Molecular and Morphological Characterization of a Brazilian Lineage of Plasmodium (Novyella) Unalis in Turdus Spp. (Passeriformes) of the Atlantic Forest, with Remarks on New Hosts and High Genetic Variation

Abstract

Plasmodium spp. are haemosporidian protozoans that alternate their live cycles between bloodsucking Culicidae dipterans and vertebrate hosts (mammals, reptiles, and birds). In birds, these parasites are the causative agents of the so-called avian malaria, a disease associated with considerable declines and extinctions in the avifauna in different geographical regions. In this work, we applied a multidisciplinary approach, light microscopy and cytochrome oxidase b (cyt b) gene sequence analysis, for characterization of Plasmodium spp. found in association with wild birds of the genus Turdus, collected in Atlantic forest fragments of southeastern Brazil. From the total 90 analyzed birds, 58 (47 Turdus rufiventris, 9 Turdus leucomelas, 1 Turdus albicollis, and 1 Turdus flavipes) were positively infected with Plasmodium unalis, a haemosporidian that was previously detected in Turdus fuscater in Colombia and in penguins in Brazil, but has never been found in association with these Turdus species of this present work. Moreover, all 7 new sequences of P. unalis cyt b gene clustered into a monophyletic clade with previously characterized P. unalis sequences with a mean genetic divergence of 1.6% and with a maximum divergence of 3.1%, indicating for a high degree of intraspecific polymorphism within this parasitic species. Together, our data highlight the existence a high degree of intraspecific variation within P. unalis and highlight the importance of integrative taxonomy to an accurate identification and characterization of avian haemosporidian parasites.

Geographic and host distribution of haemosporidian parasite lineages from birds of the family Turdidae

“…Although the morphology of pTUMIG03 and other related lineages (e.g., pTUMIG23, pTURASS03, pTURFAL03, pTURFAL04, pTURALB02, pHYLMUS01, and pCOETOR01) has not been studied so far, they might belong to the same parasite species based on their genetic similarity. In contrast, pTULEU06, which was linked to P. unalis by [67], probably belongs to a separate yet undescribed species based on our analysis (group IV in Fig. 1).…”

“…Mantilla et al [66] linked P. unalis to the MalAvi lineage pTFUS6 and mentioned several similar CytB lineages isolated from American thrushes and other birds in previous studies, pointing out that the parasite is probably widespread in the Americas. Tostes et al [67] studied Plasmodium parasites of Brazilian thrushes and linked several additional lineages to P. unalis, namely pTURUF03, pTURUF04, and pTULEU06. The central haplotype of the P. unalis group (IV in Fig.…”

Avian Malaria and Related Parasites from Resident and Migratory Birds in the Brazilian Atlantic Forest, with Description of a New Haemoproteus Species

“…Not all infections detected by PCR were confirmed by microscopy. We detected one Turdus rufiventris with pTUMIG03 lineage, which has been associated with P. unalis [29]. However, although positive for Plasmodium sp., characteristics of this species were not observed during microscopic examination of blood smears.…”

Avian haemosporidians of the genera Plasmodium and Haemoproteus from resident and Neotropical migrant birds in Colombia

“…unalis that has been previously documented in the Great Thrush ( Turdus fuscater ) in Colombia, as well as four other species of the genus Turdus in the Atlantic forest of Brazil ( Turdus rufiventris , T . leucomelas , Turdus albicollis , and Turdus flavipes ) (Mantilla et al 2013 ; Tostes et al 2018 ; Fig. 4 ).…”