Molecular prevalence and phylogenetic relationship of Haemoproteus and Plasmodium parasites of owls in Thailand: Data from a rehabilitation centre

Abstract

Owls are nocturnal raptors that are prevalently infected with haemosporidian parasites wordwide. These birds were commonly submitted to the Kasetsart University Raptor Rehabilitation Unit, Kasetsart University, Thailand and were examined using PCR-based methods for the presence of haemosporidian infections of by the genera Plasmodium and Haemoproteus. Blood samples from 167 individual owls belonging to 12 species common in Thailand were collected between September 2012 and February 2018. The overall prevalence of haemosporidians was 34.1%, with Haemoproteus infections (25.1%) being more prevalent than Plasmodium infections (9.0%). The prevalence of both Haemoproteus and Plasmodium parasites was similar in all seasons of the year. Molecular characterization revealed 17 new haemosporidian parasite lineages (11 Haemoproteus and six Plasmodium), with genetic variation among partial cytochrome b sequences ranging from 0.0% to 3.6% in Haemoproteus lineages and 0.2%-8.8% in Plasmodium lineages. Phylogenetic analysis showed that all Haemoproteus lineages detected in owls appeared in one well-supported clade together with other parasites belonging to the Parahaemoproteus subgenus, indicating their close evolutionary relationship and common transmission modality by Culicoides biting midges. This study showes the existence of prominent non-described haemosporidian parasite diversity in Thai owls and provides baseline molecular information for further research on the genetic diversity of owl haemosporidian parasites. New DNA sequence information can be used for the diagnosis of owl infections, which have been often reported during rehabilitation planning.

Keywords: Avian malaria; Haemoproteus; Haemosporidian parasites; PCR; Plasmodium; Strigiformes.

Graphical abstract

Fig. 1

Extracellular gametocytes of Haemoproteus spp. in an Asian barred owlet (A), barn owl (B), brown hawk owl (C), collared scops-owl (D), Oriental scops-owl (E), and spotted owlet (F). Wright's stain. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

Fig. 2

Monthly molecular prevalence of Haemoproteus species and Plasmodium spp. in owls in Thailand during 2012–2018. Vertical lines are 95% confidence intervals. The average temperature and rainfall in Kamphaeng Saen were reported by the Nakhon Pathom meteorological station, Thai Meteorological Department.

Fig. 3

Bayesian phylogeny based on partial cytochrome b gene (479 base pairs) of Haemoproteus species lineages. The lineages reported in this study are given in bold. MalAvi lineage codes and GenBank accession numbers are given after species names. Node values (in percentages) indicate posterior clade probabilities. Vertical bars indicate clades of Haemoproteus subgenus (A), Parahaemoproteus (B). Almost all of the Parahaemoproteus lineages recovered from owls were grouped together (clade B-1, grey box). * indicates lineages infecting Strigiformes.

Fig. 4

Colour heatmap of pairwise genetic distances estimated from nucleotide sequences of the cytochrome b gene (479 bp) of Haemoproteus spp. based on the Jukes-Canter model. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

Fig. 5

Bayesian phylogeny based on the partial cytochrome b gene (479 base pairs) of Plasmodium species lineages. Lineages reported in this study are given in bold. MalAvi lineages codes and GenBank accession numbers are given after species names. Node values (in percentages) indicate posterior clade probabilities. Four groups (I-IV) of closely related reported lineages are highlighted.

Fig. 6

Colour heatmap of pairwise genetic distances estimated from nucleotide sequences of the cytochrome b gene (479 bp) of Plasmodium spp. based on the Jukes-Canter model. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)