Rattus norvegicus as an indicator of circulation of Capillaria hepatica and Taenia taeniaeformis on a groceries trade center of Medellín, Colombia Rattus norvegicus como indicador de la circulación de Capillaria hepatica y Taenia taeniaeformis en la Plaza Minorista de Medellín, Colombia

Introduction. Rattus norvegicus, the Norway rat, plays a pivotal role in the maintenance and spread of several zoonotic bacterial, viral and parasitic pathogens of public health interest. The presence of helminthic infections near susceptible human populations can, under appropriate environmental conditions, become a risk factor for their transmission.Objective. Frequencies of infection were reported for Capillaria hepatica and larval forms of Taenia taeniaeformis in wild rats (R. norvegicus) captured in an urban area.Materials and methods. Two hundred and fifty-four adult specimens of R. norvegicus were collected in an urban zone of Medellín, Colombia. The livers of 54 specimens that showed macroscopic hepatic lesions during necropsy were examined by conventional histopathology.Results. The frequency of infestation with C. hepatica was 20.1% (51/254). Six livers (2.4%) were also positive for larvae of T. taeniaeformis. Livers infested with C. hepatica exhibited adult or juvenile parasites and oval eggs with bipolar opercula, and were associated with mild to moderate multifocal granulomatous hepatitis with leucocyte infiltrate. Granulomatous lesions and calcified residual fibroses were found with eggs but without adult parasites. Those animals with cysticerci of T. taeniaeformis showed a high frequency of hepatic cysts containing larvae as well as inflammed and fibrotic lesions.Conclusion. Zoonotic helminths circulate at high frequency in R. norvegicus that occur in urban environments. Further research about the distribution of these parasites will determine the level of health threat they present for susceptible human and domestic animal populations. doi: http://dx.doi.org/10.7705/biomedica.v32i4.442