Acridotheres tristis (Linnaeus, 1766)

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 : 212-213

Acridotheres tristis (L.) ( Sturnidae )

Haemoproteus cf. pastoris Mello, 1935 ( Fig. 1 ) (Table 1)

Locality. – Singapore, Jul.2001. One bird, caged for an unknown period was infected. A further 10 trapped free ranging individuals were negative .

Type host. – Sturnus roseus ( India) (redescribed by Bishop & Bennett, 1990; Valkiunas & Iezhova, 1993) .

The total parasitaemia in the infected bird was 33.3%, 37.3%; with trophozoites (or premature) 28.3%; gametocytes 5%; and approximately 14% double infections. The ratio of micro- to macrogametocytes was 1:4.

Description. – Both micro- and macrogametocytes at full differentiation, even when not occupying the entire volume of the erythrocyte, distort the erythrocyte and displace the nucleus. Some also completely encircle the erythrocyte nucleus. The infected erythrocyte either rounds up or elongates. The erythrocytes become enlarged when infected by trophozoites and young gametocytes (Table 1). The pigment granules (numbering 20–30) are conspicuous. The macrogametocyte nucleus is large (larger than in H. pastoris and H. kairullaevi, Valkiunas & Iezhova, 1993 ).

Remarks. – Haemoproteus pastoris has been reported from many species of Sturnidae ( Bishop & Bennett, 1990) but Hae. kairullaevi has been found only in Acr. tristis (in Kazakhestan, Valkiunas & Iezhova, 1993). Although the X = distance between the erythrocyte periphery (wall) and its nucleus;

Y = distance between the erythrocyte periphery (wall) and its nucleus on the infected side.

All measurements were made in µm and are given as mean ± standard deviation. Where relevant total parasitaemia: (% infected erythrocytes) were calculated from the blood smears. Positive blood smears, including syntypes, marked by the bird-host code will be deposited in the Zoological Reference fully grown gametocytes of Hae. pastoris from Stu. roseus occupy the entire space between the erythrocyte wall and nucleus, they do not encircle the nucleus and only moderately displace the erythrocyte nucleus (by approximately 0.7 NDR compared to approximately 0.45 in the presently described material). Immature or not fully differentiated gametocytes, which produce projections at their lateral ends, were not seen in similar stage gametocytes in Acr. tristis .. The number of pigment granules (11), is fewer than in the presently described specimens. Gametocytes of Hae. kairullaevi demonstrate a very different appearance; they occupy a smaller part of the erythrocyte and some are clearly detached from the erythrocyte wall. The infected erythrocyte nucleus remains intact and the nucleus is only slightly displaced (0.9 NDR). They contain approximately 10 pigment granules.

Conspecificity of Haemoproteus from Singapore Acr. tristis with Hae. pastoris is uncertain, and a more aged gametocytes can assume a gravid shape. Since infected blood from only one bird is available, we prefer to defer our conclusion until more data become available.

Figures

Fig.1. Haemoproteuscf.pastoris from Acridotherestristis,Singapore (from left: micrgametocyte and two macrogametocytes).