Sarcocystis neurona and related Sarcocystis spp. shed by opossums (Didelphis spp.) in South America / Sarcocystis neurona e Sarcocystis spp. relacionados, excretados por gambás (Didelphis spp.) na América do Sul

Abstract Protozoan parasites of the genus Sarcocystis are obligatory heteroxenous cyst-forming coccidia that infect a wide variety of animals and encompass approximately 200 described species. At least four Sarcocystis spp. (S. falcatula, S. neurona, S. lindsayi and S. speeri) use opossums (Didelphis spp.) as definitive hosts, and two of them, S. neurona and S. falcatula, are known to cause disease in horses and birds, respectively. Opossums are restricted to the Americas, but their distribution in the Americas is heterogeneous. Five Didelphis spp. are distributed in South America (D. aurita, D. albiventris, D. marsupialis, D. imperfecta and D. pernigra) whereas just one opossum species (D. virginiana) is found in North America. Studies conducted in the last decades show that Sarcocystis spp., derived from South American Didelphis spp., have biological and genetic differences in relation to Sarcocystis spp. shed by the North American opossum D. virginiana. The aim of this review was to address the peculiar scenario of Sarcocystis species shed by South American opossums, with a special focus on diagnosis, epidemiology, and animal infections, as well as the genetic characteristics of these parasites.

Resumo Parasitos protozoários do gênero Sarcocystis são coccídios heteroxenos formadores de cistos, que infectam variadas espécies animais e compreendem cerca de 200 espécies descritas. Pelo menos quatro Sarcocystis spp. (S. falcatula, S. neurona, S. lindsayi e S. speeri) utilizam gambás (Didelphis spp.) como hospedeiros definitivos; e duas delas, S. neurona and S. falcatula são conhecidas por causarem doença em equinos e aves, respectivamente. Gambás didelfídeos são restritos ao continente americano, contudo são distribuídos de forma heterogênea nas Américas. Cinco Didelphis spp. são distribuídos na América do Sul (D. aurita, D. albiventris, D. marsupialis, D. imperfecta e D. pernigra), enquanto somente uma espécie (D. virginiana) é encontrada na América do Norte. Trabalhos conduzidos, nas últimas décadas, mostram que Sarcocystis spp. derivados de Didelphis spp. sul-americanos possuem diferenças biológicas e genéticas, quando comparados a Sarcocystis spp. excretados pelo gambá norte-americano D. virginiana. O objetivo desta revisão é discutir a situação peculiar das espécies de Sarcocystis na América do Sul com um foco especial em diagnóstico, epidemiologia e infecções animais, assim como nas características genéticas desses parasitos.

Low prevalence of infection by Sarcocystis neurona in horses from the State of Alagoas, Brazil / Baixa prevalência da infecção por Sarcocystis neurona em cavalos do estado de Alagoas, Brasil

Abstract The aim of this study was to determine the prevalence of infection by Sarcocystis neurona in horses and identify potential risk factors. Were analyzed 427 samples from 36 farms in 21 municipalities in the Alagoas State, Brazil. Presence of anti-S. neurona antibodies was diagnosed by indirect immunofluorescence antibody test (IFAT) and was confirmed using the immunoblot test. Risk factors were assessed through investigative questionnaires on animal management on the farms. The prevalence of anti-S.neurona antibodies was 2.8% (confidence interval, CI: 1.5-4.9%) from IFAT and 1.6% (CI:0.8-3.34%) from immunoblot, and there were positive horses on 16.6% of the studied farms. None of the variables studied presented associations with serological status for S. neurona. This is the first report on infection by S. neurona in horses reared in Alagoas, Brazil showing a low exposure to S. neurona in this region, but with significant numbers of foci.

Resumo Objetivou-se neste estudo determinar a prevalência e os fatores de risco associados à infecção por Sarcocystis neurona em equinos. Foram analisadas 427 amostras de 36 propriedades localizadas em 21 municípios do estado de Alagoas. O diagnóstico de anticorpos anti-S. neurona foi realizado pela técnica de Imunofluorescência Indireta (IFI) e confirmada por immunoblot. O estudo dos fatores de risco foi realizado a partir de questionários investigativos sobre o manejo dos animais nas propriedades. A prevalência de anticorpos anti-S. neurona foi de 2,8% (I.C. 1,5-4,9%) na IFI e de 1,6% (I.C. 0,8-3,34%) no immunoblot com equinos positivos em 16,6% das propriedades estudadas. Nenhuma variável estudada apresentou associação com o status sorológico para S. neurona. Este é o primeiro relato da infecção por S. neurona em equinos criados no Estado de Alagoas, Brasil, confirmando que os animais desta região têm baixa exposição a S. neurona, mas com significativo número de focos.

Toxoplasma gondii and Neospora caninum infections in synanthropic rodents from Argentina / Infecções por Toxoplasma gondii e Neospora caninum em roedores sinantrópicos da Argentina

Abstract Toxoplasma gondii and Neospora caninum are closely related coccidian parasites (phylum Apicomplexa). This is the first study from urban synanthropic rodent species that involved serological and molecular diagnosis of T. gondii and N. caninum infection, and genotyping of T. gondii in Argentina. A total of 127 rodent samples were trap captured: Mus musculus (n = 78), Rattus norvegicus (n = 26) and Rattus rattus (n = 23). Antibodies against T. gondii and N. caninum were detected by IFAT in 32.8% (40/122) and 0.8% (1/122) of rodent samples, respectively, demonstrating contact with these protozoans. Additionally, T. gondii DNA was detected in 3.3% (4/123) of rodent central nervous system samples and 2 samples were genotyped by multilocus nPCR-RFLP. Neospora caninum DNA was not detected by PCR. The 2 genotyped samples were type III allele for all markers except for SAG-1 (type I for Rat1Arg and type II/III for Rat2Arg) and were identified as #48 and #2 (likely) according to the allele combinations reported on Toxo DB (Toxo-DB). The results of the present study revealed a wide distribution of T. gondii and less for N. caninum, in synanthropic rats and mice in the studied area.

Resumo Toxoplasma gondii e Neospora caninum são parasitas coccídeos intimamente relacionados (filo Apicomplexa). Este é o primeiro estudo de espécies de roedores sinantrópicos urbanos, o qual envolveu diagnósticos sorológicos e moleculares da infecção por T. gondii e N. caninum e genotipagem de T. gondii na Argentina. Um total de 127 amostras de roedores foram obtidas: Mus musculus (n = 78), Rattus norvegicus (n = 26) e Rattus rattus (n = 23). Anticorpos contra T. gondii e N. caninum foram detectados pela IFAT em 32,8% (40/122) e 0,8% (1/122) das amostras de roedores, respectivamente, demonstrando contato com esses protozoários. Adicionalmente, o DNA de T. gondii foi detectado em 3,3% (4/123) das amostras do sistema nervoso central de roedores e duas amostras foram genotipadas por nPCR-RFLP multilocus. O DNA de N. caninum não foi detectado por PCR. As 2 amostras genotipadas eram do tipo III para todos os marcadores, exceto para SAG-1 (tipo I para Rat1Arg e tipo II / III para Rat2Arg) e foram identificadas como # 48 e # 2 (provavelmente) de acordo com as combinações de alelos relatadas no Toxo DB (Toxo-DB). Os resultados do presente estudo indicam uma ampla distribuição de T. gondii e menor para N. caninum , em ratos e camundongos sinantrópicos na área estudada.

Toxoplasmosis congénita: Diagnóstico serológico, RPC, aislamiento y caracterización molecular de Toxoplasma gondii / Congenital toxoplasmosis: Serology, PCR, parasite isolation and molecular characterization of Toxoplasma gondii

Resumen Introducción El diagnóstico de toxoplasmosis congénita (TC) en el recién nacido es muy importante porque debe recibir tratamiento siempre, sintomático o no, para evitar o aminorar las secuelas de la enfermedad. Objetivo Evaluación comparativa de los métodos disponibles en la institución para el diagnóstico de TC. Materiales y Métodos Se evaluaron métodos diagnósticos en 67 niños cuyas madres cursaron toxoplasmosis aguda durante el embarazo. Se utilizó la técnica de Sabin Feldman para IgG al nacimiento y durante el seguimiento serológico hasta el año de vida. Para determinar IgM, IgA e IgE se utilizó la técnica immunosorbent agglutination assay (ISAGA). El diagnóstico directo se realizó por reacción de polimerasa en cadena (RPC), aislamiento y caracterización molecular del parásito. Resultados La sensibilidad (S) de ISAGA IgM fue 87%, ISAGA IgA 91% y la especificidad (E) fue 100% para ambas; cuando se realizaron en conjunto, la S aumentó a 98%. La detección de IgE contribuyó al diagnóstico cuando se la detectó sólo en la sangre del neonato y no en sangre materna. Se aisló el parásito en cuatro casos de TC, uno fue genotipo II y los otros tres, genotipos "atípicos". La S del aislamiento fue 80% y la E 100%. Conclusión Los métodos serológicos utilizados mostraron una buena eficacia diagnóstica. Un caso fue detectado sólo por el aislamiento y la caracterización molecular tiene gran valor epidemiológico.

Background. Congenital toxoplasmosis diagnosis in the newborn is a very important issue due to the need for early treatment to prevent future sequels. Aim To compare available methods at the institution for the diagnosis of congenital toxoplasmosis. Material and Methods In this study we have evaluated the different diagnostic tests used in 67 congenital exposed newborns, including serological tests, PCR, parasite isolation and molecular characterization. Results The ISAGA IgM and IgA tests showed sensitivity (Se) of 87 and 91%, respectively, and specificity (Sp) of 100%. When ISAGA IgM and IgA were performed simultaneously, the Se increased to 98% and the Sp was 100%. The presence of IgE contributed to the diagnosis when it was detected in the child's serum but not in maternal blood. In four congenital infected children the parasite was isolated and genotyped: one was genotype II and the other three were "atypical" genotypes. No parasite was isolated in children without congenital toxoplasmosis. Discussion Overall, serological tests showed a good diagnostic performance although in one case they were all negative and isolation was the only tool to identify the infection. We conclude that it is essential to use all diagnostic tests in every single exposed child, including if possible, molecular characterization due to its epidemiological implication.

Evaluación y comparación de pruebas serológicas para la detección de la neosporosis bovina en Argentina / Evaluation and comparison of serological methods for the detection of bovine neosporosis in Argentina

Neospora caninum is a protozoan parasite that causes abortion and important economic losses in cattle worldwide. The accurate diagnosis of neosporosis is essential for management and control measures. The aims of this study were: i) to evaluate the performance of an in-house enzyme-linked immunosorbent assay based on the 38 kDa native antigen (p38-ELISA) to diagnose bovine neosporosis in Argentina using a well- characterized local sera panel from experimentally infected and naturally exposed cattle and ii) to compare the diagnostic performance and agreement of three N. caninum serological tests: p38-ELISA, indirect fluorescence antibody test (IFAT) and immunoblotting (IB) using the same sera panel. Serum samples testing either positive or negative by IFAT and IB were considered "Relative Standards of Comparison" (RSC) and used for p38-ELISA evaluation. Receiver operating characteristics analysis revealed that p38-ELISA was highly accurate (area under the curve= 0.982) according to RSC with a cut-off index of 0.0905. Relative sensitivity and specificity of p38-ELISA were 97.8 % and 99.5 %, respectively and agreement between RSC and p38-ELISA was almost perfect (k= 0.97). The evaluation and performance comparison of serological tests were performed according to the definition of gold standard based on the decision of the "majority of tests". All tests displayed high sensitivity and specificity values (greater than 95 %); and excellent agreement. This study describes the accurate performance of p38-ELISA evaluated locally and the highly accurate diagnostic performance of the studied tests for the detection of anti-N. caninum antibodies in cattle from Argentina.

Neospora caninum es un parásito protozoo responsable de abortos y pérdidas económicas en bovinos. La realización de un diagnóstico serológico preciso y con resultados comparables obtenidos por diferentes pruebas contribuye al manejo de este problema y a encarar medidas de control. Los objetivos del presente trabajo fueron los siguientes: 1) evaluar en Argentina una prueba de enzimoinmunoensayo in-house con el antígeno nativo de 38 kDa de N. caninum (ELISA-p38) para el diagnóstico de la neosporosis bovina, utilizando un panel de sueros locales bien caracterizados, procedentes de bovinos infectados de modo experimental o naturalmente expuestos; 2) comparar el desempeño y establecer el nivel de concordancia de tres pruebas serológicas para la detección de N. caninum, ELISA-p38, inmunofluorescencia indirecta (IFI) e inmunoblot (IB), con el mismo panel de sueros. Los sueros que resultaron positivos o negativos a IFI e IB fueron considerados como estándares relativos de comparación (ERC) para evaluar la prueba de ELISA-p38. El análisis de característica operativa del receptor determinó que la prueba de ELISA-p38 fue altamente precisa (área bajo la curva= 0,982) usando el punto de corte 0,0905. La sensibilidad y especificidad relativa del ELISA-p38 fue 97,8 % y 99,5 %, respectivamente, con una concordancia casi perfecta (k= 0,97) respecto del ERC. La comparación del desempeño de las pruebas se realizó usando como gold standard el criterio de la decisión de la "mayoría de las pruebas". Las pruebas exhibieron altos valores de sensibilidad y especificidad (mayores del 95 %) y excelente concordancia. Este trabajo describe un buen desempeño de la prueba de ELISA-p38 evaluada localmente y adecuada performance diagnóstica de las pruebas serológicas analizadas para la detección de anticuerpos anti N. caninum en bovinos de Argentina.