Host range and susceptibility to Toxoplasma gondii infection in captive neotropical and Old-world primates.

BACKGROUND: Toxoplasmosis is an important disease affecting captive non-human primates. The goal of this study was to assess the seroprevalence and pathological findings of toxoplasmosis in different species of captive primates. METHODS: Six captive neotropical primates died naturally due to Toxoplasma gondii infection and were necropsied. Tissue samples were evaluated by histopathology and immunohistochemistry. Serum samples from 57 captive neotropical and Old-world primates housed at the Belo Horizonte zoological garden were analyzed by indirect fluorescent antibody test (IFAT), enzyme-linked immunosorbent assay (ELISA), and indirect hemagglutination assay (IHA). RESULTS: Neotropical primates had lesions compatible with toxoplasmosis with immunolabeled intralesional T gondii. All Old-World primates (10/10), but only three neotropical primates (3/47), all belonging to the Sapajus apella species (3/6), were serologically positive. CONCLUSIONS: Our results suggest a higher susceptibility of neotropical primates to toxoplasmosis. However, this study also supports the hypothesis that Sapajus apella may be naturally resistant.

In vitro and in vivo susceptibility to sulfadiazine and pyrimethamine of Toxoplasma gondii strains isolated from Brazilian free wild birds.

Little is known about the existence of drug-resistant Toxoplasma gondii strains and their possible impact on clinic outcomes. To expand our knowledge about the existence of natural variations on drug susceptibility of T. gondii strains in Brazil, we evaluated the in vitro and in vivo susceptibility to sulfadiazine (SDZ) and pyrimethamine (PYR) of three atypical strains (Wild2, Wild3, and Wild4) isolated from free-living wild birds. In vitro susceptibility assay showed that the three strains were equally susceptible to SDZ and PYR but variations in the susceptibility were observed to SDZ plus PYR treatment. Variations in the proliferation rates in vitro and spontaneous conversion to bradyzoites were also accessed for all strains. Wild2 showed a lower cystogenesis capacity compared to Wild3 and Wild4. The in vivo analysis showed that while Wild3 was highly susceptible to all SDZ and PYR doses, and their combination, Wild2 and Wild4 showed low susceptibility to the lower doses of SDZ or PYR. Interestingly, Wild2 presented low susceptibility to the higher doses of SDZ, PYR and their combination. Our results suggest that the variability in treatment response by T. gondii isolates could possibly be related not only to drug resistance but also to the strain cystogenesis capacity.

Medicines for Malaria Venture Pandemic Box In Vitro Screening Identifies Compounds Highly Active against the Tachyzoite Stage of Toxoplasma gondii.

Toxoplasmosis is a disease that causes high mortality in immunocompromised individuals, such as AIDS patients, and sequelae in congenitally infected newborns. Despite its great medical importance, there are few treatments available and these are associated with adverse events and resistance. In this work, after screening the drugs present in the Medicines for Malaria Venture Pandemic Box, we found new hits with anti-Toxoplasma gondii activity. Through our analysis, we selected twenty-three drugs or drug-like compounds that inhibited the proliferation of T. gondii tachyzoites in vitro by more than 50% at a concentration of 1 µM after seven days of treatment. Nineteen of these compounds have never been reported active before against T. gondii. Inhibitory curves showed that most of these drugs were able to inhibit parasite replication with IC50 values on the nanomolar scale. To better understand the unprecedented effect of seven compounds against T. gondii tachyzoites, an ultrastructural analysis was carried out using transmission electron microscopy. Treatment with 0.25 µM verdinexor, 3 nM MMV1580844, and 0.25 µM MMV019724 induced extensive vacuolization, complete ultrastructural disorganization, and lytic effects in the parasite, respectively, and all of them showed alterations in the division process. Treatment with 1 µM Eberconazole, 0.5 µM MMV1593541, 1 µM MMV642550, 1 µM RWJ-67657, and 1 µM URMC-099-C also caused extensive vacuolization in the parasite. The activity of these drugs against intracellular tachyzoites supports the idea that the drugs selected in the Pandemic Box could be potential future drugs for the treatment of acute toxoplasmosis.

Early diagnosis of congenital toxoplasmosis in newborn infants using IgG subclasses against two Toxoplasma gondii recombinant proteins.

The aim of this work was to evaluate the utility of ELISA-based testing of total IgG (IgGt) antibodies and its subclasses (IgG1, IgG2, IgG3 and IgG4) against soluble (STAg) and recombinant (rSAG1 and rMIC3) antigens of Toxoplasma gondii for diagnosing congenital toxoplasmosis. Sera from 217 newborns initially testing positive for specific IgM in filter paper dried blood spots were tested for specific IgM and IgG by ELFA-VIDAS. Congenital toxoplasmosis was confirmed in 175 and ruled out in 42 infants. The validity of the ELISA tests was determined using the persistence of IgG antibodies (ELFA-VIDAS kit) at the end of 12 months, which is considered the reference test for the diagnosis of congenital toxoplasmosis. The frequency of positivity with IgGt against STAg, rSAG1 and rMIC3 was found in 97.2%, 96.3% and 80.2%, respectively, of the newborns with confirmed congenital toxoplasmosis. IgG1 reacted with all three antigens, while IgG3 and IgG4 reacted preferentially with rMIC3. Higher mean values of reactivity (sample optical density/cut-off) were found for all subclasses when using rMIC3. All of the antigens showed high sensitivity and low specificity in detecting anti-T. gondii IgGt and IgG1 and low sensitivity and high specificity in detecting IgG3 and IgG4. In conclusion, the combined detection of IgG antibody subclasses against recombinant toxoplasmic antigens may be useful for the early diagnosis of congenital toxoplasmosis.

Spontaneous T. gondii neuronal encystment induces structural neuritic network impairment associated with changes of tyrosine hydroxilase expression.

Two billion people are chronically infected with Toxoplasma gondii worldwide with unknown consequences. Important neurological diseases have been associated to the brain infection, making essential to understand the neurophysiological changes associated with the neuronal encystment. T. gondii may subvert neuronal functions modifying neurotransmitter concentration in chronically infected mice but the molecular mechanisms involved are still unclear. Parasites were observed inside neuronal cells in cultures from 24-192 hs. The rate of infection increased with time. Neurite density decreased affecting network functionality. Neuronal survival was affected and we detected the presence of cysts inside neuronal bodies and dilated portions of neurites in association with a relative increase of TH-positive neuritic area without noticeable changes in DA immunofluorescence pattern. These results advance our knowledge of the interaction between T. gondii and the neuronal network of the host.

Hearing loss in congenital toxoplasmosis detected by newborn screening.

UNLABELLED: Congenital toxoplasmosis may cause sensorineural deficit in up to 20% of the patients and proper treatment in the first year improves prognosis. In Brazil, this infections impact on hearing impairment is unknown. AIM: To evaluate hearing of newborns with congenital toxoplasmosis identified by the newborn screening service. METHOD: This prospective study analyzed children with congenital toxoplasmosis identified by newborn screening (IgM anti-T.gondii) in Belo Horizonte during 2003/2004. The presence of IgM and/or IgA in the first 6 months or IgG at 12 months-of age in serology was used as case definition. Hearing tests were carried out at the time of diagnosis and 12 months later, including behavioral audiometry, evoked otoacoustic emission and brainstem evoked responses audiometry. RESULTS: Among 30.808 screened children (97% of live births), 20 had congenital toxoplasmosis, 15 (75%) were asymptomatic at birth. Nineteen children were evaluated by hearing tests. Four had sensorineural impairment (21.1%). One child had other risk factors for hearing impairment; the other three had no other risk factors but toxoplasmosis. Two properly children treated still had hearing loss, in disagreement with current literature. CONCLUSION: Results suggest that congenital toxoplasmosis, common in Brazil, is a risk factor for hearing impairment and its impact on hearing loss deserves further studies.

Molecular phylogeny of Toxoplasmatinae: comparison between inferences based on mitochondrial and apicoplast genetic sequences.

Phylogenies within Toxoplasmatinae have been widely investigated with different molecular markers. Here, we studied molecular phylogenies of the Toxoplasmatinae subfamily based on apicoplast and mitochondrial genes. Partial sequences of apicoplast genes coding for caseinolytic protease (clpC) and beta subunit of RNA polymerase (rpoB), and mitochondrial gene coding for cytochrome B (cytB) were analyzed. Laboratory-adapted strains of the closely related parasites Sarcocystis falcatula and Sarcocystis neurona were investigated, along with Neospora caninum, Neospora hughesi, Toxoplasma gondii (strains RH, CTG and PTG), Besnoitia akodoni, Hammondia hammondiand two genetically divergent lineages of Hammondia heydorni. The molecular analysis based on organellar genes did not clearly differentiate between N. caninum and N. hughesi, but the two lineages of H. heydorni were confirmed. Slight differences between the strains of S. falcatula and S. neurona were encountered in all markers. In conclusion, congruent phylogenies were inferred from the three different genes and they might be used for screening undescribed sarcocystid parasites in order to ascertain their phylogenetic relationships with organisms of the family Sarcocystidae. The evolutionary studies based on organelar genes confirm that the genus Hammondia is paraphyletic. The primers used for amplification of clpC and rpoB were able to amplify genetic sequences of organisms of the genus Sarcocystisand organisms of the subfamily Toxoplasmatinae as well.

Prenatal toxoplasmosis diagnosis from amniotic fluid by PCR.

Toxoplasmosis is one of the most common infections all over the world. Most cases are asymptomatic, except in immunosuppressed individuals and fetuses, which can be seriously damaged. Prenatal diagnosis should be made as soon as possible since treatment of the mother can minimize fetal sequelae. Our aim in this study was to test the polymerase chain reaction technique (PCR) in 86 samples of amniotic fluid from women who seroconverted during pregnancy. DNA was amplified using external primers and, in a second step, internal primers, in a nested PCR system. Samples were also inoculated into mice and the newborn were evaluated by T. gondii serology, skull x-ray, transfontanel ultrasound, fundoscopic examination, lumbar puncture and clinical examination. PCR was positive in seven cases and negative in 79. Among PCR-positive cases, two were negative by inoculation into mice and by clinical evaluation; among PCR-negative ones, three had clinical evidence of toxoplasmosis and one was positive after inoculation into mice. PCR showed values of sensitivity = 62.5% and specificity = 97.4%; the values of inoculation into mice where 42.9% and 100%, respectively. Although PCR should not be used alone for prenatal diagnosis of congenital toxoplasmosis, it is a promising method and deserves more studies to improve its efficacy.

Occurrence of anti-Toxoplasma gondii antibodies in meat and dairy goat herds in Rio Grande do Norte, Brazil.

Toxoplasmosis is caused by Toxoplasma gondii, which is the main causative agent of abortion in small ruminants. Goats are among the animals that are most susceptible to this protozoon, and the disease that it causes leads to significant economic losses and has implications for public health, since presence of the parasite in products of goat origin is one of the main sources of human infection. Because of the significant economic impact, there is an urgent need to study the prevalence of T. gondii infection among goats in Sertão do Cabugi, which is the largest goat-producing region in Rio Grande do Norte. In the present study, the ELISA assay was used to test 244 serum samples from nine farms, located in four different municipalities in the Sertão do Cabugi region, which is an important goat-rearing region. The results showed that the prevalence of anti-T. gondii antibodies was 47.1% and that there was a significant association between positivity and the variables of age (≥ 34 months), location (Lajes, Angicos and Afonso Bezerra) and farm (all the farms). The avidity test was applied to all the 115 ELISA-positive samples to distinguish between acute and chronic infection. One hundred and three samples (89.6%) displayed high-avidity antibodies, thus indicating that most of the animals presented chronic infection, with a consequent great impact on the development of the goat production system and a risk to human health.

Surto de toxoplasmose no município de Gouveia, Minas Gerais / Outbreak of toxoplamosis in Goveia, Minas Gerais

Objetivo: investigar surto de toxoplasmose no município de Gouveia-MG, no período entre fevereiro e maio de 2015. Método: foram realizados estudos descritivo e caso-controle, com análise multivariada (regressão logística) e nível de significância de 5%. Definiu-se como caso o indivíduo com toxoplasmose aguda, confirmada laboratorialmente (IgM e/ou IgG reagentes e baixa avidez de IgG), e controle o indivíduo susceptível (IgM e IgG não reagentes). Resultado: o estudo contemplou 50 casos e 68 controles, sendo a maioria dos casos do sexo masculino (43 pacientes, 86%). Os casos tiveram 10 vezes mais chance de tomar água procedente do Manancial (IC95%: 2,8-37,4; p=0,01), 5,1 vezes mais chance de ingerir linguiça (IC95%: 1,2-20,4; p=0,02) e 4,5 vezes mais chance de ser do sexo masculino (IC95%: 1,2-16,7; p=0,02), quando comparados aos controles. Conclusão: foi confirmado um surto de toxoplasmose aguda, em Gouveia - MG, de transmissão hídrica e/ou alimentar. A maior ocorrência no sexo masculino pode estar relacionada a hábitos de risco, envolvidos na transmissão da doença. Foram propostas medidas que resultaram na diminuição e no controle dos casos da doença.

Objective: to investigate the outbreak of toxoplasmosis in the municipality of Gouveia-MG, between February and May 2015. Methods: Descriptive and case control study, with multivariate analysis (logistic regression) and level of significance of 5%. For the purpose of the study, a case was defined on an individual with laboratory which confirmed acute toxoplasmosis (IgM and/or IgG with low IgG avidity) and a control was a susceptible individual (nonreactive IgM and IgG). Results: The study comprised 50 cases and 68 controls, with most cases being male (43 patients, 86%). When compared to controls, cases had 10 times greater odds of having drunk water from Stream A (IC95%: 2,8-37,4; p=0,01), 5,1 times greater odds of having ingested sausage (IC95%: 1,2-20,4; p=0,02) and 4.5 times greater odds of being of male sex (IC95%: 1,2-16,7; p=0,02). Conclusion: A water/foodborne outbreak of acute toxoplasmosis was confirmed in Gouveia-MG, affecting predominantly men. This may be associated with habits regarding disease transmission. Measures that resulted in the reduction and control of cases of this disease have been proposed.

Molecular phylogeny of Toxoplasmatinae: comparison between inferences based on mitochondrial and apicoplast genetic sequences / Filogenia molecular de Toxoplasmatinae: comparação entre inferências baseadas em sequências genéticas mitocondriais e de apicoplasto

Abstract Phylogenies within Toxoplasmatinae have been widely investigated with different molecular markers. Here, we studied molecular phylogenies of the Toxoplasmatinae subfamily based on apicoplast and mitochondrial genes. Partial sequences of apicoplast genes coding for caseinolytic protease (clpC) and beta subunit of RNA polymerase (rpoB), and mitochondrial gene coding for cytochrome B (cytB) were analyzed. Laboratory-adapted strains of the closely related parasites Sarcocystis falcatula and Sarcocystis neurona were investigated, along with Neospora caninum, Neospora hughesi, Toxoplasma gondii (strains RH, CTG and PTG), Besnoitia akodoni, Hammondia hammondiand two genetically divergent lineages of Hammondia heydorni. The molecular analysis based on organellar genes did not clearly differentiate between N. caninum and N. hughesi, but the two lineages of H. heydorni were confirmed. Slight differences between the strains of S. falcatula and S. neurona were encountered in all markers. In conclusion, congruent phylogenies were inferred from the three different genes and they might be used for screening undescribed sarcocystid parasites in order to ascertain their phylogenetic relationships with organisms of the family Sarcocystidae. The evolutionary studies based on organelar genes confirm that the genusHammondia is paraphyletic. The primers used for amplification of clpC and rpoB were able to amplify genetic sequences of organisms of the genus Sarcocystisand organisms of the subfamily Toxoplasmatinae as well.

Resumo A filogenia da subfamília Toxoplasmatinae tem sido amplamente investigada com diversos marcadores moleculares. Neste estudo, a filogenia molecular da subfamília Toxoplasmatinae foi analisada através de genes de apicoplasto e mitocondriais. Foram analisadas sequências parciais de genes de apicoplasto codificadores da protease caseinolítica (clpC), e da subunidade beta da RNA polimerase (rpoB) e de gene mitocondrial codificador de citocromo B (cytB). Foram investigadas cepas adaptadas em laboratório de Sarcocystis neurona eSarcocystis falcatula, parasitos estreitamente relacionados, além de Neospora caninum, Neospora hughesi, Toxoplasma gondii (cepas RH, CTG e PTG),Besnoitia akodoni, Hammondia hammondi e duas linhagens geneticamente divergentes de Hammondia heydorni. A análise molecular, baseada em genes de organelas, não diferenciou claramenteN. caninum de N. hughesi, porém foi possível confirmar as duas linhagens de H. heydorni. Foram encontradas pequenas diferenças entre as cepas adaptadas em laboratório deS. falcatula e S. neurona em todos os marcadores moleculares avaliados. Concluindo, filogenias congruentes foram reconstruídas com os três diferentes genes que podem ser úteis em triagem de parasitos sarcocistídeos não identificados, para identificar sua relação com organismos da família Sarcocystidae. Os estudos evolutivos com genes organelares confirmam que o gênero Hammondia é parafilético. Osprimers utilizados para amplificação declpC e rpoB foram capazes de amplificar sequências genéticas de organismos do gênero Sarcocystis e da subfamília Toxoplasmatinae.

Relationship of Leishmania-specific IgG levels and IgG avidity with parasite density and clinical signs in canine leishmaniasis.

The clinical status and tissue parasite burden of the skin and spleen of 40 dogs naturally infected with Leishmania chagasi (syn. Leishmania infantum), together with 5 uninfected control dogs, were assessed. On the basis of the clinical evaluation, infected dogs were classified as asymptomatic (AD) or symptomatic (SD). Infected animals were also grouped according to their parasite load as exhibiting low (LP), medium (MP) and high (HP) parasitism. The results indicated a high parasite load in the skin samples of SD animals in relation to the AD group. The serum immunoglobin isotype profiles of the studied animals revealed increased levels of IgG(1) in the AD and LP dogs, whereas high levels of IgG(2) were correlated with SD and HP dogs. The avidity index (AI) of IgG(total) in the SD group was high in comparison of that of the AD group. Moreover, animals with a larger parasite burden either in the spleen or skin showed higher AI values than animals with lower parasitism. Based on these findings, it is suggested that CVL commences with an asymptomatic clinical form with low parasitism, high production of IgG(1) and low affinity of IgG(total) molecules, and evolves into a symptomatic clinical form with higher parasitism intensity, higher IgG(2) levels, and high affinity of IgG(total).

Occurrence of anti-Toxoplasma gondii antibodies in meat and dairy goat herds in Rio Grande do Norte, Brazil / Ocorrência de anticorpos anti-Toxoplasma gondii em rebanhos caprinos de corte e leiteiros do Rio Grande do Norte, Brasil

Toxoplasmosis is caused by Toxoplasma gondii, which is the main causative agent of abortion in small ruminants. Goats are among the animals that are most susceptible to this protozoon, and the disease that it causes leads to significant economic losses and has implications for public health, since presence of the parasite in products of goat origin is one of the main sources of human infection. Because of the significant economic impact, there is an urgent need to study the prevalence of T. gondii infection among goats in Sertão do Cabugi, which is the largest goat-producing region in Rio Grande do Norte. In the present study, the ELISA assay was used to test 244 serum samples from nine farms, located in four different municipalities in the Sertão do Cabugi region, which is an important goat-rearing region. The results showed that the prevalence of anti-T. gondii antibodies was 47.1% and that there was a significant association between positivity and the variables of age (≥ 34 months), location (Lajes, Angicos and Afonso Bezerra) and farm (all the farms). The avidity test was applied to all the 115 ELISA-positive samples to distinguish between acute and chronic infection. One hundred and three samples (89.6%) displayed high-avidity antibodies, thus indicating that most of the animals presented chronic infection, with a consequent great impact on the development of the goat production system and a risk to human health.

A toxoplasmose é causada pelo Toxoplasma gondii, principal agente causador de aborto em pequenos ruminantes. Os caprinos são uns dos animais mais suscetíveis a esse protozoário, levando a perdas econômicas significativas e implicações para a saúde pública, uma vez que a presença do parasito em produtos de origem caprina é uma das principais fontes de infecção humana. Devido ao impacto econômico significativo torna-se urgente estudar a prevalência da infecção, pelo T. gondii, entre caprinos do Sertão do Cabugi, a maior região produtora de caprinos no Rio Grande do Norte. O presente estudo utilizou o ELISA para testar 244 amostras de soro de 9 fazendas, situadas em 4 diferentes cidades na região do Sertão do Cabugi; uma importante região de criação de cabras. Os resultados mostraram uma prevalência de 47,1% para anticorpos anti- T. gondii e uma significativa associação entre a positividade e as variáveis idade (≥ 34 meses), localização (Lajes, Angicos e Afonso Bezerra e propriedade (todas as fazendas). O teste de avidez foi aplicado a todas as 115 amostras positivas pelo ELISA para discriminar entre infecção aguda e crônica. Cento e três amostras (89,6%) apresentaram anticorpos de alta avidez; indicando que a maioria dos animais estavam em infecção crônica, gerando um grande impacto sobre o desenvolvimento do sistema de produção em cabras e um risco para a saúde humana.

Early diagnosis of congenital toxoplasmosis in newborn infants using IgG subclasses against two Toxoplasma gondii recombinant proteins

The aim of this work was to evaluate the utility of ELISA-based testing of total IgG (IgGt) antibodies and its subclasses (IgG1, IgG2, IgG3 and IgG4) against soluble (STAg) and recombinant (rSAG1 and rMIC3) antigens of Toxoplasma gondii for diagnosing congenital toxoplasmosis. Sera from 217 newborns initially testing positive for specific IgM in filter paper dried blood spots were tested for specific IgM and IgG by ELFA-VIDAS®. Congenital toxoplasmosis was confirmed in 175 and ruled out in 42 infants. The validity of the ELISA tests was determined using the persistence of IgG antibodies (ELFA-VIDAS® kit) at the end of 12 months, which is considered the reference test for the diagnosis of congenital toxoplasmosis. The frequency of positivity with IgGt against STAg, rSAG1 and rMIC3 was found in 97.2%, 96.3% and 80.2%, respectively, of the newborns with confirmed congenital toxoplasmosis. IgG1 reacted with all three antigens, while IgG3 and IgG4 reacted preferentially with rMIC3. Higher mean values of reactivity (sample optical density/cut-off) were found for all subclasses when using rMIC3. All of the antigens showed high sensitivity and low specificity in detecting anti-T. gondii IgGt and IgG1 and low sensitivity and high specificity in detecting IgG3 and IgG4. In conclusion, the combined detection of IgG antibody subclasses against recombinant toxoplasmic antigens may be useful for the early diagnosis of congenital toxoplasmosis.

Deficiência auditiva na toxoplasmose congênita detectada pela triagem neonatal / Hearing loss in congenital toxoplasmosis detected by newborn screening

A toxoplasmose congênita pode causar déficit neurossensorial em até 20 por cento dos casos e o tratamento no primeiro ano de vida melhora o prognóstico. No Brasil, desconhece-se o impacto da infecção na hipoacusia. OBJETIVO: Avaliar a audição de crianças com toxoplasmose congênita identificadas pela triagem neonatal. MATERIAL E MÉTODO: Estudo prospectivo de crianças com toxoplasmose congênita identificadas pela triagem neonatal (IgM anti-T. gondii) em Belo Horizonte, durante 2003/2004. Realizada sorologia confirmatória (mãe/filho) e consideradas positivas as crianças apresentando IgM e/ou IgA nos primeiros seis meses ou IgG aos 12 meses de vida. Avaliações auditivas ao diagnóstico e após 12 meses incluíram Audiometria Comportamental, Emissões Otoacústicas, Imitanciometria, Audiometria de Tronco Encefálico. RESULTADOS: Dentre 30.808 crianças triadas (97 por cento dos nascidos vivos), 20 apresentavam toxoplasmose congênita, 15 (75 por cento) com infecção subclínica. Dezenove crianças realizaram avaliação auditiva. Quatro apresentaram déficit neurossensorial (21,1 por cento). Uma criança apresentou outros fatores de risco para hipoacusia; nas outras três, a toxoplasmose foi o único fator observado. Duas crianças, tratadas adequadamente com antiparasitários, apresentaram déficit auditivo, em desacordo com a literatura. CONCLUSÃO: Os achados sugerem que a toxoplasmose congênita, prevalente no Brasil, é um fator de risco para hipoacusia e o impacto dessa infecção nas perdas auditivas deve ser estudado.

Congenital toxoplasmosis may cause sensorineural deficit in up to 20 percent of the patients and proper treatment in the first year improves prognosis. In Brazil, this infection’s impact on hearing impairment is unknown. AIM: To evaluate hearing of newborns with congenital toxoplasmosis identified by the newborn screening service. METHOD: This prospective study analyzed children with congenital toxoplasmosis identified by newborn screening (IgM anti-T.gondii) in Belo Horizonte during 2003/2004. The presence of IgM and/or IgA in the first 6 months or IgG at 12 months-of age in serology was used as case definition. Hearing tests were carried out at the time of diagnosis and 12 months later, including behavioral audiometry, evoked otoacoustic emission and brainstem evoked responses audiometry. RESULTS: Among 30.808 screened children (97 percent of live births), 20 had congenital toxoplasmosis, 15 (75 percent) were asymptomatic at birth. Nineteen children were evaluated by hearing tests. Four had sensorineural impairment (21.1 percent). One child had other risk factors for hearing impairment; the other three had no other risk factors but toxoplasmosis. Two properly children treated still had hearing loss, in disagreement with current literature. CONCLUSION: Results suggest that congenital toxoplasmosis, common in Brazil, is a risk factor for hearing impairment and its impact on hearing loss deserves further studies.

Avaliaçäo de antígenos do Trypanosoma cruzi para a reaçäo de hemaglutinaçäo indireta: I. Diferentes extratos antigênicos / Evaluation of Trypanosoma cruzi antigens for indirect hemagglutination reaction: I. Different antigenic extracts

Alguns procedimentos descritos na literatura (ultrasom, água destilada, NaOH, TRITON x 100 e congelamento-descongelamento) foram avaliados determinando o melhor extrato antigênico para a reaçäo de hemaglutinaçäo indireta (RHI) no diagnóstico sorológico da doença de Chagas. Para isso, foram ensaiados 30 soros de indivíduos chagásicos e 30 soros de indivíduos näo chagásicos. A reaçäo de imunofluorescência indireta foi considerada como reaçäo de referência no cálculo dos índices de co-positividade (i.c.p.) e co-negatividade (i.c.n.). O valor do i.c.p. para a RHI com antígeno obtido por NaOH foi mais elevado do que para os outros antígenos. Os cinco antígenos apresentaram valores máximos para o i.c.n., indicando boa especificidade. Os títulos apresentados pelos soros chagásicos com antígeno obtido por NaOH foram, significativamente, superiores aos demais antígenos. A avaliaçäo de cinco partidas de antígeno extraídas por NaOH em épocas diversas indicam boa sensibilidade, especificidade e reprodutibilidade de resultados, traduzidas pelos valores elevados para os i.c.p e i.c.n., além de títulos próximos entre sí

Avaliaçäo de antígenos do Trypanosoma cruzi para a reaçäo de hemaglutinaçäo indireta: II. Antígenos de diferentes amostras e formas evolutivas / Evaluation of Trypanosoma cruzi antigens the indirect hemagglutination reaction: II. Antigens of different samplings and evolutive forms

Para aprimorar a sensibilidade e a especificidade da reaçäo de hemaglutinaçäo indireta no diagnóstico da doença de Chagas, foram utilizados eritrócitos sensibilizados com antígeno de epimastigotas de diferentes amostras (clones A1.7, B12, C1 e cepas D150 e Y), de tripomastigotas metacíclicos de cultura (TMC) e de tripomastigotas de cultura de células (TCC) do Trypanosoma cruzi. Foram titulados 132 soros de indivíduos chagásicos e 161 soros de näo chagásicos, diagnósticados pela reaçäo de imunofluorescência indireta (RIFI), considerada como reaçäo de referência no cálculo dos índices de co-positividade (i.c.p.), co-negatividade (i.c.n.) e concordância. Utilizando o título discriminante (T.D.) de 1:40, os antígenos da cepa Y e do clone B12 apresentaram valores elevados para os três índices calculados, indicando boa sensibilidade e especificidade em relaçäo à RIFI. Os antígenos dos clones A1.7 e Cl apresentaram baixa especificidade considerando o TD. de 1:40, mas ocorreu um aumento acentuado para o i.c.n. considerando o T. D. de 1:80, indicando um aumento de especificidade relativa sem alteraçäo significativa da sensibilidade relativa. Com os antígenos T.M.C. e T.C.C. foram observados títulos mais baixos e valores menores para o i.c.p., indicando pouca sensibilidade em relacäo à RIFI

Diagnosis of human toxoplasmosis by a dot enzyme-linked immunosorbent assay

O Dot-ELISA foi padronizado e avaliado para o imunodiagnostico da toxoplasmose humana. Entre 538 amostras testadas pela reacao de Imunofluorescencia Indireta (teste de referencia) 183 foram positivas considerando-se os soros reagentes nas diluicoes >= 1:16 (34 por cento). Utilizando-se a diluicao 1:256 como titulo discriminante para o Dot-ELISA, foram observados 192 soros positivos (36 por cento)...

Prenatal toxoplasmosis diagnosis from amniotic fluid by PCR

Toxoplasmosis is one of the most common infections all over the world. Most cases are asymptomatic, except in immunosuppressed individuals and fetuses, which can be seriously damaged. Prenatal diagnosis should be made as soon as possible since treatment of the mother can minimize fetal sequelae. Our aim in this study was to test the polymerase chain reaction technique (PCR) in 86 samples of amniotic fluid from women who seroconverted during pregnancy. DNA was amplified using external primers and, in a second step, internal primers, in a nested PCR system. Samples were also inoculated into mice and the newborn were evaluated by T. gondii serology, skull x-ray, transfontanel ultrasound, fundoscopic examination, lumbar puncture and clinical examination. PCR was positive in seven cases and negative in 79. Among PCR-positive cases, two were negative by inoculation into mice and by clinical evaluation; among PCR-negative ones, three had clinical evidence of toxoplasmosis and one was positive after inoculation into mice. PCR showed values of sensitivity = 62.5 and specificity = 97.4; the values of inoculation into mice where 42.9 and 100, respectively. Although PCR should not be used alone for prenatal diagnosis of congenital toxoplasmosis, it is a promising method and deserves more studies to improve its efficacy.

Validity of serology for American trypanosomiasis with eluates from filter paper

This study evaluates whether blood collected on filter paper kept at 4 degrees C and tested at different intervals of time (1, 7, 15, 30 and 60 days after collection) would present similar results when compared to the serum samples and whether the type of filter paper influences the results. Eluates from filter paper samples were tested for Trypanosoma cruzi antibodies using indirect immunofluorescence antibody test (IFAT), indirect haemagglutination (IHA) and enzyme-linked immunosorbent assay (ELISA) as reference, the antibody titer in sera. Analysis of data showed that results obtained with IFAT, IHA (cut off point = 1:40) and ELISA in sera had similar sensitivity and good concordance among reactions. The use of a multiple linear regression model indicated that titer fall in eluates occurs up to the 7th day after the collection, and it is more marked for samples with lower antibodies titers. However, no significant differences were observed by IFAT, IHA (cut off point = 1:20) and ELISA in the proportion of positive reactions between sera and eluates. The results also showed that Melitta, Klabin or Whatman (reference) filter papers could be indicated for surveys, since they have shown similar capacity of maintenance of anti-T. cruzi immunoglobulins.