Isolation of Leptospira interrogans from suburban rats in Tandil, Buenos Aires, Argentina.

The main objective of this study was to investigate the role of wild rodents as Leptospira spp. reservoirs in a suburban area of Tandil city, Buenos Aires province (Argentina), where a person had died due to pulmonary leptospirosis. The specific objectives were: to estimate the rodent density near the patient's home, to determine the serological prevalence and isolation of leptospirosis from wild rodents, and to identify the isolated strains. The area examined was a suburban neighbourhood in Tandil near the Langueyú stream, where the patient's house is located. Rattus norvegicus were trapped on the stream banks during two nights and a high capture rate (70%), was obtained. All rats (42) were examined serologically by the microscopic agglutination test (MAT), and 22 of them (52.3%) reacted with Leptospira serovars castellonis, canicola, grippotyphosa, icterohaemorrhagiae and hebdomadis at a titer of 1:50. The kidneys from 25 animals were cultured, and 24 isolates of L. interrogans (96%) were obtained. The isolated strains were identified as Icterohaemorrhagiae serogroup by MAT performed with rabbit hyperimmune reference sera. These findings showed a high density of suburban rodents highly infected with pathogenic leptospira, sharing environment in close contact with humans with evidence of leptospiral disease.

Evaluation of the risk of transmission of Trichinella in pork production systems in Argentina.

Recently, there has been interest in programs that certify pork production practices that minimize the risk of exposure of pigs to Trichinella spiralis. Certification might be useful for reducing the risk of human trichinellosis from pork in Argentina, but more information is needed on pig production practices and sources of Trichinella infection in Argentinian pigs. In this study, 21 pig farms were assessed for Trichinella infection including some farms using total and partial confinement management, and others with pigs raised exclusively outdoors. A total of 3224 muscle samples were collected from pigs raised on these farms and tested to determine the presence of T. spiralis larvae by artificial digestion. Serum samples from the same 3224 pigs were tested for antibodies to T. spiralis by ELISA. For each farm, a questionnaire was completed summarizing information about management factors and this information was used to assess risk factors for exposure of T. spiralis. Based on the results, pigs raised outdoors were more likely to be infected than pigs raised in total or partial confinement (p< or =0.05). Pigs fed waste products containing meat were 12.5 times more likely to be infected than pigs not fed waste containing meat (p<0.01). The role played by rats in transmission of Trichinella is unclear; however, on farms with evidence of wild animals and access of pigs to wildlife carcasses, the prevalence of Trichinella infection was significantly higher. All pigs raised under good hygienic and sanitary conditions were negative for Trichinella infection by both artificial digestion and ELISA.