Molecular characterization of two hantavirus strains from different rattus species in Singapore

<p>Abstract</p> <p>Background</p> <p>Hantaviruses cause human disease in endemic regions around the world. Outbreaks of hantaviral diseases have been associated with changes in rodent population density and adaptation to human settlements leading to their proliferation in close proximity to human dwellings. In a parallel study initiated to determine the prevalence of pathogens in Singapore's wild rodent population, 1206 rodents were trapped and screened. The findings established a hantavirus seroprevalence of 34%. This paper describes the molecular characterization of hantaviruses from <it>Rattus norvegicus </it>and <it>Rattus tanezumi</it>, the predominant rodents caught in urban Singapore.</p> <p>Methodology</p> <p>Pan-hanta RT-PCR performed on samples of <it>Rattus norvegicus </it>and <it>Rattus tanezumi </it>indicated that 27 (2.24%) of the animals were positive. sequence analysis of the S and M segments established that two different hantavirus strains circulate in the rodent population of Singapore. Notably, the hantavirus strains found in <it>Rattus norvegicus </it>clusters with other Asian Seoul virus sequences, while the virus strains found in <it>Rattus tanezumi </it>had the highest sequence similarity to the Serang virus from <it>Rattus tanezumi </it>in Indonesia, followed by Cambodian hantavirus isolates and the Thailand virus isolated from <it>Bandicota indica</it>.</p> <p>Conclusions</p> <p>Sequence analysis of the S and M segments of hantavirus strains found in <it>Rattus norvegicus </it>(Seoul virus strain Singapore) and <it>Rattus tanezumi </it>(Serang virus strain Jurong TJK/06) revealed that two genetically different hantavirus strains were found in rodents of Singapore. Evidently, together with Serang, Cambodian and Thailand virus the Jurong virus forms a distinct phylogroup. Interestingly, these highly similar virus strains have been identified in different rodent hosts. Further studies are underway to analyze the public health significance of finding hantavirus strains in Singapore rodents.</p

Rapid detection of Mycobacterium tuberculosis by recombinase polymerase amplification.

Improved access to effective tests for diagnosing tuberculosis (TB) has been designated a public health priority by the World Health Organisation. In high burden TB countries nucleic acid based TB tests have been restricted to centralised laboratories and specialised research settings. Requirements such as a constant electrical supply, air conditioning and skilled, computer literate operators prevent implementation of such tests in many settings. Isothermal DNA amplification technologies permit the use of simpler, less energy intensive detection platforms more suited to low resource settings that allow the accurate diagnosis of a disease within a short timeframe. Recombinase Polymerase Amplification (RPA) is a rapid, low temperature isothermal DNA amplification reaction. We report here RPA-based detection of Mycobacterium tuberculosis complex (MTC) DNA in <20 minutes at 39 °C. Assays for two MTC specific targets were investigated, IS6110 and IS1081. When testing purified MTC genomic DNA, limits of detection of 6.25 fg (IS6110) and 20 fg (IS1081)were consistently achieved. When testing a convenience sample of pulmonary specimens from suspected TB patients, RPA demonstrated superior accuracy to indirect fluorescence microscopy. Compared to culture, sensitivities for the IS1081 RPA and microscopy were 91.4% (95%CI: 85, 97.9) and 86.1% (95%CI: 78.1, 94.1) respectively (n = 71). Specificities were 100% and 88.6% (95% CI: 80.8, 96.1) respectively. For the IS6110 RPA and microscopy sensitivities of 87.5% (95%CI: 81.7, 93.2) and 70.8% (95%CI: 62.9, 78.7) were obtained (n = 90). Specificities were 95.4 (95% CI: 92.3,98.1) and 88% (95% CI: 83.6, 92.4) respectively. The superior specificity of RPA for detecting tuberculosis was due to the reduced ability of fluorescence microscopy to distinguish Mtb complex from other acid fast bacteria. The rapid nature of the RPA assay and its low energy requirement compared to other amplification technologies suggest RPA-based TB assays could be of use for integration into a point-of-care test for use in resource constrained settings

Comparative study of telecommunications policies in Hong Kong, Malaysia and Singapore.

To a large extent, the rise of new telecommunications operators in recent years in the Asia- Pacific has been triggered by important policy reforms. Most countries in the region have embraced some form of liberalization and have developed a number of legal instruments to foster private investment in the telecommunications sector. In the emerging economies—which account for the largest number of countries and population of the region—market reform has taken a different path than those of the more developed countries. In most of these nations, privatization of the national carrier has been largely absent or has been confined to a limited number of shares sold in the stock market mostly to local investors. Competition has been introduced in selected segments of the market, while the state has kept—in the form of ownership and'or regulation—a strong presence in the sector.Master of Business Administration (Management of Information Technology

CYPHER versus TAXUS stent for bifurcation lesions beyond 30?days-long-term follow-up results

10.1016/j.ijcard.2006.05.065International Journal of Cardiology1173422-42

Incidence, predictors, and outcomes of device failure of X-sizer thrombectomy: Real-world experience of 200 cases in 5 years

10.1016/j.ahj.2006.10.007American Heart Journal153

Sirolimus-eluting, bioabsorbable polymer-coated constant stent (Cura??) in acute ST-elevation myocardial infarction: A clinical and angiographic study (CURAMI registry)

Journal of Invasive Cardiology194182-18

Tuberculosis detection by indirect smear microscopy vs RPA IS<i>6110</i>.

<p>Testing pulmonary specimens (n = 90) by indirect smear microscopy and RPA IS<i>6110</i> to detect tuberculosis, with comparison to liquid culture based test data. RPA <i>IS6110</i> was more sensitive than indirect smear microscopy (87.5% (95% CI: 81.7, 93.2) vs 70.8% (95% CI: 62.91, 78.75)) and also more specific (95.4 (95% CI: 92.3, 98.1) vs 88% (95% CI: 83.6, 92.4)).</p

DNA amplification by Recombinase Polymerase Amplification.

<p>The three core proteins, recombinase, single-strand DNA binding protein (SSB) and strand-displacing polymerase enable PCR-like DNA amplification without the need for thermal cycling or an initial chemical or thermal melting step. This diagram was created by TwistDx Ltd (<a href="http://www.twistdx.co.uk/our_technology/" target="_blank">http://www.twistdx.co.uk/our_technology/</a>) and is licensed under a Creative Commons Attribution 3.0 United States License.</p

Oligonucleotide primers and probes.

<p>The oligonucleotides chosen for amplification and detection of IS<i>6110</i> and IS<i>1081</i> are shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0103091#pone-0103091-t002" target="_blank">Table 2</a>. F = dT-FAM, H = tetra hydrofuran and Q = dT-Black Hole Quencher 1.</p