Abstract
Current loss of biodiversity is commonly attributed to the deterioration of habitats or to regional climate change,5 and rarely is infectious disease considered a driver of biodiversity loss.8 However, a given pathogen can potentially reduce the recruitment of individuals, limiting their survival or altering their biological efficacy, consequentially leading to a possible extinction event4,7 particularly when the population is already threatened by other factors. In this study we provide serological data for the Galapagos sea lion (Zalophus wollebaeki), which has recently changed its conservation status to endangered.2,9 Compared to some sea lion colonies devoid of human settlements (such as Santa Fe colony, SF), the colony of sea lions at San Cristobal (SC) are closely associated with a human urban settlement and to their domestic animals. We investigated if the risk of infection by Brucella spp., a common bacterium in domestic animals that is known to infect marine mammals, and that often causes abortions in the hosts,1,6 is higher in SC than in SF because of the proximity to the human settlement. We used the semiquantitative Brucelloslide agglutination Test Card (bioMérieux, France) in serum samples collected from 80 pups (SC = 54, SF = 26) during 2009 to 2010. We found high prevalence in both colonies (40.7% and 46.1% SC SF; Fisher exact test, p = 0.81) with low levels of aggregation (20%) of specific antibodies. Because the antigen test detects B. bovis, B. mellitensis and B. canis, and not marine species of Brucella, our results suggest that human settlements have an impact on the transmission of pathogens from domestic animals to the sea lions, and that the effect is not limited to SC, possibly due to animal movements between colonies.3 We conclude that the risk of emergence and establishment of infectious diseases derived from human settlements may have a potential impact for the entire species, potentially leading to an even greater conservation problem for the already endangered Galapagos sea lion.
* Presenting author
Literature Cited
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