Molecular diagnosis of symptomatic toxoplasmosis: a 9-year retrospective and prospective study in a referral laboratory in São Paulo, Brazil

ABSTRACT Symptomatic forms of toxoplasmosis are a serious public health problem and occur in around 10-20% of the infected people. Aiming to improve the molecular diagnosis of symptomatic toxoplasmosis in Brazilian patients, this study evaluated the performance of real time PCR testing two primer sets (B1 and REP-529) in detecting Toxoplasma gondii DNA. The methodology was assayed in 807 clinical samples with known clinical diagnosis, ELISA, and conventional PCR results in a 9-year period. All samples were from patients with clinical suspicion of several features of toxoplasmosis. According to the minimum detection limit curve (in CT), REP-529 had greater sensitivity to detect T. gondii DNA than B1. Both primer sets were retrospectively evaluated using 515 DNA from different clinical samples. The 122 patients without toxoplasmosis provided high specificity (REP-529, 99.2% and B1, 100%). From the 393 samples with positive ELISA, 146 had clinical diagnosis of toxoplasmosis and positive conventional PCR. REP-529 and B1 sensitivities were 95.9% and 83.6%, respectively. Comparison of REP-529 and B1 performances was further analyzed prospectively in 292 samples. Thus, from a total of 807 DNA analyzed, 217 (26.89%) had positive PCR with, at least one primer set and symptomatic toxoplasmosis confirmed by clinical diagnosis. REP-529 was positive in 97.23%, whereas B1 amplified only 78.80%. After comparing several samples in a Brazilian referral laboratory, this study concluded that REP-529 primer set had better performance than B1 one. These observations were based after using cases with defined clinical diagnosis, ELISA, and conventional PCR.

Molecular diagnosis of symptomatic toxoplasmosis: a 9-year retrospective and prospective study in a referral laboratory in São Paulo, Brazil.

Symptomatic forms of toxoplasmosis are a serious public health problem and occur in around 10-20% of the infected people. Aiming to improve the molecular diagnosis of symptomatic toxoplasmosis in Brazilian patients, this study evaluated the performance of real time PCR testing two primer sets (B1 and REP-529) in detecting Toxoplasma gondii DNA. The methodology was assayed in 807 clinical samples with known clinical diagnosis, ELISA, and conventional PCR results in a 9-year period. All samples were from patients with clinical suspicion of several features of toxoplasmosis. According to the minimum detection limit curve (in CT), REP-529 had greater sensitivity to detect T. gondii DNA than B1. Both primer sets were retrospectively evaluated using 515 DNA from different clinical samples. The 122 patients without toxoplasmosis provided high specificity (REP-529, 99.2% and B1, 100%). From the 393 samples with positive ELISA, 146 had clinical diagnosis of toxoplasmosis and positive conventional PCR. REP-529 and B1 sensitivities were 95.9% and 83.6%, respectively. Comparison of REP-529 and B1 performances was further analyzed prospectively in 292 samples. Thus, from a total of 807 DNA analyzed, 217 (26.89%) had positive PCR with, at least one primer set and symptomatic toxoplasmosis confirmed by clinical diagnosis. REP-529 was positive in 97.23%, whereas B1 amplified only 78.80%. After comparing several samples in a Brazilian referral laboratory, this study concluded that REP-529 primer set had better performance than B1 one. These observations were based after using cases with defined clinical diagnosis, ELISA, and conventional PCR.

Understanding Toxoplasmosis in the United States Through "Large Data" Analyses.

BACKGROUND: Toxoplasma gondii infection causes substantial morbidity and mortality in the United States, and infects approximately one-third of persons globally. Clinical manifestations vary. Seropositivity is associated with neurologic diseases and malignancies. There are few objective data concerning US incidence and distribution of toxoplasmosis. METHODS: Truven Health MarketScan Database and International Classification of Diseases, Ninth Revision (ICD-9) codes, including treatment specific to toxoplasmosis, identified patients with this disease. Spatiotemporal distribution and patterns of disease manifestation were analyzed. Comorbidities between patients and matched controls were compared. RESULTS: Between 2003 and 2012, 9260 patients had ICD-9 codes for toxoplasmosis. This database of patients with ICD-9 codes includes 15% of those in the United States, excluding patients with no or public insurance. Thus, assuming that demographics do not change incidence, the calculated total is 61 700 or 6856 patients per year. Disease was more prevalent in the South. Mean age at diagnosis was 37.5 ± 15.5 years; 2.4% were children aged 0-2 years, likely congenitally infected. Forty-one percent were male, and 73% of women were of reproductive age. Of identified patients, 38% had eye disease and 12% presented with other serious manifestations, including central nervous system and visceral organ damage. Toxoplasmosis was statistically associated with substantial comorbidities, including human immunodeficiency virus, autoimmune diseases, and neurologic diseases. CONCLUSIONS: Toxoplasmosis causes morbidity and mortality in the United States. Our analysis of private insurance records missed certain at-risk populations and revealed fewer cases of retinal disease than previously estimated, suggesting undercoding, underreporting, undertreating, or differing demographics of those with eye disease. Mandatory reporting of infection to health departments and gestational screening could improve care and facilitate detection of epidemics and, thereby, public health interventions.

Toxoplasmose e Toxoplasma gondii / Toxoplasmosis and Toxoplasma gondii

A infecção por Toxoplasma gondii é hoje muito disseminada ao redor do mundo, especialmente no Brasil. A coletânea parte da história da descoberta desse parasita e da doença por ele causada, a toxoplasmose, e visita os diferentes aspectos relacionados ao tema. São apresentados o ciclo evolutivo, a epidemiologia, o diagnóstico, o quadro clínico e o tratamento, em uma ampla revisão sobre o assunto, provavelmente a mais completa já realizada. Somente nos anos 1970 desvendou-se o ciclo de vida desse protozoário, do qual o gato é hospedeiro definitivo. Outros animais de sangue quente, entre eles o ser humano, são hospedeiros intermediários. Muitos indivíduos infectados pelo T. gondii não apresentam sintomas, mas, quando a doença se manifesta, pode ter diferentes configurações, afetando gânglios, olhos, coração, pulmões, fígado, cérebro e meninges, ou articulações. Além de uma completa revisão, a obra também traz para o leitor o que há de mais atual no conhecimento científico acerca da toxoplasmose e do T. gondii. O livro cobre praticamente todos os campos do conhecimento sobre o agente etiológico e a doença, apresentando novos aspectos, particularmente em relação à bioquímica, à interação entre o parasita e a célula hospedeira e à resposta imunológica à infecção.

Association between the risk of congenital toxoplasmosis and the classification of toxoplasmosis in pregnant women and prenatal treatment in Brazil, 1994-2009.

OBJECTIVES: The objectives of this study were to analyze the association between the classification of toxoplasmosis in the pregnant woman (TP) according to the classification of Lebech et al. and the incidence of congenital toxoplasmosis (CT), also taking into consideration prenatal treatment. METHODS: A clinical cohort study of 524 children followed-up until 1 year of age was conducted. Adjusted odds ratios (OR) were estimated by logistic regression. RESULTS: Of 519 pregnant women, 61.3% were not classified due to the incompleteness of hospital records. Among the pregnant women classified as confirmed cases of TP (n=19), the CT risk was six times greater than in the probable/possible group. No case of CT was identified in the group of pregnant women classified as unlikely to have TP. The children with no prenatal treatment (46.2% n=242/524) presented a risk almost three times greater of CT than the treated children (OR 2.77, 95% confidence interval (CI) 1.54-4.97; p=0.001). Complete prenatal treatment was identified as a protecting factor for CT (OR 0.35, 95% CI 0.19-0.65; p=0.001). CONCLUSIONS: A lack or incomplete prenatal treatment was identified as an important risk factor for CT in this study. The proportions of non-classified mothers and children with no prenatal treatment reflect the need to improve prenatal care in Brazil.

Infection and rejection in liver transplant patients: a 10-year Swiss single-centre experience.

INTRODUCTION: Graft rejection and infection remain major morbidities following orthotopic liver transplantation (OLT). Rejection treatment may be associated with an increased rate of infectious complications. The aim of this study was to determine the relationship between rejection, rejection therapy and the risk of associated infections. MATERIALS AND METHODS: A retrospective study of all adult patients undergoing OLT between July 1987 and July 1997 at a single university medical centre was carried out. Data for all transplant recipients were collected using predetermined definitions for infectious complications. RESULTS: One hundred OLTs were performed on 98 patients (two patients received a second transplant). The cohort consisted of 33 women and 65 men with a mean age of 47 years. Seventy-eight patients developed a total of 228 infectious episodes: 107 bacterial, 101 viral, 17 fungal and 3 protozoan. The majority of infections occurred within the first month of OLT. Thirty patients without rejection developed 42 infectious episodes, whereas 70 patients with at least one treated rejection episode developed 186 infectious episodes. The overall rate of infection was 44.4 episodes per 1000 patient-days in the 30 days before rejection, and 94.4 episodes per 1000 patient-days in the 30 days following rejection treatment. CONCLUSIONS: Infections occurred more frequently during the first month post-transplantation. Following OLT, rejection is associated with a higher incidence of infection, mainly of viral origin, concurrent with increased immunosuppressive therapy.

Seroepidemiology of toxoplasmosis in the Lublin region.

Reported are results of serologic examinations for the presence of anti-Toxoplasma antibodies by direct agglutination in 1,497 people: 1,327 forestry workers and 86 farmers occupationally exposed to T. gondii from the Lublin region (eastern Poland) and 84 inhabitants of the city of Lublin examined as the control group, including 50 blood donors and 34 workers from forestry headquarters. 58.5% positive results in forestry workers, 56.9% in farmers and 46.4% in the control group were obtained. The highest percentages of positive results were obtained in Sosnowica, Wlodawa and Sobibor, all localities in the Chelm district. This finding and the prevalence of clinical cases may suggest that the Chelm district (easternmost area of the Lublin region, bordering Ukraine) is an endemic area of toxoplasmosis. A case of toxoplasmosis in a 39 year old farmer is described in whom reinfection was identified 20 years after primary diagnosis. Rapid increase in specific serologic titres and symptoms typical for toxoplasmosis were noted. The rest of the family and household animals were also found to be positive which supports the suggestion of a family-environmental case of toxoplasmosis. Survey for anti-Toxoplasma antibodies in various domestic and wild animals comprised sera from 262 cows, 120 pigs, 34 geese, 65 chickens, 3 roe deer and 10 sheep from the Lublin region. High percentages of positive results were found in cattle (53.8%) and in pigs (15%). Fowl were positive only in 0-5.9%. The cattle and pigs from the Chelm district are most probably the main sources of toxoplasmosis threatening humans in this area.

Outbreak of toxoplasmosis associated with municipal drinking water. The BC Toxoplasma Investigation Team.

BACKGROUND: Outbreaks of toxoplasmosis are recognised infrequently. In March, 1995, a sudden increase of serologically diagnosed cases of acute toxoplasmosis was noted in the Greater Victoria area of British Columbia, Canada. Concurrently, but independently, seven cases of acute toxoplasma retinitis were diagnosed against a background of no cases in the previous 5 years. METHODS: Cases were defined by serological testing, clinical presentation, and residence in Greater Victoria. A screening programme for women who were or had been pregnant was started. Geographical mapping of cases, and case-control studies of symptomatic cases and of women enrolled in the screening programme were done. FINDINGS: 100 individuals aged 6 to 83 years met the definition for an acute, outbreak-related case. 94 resided in Greater Victoria and six had visited it; 19 had retinitis, 51 had lymphadenopathy, four others had symptoms consistent with toxoplasmosis, seven had other symptoms, 18 were symptom-free, and one would not provide information. 36 (0.9%) of 3812 screened pregnant and postnatal women were cases. Excess cases were not detected outside Greater Victoria and no conventional source of toxoplasmosis was implicated. Mapping studies of cases and of the screened women, and both case-control studies showed significant associations between acute infection and residence in the distribution system of one reservoir supplying water to Greater Victoria (ORs or RRs: 3.53, 3.05, 8.27, and 5.42, respectively). The epidemic curve appeared bimodal, with peaks in December, 1994, and March, 1995, that were preceded by increased rainfall and turbidity in the implicated reservoir. INTERPRETATION: A municipal water system that uses unfiltered, chloraminated surface water was the likely source of this large community-wide outbreak of toxoplasmosis.

Toxopert-I: knowledge-based automatic interpretation of serological tests for toxoplasmosis.

Primary infection with Toxoplasma gondii, a parasite found in most regions of the world, is asymptomatic in more than 80% of cases. However, primary infection with Toxoplasma gondii in a pregnant woman might cause fetal infection and severe damage. Most cases do not require treatment. This applies to women without any infection (denoted as seronegative) and women who have acquired the infection before conception (denoted as latent). In contrast, women with postconceptual infection require immediate treatment to prevent or ameliorate fetal infection. We have developed an expert system, called Toxoport-I, designed for routine laboratory work, which automatically interprets serological test results of toxoplasma infection. By using the system the clinician can also examine questionable cases by interactively exploring possible results. We used a popular method of designing expert systems applied to medical interpretation and therapy advice, the rule-based one. In order to meet the requirements of automatic interpretation in toxoplasma serology the following characteristics were introduced: the interpretation of sequences of test results, the possibility of excluding inconsistent test results and the adaptability of the knowledge base. A decision graph that covers the different kinds of infections as well as therapy and recommendations for further tests was designed, implemented and was clinically tested by carrying out a retrospective study including 1000 pregnant women. A comparison of Toxoport-I and the clinician's interpretations yielded sensitivity and specificity rates of over 99% each.

Classification system and case definitions of Toxoplasma gondii infection in immunocompetent pregnant women and their congenitally infected offspring. European Research Network on Congenital Toxoplasmosis.

Classification systems and case definitions provide the foundations upon which clinical and epidemiological studies are based. The European Research Network on Congenital Toxoplasmosis acknowledged the lack of such a system or definitions within its field of interest and established a working group to address the issue. Congenital Toxoplasma gondii infection was defined as occurring in four separate patient groups: pregnant women, fetuses, infants, and individuals > 1 year of age. The likelihood of Toxoplasma gondii infection was separated into five mutually exclusive categories: definite, probable, possible, unlikely, and not infected. Inclusion within a specific category is dependent upon the case definition, which is in turn derived from criteria based on serological, parasitological, and clinical information. Notes are included within the classification not only to clarify the definitions, but also to improve the reliability and quality of diagnosis. The goal is to construct a system that encompasses all aspects of congenital toxoplasmosis, which is applicable to different countries and health services, suitable for large epidemiological studies, aids the diagnosis and management of individual cases, and lends itself to computerisation.

Toxoplasmosis / Toxoplasmosis

La toxoplasmosis es una zoonosis causada por TOXOPLASMA GONDII el cual es un parásito intracelular obligado, capaz de afectar a las células de todos los vertebrados mediante la formación de quistes. Existen más de veinte especies de TOXOPLASMA, siendo su principal reservorio el gato. Su distribución es cosmopolita, aunque es más frecuente en climas cálidos y húmedos. En virtud de que representa un importante problema para la salud pública, se elaboró el presente documento, en el cual se reúnen conocimientos básicos sobre la toxoplasmosis, mismos que son concernientes a: definición; clasificación taxonómica; agente etiológico; ciclo biológico; ubicación histórica; epidemiología y epizootiología; distribución geográfica; transmisión; morbilidad y mortalidad; toxoplasmosis en México; manifestaciones más frecuentes en los animales; toxoplasmosis en animales domésticos; patogenia y patología; inmunoprofilaxis; cuadro clínico; clasificación inmunológica; diagnóstico; detección de antígenos; tratamiento y, prevención y control

Toxoplasma gondii.

Toxoplasmosis encompasses a variety of clinical conditions. Serious sequelae are seen in congenital toxoplasmosis and in infections of the immunocompromised host. In the former, prevention of maternal acquisition of toxoplasmosis during pregnancy is paramount. Infection in the compromised host often presents with neurologic abnormalities. Unfortunately, the HIV syndrome itself or other opportunistic infections can present in a similar manner. Often, empiric treatment for toxoplasmosis is begun based on clinical findings and an enhancing lesion noted on the head CT. Pyrimethamine and sulfadiazine remain the drugs of choice for toxoplasmosis and are able to penetrate blood-brain barriers. Currently, trials using other agents are in progress.

[Toxoplasmosis. A common infection, not very often recognized clinically]. / Toxoplasmósis. Una infección frecuente, clínicamente poco reconocida.

Epidemiological survey and microscopical diagnosis point out that toxoplasmosis is a cosmopolitan infection usually with percentages of positivity higher than 20 per cent. Even in places with prosperous economical conditions the human infections can be relatively high due to the habit of eating raw meat or not properly exposed to temperatures lethal to Toxoplasma gondii. But sometimes they can be explained by cultural patterns or to individual psicological factors in relation to cats, the definitive hosts and important sources of parasites. It is explained how to infections occur and terms are defined. Even now in some circumstances the source of infection is not known. A discussion is presented on the diagnosis. The taxonomy of the parasite is presented in brief.