Comprehensive Map of Canine Angiostrongylosis in Dogs in Spain

SIMPLE SUMMARY: Angiostrongylus vasorum (A. vasorum) is the causal agent of canine angiostrongylosis, an emerging disease in Europe. In Spain, A. vasorum mainly affects wild animals (red foxes and wolves), although studies in domestic dogs are scarce but show evidence of an expansion of the disease. The aim of this study was to analyze the presence of A. vasorum in domestic dogs throughout Spain, taking into account that there were still provinces where this canine infection has not been studied. Blood samples from 5544 domestic dogs were collected from January 2020 to March 2022. These samples were tested for the presence of circulating A. vasorum antigens. The overall prevalence of canine angiostrongylosis in Spain was 1.39%. No significant differences were found for sex and age, but significant differences were found for habitat. Infected domestic dogs were reported in most Spanish provinces, with lower prevalence observed for inland provinces and higher prevalence observed for provinces along the coast, where climatic factors seem to be determinant in the establishment of the parasite. ABSTRACT: Canine angiostrongylosis is an emerging disease caused by Angiostrongylus vasorum, mainly affecting wild carnivores and dogs. In Spain, there are studies reporting infections in foxes, wolves, and badgers in different regions of the country. However, there are hardly any publications on its prevalence in dogs. The aim of this study was to complete and update the epidemiologic map of A. vasorum in dogs in Spain. A total of 5619 canine blood samples from all autonomous cities and provinces of Spain were collected and tested for the presence of circulating A. vasorum antigens. The overall apparent prevalence of canine A. vasorum infection in Spain was 1.39%. No significant differences were found for sex or age, but significant differences between outdoor and indoor/outdoor dogs were found. A high prevalence was also observed in the northern third of the country, where an oceanic climate prevails, being humid and rainy and where abundant vegetation can be found, thus favoring the proliferation of intermediate hosts. The results suggest that A. vasorum canine infections are heterogeneously present in a large part of the territory, demonstrating its expansion throughout the country, and therefore, awareness and prevention campaigns for this disease should be promoted.