A pilot sero-epidemiological study was performed in Palawan, The Philippines, in a community within which annual malarial transmission takes place. Sera obtained from splenomegalic and asymptomatic children with current falciparum infection (Group I) were examined using a Western blotting technique to determine the reactivity to electrophoresed antigenic molecules of Plasmodium falciparum (P.f.) . Group I sera consistently exhibited specific reactivity of IgG to a 23kD molecule, to which sera obtained from another group of asymptomatic children with neither parasitemia nor splenomegaly (Group II) exhibited no distinct reactivity. A 58kD molecule was also exhibited by the Group I sera, while several Group II sera reacted with a 52 kD molecule in association with the 47kD which was reported to be indicative of present and/or recent past clinical episode of falciparum infection. Determination of the immunological features of the antigenic molecules of parasites by this type of sero-epidemiological study will provide a new assay system for evaluation of immune status in communities endemic for malaria.

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Simulium (Simulium) yongi sp. nov. is described based on reared females, reared males, pupae and mature larvae collected from Peninsular Malaysia. The immatures of this species were previously misassociated with an adult female holotype of S. (S.) pahangense Takaoka and Davies. This new species is characterized by the combination of the following features : scutum unpatterned, tarsal claws simple and anterior gonapophysis enlarged and widely bare along posterior margin in the female; ventral plate transverse without toothed margins and style with a prominent basal protuberance pointed dorsally in the male; and gill with six filaments per side and cocoon wall-pocket-shaped, with very thin and almost transparent wall in the pupa. This species seems to be related to S. (S.) rudnicki Takaoka and Davies from Langkawi Island, Peninsular Malaysia, S. (S.) ufengense Takaoka from Taiwan, S. (S.) fuzhouense Zhang and Wang from Fujian, south China, and S. (S.) taipokauense Takaoka, Davies and Dudgeon from Hong Kong, from which it differs readily by the darker legs.

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A new subgenus, Daviesellum, in the genus Simulium is established to accommodate two species from Thailand and Peninsular Malaysia. One of these species is Simulium pahangense, for which the male and larval silk-gland chromosomes are described for the first time. A new species, S. courtneyi, is illustrated and described from larvae, pupae and pharate males and females. The immature stages of both species inhabit torrential habitats, and larvae of both species contain the trichomycete fungus Harpella melusinae, representing the first record of this species from Thailand. Simulium (Daviesellum) is related perhaps most closely to the subgenera Gomphostilbia and Morops. Sulcicnephia unidens is synonymized with S. (D.) pahangense.

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Infection with Toxoplasma gondii is a frequent cause of retinal disease, and relatively high prevalence of the disease has been reported in Brazil. We experienced acquired and congenital forms of ocular toxoplasmosis in an Amazonian Japanese settlement, Tomé-Açu. Fundus photographs of the patients representing typical lesions of chronic retinitis are shown.

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