Prevalence of new and known species of haemoparasites in feral pigeons in northwest Italy.

Background: Haemoparasites in feral pigeons have been studied in several countries but no data are available from Italy. The aim of this work was to evaluate the prevalence and diversity of Haemoproteus spp./Plasmodium spp. and Leucocytozoon spp. in feral pigeons from northwest Italy, as well as the association between infection and host age or sex.

Methods: Feral pigeons were collected during a regional culling programme from the Piedmont region (northwest Italy) and subjected to necropsy. Infections were detected from DNA extracted from the spleen following a nested PCR protocol. The association between sex or age and infection status was evaluated using the chi-squared test for independence or Fisher's exact test.

Results: Out of 51 animals, 15 were positive for Haemoproteus/Plasmodium spp. and eight for Leucocytozoon spp., with a significant difference between haemoparasites prevalence. There was no significant association between age or sex and infection status. The coinfection with different haemoparasites was very significant (p < 0.01), showing a greater relative risk to be infected by a second haemoparasite in birds already infected, in particular in male and in adult pigeons. DNA sequencing of Leucocytozoon spp. showed six different lineages in pigeons, and one of Haemoproteus and Plasmodium, respectively.

Conclusions: Blood parasites are continuously circulating around the world, and the results presented in the paper suggest that cross infection of feral pigeons with haemoparasites typical of other migratory or nonmigratory bird species is possible. Moreover, the geographical location of Italy along the main migratory routes is a crucial factor to be considered for migratory birds, because they can be affected by blood parasites detected in feral pigeons, and vice versa.