Um total de 25 isolados do vírus da diarréia viral bovina (BVDV), sendo 15 originarias do Peru e 10 do Chile foram sujeitas a caracterização genética. A árvore filogenética baseada na análise da região proximal não-codificante (5'UTR) do genoma viral demonstrou que as 25 estirpes pertencem ao genótipo 1 do vírus BVD. Vinte e três destas estirpes puderam adicionalmente ser subdivididas no subtipo 1b, enquanto duas das 10 estirpes isolados provenientes do Chile foram identificadas como pertencentes ao subtipo 1a. Em conclusão, 23 de um total de 25 isolados analisados pertencem ao genótipo 1, subtipo 1b. Este é o subtipo de BVDV predominante em muitos países do mundo, incluindo os EUA. A elevada similaridade genética com isolados descritos anteriormente em outras regiões do mundo realça o papel do comércio internacional de gado no estabelecimento de diversidade genética do vírus BVD. Tanto o Peru como o Chile têm historia de importação de grandes quantidades de gado dos Estados Unidos e da Europa, no entanto sem suficiente documentação comprovativa do estado sanitário no que concerne a esta virose.

Twenty-five BVDV strains, detected in serum from persistently infected cattle from Peru (n=15) and Chile (n=10) were genetically characterized. The phylogenetic analysis based on the 5' UTR showed that all 25 strains belonged to genotype 1. Twenty-three of the strains could further be subdivided into subtype 1b, and two out of ten Chilean strains into subtype 1a. In conclusion, in total 23 out of 25 strains analyzed were of genotype 1, subtype 1b. This is the predominant BVDV subtype in many countries all over the world, including USA. The close homology with previously described strains reflects the influence of livestock trade on the diversity of BVDV circulating within and between countries and continents. Peru and Chile have imported large numbers of cattle from USA and Europe, mostly with insufficient or lacking health documentation.

Background: Swine hepatitis E virus (HEV) has a cross-reaction with human anti-HEV antibodies. Therefore, pigs could be an animal reservoir, rendering hepatitis E as a zoonosis. The spread of this infection among infected pigs across countries would be possible through trading. Previously, using an anti-human conjugate, we detected anti-HEV antobodies in adult pigs in Chile. Aim: To detect anti-HEV (ELISA) in a cohort of swine at different ages. Material and Methods: Two hundred pigs aged 42 to 360 days, divided in 20 groups of 10 animals were tested. Anti-HEV was detected by ELISA using anti-pig IgG horseradish peroxidase instead of anti-human conjugates. Results: Anti-HEV were detected in one animal aged 90 days, two animals aged 120 days, one animal aged 260 days and 2 animals aged 360 days, five pregnant sows and two old hogs. This represents a total of 14 animals or 7% of the sample. Conclusions: There is a significant prevalence of anti-HEV in pigs from 90 days of birth, suggesting that these swine are aprobable reservoir (RevMéd Chile 2007; 135: 997-1001)

Background: Sanitary and socioeconomic changes and the identification of new causative virus, have changed the epidemiology of hepatitis in Chile. Aim: To study the natural history of acute hepatitis caused by virus A, E and non A-E in Chilean adults. Patients and methods: A special study protocol was followed for patients with a clinical picture of acute hepatitis. Anti HAV IgM, anti HBc IgM, anti HEV IgG and IgM and Anti HCV antibodies were determined by ELISA. Results: Fifty nine patients (30 male), aged 15 to 58 years old were studied. Eighty nine percent had jaundice and 50 to 70% had malaise and abdominal pain. Virus A was positive in 80%, virus E in 7%. In 14% of patients, all viral markers were negative. The evolution was typical in 78%, biphasic in 14% and cholestatic in 5%. One patient had a prolonged and one a fulminant course. Mean ALT was 1148 U/l and mean total bilirubin was 5.5 mg/dl. Seventy three percent of cases occurred during early winter and spring and 27% during summer and early autumm. Conclusions: The main etiology of acute viral hepatitis in Chile is virus A and most cases occur during the rainy season. Clinical features of hepatitis non A-E are similar to enteral transmission forms. (Rev Méd Chile 2001; 129: 523-30)

Background: As sanitary and economic conditions improve, the prevalence of antibodies to hepatitis A is now significantly lower. Aim: To evaluate the prevalence of hepatitis A virus antibodies in healthy Chilean adults. Material and methods: Antibodies to hepatitis A virus were measured, using a commercial ELISA assay, in 215 voluntary blood donors (163 male, aged 19 to 30 years old) and 295 medical students and health personnel (156 male, aged 19 to 39 years old), residing in Valdivia, Chile. Results: Antibodies against hepatitis A virus were found in 68,2% of the total sample (351/510). Ninety percent of flood donors and 54% of health personnel and students were positive (p <0.01). Age specific prevalence in blood donors 19 to 22, 23 to 29 and 27 to 30 years old was 81,0%, 95,2% and 95,6% respectively. Among the same age groups in medical students, the prevalence was 47,9%, 53,2% and 61,9% respectively (p <0.01). Conclusions: This study indicates a reduction in the prevalence of hepatitis A virus antibodies among adults in Valdivia (Chile). Differences detected between individuals are probably related to different socioeconomic levels. Medical students have an increased risk for hepatitis A infections than the general population.

Background: Pathogenic strains of Yersinia enterocolitica harbor a virulence plasmid of 45-48 megadalton that can be detected using different techniques. Rodents are important reservoirs of Y enterocolitica. Aim: To investigate the carrier status of Y enterocolitica in murine rodents. Material and methods: Two hundred sixty one mice and rats were captured in rural and urban areas of Valdivia. Y enterocolitica was cultured from viscera and fecal homogenates. Virulence plasmids were detected using crystal violet binding. Results: Thirteen Y enterocolitica strains were isolated from 11 rodents. Ten strains belonged to the biotype 1 and three to the biotype 4, serotype O:3. The most frequently infected rodent species were R norvergicus (20%), followed by A longipilis (11%), A olivaceus (2%) and O longicaudatus (2%). Conclusions: Rodents, and specially the domestic rat, can be an important source of Y enterocolitica infection for human and susceptible animal species.