Rabies virus strains circulating in Bhutan: implications for control.

We report a molecular epidemiological study of rabies virus strains circulating in animal populations in Bhutan, and investigate potential origins of these viruses. Twenty-three rabies virus isolates originating from dogs and other domestic animals were characterized by sequencing the partial nucleoprotein (N) gene (395 bp). Phylogenetic analysis was conducted and the Bhutanese isolates were compared with rabies viruses originating from other parts of the world. Phylogenetic analysis showed that Bhutanese isolates were highly similar and were closely related to Indian strains and South Asian Arctic–like–1 viruses. Our study suggests that the rabies viruses spreading in southern parts of Bhutan have originated from a common ancestor, perhaps from the Indian virus strain. Keywords: molecular epidemiology, rabies, Arctic–like virus, BhutanThailand Research Fund (grant No.DBG5180026

Rabies virus strains circulating in Bhutan: implications for control.

postprintWe report a molecular epidemiological study of rabies virus strains circulating in animal populations in Bhutan, and investigate potential origins of these viruses. Twenty-three rabies virus isolates originating from dogs and other domestic animals were characterized by sequencing the partial nucleoprotein (N) gene (395 bp). Phylogenetic analysis was conducted and the Bhutanese isolates were compared with rabies viruses originating from other parts of the world. Phylogenetic analysis showed that Bhutanese isolates were highly similar and were closely related to Indian strains and South Asian Arctic–like–1 viruses. Our study suggests that the rabies viruses spreading in southern parts of Bhutan have originated from a common ancestor, perhaps from the Indian virus strain. Keywords: molecular epidemiology, rabies, Arctic–like virus, BhutanThailand Research Fund (grant No.DBG5180026

Transmission dynamics of rabies virus in Thailand: Implications for disease control

BACKGROUND: In Thailand, rabies remains a neglected disease with authorities continuing to rely on human death statistics while ignoring the financial burden resulting from an enormous increase in post-exposure prophylaxis. Past attempts to conduct a mass dog vaccination and sterilization program have been limited to Bangkok city and have not been successful. We have used molecular epidemiology to define geographic localization of rabies virus phylogroups and their pattern of spread in Thailand. METHODS: We analyzed 239 nucleoprotein gene sequences from animal and human brain samples collected from all over Thailand between 1998 and 2002. We then reconstructed a phylogenetic tree correlating these data with geographical information. RESULTS: All sequences formed a monophyletic tree of 2 distinct phylogroups, TH1 and TH2. Three subgroups were identified in the TH1 subgroup and were distributed in the middle region of the country. Eight subgroups of TH2 viruses were identified widely distributed throughout the country overlapping the TH1 territory. There was a correlation between human-dependent transportation routes and the distribution of virus. CONCLUSION: Inter-regional migration paths of the viruses might be correlated with translocation of dogs associated with humans. Interconnecting factors between human socioeconomic and population density might determine the transmission dynamics of virus in a rural-to-urban polarity. The presence of 2 or more rabies virus groups in a location might be indicative of a gene flow, reflecting a translocation of dogs within such region and adjacent areas. Different approaches may be required for rabies control based on the homo- or heterogeneity of the virus. Areas containing homogeneous virus populations should be targeted first. Control of dog movement associated with humans is essential

DNA barcoding of Aristolochia plants and development of species-specific multiplex PCR to aid HPTLC in ascertainment of Aristolochia herbal materials.

The anecdotal evidence is outstanding on the uses of Aristolochia plants as traditional medicines and dietary supplements in many regions of the world. However, herbal materials derived from Aristolochia species have been identified as potent human carcinogens since the first case of severe renal disease after ingesting these herbal preparations. Any products containing Aristolochia species have thus been banned on many continents, including Europe, America and Asia. Therefore, the development of a method to identify these herbs is critically needed for customer safety. The present study evaluated DNA barcoding of the rbcL, matK, ITS2 and trnH-psbA regions among eleven Aristolochia species collected in Thailand. Polymorphic sites were observed in all four DNA loci. Among those eleven Aristolochia species, three species (A. pierrei, A. tagala and A. pothieri) are used as herbal materials in Thai folk medicine, namely, in Thai "Krai-Krue". "Krai-Krue" herbs are interchangeably used as an admixture in Thai traditional remedies without specific knowledge of their identities. A species-specific multiplex PCR based on nucleotide polymorphisms in the ITS2 region was developed as an identification tool to differentiate these three Aristolochia species and to supplement the HPTLC pattern in clarifying the origins of herbal materials. The combination of multiplex PCR and HPTLC profiling achieves accurate herbal identification with the goal of protecting consumers from the health risks associated with product substitution and contamination

DNA barcoding of Bacopa species coupled with high-resolution melting analysis

In Thailand, there are three species of Bacopa, namely, B. monnieri, B. caroliniana and B. floribunda. Among these Bacopa species, B. monnieri is the only medicinal species used for the treatment of cognitive impairment and improvement of cognitive abilities because of its bioactive constituents, bacoside A and B. However, due to the similar characteristics of plants, it is difficult to differentiate among related species, resulting in confusion during identification. For this reason, to ensure therapeutic quality for consumers, authentication is important. In this study, the three abovementioned Bacopa species were evaluated using barcoding coupled with high-resolution melting (Bar-HRM) analysis based on primers designed for the trnL-F sequences of the three species. The melting profiles of the trnL-F amplicons of B. caroliniana and B. floribunda were clearly different from the melting profile of the trnL-F amplicon from B. monnieri; thus, the species could be discriminated by Bar-HRM analysis. Bar-HRM was then used to authenticate commercial products in various forms. The melting curves of the six commercial samples indicated that all the tested products contained genuine B. monnieri species. This method provides an efficient and reliable authentication system for future commercial herbal products and offers a reference system for quality control.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author