Prevalence of Dirofilaria immitis in dogs from Barcelona: Validation of a geospatial prediction model

- The current canine prevalence of heartworm was 2.4% in the province of Barcelona.
- Infected dogs were located in districts close to parks in the urban area of Barcelona.
- D. immitis is unevenly distributed and associated to areas with high risk of infection.
- GIS can be used to determine the need of implementation of prophylactic protocols.

Like other vector borne infections, the distribution of dirofilariosis caused by Dirofilaria immitis is influenced by climatic factors, which regulate the diversity and abundance of mosquito species able to transmit the parasite. Geographical Information Systems (GIS) can predict the distribution and epidemiological behavior of dirofilariosis based on temperature and humidity data. This study analyses the prevalence and current distribution of canine dirofilariosis in the province of Barcelona (Northeastern Spain), and uses a GIS model to evaluate the relationship between the spatial distribution of positive cases and different geo-environmental factors. Canine dirofilariosis is present in all the studied regions but unevenly distributed. The general prevalence is 2.4%, being located most of positive dogs in areas where the model predict both high number of annual generations of D. immitis in vectors and humidity, as a consequence of the presence of irrigated crops or the proximity to the sea. Furthermore, in the urban area of Barcelona, infected dogs were located in districts surrounded or close to parks and green areas. The model can be used as a tool to determine the need of implementation of prophylactic protocols in pets living in municipalities from these regions, based on the geo-environmental characteristics of the area.