Two new black-fly species, Simulium (Gomphostilbia) guniki sp. nov. and S. (Nevermannnia) borneoense sp. nov., are described from adult flies emerged from pupae, collected from Sabah in Malaysia. S. guniki is assigned in the ceylonicum species-group, and is characterized by the darkened legs in the adults of both sexes, eight pupal gill filaments almost sessile, and the small postgenal cleft of the larva. S. borneoense, which is assigned to the feuerborni species-group, is most distinctive by having the four pupal gill filaments per side (in place of usual six filaments). In addition, three species of Simulium (Gomphostilbia) , i.e., S. dentistylum, S. parahiyangum, and S. sheilae, are newly recorded from Sabah.

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This paper showed the trend in the number of paper published on emerging and reemerging diseases by using the list of the Medline, which is one of the most valuable databases in the clinical and biological medicine. The number of research papers published on the emerging and reemerging infections in that database decreased in 1997, in comparison with those between 1994 and 1996, in spite of the fact that the total number of the paper published has been increasing year by year. There is also a report showing that the number of the published papers of noticeable infectious diseases such as AIDS, Hepatitis B, Gonorrhea, Pertussis and Tuberculosis declined by 15% or more in the USA from 1993 to 1995. It also became clear that USA is the highest in rank for the number of papers published and it was well ahead of the other countries. However, as for Vibrio cholerae O139, Human T-lymphtropic Virus type 1 and Plague, a lot of papers have been published by responding countries like India, Japan and Russia, respectively. This result might be showing that research activity of each country for each disease relates to the extent of their concern over each disease.

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Experimental Acanthamoeba keratitis was induced in 24 female Dutch rabbits to examine the clinical effects of infecton in the eye and to study the usefulness of a new histopathological technique for evaluating rabbit models of this infection. One eye of each animal in group A or B received an instillation of 1.3×10⁴ (group A) or 1.3×10⁵ (group B) amoeba cysts/eye; phosphate-buffered saline (PBS) solution was instilled into the contralateral eye as the control; animals in groups C and D received intrastromal injections of 5.0×10³ (group C) or 1.5×10⁴ (group D) cysts/eye in one eye and injection of an equal volume of PBS in the contralateral eye. Animals were observed daily for 5 to 84 days. Two rabbits in group D were killed on day 5 and enucleated eyes were embedded in paraffin and stained with hematoxylin-eosin or iodine-potassium iodide. In groups A and B, clinical signs of corneal injury disappeared by 4 hours after inoculation and signs of infection disappeared by day 2. In contrast, all eyes that had been injected with Acanthamoeba (groups C and D) developed severe keratitis, including keratoneuritis and corneal ulcer, followed by neovascularization or corneal perforation. Histologic examination showed infiltrates of leukocytes, lymphocytes, eosinophils, plasmacytes and spindle-shaped cells. The most extensive cell infiltration, and also exocytosis, liquefaction degeneration and intrastromal trophozoites, were seen in th limbic conjunctiva and palpebral conjunctiva. In addition, there was evidence of migration of inflammatory cells to the ciliary body and intravitreal space. This study showed that injection of Acanthamoeba into corneal stroma causes severe infection of the cornea and other eye tissues and that iodine-potassium iodide staining of paraffin embedded specimens is useful to detect Acanthamoeba trophozoites and cysts.

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Two new black-fly species, Simulium (Gomphostilbia) lehi sp. nov. and S. (G.) sarawakense sp. nov., are described from adult flies reared from pupae, collected in Sarawak State, Malaysia. In addition, three known species of Simulium s.l., i.e., S. (G.) sheilae, S. (Nevermannia) aureohirtum, S. (Simulium) laterale, are newly recorded from Sarawak.

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Five geographic strains of Aedes albopictus from Japan and Southeast Asia and three strains of Aedes aegypti from Indonesia and Pakistan were compared for their susceptibility to oral infection with the human virus, dengue-1 Mochizuki strain (isolated in 1943, Japan) and A88 strain (isolated in 1988, Indonesia). Female mosquitoes, aged 3-4 days, were infected with a virus-erythrocyte-sucrose suspension. After 14 days of incubation at 25-30°C, viral infection in mesenteron (midgut) or in head-thorax (salivary gland) of each individual mosquito was identified by the reverse transcriptase-polymerase chain reaction (RT-PCR) amplification of dengue-1 virus envelope gene. Although the results of susceptibility varied in some extent in different strains of mosquitoes and viral strains, the oral susceptibility to both dengue-1 virus strains was not significantly different among dengue vector mosquitoes from Japan and Southeast Asia.

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Nucleotide sequences of a subregion of the mitochondrial 16S ribosomal RNA gene of 10 species of a blackfly subgenus Simulium (Nevermannia) , which include four species of feuerborni species-group, two species of ruficorne species-group, three species of vernum species-group and an ungrouped species (S. konoi), were determined. Phylogenetic analyses of the sequences of the Nevermannia species and other species of related subgenera of Simulium s.l. showed that the feuerborni and vernum species-groups were closely related, but the ruficorne species-group and S. konoi were not. Variations between the ruficorne species-group and other Nevermannia species were larger than those between Nevermannia species (excluding the ruficorne species-group) and other subgenera species. These molecular data suggest that revision of the definition of the subgenus Nevermannia is needed.

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