In order to elucidate T. gondii infection in a regional hospital in southern Taiwan, serum samples were taken from 173 selected individuals. Among them, 91 serum samples were taken from uremic patients under regular hemodialysis, 34 from human immunodeficiency virus (HIV) infected patients and 48 from healthy adults. Of these 173 samples analyzed by commercial enzyme-linked immunosorbent assay (ELISA) kits including anti-T. gondii IgG and IgM, 21 were seropositive (12.1%) of T. gondii infection. Among 91 uremic patients, 11 (12.1%) were seropositive for IgG. Among 34 HIV-infected patients, 9 (26.5%) were seropositive for IgG and 3 (8.8%) were seropositive for IgM. ELISA data were tested by ANOVA and statistical significances were detected among these groups. The most common band revealed by Western blot assay was the 30 kDa antigen which appeared in 8 of 11 (72.7%) uremic IgG-positive patients and 4 of 9 (44.4%) HIV-infected patients. Serodiagnosis of T. gondii infection reveals a higher positive rate among HIV-infected patients, uremic patients under hemodialysis are also at risk for reactivation of latent toxoplasmal infection. Serological screening for anti-T. gondii antibodies among HIV-infected patients and hemodialytic patients as well as sustained follow-up to detect recent infection are extremely important.

El Toxoplasma gondii, agente causal de la toxoplasmosis, es un parásito importante en la salud animal, por ser una de las principales infecciones parasitarias que ocasiona problemas reproductivos, y también constituye una zoonosis muy importante alrededor del mundo. El objetivo del presente estudio fue determinar la seroprevalencia de Toxoplasma gondii en alpacas de la Unidad de Producción de Cochas de la SAIS Túpac Amaru, ubicada en el distrito de Canchayllo, Provincia de Jauja, Departamento de Junín. Para tal fin, se recolectaron sueros sanguíneos procedentes de 200 alpacas entre hembras y machos, en el mes de diciembre de año 2000, para la detección de anticuerpos mediante la técnica de Hemaglutinación Indirecta (HAI). Los resultados generales indicaron que el 21 ± 5.64 % (42/200) de las muestras de alpacas presentaron anticuerpos con títulos que variaron desde 1/16 hasta 1/1024. La seroprevalencia hallada en machos 26.47 10.49 % (18/68) fue mayor que en hembras 18.18 6.57 % (24/132), y por rangos de edad desde los 8 a 12 meses, de 12 hasta 36 meses y más de 36 meses las seroprevalencias fueron 33.33 16.08 %, 15.38 9.81, 20 7.31 respectivamente. Al realizar el análisis estadístico respectivo mediante la Prueba de regresión Logística no se encontró relación estadística significativa entre la presencia de anticuerpos contra T. gondii y el sexo de las alpacas, pero si entre la edad del animal y la infección por T. gondii, siendo las alpacas más jóvenes (8 a 12 meses) aproximadamente 2,9 veces más susceptibles que los otros dos grupos etéreos, este resultado podría deberse a la presencia de anticuerpos maternales, manejo de los animales, factores ambientales y frecuencia del hospedero definitivo. La prevalencia encontrada en el presente estudio fue moderada, por lo tanto, se hace necesario la realización de más estudios a fin de determinar el verdadero rol de este parásito en los problemas reproductivos de las alpacas. / Toxoplasma gondii, causative agent of toxoplasmosis, is an important parasite in animal health because it is one of the major parasitic infections that produce reproductive problems, and also it is an important zoonosis worldwide. The objective of this study was to determine the seroprevalence of antibodies against Toxoplasma gondii in alpacas from the Unit of Production of Cochas of the SAIS Tupac Amaru, located in the district of Canchayllo, Province of Jauja, Departament of Junin, Perú. To this end, sera from 200 alpacas among females and male were gathered in the month of December of 2000, for the detection of antibodies by using the method of Indirect Hemaglutination (IHA). 21 5.64 % (42/200) of the samples showed antibodies, with titles ranging from 1/16 up to 1/1024. The seroprevalence found in males was 26.47 (10.47% (18/64), and it was greater than in females, 18.18 6.57 % (24/132), and for age groups, from the birth until 1 year old, more than 1 up to 2 years old and more than 3 years old; the seroprevalence found was 33.33 16.08%, 15.38 9.8, 20 7.31 respectively. The analysis by using The Logistic regression found that the genus did not represent a risk factor. The age did represent a risk factor, being younger alpacas (8 to 12 months) more susceptible than other age groups. These results are coherent with other studies obtained in different parts of world, however, it is observed that there are differences with recent studies obtained in Peru; this, this could be due to environmental factors, frequency of the definitive host. Prevalence found in the present study was moderate, should be done further studies to determine the real importance of T. gondii in the occurrence of abortion in alpacas.

El objetivo del presente trabajo fue determinar la frecuencia de anticuerpos contra Toxoplasma gondii en gatos de Lima Metropolitana. Además, estimar el grado de concordancia entre las técnicas de diagnóstico de inmunofluorescencia indirecta y hemaglutinación indirecta. Se analizaron las muestras de sueros de 178 gatos, obtenidas de diferentes clínicas veterinarias de Lima Metropolitana. Los resultados mostraron una frecuencia de reactores a Toxoplasma gondii de 17.9% con un intervalo de confianza de 95% entre 12.0 y 23.5% para la técnica IFI y 11.2% con un intervalo de confianza de 95% entre 6.6 y 15.8% para la técnica HAI. La evaluación de reactores según edad y sexo, no mostraron diferencia estadística significativa (p>0,05). Por otro lado, al evaluar el grado de concordancia entre ambas pruebas se halló un valor de Kappa (K) igual a 0.73 indicando que el grado de concordancia entre ambas pruebas fue del tipo sustancial; mientras que con la prueba de Mc Nemar se encontró significancia estadística (p menor 0.05), entendiendo que las pruebas no pueden ser reemplazadas mutuamente. / The aim of the present work was to estimate the frequency of Toxoplasmosis in cats in the city of Metropolitan Lima. Aside from determining the rate of concordance between the Indirect immunofluorescence (IFI) and Indirect haemaglutination (HAI) Assays, two of the very common diagnostic tests for Toxoplasmosis in our area, a number of 178 cat serum samples, collected in veterinary clinics of this city, were analyzed. The results determined a frequency of reactors to Toxoplasma gondii in 17.90% with a 95% confidence interval (CI) between 12.00% and 23.50% for IFI test and in 11.20% with a 95% confidence interval (CI) between 6.60% and 15.80% for HAI test. The evaluation of reactors, according to age and sex, did not provide statistically significant difference (p> 0, 05). On the other hand, when the rate of concordance among both assays was tested, there was a value of Kappa (K) similar to 0.73 indicating that the concordance is substantial between the two test; while in Mc Nemar’s test, there was statistically significant difference (p less 0.05), indicating that both tests cannot be replaced reciprocally.

Toxoplasma gondii es un patógeno intracelular obligatorio dentro del Phylum Apicomplexa, con un amplio rango de hospederos incluyendo muchas aves y mamíferos en el mundo. El objetivo del estudio fue determinar la seroprevalencia de anticuerpos anti-Toxoplasma gondii en alpacas de la Unidad de Producción de Cuyo de la SAIS Pachacútec, ubicada en el distrito de Marcapomacocha, Provincia de Yauli, Departamento de Junín. Para tal fin se recolectaron en el mes de enero del 2003, sueros sanguíneos de 258 alpacas hembras para la detección de anticuerpos de Toxoplasma gondii; mediante la técnica de Inmunofluorescencia Indirecta (IFI), encontrándose que el 8.53±3.41% (22/258) de las muestras, presentaban anticuerpos contra el parásito; siendo estos menores en proporción con los hallados en alpacas de otras zonas ganaderas del país, por lo tanto se hace necesario la continuar con estudios similares a fin de determinar el verdadero rol de este parásito con los problemas reproductivos en alpacas. / Toxoplasma gondii is an obligate intracellular pathogen within the phylum Apicomplexa, with a broad host range including many birds and mammals in the world. The objective of this study was determine the seroprevalence of antibodies against Toxoplasma gondii in alpacas in the United of Production of Cuyo at the SAIS Pachacutec, located in the district of Marcapomacocha, Province of Yauli, Departament of Junin. In order to do this, 258 sera from female alpacas were collected in the month of January of 2003. Sera was tested against Toxoplasma gondii antibodies using Indirect Immunoflorescence (IFI), being that 8.53±3.41% (22/258) of the samples showed antibodies against the parasite. These results show a lower proportion compared to those findings in alpacas from other zones of the country; therefore, it is necessary to continue with similar studies, which will determine the real pathological role of this parasite in alpacas.

Toxoplasma gondii y Neospora caninum son dos protozoarios apicomplexos de distribución mundial y potenciales causantes de enfermedades neuromusculares en canes. Sin embargo, en el Perú son escasos los estudios sobre la implicancia de estos agentes en la especie canina. Así, el objetivo de este estudio fue determinar la frecuencia de anticuerpos IgG contra Neospora caninum y Toxoplasma gondii en canes con alteraciones neuromusculares y observar el tipo de asociación que existe entre la presencia de anticuerpos y la afección neuromuscular. Para el estudio fueron examinados 96 sueros de canes con signos clínicos de afección neuromuscular y 120 sueros de canes sin presencia de signos neuromusculares. Todas las muestras fueron obtenidas en la Clínica de Animales Menores de la FMV – UNMSM. Luego, el diagnóstico se realizó a través de la prueba de Inmunofluorescencia Indirecta (IFI) para la detección de anticuerpos IgG, considerándose positivos los sueros que presentaron fluorescencia completa del taquizoíto en la dilución 1:50. En los canes con afección neuromuscular, la frecuencia para Toxoplasma gondii fue de 23.96 ± 8.5% (23/96) y para Neospora caninum fue de 5.21 ± 4.4 (5/96), mientras que en los canes sin afección neuromuscular la frecuencia para Toxoplasma gondii fue de 3.34 ± 3.1 (4/120) y para Neospora caninum fue de 1.67 ± 2.5 (2/120). Finalmente, se observó que existe asociación entre la afección neuromuscular y la presencia de anticuerpos anti-Toxoplasma gondii, mientras que no se halló asociación entre tal afección y la presencia de anticuerpos anti-Neospora caninum. / Toxoplasma gondii and Neospora caninum are two apicomplex protozoans that can cause neuromuscular diseases in dogs. In Peru, are only a few studies on the implication of these agents in the canine species. The target of this investigation was to find the association between IgG antibodies and neuromuscular diseases. In this study, 96 sera of dogs with clinical signs of neuromuscular disease and 120 sera of dogs without neuromuscular signs were examinated. All the samples were obtained at the Small Animal Clinic of the FMV – UNMSM. The diagnosis was performed by means of indirect immunofluorescence test (IFI) for the detection of IgG antibodies, considering positive the sera that showed complete fluorescence of the tachyzoite in the dilution 1:50. In the dogs with neuromuscular disease, the frequency for Toxoplasma gondii was 23.96 ± 8.5% (23/96) and for Neospora caninum was 5.21 ± 4.4 (5/96), meanwhile, in the dogs without neuromuscular disease the frequency for Toxoplasma gondii was 3.34 ± 3.1 (4/120) and for Neospora caninum was 1.67 ± 2.5 (2/120). Finally, it was observed association between the neuromuscular disease and the presence of anti-Toxoplasma gondii antibodies, while did not find association between such disease and the presence of anti-Neospora caninum antibodies.

El Toxoplasma gondii es un protozoo, que tiene como hospedero definitivo a los felinos y como hospederos intermediarios, a un amplio rango de hospederos entre ovinos, caprinos, porcinos, aves y humanos. Este protozoo, presenta una distribución mundial y es causante de problemas reproductivos en el ganado, principalmente el ovino. Su importancia radica en la implicancia zoonótica. Los estudios realizados en camélidos sudamericanos silvestres como la vicuña son escasos, sobre todo aquellos dirigidos a determinar los problemas de tipos reproductivos y epidemiológicos. El objetivo del presente estudio fue estimar la seroprevalencia de T. gondii en vicuñas de la Reserva Nacional de Pampa Galeras, en el Departamento de Ayacucho, para lo cual se muestrearon 191 vicuñas, entre machos y hembras, a las cuales se les realizó la prueba de Inmunofluorescencia indirecta. La seroprevalencia obtenida fue de 5.8 ± 3.3 %, no observándose diferencias estadísticas significativas en los resultados, al evaluar las variables sexo y grupo etáreo relacionados a los reactores a la prueba serológica. El presente estudio demuestra la infección por T. gondii en vicuñas de la Reserva Nacional de Pampa Galeras-Proyecto San Cristóbal y Aledaños. Palabras Clave: Toxoplasmosis, CSA silvestre, serología, anticuerpos, Ayacucho. / Toxoplasma gondii is a protozoan parasite, which definitive host is the feline and has a wide range of species like sheep, goats, pigs, birds and humans as intermediate hosts. This protozoan is worldwide distributed and causes reproductive problems in cattle, specially sheep. Its importance takes root in its zoonótica implication. Studies performed in wild South American camelids like the vicunas are scarce, specially those directed to determine reproductive and epidemiological problems. The objective of this study was to determine the Seroprevalence of T. gondii in vicunas of the National Reserve of Pampa Galeras in the department of Ayacucho. Therefore, 191 serum of vicunas were evaluated, male and female, by using the inmunofluorescent antibody test (IFAT). The Seroprevalence obtained was 5.8 % +/- 3.3. Significant statistical differences were not observed in the results, comparing the variables age and sex. The present study demonstrates that infection of T. gondii in vicunas of the National Reserve of Pampa Galeras occurred. Key Words: Toxoplasmosis, wild SC , serology, antibodies, Ayacucho.

Reproduction de : Thèse doctorat : Ecologie parasitaire : Reims : 2007. / Titre provenant de l'écran titre. Bibliogr. p. 245-272.

Thèse de doctorat : Sciences de la vie et de la santé : Tours : 2008. / Titre provenant de l'écran-titre.

Thesis (Ph.D.)--Murdoch University, 2008. / Thesis submitted to the Faculty of Health Sciences. Includes bibliographical references (leaves 139-154)

Toxoplasma gondii is the causative agent of Toxoplasmosis in human and animals. T. gondii isolates are highly diverse. Hundreds of genotypes have been identified, but only three clonal lineages, namely Type I, II and III are prevalent worldwide. In mouse model, T. gondii strains can be divided into three groups based on their virulence, including the virulent (LD100=1), the intermediately virulent (LD50 = 103-104) and the non virulent (LD50 > 105). The clonal Type I, II and III T. gondii strains belong to these three groups, respectively. Epidemiologic studies suggest the difference of virulence in mice may relate to the severity of toxoplasmosis in human infection. Therefore, it is necessary to understand biological differences in genetically different T. gondii strains and their effect on the host responses. To date, the majority of data published on this aspect has been limited to in vitro assays. Here, we used in vivo assays to investigate host responses upon infection of distinct Toxoplasma strains. Our studies examined host response to infection of the three widespread clonal lineages of T. gondii using a mouse model. The following results were revealed: (i) increased tissue burden in mice is the indicator of virulence of T. gondii. Quantification of parasite burden in the spleen of mice showed significantly more parasites for Type I strain than that of Type II and III strains, with the latter two having comparable parasite burdens. Given that the Type II strains are more virulent than the Type III strains in mice; this result suggests that difference in host response is the result of specific parasite-host interaction, which is not simply due to the difference of parasite tissue load. (ii) gene expression in the host is strongly influenced by parasite genetic background. Transcriptional profiles of mice infected with the above three types of T. gondii strains showed that the overall gene expression patterns are similar between Type I and Type II infected mice and both stimulated stronger and more polarized change comparing to Type III strain. These results emphasize the importance of studying T. gondii pathogenesis in the host with the consideration of parasite genetic diversity. Such research could possibly aid in select appropriate regimes to treat toxoplasmosis caused by diverse T. gondii strains.