The Canine Distemper is one of the main infectious diseases in domestic dogs. The introduction of live attenuated-viral vaccines has helped to maintain the disease under control. However, in the past few decades it has been observed worldwide a rising number of cases even in vaccinated animals. The Canine Distemper Virus lineages circulating in the world have been described based on the hemagglutinin analyses, due to its high degree of genetic variability. Recently, new studies have reported greater variations in the amino acidic sequence of a region in the fusion protein. In order to determine the variability of the field strains in comparison with the vaccines and strains from other lines, in this dissertation the genomic variability of the Fsp region from the canine distemper virus fusion protein gene is analyzed. With this purpose, a Polymerase Chain Reaction with reverse transcription, capable of amplifying this variable region, was implemented, and identified through its nucleotide sequence. These sequences were compared with vaccine strains and with field strains of known lineages. Additionally, a phylogenetic tree was built for this variable region. The results of the nucleotides comparison show that the field strains have more homology to the vaccine strain Onderstepoort and according to phylogeny, it would belong to the America 1 lineage.

Tetracyclines are a group of broad-spectrum antibiotics whose general usefulness has been reduced with the onset of bacterial resistance.

The fundamental difference between a virus and microorganisms lies in the way they generate progeny and some viruses destroy the cell membrane, a phenomenon called cytolysis. The herpes virus has this cytolytic capacity and in veterinary medicine, several important herpes viruses have been described, among which is the Canine Herpes Virus type 1 (CaHV-1) and this study contributed both to the genomic characterization of a national isolate of the CaHV-1 virus -called RP5-as well as to small animal veterinary medicine with a specific, sensitive, and fast diagnostic method result. For this, detection of the CaHV-1 glycoprotein C gene was performed by Polymerase Chain Reaction using a pair of primers designed in silico. Using a temperature gradient thermocycler, the alignment temperature (55ºC) was established by the clear and unequivocal observation of a DNA fragment of approximately 200 bp. These fragments were sequenced and a percentage of nucleotide identity (NIP > 94%) was established with respect to the official GenBank data and indicates that the amplified fragment corresponds to the gC gene fragment of CaHV-1. Thus, this methodology constitutes another technique of choice for the detection of CaHV-1 in Small Animal Medicine.

No abstract

The ocurrence of Yersinia enterocolitica in tonsils and rectal swabs from 100 healthy pigs and the rectal swabs of 100 healthy cattle slaughtered at Santiago-Clule were analysed. Yersinia entemcolitica was isolated from 48 (48"o) pigs but not from cattle. 98.20/0 of strains were of 4 / 0 3 bioserogroup, considered to be pathogenic for humans. AU of the strains were resistant to penicillin producing beta-lactamase. Most of them were resistant to neornicin and tetracycline. The p W marker was used to demostrate pathogenicity in all strains by four different assays: 65.5% of the strains were p W positive by their plasmid profile; 73.3' /0 by crystal violet binding; 84.5% by calcium dependency and 87.9% by hybridization with probe associated with cytotoxicity to Hep-2 cells in vitro. All of the Yersinia entemcoliticu strains were p W positive with at least one of the four tests analysed, 46/58 strains were positive by three tests simultaneously. The similarities between associated cytotoxic genes of porcine and human strains is discussed. The phenotypic and genotypic characteristics demostrated by the isolates strains suggest that the pigs in Chile are reservoir of potential pathogenic Yersinia entemcolitica for humans. ResumenSe analiz6 el tejido tonsilar e hisopos rectales de 100 cerdos sanos e hisopos rectales de 100 bovinos sanos sacrificados en un matadero de Santiago, Chile. Un 48% de 10s cerdos fueron portadores asintomiticos de Yersinia enterocoLiticu sea a nivel tonsilar y/o rectal, mientras que en la especie bovina no se aislo este microorganismo. En las cepas aisladas de cerdos se encontro un predominio casi absoluto (98.2'/0) del bioserogrupo 4 / 0 3 , reconocido como el principal patbgeno para el hombre. La totalidad de las cepas fueron resistentes a penicilina y produjeron beta-lactamasa. La mayoria de las cepas fueron resistentes a neomicina y tetraciclina, sola o en asociacion. En la evaluacion de la patogenicidad de las cepas porcinas, utilizando como marcador el p W , se obtuvieron 10s sigujentes porcentajes de cepas positivas: 6S.S0/0 de cepas p W (f) por perfil plasmidial; 79.3% por prueba de afinidad con cristal violeta; 84.5% por dependencia de calcio y 87.9% mediante hibrichzacibn con sonda asociada a genes de citotoxicidad. Es importante destacar que la totalidad de las cepas aisladas fueron p W (+) por a1 menos una de las cuatrn tCcnicas probadas y que, 46 de 58 cepas lo fueron por 3 ttcnicas a la vez. Se plantea la similitud de genes asociados a citotoxicidad entre cepas porcinas y humanas. Las caractensticas demostradas por las cepas aisladas de cerdos permiten concluir que, en Chile, la especie porcina constituye un reservorio de cepas de Yersinia entemcolitica potencialmente patogenas para el hombre. I' s. (:c,pynRtlt clearance center Code statement: 0931-1 793/97/4406-0347$14.00/0