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Background Southeast Asian populations are increasingly affected by allergic airway diseases. Etiology and specific causes, however, are still unknown. The aim of this study is therefore to identify allergens and risk factors for the high prevalence of allergic airway disease in the tropical urban environment. Methods Symptoms of allergic rhinitis (AR), asthma, and allergic dermatitis were recorded in two independent cohorts of 576 and 7373 ethnic Chinese individuals living in Singapore. Reactivity against common allergens was determined by skin prick tests (SPT); specific immunoglobulin E (sIgE) titers against 12 common allergens, as well as total serum IgE (tIgE), were measured in the smaller cohort. Results Immunoglobulin E sensitization was almost exclusively directed against house dust mite (HDM) allergens. More than 80% of individuals were HDM-sIgE positive. Of these, less than 30% also had sIgE for other allergens, and similarly, few of the HDM-sIgE-negative individuals reacted to other allergens. Titers for HDM-sIgE were 8-30 times higher than other non-HDM allergen titers and correlated directly with total serum tIgE levels. Migrants from nontropical countries typically arrived with low or undetectable HDM-sIgE but developed substantial titers in a time-dependent fashion. Importantly, prolonged stay in Singapore also resulted in the manifestation of AR and asthma symptoms, contributing to some of the highest national prevalence rates worldwide. Conclusion In a tropical urban environment, the allergic response is dominated by a single allergen class. The mono-specific IgE sensitization against HDM translates into increased prevalence of allergic airway diseases, which now impact a large proportion of the population in Singapore. [ABSTRACT FROM AUTHOR]

AbstractBackground: Hepatitis G Virus (HGV)/GB Virus-C (GBV-C) is a newly discovered RNA virus. Nucleotide sequence comparison and phylogenetic studies of the 5′ untranslated region (5′UTR) within the viral genome have identified at least three different types which have provisionally been classified as type 1 (West African origin), type 2 (North American origin) and type 3 (Asian origin). Methods and Results: The products of RT-PCR were sequenced by using blood donors and patients infected with HGV/GBV-C in Australia, Papua New Guinea and the Solomon Islands to investigate the genotype distribution in this area of the world. All the Australian isolates showed strong sequence homology with type 2, while the Papua New Guinea and Solomon Islands sequences were more closely related, but differ from type 3, which has previously been reported from isolates studied within Asia. Conclusions: Phylogenetic analysis suggests that these latter sequences are either a new HGV/GBV-C Pacific type or a subtype of the Asian type RNA virus. Isolates homologous with type 1 were not identified in these population groups. [ABSTRACT FROM AUTHOR]

The sequence of the coding regions of the PrP genes of the Arabian oryx and greater kudu have been determined and compared with the related sheep and bovine PrP gene sequences. The oryx gene sequence was found to be very closely related to that of the sheep, encoding just one amino acid difference. The greater kudu gene sequence was found to be more closely related to the bovine, encoding four amino acid differences. The possible influence that the gene sequences have on the transmission of spongiform encephalopathy to these antelope species is discussed. [ABSTRACT FROM AUTHOR]