TOXOPLASMOSIS-RELATED KNOWLEDGE AMONG PREGNANT AND POSTPARTUM WOMEN ATTENDED IN PUBLIC HEALTH UNITS IN NITERÓI, RIO DE JANEIRO, BRAZIL

The present study conducted a toxoplasmosis-related knowledge level survey with 400 pregnant and puerperal women attended in public health units in the municipality of Niterói, Rio de Janeiro. Only 111 (27.8%) women claimed to know about the disease. Most of them (n = 289; 72.2%) had never heard about toxoplasmosis nor knew how to prevent the infection by Toxoplasma gondii. A significant difference (p = 0.013) regarding the presence of anti-T. gondii IgG was observed between women who claimed to know about the disease and those who had never heard about it. These results highlight the importance of a systematic serological screening process for toxoplasmosis, as well as the importance of primary prevention by accurate information during prenatal care, an important Public Health action to be implemented.

TOXOPLASMOSIS IN MEXICO: EPIDEMIOLOGICAL SITUATION IN HUMANS AND ANIMALS

Toxoplasmosis is a parasitic disease widely distributed throughout the world, infecting a wide variety of animal species including humans. In Mexico, this parasite has been detected in different parts of the country, particularly in the tropical areas where the parasite can remain infective for long periods of time due to the environmental conditions (i.e. high temperature and humidity over the whole year). Several epidemiological studies have been conducted in both human and animal populations, but despite the wide distribution of the agent in the country, there is a significant lack of knowledge on the parasite transmission, treatment alternatives and control measures. The lack of feral cat populations and control measures in sites of meat production for human consumption are playing a role that has led to the wide spread of the disease in the country, particularly in tropical areas of Southeastern Mexico. For these reasons, this manuscript aims to review the published information on relevant epidemiological aspects of infection with T. gondii in humans and animals from Mexico.

HUMAN TOXOPLASMOSIS OUTBREAKS AND THE AGENT INFECTING FORM. FINDINGS FROM A SYSTEMATIC REVIEW

SUMMARY Toxoplasmosis, a worldwide highly prevalent zoonotic infection, is transmitted either by the oocysts, from water and soil, or the tissue cysts, in raw or undercooked infected meat, of Toxoplasma gondii. An ongoing debate is whether there are differences between the clinical and epidemiological characteristics of the outbreaks due to one or the other infective form of the agent. We performed a systematic review, recovering 437 reported outbreaks of which 38 were selected. They were complete reports containing ascribed Toxoplasma infecting form, and clinical and demographic data. There was no gender or age group selection in the outbreaks, which were described more often in the Americas. A large number of individuals were affected when oocysts, associated with soil and water contaminated with cat feces, were considered the transmission source. Onset of symptoms occurred early when the infection was ascribed to meat tissue cysts (11.4 ± 6.7 days) with sharpened temporal distribution of cases, while a broader and prolonged appearance of new cases was observed when oocysts in water were the source of the infection (20 ± 7 days, p < 0.001). Such information may be useful in the design and implementation of control strategies.

Toxoplasma-SPECIFIC IgG SUBCLASS ANTIBODY RESPONSE IN CEREBROSPINAL FLUID SAMPLES FROM PATIENTS WITH CEREBRAL TOXOPLASMOSIS

SUMMARY Cerebral toxoplasmosis can be highly debilitating and occasionally fatal in persons with immune system deficiencies. In this study, we evaluated the Toxoplasma gondii-specific IgG subclass antibody response in 19 cerebrospinal fluid (CSF) samples from patients with cerebral toxoplasmosis who had a positive IgG anti-T. gondii ELISA standardized with a cyst antigen preparation. There were no significant differences between the rates of positivity and the antibody concentrations (arithmetic means of the ELISA absorbances, MEA) for IgG1 and IgG2, but the rates of positivity and MEA values for these two IgG subclasses were significantly higher than those for IgG3 and IgG4. The marked IgG2 response in CSF from patients with cerebral toxoplasmosis merits further investigation.

ACUTE TOXOPLASMOSIS IN A BREASTFED INFANT WITH POSSIBLE TRANSMISSION BY WATER

Toxoplasma gondii transmission via breastfeeding has been discussed; however, no cases have been confirmed to date. This article describes a case of acute toxoplasmosis diagnosed in a mother and her six-month-old breastfed infant. The study accounts for the possibility of breast milk transmission and directs both clinicians and pediatricians to the hypothesis that both patients acquired toxoplasmosis via water ingestion.

Tratamiento de la toxoplasmosis, observaciones en 112 pacientes

En los últimos 5 anos hemos tratado 112 casos de toxoplasmosis. La mayor parte presentaba abortos o coriorretinitis; algunos presentaban meningo-encefalitis, miocarditis y otras formas. Ocho por ciento de los pacientes presentaban dos cuadros anatomoclínicos de toxoplasmosis. Se administro en forma alterna pirimetamina, sulfametopirazina o espiramicina durante períodos prolongados, practicando reacción de Sabin y Feldman cada tres meses. La meta es negativizar la prueba serológica, la cual generalmente logramos. Clinicamente se aprecia curación al observar la desaparición de los fenômenos inflamatorios en el fondo del ojo, la desaparición de adenopatías u otros signos clínicos, ó el desarrollo de embarazos normales con productos normales en mujeres abortadoras. Considerando los graves problemas que hemos visto en hijos de madres con toxoplasmosis, preferimos tratar a éstas antes de nuevos embarazos.

Analysis of Toxoplasma gondii antigens with sera from toxoplasmosis patients

Some proteins of the Toxoplasma gondii are recognized by IgG, IgM and IgA antibodies in patients with acute and chronic toxoplasmosis, depending on the strain and stage of the Toxoplasma. Sixty-nine sera from immunocompetent individuals were studied through the Western-Blot Test: 20 has an acute infection, 29 has a chronic toxoplasmosis infection and 20 were healthy (seronegatives). The protein analysis revealed by IgG and IgM antibodies were performed through the Immunoplot method in order to know their recognition frequency (f) and be valued as infection markers. In the acute phase, the IgM antibodies showed a recognition frequency (f = 0.60) for the 60kDa protein, and in the chronic phase the IgG antibodies showed a recognition frequency (f = 0.68) for the 12kDa protein. Seronegatives revealed no type of band. The protein of 12kDa can be a diagnostic marker of the chronic phase while protein 60kDa of the acute phase of toxoplasmosis.

Chagas' disease: study of congenital transmission in cases of acute maternal infection

We studied three pregnant women with acute chagasic infection. Two patients, infected in the third trimester of pregnancy, had uninfected children. The third patient, infected earlier, had an infected newborn. These results encourage research on risk factors of transmission and on medical decisions concerning pregnant women with acute Chagas' disease.

Avidity of IgG antibodies against excreted/secreted antigens of Toxoplasma gondii: immunological marker for acute recent toxoplasmosis

Detection of anti-toxoplasma IgM antibodies has frequently been used as a serological marker for diagnosing recently acquired toxoplasmosis. However, the persistence of these antibodies in some patients has complicated the interpretation of serological results when toxoplasmosis is suspected. The purpose of the present study was to evaluate the avidity of IgG antibodies against excreted/secreted antigens of Toxoplasma gondii by means of immunoblot, to establish a profile for acute recent infection in a single serum sample and confirm the presence of residual IgM antibodies obtained in automated assays. When we evaluated the avidity of IgG antibodies against excreted/secreted antigens of Toxoplasma gondii by means of immunoblot, we observed phase-specific reactivity, i.e. cases of acute recent toxoplasmosis presented low avidity and cases of non-acute recent toxoplasmosis presented high avidity towards the 30kDa protein fraction, which probably corresponds to the SAG-1 surface antigen. Our results suggest that the avidity of IgG antibodies against excreted/secreted antigens of Toxoplasma gondii is an important immunological marker for distinguishing between recent infections and for determining the presence of residual IgM antibodies obtained from automated assays.

Etiological treatment of young women infected with Trypanosoma cruzi, and prevention of congenital transmission

The objective was to detect Trypanosoma cruzi infection in 32 children in Salta, Argentina, born to 16 chronically infected young women who were treated with benznidazole. Tests were performed to assess the efficacy of treatment after 14 years. At the end of the follow up, 87.5% of the women were non-reactive to EIA tests, 62.5% to IHA and 43.8% to IFA. 62.5% of the women were non-reactive according to two or three serological tests. No infected children were detected among the newborns of mothers treated before their pregnancy.

In vitro action of antiparasitic drugs, especially artesunate, against Toxoplasma gondii

INTRODUCTION: Toxoplasmosis is usually a benign infection, except in the event of ocular, central nervous system (CNS), or congenital disease and particularly when the patient is immunocompromised. Treatment consists of drugs that frequently cause adverse effects; thus, newer, more effective drugs are needed. In this study, the possible activity of artesunate, a drug successfully being used for the treatment of malaria, on Toxoplasma gondii growth in cell culture is evaluated and compared with the action of drugs that are already being used against this parasite. METHODS: LLC-MK2 cells were cultivated in RPMI medium, kept in disposable plastic bottles, and incubated at 36ºC with 5% CO2. Tachyzoites of the RH strain were used. The following drugs were tested: artesunate, cotrimoxazole, pentamidine, pyrimethamine, quinine, and trimethoprim. The effects of these drugs on tachyzoites and LLC-MK2 cells were analyzed using nonlinear regression analysis with Prism 3.0 software. RESULTS: Artesunate showed a mean tachyzoite inhibitory concentration (IC50) of 0.075µM and an LLC MK2 toxicity of 2.003µM. Pyrimethamine was effective at an IC50 of 0.482µM and a toxicity of 11.178µM. Trimethoprim alone was effective against the in vitro parasite. Cotrimoxazole also was effective against the parasite but at higher concentrations than those observed for artesunate and pyrimethamine. Pentamidine and quinine had no inhibitory effect over tachyzoites. CONCLUSIONS: Artesunate is proven in vitro to be a useful alternative for the treatment of toxoplasmosis, implying a subsequent in vivo effect and suggesting the mechanism of this drug against the parasite.

Genetic polymorphism for IFNγ +874T/A in patients with acute toxoplasmosis

INTRODUCTION: A single nucleotide polymorphism (SNP) in the gene encoding gamma interferon influences its production and is associated with severity of infectious diseases. This study aimed to evaluate the association of IFNγ+874T/A SNP with duration of disease, morbidity, and development of retinochoroiditis in acute toxoplasmosis. METHODS: A case-control study was conducted among 30 patients and 90 controls. RESULTS: Although statistical associations were not confirmed, A-allele was more common among retinochoroiditis cases and prolonged illness, while T-allele was more frequent in severe disease. CONCLUSIONS: Despite few cases, the results could indicate a relation between IFNγ+874T/A single nucleotide polymorphism and clinical manifestations of toxoplasmosis.