Zoonotic pathogens in an island invader: the case of the northern raccoon (Procyon lotor) in Mallorca (Balearic Islands)

Introduced to Europe in Germany in 1934, the northern raccoon (Procyon lotor) is an invasive carnivoran that has since spread widely across the continent and now thrives in Mediterranean ecosystems. This study investigated the occurrence of selected vector-borne, lung, and enteric pathogens, as well as associated tick species, in 75 raccoons necropsied on Mallorca Island (Spain), through molecular screening of spleen, lung, fecal, and ectoparasite samples. Tick infestation was recorded in 61.3% of raccoons, with all collected ticks (n = 326) identified as Rhipicephalus secundus, representing the first molecular confirmation of this species in Spain. Overall, 24% of raccoons were positive for at least one pathogen. Leishmania infantum was detected in 1.5% of spleen samples, while 22.6% of fecal samples were positive for Cryptosporidium spp. (i.e., Cryptosporidium muris, Cryptosporidium parvum, Cryptosporidium ditrichi, and Cryptosporidium skunk genotype). All samples tested negative for Anaplasmataceae, Babesia spp., Borrelia spp., Baylisascaris procyonis, Dirofilaria immitis, Dirofilaria repens, Metastrongylidae, and Rickettsia spp. These findings suggest that an invasive carnivoran may impact not only the ecology of native species and ecosystem integrity, but also the epidemiology of zoonotic pathogens. Therefore, effective measures are needed to prevent further releases into the wild and to support the control and eradication of this invasive species.