Current State of Canine Heartworm in Portugal.

Simple Summary: Portugal's favourable climate renders it a hotspot for Dirofilaria immitis in dogs, leading to endemicity. This study aimed to provide an updated assessment of disease prevalence in Portuguese dogs, considering various factors. A total of 1367 dogs were tested, revealing an overall prevalence of 5.9%. The disease is spreading northward, with coastal areas exhibiting higher rates. Aveiro has experienced a significant increase, while the prevalence in other regions has either stabilised or decreased. Outdoor activities and older age were identified as risk factors for infection. No cases were found in the Azores. The study highlights the need for preventive measures and public awareness to combat this zoonotic disease. The favourable geo-climatic conditions in Portugal have made it highly conducive to the development of Dirofilaria immitis in dogs, leading to its identification as an endemic region. This nematode is rapidly spreading across Europe, particularly in northeastern countries. The objective of this study was to provide an updated assessment of the prevalence of this disease in Portuguese dogs, analysing the results in relation to epidemiological and geo-environmental factors, and to identify potential risk factors. A total of 1367 dogs from all continental and insular districts were included in the study and tested for D. immitis antigens. The overall prevalence was found to be 5.9%. It was observed that the disease is spreading northward, with previously unaffected districts now reporting cases, and that the prevalence in coastal districts exceeded that of inland ones. Notably, the Aveiro district exhibited a significant increase in D. immitis prevalence, while in certain districts such as Setúbal, Santarém, Madeira, or Faro, a stabilisation or decrease in prevalence was noted. Furthermore, outdoor and older dogs were found to be at a higher risk of infection. No positive cases were detected in the Azores. Most of the infected dogs were located in areas of high and medium risk of infection. This study underscores the importance of implementing pharmacological prophylaxis, vector control strategies, and public awareness programs to control the spread of this zoonotic disease. [ABSTRACT FROM AUTHOR]