Ninox scutulata (Raffles)

Paperna, Ilan, Keong, Malcolm Soh Chu & May, Charlotte Yap Aye, 2008, Haemosporozoan Parasites Found In Birds In Peninsular Malaysia, Singapore, Sarawak And Java, Raffles Bulletin of Zoology 56 (2), pp. 211-243 : 237-238

Ninox scutulata (Raffles)

Locality. – Singapore: Jun.2001 (Owl 1). Parasitaemia was predominant by gametocytes (64%). The trophozoites (35%) could be either of Plasmodium or of coexisting Haemoproteus infection, only one erythrocyte with two binucleate round schizonts was detected.

Etymology. – Named by its host generic name.

Description. – The erythrocyte infected with two schizonts (16.5 × 6.2, with 4.8 × 3.4 nucleus) is elongated (see table 19) with the nucleus (4.8 × 3.4) retained in median position. The schizonts were in polar positions (approximately 3.2–3.5 in diameter) each with two nuclei. The rounded gametocytes develop at the polar end of the erythrocyte, the macrogametocytes are 9.8–11.2 × 2.7–4.2 with 2.4–3.1 × 2.0–2.2 nucleus; the microgametocytes are 8.4–11.2 × 4.2–6.3 in size. The infected erythrocyte may become elongated or swallen, but its nucleus retains a median position: NDR in macrogametocytes 0.71–0.72, in microgametocytes 0.67–0.94. The erythrocytes infected with macrogametocytes are 14.7–16.1 × 6.2–7.7, with 5.5–6.2 × 2.9–3.1 nucleus and infected with microgametocytes are 14.0–17.9 × 4.2–7.4 with 6.7–8.0 × 2.7–2.8 nucleus (non- infected 14.5 ± 0.18 × 6.6 ± 0.27, with 6.5 ± 0.46 × 3.0 ± 0.62 nucleus, n = 5). The pigment granules, together with volutin, are aggregated in the schizonts and scattered in the gametocytes.

Remarks. – No displacement of the erythrocyte nucleus, inpite of the round shape of the gametocyte excludes a possible relationship with the subgenus Haemamoeba , as well as with Pla. (H.) subpraecox (Grassi & Felletti, 1892) reported from owls. Rounded gametocytes without, or with moderate displacement of the erythrocyte nucleus are found in Pla. juxtanucleare Versiani & Gomes 1941, of galliform birds. Schizonts are reminiscent of the presently described, but Pla. juxtanucleare gametocytes are considerably smaller. Neither the schizonts, nor the gametocytes found in N. scutulata bear resemblance to Pla. (Giovannolaia) fallax Schwetz 1930, described from the strigiid Ciccaba woodfordi . Laird (1997) demonstrates, however, gametocytes he names Pla. fallax from Thai and the Philippine owls ( Otus lempiji and Ninox philippensis ) located “hooked around the distal end of the erythrocyte nucleus”; which might be reminiscent of the gametocytes of the presently described species.

The gametocytes sometimes cannot be readily distinguished from juvenile Hae. syrnii gametocytes. There are a few species with round or polar-positioned gametocytes identified as Haemoproteus on the argument that schizogonic stages could not be found {see Valkiunas, [1997 (2005): Hae. ortalidum, Hae. parus, Hae. souzalopesi}. The finding of binucleate schizonts, however, favoured the affiliation of this infection to Plasmodium . A PCR test of a blood samples from this host was positive for Plasmodium : genebank accession no. AY099035.1 (Perkins & Schall, 2002).