Review of Genetic Information of Morphologically Described <i>Haemoproteus</i> Parasites Recorded in GenBank and MalAvi Databases

Haemoproteus Kruse, 1890 (Haemosporida: Haemoproteiidae) parasites are known for their high genetic diversity, avian host-specificity, and wide geographical distribution. Currently, 2019 lineages are registered as Haemoproteus species, but only 160 of them have been linked to morphospecies. Two main open access and independent databases are used to compile genetic, geographical, and host information on Haemoproteus parasites: GenBank and MalAvi. However, the data registered are not integrated, representing an obstacle in investigating Haemoproteus parasites. Here, we review all reported avian Haemoproteus lineages convincingly linked to morphospecies. First, we collected all records from GenBank and MalAvi and extracted Haemoproteus parasites identified from wild birds using the cytochrome b gene, with clear evidence of gametocytes being present in blood smears. This led to 135 lineages that were phylogenetically analyzed and compared regarding their distribution across bird species, families, orders, and geographic regions. Most lineages were identified from Passeriformes (68.8%, 95 lineages) and Columbiformes (13.8%, 19 lineages). Phylogenetic analysis shows the relation between bird host families and parasite lineages, confirming that Haemoproteus parasites are highly host-specific and that morphospecies tend to cluster phylogenetically. The global patterns of host-bird specificity and distributions show that lineages linked with morphospecies were skewed toward Europe and South America. Additionally, there are discrepancies between the two databases, as well as lineages in MalAvi linked to morphospecies without clear evidence of morphological identification. In conclusion, the research on Haemoproteus parasites would benefit from establishing a clear protocol for data registration and integrating the morphological and molecular methods for parasite screening.