Exo-erythrocytic development of two Haemoproteus species (Haemosporida, Haemoproteidae), with description of Haemoproteus dumbbellus, a new blood parasite of bunting birds (Emberizidae)

Comparative Analysis of the Exo-Erythrocytic Development of Five Lineages of Haemoproteus majoris, a Common Haemosporidian Parasite of European Passeriform Birds

“…Finally, two birds with H. majoris infections were found to be co-infected with other Haemoproteus spp., and other exo-erythrocytic stages were found. These exo-erythrocytic stages were meronts of small sizes following the capillaries of the lungs (Figure 3G), and they were similar to meronts found in H. dumbbellus [30] of one individual or bigger and clustered together in a blood vessel of the lungs (Figure 3H,I) of the second individual. No meronts were previously reported in H. majoris infections, only megalomeronts (this study, [9,12]).…”

Unexpected absence of exo-erythrocytic merogony during high gametocytaemia in two species of Haemoproteus (Haemosporida: Haemoproteidae), including description of Haemoproteus angustus n. sp. (lineage hCWT7) and a report of previously unknown residual bodies during in vitro gametogenesis

“…life cycle is obvious, but details of the development remain insufficiently investigated in most described parasite species. For example, it remains unclear if megalomeronts (huge-sized tissue stages) develop in all Haemoproteus species and what is their relationship with meronts (small-sized tissue stages) during development in birds ( Duc et al, 2023a , 2023b ; Himmel et al, 2024 ). These issues are important for better understanding the mechanisms of pathologies during avian haemoproteosis.…”

“…Consequently, these findings were questioned and assumed to relate to other apicomplexan protists ( Bennett et al, 1993 ). Recent molecular studies, and particularly the application of chromogenic in situ hybridization (CISH) diagnostic methods, which use genus- and species-specific probes targeting the parasites’ RNA, have proved that tissue stages of Haemoproteus parasites are remarkably diverse and are responsible for the damage of various internal organs ( Ilgūnas et al, 2019 ; Himmel et al, 2019 , Himmel et al, 2024 ; Duc et al, 2023a , 2023b ). Marked damage of lungs, heart, brain, and many other organs by Haemoproteus spp.…”

“…Marked damage of lungs, heart, brain, and many other organs by Haemoproteus spp. exo-erythrocytic stages hardly can be considered as benign in affected hosts ( Ortiz-Catedral et al, 2019 ; Hernández-Lara et al, 2021 ; Duc et al, 2023a , 2023b ; Himmel et al, 2024 ; Cococcetta et al, 2023 ). Nevertheless, the virulence and patterns of exo-erythrocytic development remain only fragmentally investigated in haemoproteids and remain unassessed in most described species ( Valkiūnas and Iezhova, 2017 ; Duc et al, 2023a , 2023b ; Himmel et al, 2024 ).…”

“…exo-erythrocytic stages hardly can be considered as benign in affected hosts ( Ortiz-Catedral et al, 2019 ; Hernández-Lara et al, 2021 ; Duc et al, 2023a , 2023b ; Himmel et al, 2024 ; Cococcetta et al, 2023 ). Nevertheless, the virulence and patterns of exo-erythrocytic development remain only fragmentally investigated in haemoproteids and remain unassessed in most described species ( Valkiūnas and Iezhova, 2017 ; Duc et al, 2023a , 2023b ; Himmel et al, 2024 ). These are obstacles to better understand the general patterns of exo-erythrocytic development in haemoproteids, particularly for unravelling the question if the development of both meronts and megalomeronts is obligatory for each Haemoproteus species or if these different tissue stages occur independently in some parasite species.…”