No evidence of avian malaria in two Mediterranean endemic seabirds

In birds, pathogens and diseases—such as avian malaria—can have severe detrimental effects on individual fitness. Pathogen prevalence can vary across species and may differ between populations living in different localities, but screening can aid in our understanding of a disease’s distribution and parasite-host interactions. Although seabirds generally exhibit low avian malaria infection patterns, blood parasites of several species and populations have never been investigated in detail. Using molecular techniques, we screened for blood parasites in two Mediterranean seabirds, the Scopoli’s Shearwater Calonectris diomedea and the Mediterranean Storm Petrel Hydrobates pelagicus melitensis. In addition, we searched for and sampled potential vector insects at each seabird colony. DNA was extracted from blood samples (or whole specimens for vector insect species), and polymerase chain reaction was performed to assess the presence of Plasmodium, Haemoproteus, and Leucocytozoon, the most frequent infective protozoan genera. Our results showed no evidence of haemosporidians, either in the sampled species or in the vector insects. The low prevalence of parasites in these species could reflect the absence or rarity of the vector for transmission. Thus, extreme care must be taken when releasing individuals into the wild to avoid introducing infection into new seabird populations.