIPAL FINDINGS

A decision-analytic and cost-minimization model was constructed to compare monthly maternal serological screening, prenatal treatment, and post-natal follow-up and treatment according to the current French (Paris) protocol, versus no systematic screening or perinatal treatment. Costs are based on published estimates of lifetime societal costs of developmental disabilities and current diagnostic and treatment costs. Probabilities are based on published results and clinical practice in the United States and France. One- and two-way sensitivity analyses are used to evaluate robustness of results. Universal monthly maternal screening for congenital toxoplasmosis with follow-up and treatment, following the French protocol, is found to be cost-saving, with savings of $620 per child screened. Results are robust to changes in test costs, value of statistical life, seroprevalence in women of childbearing age, fetal loss due to amniocentesis, and to bivariate analysis of test costs and incidence of primary T. gondii infection in pregnancy. Given the parameters in this model and a maternal screening test cost of $12, screening is cost-saving for rates of congenital infection above 1 per 10,000 live births. If universal testing generates economies of scale in diagnostic tools-lowering test costs to about $2 per test-universal screening is cost-saving at rates of congenital infection well below the lowest reported rates in the United States of 1 per 10,000 live births.

CONCLUSION/SIGNIFICANCE

Universal screening according to the French protocol is cost saving for the US population within broad parameters for costs and probabilities.

Unresolved questions about the most successful known parasite

Every 3 years, the International Congress on Congenital Toxoplasmosis meeting gathers experts with different backgrounds who are involved in congenital toxoplasmosis: gynecologists, pediatricians, ophthalmologists, microbiologists, epidemiologists and research scientists. Most attendees come from the Americas and Europe, where substantial work has been performed to better understand this disease. Two presentations that stressed major current issues in the field of toxoplasmosis are summarized here.

Direct genotyping of Toxoplasma gondii in ocular fluid samples from 20 patients with ocular toxoplasmosis: predominance of type II in France

We report the direct genotyping analysis of Toxoplasma gondii in ocular samples collected from 20 patients, as well as associated clinical and epidemiological data. This work was aimed at better understanding the impact of genotypes of Toxoplasma gondii strains on toxoplasmic retinochoroiditis. For this purpose, we studied the aqueous humor (AH) or vitreous humor (VH) of 20 patients presenting with ocular toxoplasmosis (OT) in 2 hospitals in France. Genetic characterization was obtained with microsatellite markers in a multiplex PCR assay. In contrast to the results of previous studies, we found no association between atypical Toxoplasma gondii genotypes and the occurrence of OT. Considering the local epidemiological data, our OT patients seemed to be infected more frequently by ordinary type II strains found in the environment. In conclusion, direct genotyping of Toxoplasma gondii strains from aqueous or vitreous humor showed a predominance of the type II genotype in ocular toxoplasmosis; this may be due to a high exposure rate of this genotype in humans.

Toxoplasma gondii: P30 peptides recognition pattern in human toxoplasmosis

In this study, human sera reactivity against nine peptides derived from the Toxoplasma gondii P30 protein was assessed by ELISA in patients with different clinical forms of toxoplasmosis. Same as has been reported in mice, sera from congenital, ocular and chronic asymptomatic toxoplasmosis patients recognized more strongly peptides from the protein's carboxy-terminus, being peptide 2017 (amino acids 301-320) the one most strongly recognized by sera from patients with ocular toxoplasmosis. Serum samples collected from 13 patients without ocular infection, 13 with inactive chorioretinal scars, 6 with active ocular infection and 10 seronegative individuals were then screened for anti-2017 IgG. Peptide 2017 was recognized by all patients' samples but not by sera from T. gondii-seronegative individuals. No statistically significant differences were found between the absorbance levels of groups with and without lesions or with active or inactive ocular lesions, as determined by ANOVA.

Novel triazine JPC-2067-B inhibits Toxoplasma gondii in vitro and in vivo

BACKGROUND AND METHODOLOGY

Toxoplasma gondii causes substantial morbidity, mortality, and costs for healthcare in the developed and developing world. Current medicines are not well tolerated and cause hypersensitivity reactions. The dihydrotriazine JPC-2067-B (4, 6-diamino-1, 2-dihydro-2, 2-dimethyl-1-(3'(2-chloro-, 4-trifluoromethoxyphenoxy)propyloxy)-1, 3, 5-triazine), which inhibits dihydrofolate reductase (DHFR), is highly effective against Plasmodium falciparum, Plasmodium vivax, and apicomplexans related to T. gondii. JPC-2067-B is the primary metabolite of the orally active biguanide JPC-2056 1-(3'-(2-chloro-4-trifluoromethoxyphenyloxy)propyl oxy)- 5-isopropylbiguanide, which is being advanced to clinical trials for malaria. Efficacy of the prodrug JPC-2056 and the active metabolite JPC-2067-B against T. gondii and T. gondii DHFR as well as toxicity toward mammalian cells were tested.

PRINCIPAL FINDINGS AND CONCLUSIONS

Herein, we found that JPC-2067-B is highly effective against T. gondii. We demonstrate that JPC-2067-B inhibits T. gondii growth in culture (IC50 20 nM), inhibits the purified enzyme (IC50 6.5 nM), is more efficacious than pyrimethamine, and is cidal in vitro. JPC-2067-B administered parenterally and the orally administered pro-drug (JPC-2056) are also effective against T. gondii tachyzoites in vivo. A molecular model of T. gondii DHFR-TS complexed with JPC-2067-B was developed. We found that the three main parasite clonal types and isolates from South and Central America, the United States, Canada, China, and Sri Lanka have the same amino acid sequences preserving key binding sites for the triazine.

SIGNIFICANCE

JPC-2056/JPC-2067-B have potential to be more effective and possibly less toxic treatments for toxoplasmosis than currently available medicines.