Birds as hosts of blood parasites

Avian populations can be threatened by parasitic infections with avian Haemosporidia (Haemoproteus spp., Leucocytozoon spp., Plasmodium spp.)¹. The haemosporidian prevalence in different bird taxa², or in the same taxa in different regions³, can vary considerably. The parasites are transmitted by vectors as mosquitos(Plasmodium), biting midges (Haemoproteus and Leucocytozoon), and black flies (Leucocytozoon)². Factors as habitat, species-specific behavior, host and vector density, and climate/‑changes could explain prevalence differences². However, in contrast to quite a few herbivorous Psittaciformes species (parrots and cockatoos) that ingest antiparasitic secondary metabolites and did not harbor hemosporidian infections², common German songbird species¹ or columbid species, such as the endangered European Turtle Dove³, are often infected and thus may suffer fitness losses.

To detect the magnitude and genetic diversity of the haemosporidian infections of native species, their blood was examined by PCR for parasitic DNA (mitochondrial cytochrome b gene, ribosomal 18S RNA)^1,3. An infection rate of 71% of adults with Leucocytozoon as well as two new Leucocytozoon-lineages and two new host-lineage associations were discovered in the songbirds examined¹. The study of the six columbid species revealed a 42% infection rate with a total of 15 different haemosporidian lineages, with five lineages described for the first time³. Further research that also provides monitoring rationales for changes associated with global change is therefore needed³.

Fig. 1: Median-joining network of Leucocytozoon spp. The circles represent lineages, and the size of the circles is proportional to the frequencies of the lineages in the population. A hatch mark represents a mutation. The sampled host species are represented by different colors. The names of the lineages are noted at the corresponding circles^{1 (Fig.:3 S.11)}.

Fig. 2: Phylogeny of mitochondrial cytochrome b gene lineages of avian haemosporidian parasites isolated from blood samples of Columbiformes. The four different clades Leucocytozoon (L), Plasmodium (P), H. (Haemoproteus) (H) and H. (Parahaemoproteus) (ParaH) are shown in the overview tree and in one individual zoomed-in tree each together with lineage names. Lineages found in the present study are shown in bold. Newly discovered lineages are marked with ‘*’^{3 (Fig. 4 p. 1414)}.

References

1. Schumm, Y. R., Wecker, C., Marek, C., Wassmuth, M., Bentele, A., Willems, H., Reiner, G. & Quillfeldt, P. (2019). Blood parasites in Passeriformes in central Germany: prevalence and lineage diversity of Haemosporida (Haemoproteus, Plasmodium and Leucocytozoon) in six common songbirds. PeerJ, 6, e6259. https://peerj.com/articles/6259/

2. Masello, J. F., Martínez, J., Calderón, L., Wink, M., Quillfeldt, P., Sanz, V., Theuerkauf, J., Ortiz-Catedral, L., Berkunsky, I., Brunton, D., Díaz-Luque, J.A., Hauber, M.E., Ojeda, V., Barnaud, A., Casalins, L., Jackson, B., Mijares, A., Rosales, R., Seixas, G., Serafini P., Silva-Iturriza, A., Sipinski, E., Vásquez, R. A., Widmann, P., Widmann, I. & Merino, S. (2018). Can the intake of antiparasitic secondary metabolites explain the low prevalence of hemoparasites among wild Psittaciformes? Parasites & vectors, 11(1), 1-15.
https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-018-2940-3

3. Schumm, Y. R., Bakaloudis, D., Barboutis, C., Cecere, J. G., Eraud, C., Fischer, D., Hering, J., Hillerich, K., Lormée, H., Mader, V., Masello, J.F., Metzger, B., Rocha, G., Spina, F. & Quillfeldt, P. (2021). Prevalence and genetic diversity of avian haemosporidian parasites in wild bird species of the order Columbiformes. Parasitology research, 120(4), 1405-1420.
https://link.springer.com/content/pdf/10.1007/s00436-021-07053-7.pdf