Plasmodium spp. in wild birds from the São Paulo Zoo: species Identification by microscopy and DNA barcoding

Abstract

Plasmodium spp. (Apicomplexa: Haemosporida) is a protozoan of cosmopolitan distribution. Currently, 38 species of Plasmodium are officially recognized in birds. The birds have a prominent place in studies of this parasite, because for many years were used as experimental models in studies of human malaria, enabling a better understanding of the cycle of this parasite and the study of antimalarial drugs. In the second half of the 20th century, parasites of birds were replaced by parasites of rodents and by the development of in vitro culture of P. falciparum. Unfortunately, these findings undermined the biological investigations of these parasites in birds. The taxonomy of these parasites is still very controversial and most studies are based solely on morphology. Although recent studies using molecular biology techniques have created gene sequences that have been deposited in GenBank, the parasites of these sequences were diagnosed only until genus, and in some cases, until even broader taxonomical levels. Furthermore, many sequences were misidentified, hampering molecular studies with this group. Therefore, the combination of microscopy, PCR and sequencing is essential for correct identification of these parasites. In Brazil, a country of remarkable diversity of birds, there are few studies of the incidence of hematozoa in these animals, most of which involved only the analysis of blood smears. In São Paulo, this survey was conducted more than thirty years ago and Plasmodium sp. was detected in 1.8% of the samples, although the species of the parasites have not been identified. Thus, this study aims to determine the incidence of Plasmodium spp. in captive birds from the Sao Paulo Zoo and free-living birds that migrate and inhabit the region. The research will be done by molecular biology techniques and microscopic analysis of blood smears, mainly aiming to establish a DNA barcode for the Plasmodium species identified. (AU)