A light and electron microscopic study of Sarcocystis orientalis sp. n. was made. The life cycle of this parasite is in two hosts. Gametogony is in the intestinal epithelial cells of a predator, Python reticulatus. Isospora-like oocysts developed. Sporocysts average 9.1 by 7.7 mum. Rats (Rattus norvegicus) were infected with sporocysts and asexual stages developed. Ten days after infection large zoites (average 7.85 by 2.48 mum) were observed free in peripheral blood and within white blood cells. Small schizonts producing merozoites 2-3 mum long were seen in lung tissue. Tissue cysts developed in skeletal muscle and produced numerous cystozoites (average 5.53 by 1.38 mum). Fine structure was similar to previously described Sarcocystis spp.
Infective larvae of Wuchereria, Brugia, Breinlia, Dirofilaria and Setaria species from an experimental vector, Aedes togoi, are compared. The distinctive bubble-like caudal papillae of Wuchereria bancrofti are readily distinguishable from the protuberant ones of Brugia spp; the 'ear-like' papillae of Breinlia are distinct from the 'knob-like' ones of Dirofilaria or the 'thorn-like' terminal papilla of Setaria.
Similar HLA association was found in patients with elephantiasis in Sri Lankans and Southern Indians. HLA-B15 was observed in 13/44 (30%) Sri Lankan patients with elephantiasis compared to 1/27 (4%) Sri Lankan controls (p = .0058; RR = 10.9) and in 5/8 (28%) Southern Indian elephantiasis compared to 10/101 (10%) Southern Indian controls (p = 0.04; RR = 3.5). In combining the data, the significance of the difference of the frequency of B15 between patients with elephantiasis and controls was even more marked (p = 0.00045; corrected p = 0.012; RR = 4.4).