Patent Dirofilaria immitis infection in Galapagos sea lion rookeries in San Cristóbal Island

The Galapagos sea lion (Zalophus wollebaeki) is an endemic and endangered speciesthat plays a vital role in the ecosystem dynamics of the archipelago. In recent decades they have faceda significant population decline,related to the effects ofclimate variability and anthropogenic influences. Thus, the co-occurrence of sea lion resting areas with mosquito breeding sites and the presence of free-roaming domestic dogs presents significant health risks related to parasite transmission. This research demonstrates the occurrence of Dirofilaria immitis(canine heartworm) in Z. wollebaeki, indicating their possible function as a definitive host for this parasite. Blood samples collected in august 2023from 50 individuals (juveniles and adults) in two rookeries of San Cristóbal Island, revealed a 2% prevalence of D. immitisin juvenile females, as confirmed by Knott's test and PCR analysis. Results of this work emphasizes the critical necessity for effective monitoring and conservation strategies to address the threat posed by D. immitis and to safeguard thisendangered species.