Texia Gorman

SEROPREVALENCE OF TOXOPLASMA GONDII INFECTION IN SHEEP AND ALPACAS (LLAMA PACOS) IN CHILE

Serum samples from 408 sheep from different regions of Chile and 447 alpacas (Llama pacos) from the north of the country were tested for Toxoplasma gondii antibodies. The indirect haemagglutination test (IHAT) was used in both species and the indirect immunofluorescence test (IIFT) was also used on the sheep samples in order to compare the performance of the tests in that species. In both tests, titers > or = 1:16 were considered diagnostically significant. Sera from 49 sheep (12%) were positive to T. gondii antibodies by the IHAT. When using the IIFT, 114 sheep sera (28%) were positive. The different results obtained in sheep sera between the tests were significant (p < 0.0001). No differences were observed between geographical locations or sex of the sampled sheep regarding serological detection of T. gondii antibodies in sheep. As expected, adult sheep showed higher T. gondii reactivity than young sheep (p = 0.0008). The corrected prevalence of toxoplasmosis in alpaca was 16.3% (32 positive out of 447). The rather low prevalence in alpacas may be associated with their extensive management as well as the extreme climatic conditions of The Andes which apparently would not be favorable for the transmission of the parasite.

Flea species from dogs in three cities of Chile.

The purpose of this study was to establish the pattern of flea infestation in dogs in the cities of Santiago (33 degrees latitude south, 70 degrees longitude west), Concepción (36 degrees latitude south, 73 degrees longitude west) and Osorno (40 degrees latitude south, 73 degrees longitude west), located in different parts of Chile. The only species of fleas found on dogs from the three cities were Ctenocephalides felis felis (41.8%), Ctenocephalides canis (39.4%) and Pulex irritans (18.8%). Although the three species were found in the three cities, differences regarding their frequencies were detected (p<0.05). C. felis was the predominant species found on dogs in Santiago (80.5%). In Concepción, their frequencies followed a similar trend. However in Osorno, the most southern city, the predominant species was C. canis (78.7%).

Parasitos de los animales domésticos en Chile

PARASITES OF DOMESTIC ANIMALS IN CHILE An up-to-date list of the parasites that have been identified in horses, cattle, sheep, goats, llamas, alpacas, pigs, dogs, cats, rabbits, chickens and pigeons in Chile, according to the studies performed at the University of Chile and other Universities and Institutes.

Immunodiagnosis of fasciolosis in horses and pigs using Western blots

Crude and partially purified somatic (S) and excretory-secretory (ES) antigens of Fasciola hepatica were subjected to Western blot analysis in order to identify polypeptides that would enable specific and sensitive immunodiagnosis of horse and pig fasciolosis to be undertaken. Sera from 20 horses and 20 pigs with natural infections of F. hepatica and the same number of uninfected hosts of each species were tested, together with sera from 2 pigs with Cysticercus cellulosae infections. Using crude S antigens, sera from infected horses and pigs reacted specifically with a wide range of polypeptides of 14-19, 22-30, 35-37 and 42 kDa. Likewise, specific reactivity between polypeptides of 14-17, 22-30 and 40-42 kDa in crude ES antigens and sera from infected horses and pigs was obtained. Against the criteria of high sensitivity and specificity, the 22-30-kDa polypeptides would appear to be the most suitable candidate antigens for use in the immunodiagnosis of fasciolosis in horses and pigs.

Sarcocystis sp. in guanaco (Lama guanicoe) and effect of temperature on its viability

The biology of the Sarcocystis sp. that infect guanacoes was studied by feeding the infected meat to dogs, cats, rats and mice. Tissues from guanaco, heavily infected with macrocysts, were fed to these animals and their faeces collected daily and examined for the presence or absence of sporocysts. It was shown that only dogs were suitable definitive hosts. The effect of cooking and freezing on the viability of this protozoan organism was also investigated. Freezing to -18 degrees C and -24 degrees C and cooking were effective for inactivating Sarcocystis in guanaco meat. These methods could therefore be used instead of condemning guanaco carcasses infected with Sarcocystis.

Parasitismo gastrointestinal en perros de comunas de Santiago de diferente nivel socioeconómico

The prevalence of canine parasites was estimated in three counties from the Metropolitan Regionwith different socioeconomical conditions which were Providencia (ABC1 level), Quinta Normal (Dlevel) and La Pintana (E level). Faecal samples of 582 dogs were examined by Zinc flotation method,modified Teleman method and staining of faecal smears with Ziehl- Neelsen. A third of the dogs(30.2%) were found positive to some type of parasitism with significant higher prevalence in youngerdogs (3 to 6 months old) with 49% of infection versus 25.6% of older dogs. The percentage of positivesamples was significantly higher in stray dogs than those kept indoors (40% versus 28%). Significantdifferences in the frequency of parasites were also found between La Pintana and Providencia, (oddsratio of 2.61), and between La Pintana and Quinta Normal (odds ratio of 1.85) p < 0.05), but nodifferences were found between Providencia and Quinta Normal. A total of 118 samples werepositive to helminths (67%) and 41samples to protozoa (23.3%), as single infections while mixedinfections were recorded in 17 cases (9.7%).

Inmunodiagnóstico de fasciolosis humana y ovina empleando una fracción de 24-29 kDa de Fasciola hepatica obtenida mediante inmunoadsorción

* Departamento de Medicina Preventiva Animal, Facultad de Ciencias Veterinarias y Pecuarias. Universidad deChile. Casilla 2 Correo 15, Stgo. Chile.** Escuela de Tecnologia Medica y Departamento de Ciencias Biologicas. Universidad Nacional Andres Bello. Stgo. Chile.MARCOS SILVA**, TEXIA GORMAN* y HECTOR ALCAINO*

Purificación de antígenos de Fasciola hepatica mediante electroelución y su aplicación inmunodiagnóstica mediante Western Blot en la infección animal

La electroelucion implementada en este estudio logro purificar por separado dos polipeptidos, uno de 14 y otro de 29 kDa. La eficiencia diagnostica de cada uno de estos polipeptidos medida a traves de Western blot indico una sensibilidad de 95% y 97,5% respectivamente y ambos una especificidad de 100%. Ademas se concluye que son de utilidad en la pesquisa de infecciones prepatentes

Coccidias aviares de gallineros industriales de Chile

With the purpose of identifying the coccidia species in poultry farms of Chile, 51 fecal samples (of 50 chickens each)were collected. Through flotation coprological examination of 10% of samples, oocysts of Eimeria maxima were identified. The remaining portion of the samples, was suspended in a 2.5% potassium bichromate solution, to allow the sporulation of oocysts which were then suspended in tap water and administered to 6 chickens 21 days old free of coccidia infection through a gastroesophagic tube. The identification of Eimeria species was done through measurement of the prepatent period, size of squizonts and type and locations of the intestinal lesions produced. Seven Eimeria species were found with the next frequency: E. maxima 48 %, E. praecox 62%, E. mitis 68%, E. tenella 14%, E. necatrix 14%, E. mivati 8% and E. acervulina 48%. E. brunetti and E. hagani were not detected. Mixed infections were the most frequent finding, being very common to detect the presence of 4 species simultaneously.

INMUNODIAGNOSTICO DE FASCIOLOSIS BOVINA MEDIANTE ELISA Y WESTERN BLOT

Se evaluo y caracterizo la respuesta inmune humoral de bovinos naturalmente infectados con Fasciola hepatica frente a un extracto total de antigenos de excrecion-secrecion (E-S) y a una fraccion antigenica semipurificada cromatograficamente (<30 kDa), seleccionada previamente por su eficiencia diagnostica en otras especies. Ambos preparados antigenicos fueron analizados mediante ELISA en microplaca y electroforesis en geles de poliacrilamida en condicion de denaturacion (SDS-PAGE) y posterior inmuno-electrotransferencia enzimatica o Western blot. Para ello se emplearon 52 sueros de bovinos con fasciolosis comprobada mediante examen post mortem, 18 sueros de animales sin la infeccion y 48 sueros de vacunos infectados con hidatidosis, perosin fasciolosis. La sensibilidad y especificidad obtenidas en el ELISA con el extracto crudo E-S fueron de 53% y 100%, respectivamente, en tanto que con la fraccion semipurificada a igual especificidad (100%) se presento una sensibilidad mayor ( 90%). A traves de Western blot, empleando el extracto antigenico total E-S hubo un reconocimiento especifico de bandas correspondientes a los 14, 22, 27-29 y 37-38 kDa. Las bandas de 37-38 y 27-29 kDa destacaron por su sensibilidad y frecuencia, identificadas por el 90% y 100% de los infectados, respectivamente. Con el antigeno semipurificado, se evidencio una banda polipeptidica de 28-30 kDa, reconocida por todos los sueros con fasciolosis. Los resultados demuestran, por un lado, la existencia de diversas fracciones polipeptidicas que potencialmente pueden ser promisorias en el inmunodiagnostico de fasciolosis bovina