A preliminary survey for avian pathogens in Columbiform birds on Socorro Island, Mexico.

To assess the potential disease risks posed by resident Columbiformes to the reintroduction of the Socorro Dove Zenaida graysoni to Socorro Island, Mexico, the endemic Socorro Ground Dove Columbina passerina socorrensis and the recently arrived Mourning Dove Zenaida macroura, were screened for ecto- and endoparsites, haemosporidia, Trichomonas gallinae, Chlamydophila psittaci and avian pox. All of the Mourning Doves and Socorro Ground Doves sampled appeared healthy upon capture. We detected Haemoproteus spp. in 88% of Mourning Dove and 30% of Socorro Ground Dove samples using microscopy. Two polymerase chain reaction (PCR) DNA amplification methods detected either Haemoproteus spp. or Plasmodium spp. Pooling results from both tests yielded positives in 100% of the Mourning Doves and 52% of the Socorro Ground Doves. A nested PCR detected Leucocytozoon spp. in 94% of the Mourning Doves and 61% of the Socorro Ground Doves sampled. Thus, at least two genera of haemosporidia are present in columbids of Socorro Island. Microscopy for T. gallinae yielded positives in 33% of Mourning Dove and 30% of Socorro Ground Dove samples. C. psittaci was not detected using PCR on either cloacal swab samples or tissue samples from tested Mourning Doves or Socorro Ground Doves. Necropsies revealed neither lesions indicative of the wet form of avian pox, nor internal lesions associated with trichomoniasis. These results suggest that Socorro Doves selected for reintroduction should be screened carefully to evaluate potential immunological challenges by native haemosporidians and to avoid introduction of other diseases apparently absent from native Columbiformes on Socorro Island.