Haemoproteus columbae

Prompiram, Phirom, Mongkolphan, Chalisa, Poltep, Kanaporn, Chunchob, Supatra, Sontigun, Narin & Chareonviriyaphap, Theeraphap, 2023, Baseline study of the morphological and genetic characteristics of Haemoproteus parasites in wild pigeons (Columba livia) from paddy fields in Thailand, International Journal for Parasitology: Parasites and Wildlife 21, pp. 153-159 : 156

3.2. Morphological characteristics of H. columbae

The gametocytes of H. columbae showed elongated growth along with the host nucleus and membrane of erythrocyte to both poles of erythrocytes, while fully grown gametocytes showed a predominantly halteridial form. The entire outline was found in mature gametocytes ( Fig. 1a and b ), but amoeboid form growth covered nearly both sites of the host nucleus pole found in immature gametocytes ( Fig. 1e–f, i–j ). They usually extended along the length and freely in the cytoplasm of erythrocytes and did not touch the host cell or nucleus membrane ( Fig. 1a and b ). The gametocyte nuclei were round to ovoid and stained pink, usually with the pigment and pose in the middle along with the host nucleus, resulting in the host nucleus being displaced to another side. Microgametocytes showed distinctly more displacement than macrogametocytes. Volutin granules were randomly distributed in the cytoplasm of fully grown gametocytes ( Fig. 1a and b ), with large discrete volutin granules possibly clumping into the group observed in microgametocytes ( Fig. 1c–d, g–h ). A smaller pigment area was usually found in microgametocytes. Pigment granules (hemozoin) were observed inside the volutin granules of fully grown microgametocyte ( Fig. 1d and h ). The gametocytes showed dimorphism, with the cytoplasm having a dark blue color and distinctly small pink nucleus of macrogametocytes, but pale staining with large pale pink nuclei in microgametocytes ( Fig. 1 ).

The morphometry of uninfected and infected erythrocyte with macro- and microgametocyte are shown in Table 2. Erythrocyte infection with H. columbae resulted in significant hypertrophy in all three dimensions (all P <0.01): length, width, and area of infected erythrocytes. In contrast, the nuclei of erythrocytes showed less impact from H. columbae infection , but the atrophied width of the nuclei may have indicated macrogametocyte infection (P <0.05). Erythrocyte distortion of each infection of the three cyt b lineages was consistent with the effect of H. columbae , although COQUI05 infection showed minor variation with a significantly different length and area of the host nucleus (shown in Supplementary Fig. 1 ). Comparisons between macro- and microgametocytes, the length of erythrocytes, and their nuclei revealed different impacts of infection. Furthermore, dimorphism was observed among the dimension of gametocytes in terms of their nucleus and number of pigments, but not the width of gametocytes (P = 0.54), as shown in Table 2.

Figures

Fig. 1. Haemoproteus columbae from the blood of wild pigeons (Columba livia); cytochrome b lineage HAECOL1 (a–d), COLIV03 (e–f) and COQUI05 (i–l); macrogametocytes (a–b; e–f; i–j) and microgametocytes (c–d; g–h; k–l); simple arrows: nuclei of erythrocytes; short triangle-head arrows: volutin granules; long trianglehead arrows: pigment granules; scale bar = 10 μm.