Health monitoring assessments are neglected in freshwater fish conservation. Role of infectious diseases in population dynamic is often unknown. In Portugal, six cyprinid species are endangered. Among them, Iberochondrostoma lusitanicum presents a diverse distribution; allowing epidemiological comparisons of host-pathogen evolution. Due to its impact, Aeromonas spp.—especially A. hydrophila—represent suitable models to unravel the impact of bacteria in wild fishes.
In order to evaluate the prevalence of Aeromonas spp. in I. lusitanicum, 64 individuals were collected at four river basins. Fish skin was swabbed and morphometric and lesion data recorded. Bacterial conventional isolation was performed. Preliminary results revealed a high prevalence (100%) of Aeromonas spp. in I. lusitanicum. The rate of lesions displayed was variable according to sampled population—higher at Jamor (94.6%), Laje (94.4%) and Samarra (90.9%); and lower at Lizandro (67.5%). Rate of lesions was dependent from location (p<0.001), influenced by fish without lesions at Lizandro (lower human density).
Our results confirm the presence and high prevalence of potential fish pathogens—Aeromonas spp.—in different critically endangered populations of I. lusitanicum. Further prospects include the characterization of the field isolates regarding their virulence and resistance profiles in order to establish pathogenic potential and concern for public health, determination of seasonal pathogen dynamics, and establishment of the influence of ex situ breeding programs on the development of bacterial infections. Such measures will allow a better understanding regarding the epidemiology of Aeromonas spp. in I. lusitanicum and its impact to the species conservation, as well as to public health.
This work was supported by CIISA - Centre for Interdisciplinary Research in Animal Health, faculty of veterinary medicine, University of Lisbon (Project UID/CVT/00276/2013). Miguel Grilo holds a PhD fellowship (C10571K) from University of Lisbon. The authors would also like to thank MARE: Marine and Environmental Sciences Centre - ISPA (UID/MAR/04292/2013), Cristina Lima, Pedro Duarte Coelho and Sónia Fernandes (ISPA) and Sara Valente (FVM-ULisbon).