Evidencia serológica de circulación de Leptospira spp en Rattus norvegicus naturalmente expuestos en una zona urbana colombiana / Serological evidence of Leptospira spp circulation in naturally-exposed rats (Rattusnorvegicus) in a Colombian urban area

Objetivo Determinar la frecuencia de anticuerpos dirigidos contra especies de Leptospira patógenas en reservorios naturales, con el propósito de establecer evidencia de su papel potencial en la dispersión ambiental de Leptospira y por consiguiente su actuación como agente diseminador de la infección tanto al humano como a otras especies susceptibles. Materiales y métodos El muestreo se llevó a cabo en la Plaza Minorista durante el periodo comprendido entre agosto de 2006 y abril de 2007, en el cual se capturaron 254 roedores Rattus norvegicus. Se obtuvo sangre de estos por punción cardiaca y el suero resultante se procesó con la prueba de Microaglutinación. Resultados El análisis serológico para verificar las serovariedades circulantes de Leptospira spp, dio como resultado que 64 roedores (25,2 por ciento, 95 por ciento CI=19,5-30,1) tuvieron títulos positivos para al menos una de las 11 serovariedades probadas. Conclusiones Los datos muestran que no solo la serovariedad Icterohaemorrhagiae está asociada con esta especie reservoria; también lo están otras serovariedades como Grippothyphosa y Canícola. El estudio permitió determinar la frecuencia de anticuerpos contra especies patógenas de Leptospira para reservorios procedentes de una zona urbana colombiana. Estos datos son relevantes para las entidades de salud pública por constituir la base para la implementación de campañas de control adecuadas para esta zona del país y como modelo de otros estudios similares en otras ciudades colombianas.

Objective Assessing the frequency of antibodies directed against pathogenic Leptospira species found in natural reservoirs for establishing evidence of their potential role in the environmental dispersion of Leptospira and consequent dissemination of the infection to humans as well as to other susceptible species. Material and methods A survey was carried out in the Plaza Minorista from August 2006 to April 2007 in which 254 rats (Rattusnorvegicus) were captured. Blood was obtained from these rodents by cardiac puncture and the resulting serum was used for microagglutination tests. Results Serological analysis for verifying Leptospira spp circulating serovars resulted in 64 rodents (25.2 percent;19.5-30.1 95 percentCI) having positive antibody titres for at least 11 of the serovars tested. Conclusions Frequency data regarding the antibodies so detected showed that the Icterohaemorrhagiae serovar was not the only one possibly associated with this reservoir species, but also with others such as the Grippothyphosa and Canícolaserovars. The study determined the frequency of antibodies against pathogenic Leptospira species for reservoirs from an urban area in Colombia. This data is relevant for public health authorities and might constitute the basis for implementing appropriate control campaigns for this area of the country and, likewise, this work could serve as a model for similar studies in other Colombian cities.

Hantavirus antibodies in rodents and human cases with pulmonary syndrome, Río Negro, Argentina / Anticuerpos contra hantavirus en roedores y casos humanos con síndrome pulmonar, Río Negro, Argentina

In Río Negro Province, Argentina, human cases of hantavirus pulmonary syndrome (HPS) appeared in the region of subantartic forests. The Andes virus (ANDV) has been identified in the region both in Oligoryzomys longicaudatus rodents and in humans, with the main transmission being from rodents to humans but also showing the possibility of human to human transmission. Between 1996 and 2004, in 40 campaigns, 29.960 night-traps for capturing live rodents were set up. Blood samples were obtained from the rodents and processed using enzyme immunoassay with recombinant antigens made from ANDV. A total of 1767 rodents were captured, with a capture success of 5.9% and an antibody prevalence of 2.1%. Important differences were observed among the species captured from Andes and Steppe regions. Seropositive Oligoryzomys longicaudatus, Abrotrix olivaceus, Abrotrix xanhtothinus and Loxodontomus microtus were captured. During the 1993-2004 period, 40 HPS cases were registered.

En la Provincia de Río Negro, Argentina, se presentaron casos humanos de síndrome pulmonar por hantavirus (SPH) en la región de los bosques subantárticos. El virus Andes (AND) fue identificado en la región, tanto en el roedor Oligoryzomys longicaudatus como en seres humanos, demostrándose la transmisión principalmente del roedor al hombre y la posibilidad de la transmisión de persona a persona. Para ello, se procedió a la colocación de 29.960 trampas para captura viva de roedores, tipo Sherman, en 40 operativos efectuados desde 1996 hasta 2004. Se obtuvieron muestras de sangre de los roedores, las que fueron procesadas mediante enzimoinmunoensayo con antígenos recombinantes elaborados a partir de virus AND. Fueron capturados 1767 roedores, con un éxito de trampeo del 5.9% y una prevalencia de anticuerpos contra hantavirus del 2.1%. Se observaron importantes diferencias en las especies capturadas en cada una de las regiones. Se capturaron O. longicaudatus, Abrothrix olivaceus y Abrothrix xanhtothinus y Loxodontomys microtus seropositivos. Se registraron 40 casos humanos en el período 1993-2004.

Hepatic Cirrhosis Occurring in a Young Woodchuck (Marmota monax) Due to Vertical Transmission of Woodchuck Hepatitis Virus (WHV)

Histologic and clinicopathologic findings of a woodchuck (Marmota monax) vertically infected with woodchuck hepatitis virus (WHV) are presented. The liver exhibits marked cirrhotic changes, which is characteristic of the pre-transformation phase of WHV. At necropsy, the woodchuck exhibited ascites and the liver had a grossly nodular appearance. Microscopically, focal hepatocyte necrosis and inflammatory cells were observed in midzonal and periportal areas in the liver. In Macchiavellos stained sections, cytoplasmic inclusion bodies appeared reddish granular materials. We believe that this may represent a new suitable and cost-effective cirrhotic model for the disease processes associated with hepadnaviruses in a number of other species, most notably Hepatitis B virus infection in man.

Isolation and PCR detection of rickettsiae from clinical and rodent samples in Malaysia.

Isolation of rickettsiae from patients' blood samples and organ samples of wild rodents from areas with high seroprevalence of rickettsial infections was attempted using cell culture assay and animal passages. L929 mouse fibroblast cells grown in 24 well tissue culture plate were inoculated with buffy coat of febrile patients and examined for the growth of rickettsiae by Giemsa, Gimenez staining and direct immunofluorescence assay. No rickettsiae were isolated from 48 patients' blood samples. No symptomatic infections were noted in mice or guinea pigs infected with 50 organ samples of wild rodents. There was no rickettsial DNA amplified from these samples using various PCR detection systems for Orientia tsutsugamushi, typhus and spotted fever group rickettsiae.