The development and validation of a one-step, real-time, and quantitative dengue virus serotype-specific reverse transcription-loop-mediated isothermal amplification (RT-LAMP) assay targeting the 3 noncoding region for the rapid detection and differentiation of dengue virus serotypes are reported. The RT-LAMP assay is very simple and rapid, wherein the amplification can be obtained in 30 min under isothermal conditions at 63°C by employing a set of four serotype-specific primer mixtures through real-time monitoring in an inexpensive turbidimeter. The evaluation of the RT-LAMP assay for use for clinical diagnosis with a limited number of patient serum samples, confirmed to be infected with each serotype, revealed a higher sensitivity by picking up 100% samples as positive, whereas 87% and 81% of the samples were positive by reverse transcription-PCR and virus isolation, respectively. The sensitivity and specificity of the RT-LAMP assay for the detection of viral RNA in patient serum samples with reference to virus isolation were 100% and 93%, respectively. The optimal assay conditions with zero background and no cross-reaction with other closely related members of the Flavivirus family (Japanese encephalitis, West Nile, and St. Louis encephalitis viruses) as well as within the four serotypes of dengue virus were established. None of the serum samples from healthy individuals screened in this study showed any cross-reaction with the four dengue virus serotype-specific RT-LAMP assay primers. These findings demonstrate that RT-LAMP assay has the potential clinical application for detection and differentiation of dengue virus serotypes, especially in developing countries.Dengue virus is a mosquito-borne flavivirus and the most widely prevalent arbovirus in tropical and subtropical regions of Asia, Africa, and Central and South America (4). There are four distinct serotypes, DEN-1, DEN-2, DEN-3, and DEN-4, which produce a spectrum of illness ranging from inapparent infection to moderate febrile illness and severe and fatal hemorrhagic disease. In recent years, dengue fever (DF) and its more serious forms, dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS), have emerged as a major public health problems, with expanded geographic distributions and increased epidemic activities (20).Dengue virus infection induces a life-long protective immunity to the homologous serotype but confers only partial and transient protection against subsequent infection by the other three serotypes. Therefore, multiple and sequential infections with the four dengue virus serotypes would be expected for people living in a region where dengue is hyperendemic due to the lack of cross-protective neutralizing antibodies. Seroepidemiological studies have shown that secondary infection is a major risk factor for DHF and DSS through antibody-dependent enhancement (6, 16). Therefore, rapid detection and differentiation between primary and secondary dengue virus infections and determination of the dengue virus serotypes of past and current ...

Dengue virus (DENV) causes fever and severe haemorrhagic symptoms in humans. The DEN2 16681 strain, derived from a dengue haemorrhagic fever patient, has been widely used in studies related to DENV pathogenesis, such as mouse and non-human primate haemorrhagic models and human vascular endothelial-cell permeability. To clarify the entry mechanism of the 16681 strain, we characterized a novel cell receptor for this strain. Our two major findings were as follows: firstly, the SDC2 membrane protein was an effective DEN2 16681 receptor in a cloned K562 cell line. Secondly, a heparan sulfate (HS) glycochain (of four glycochains in SDC2) is the specific binding site of DENV and seems to be involved in tissue-culture adaptation. Our findings present an entry mechanism that could be implicated for DENV adaptation and HS-mediated DENV infection.

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SUMMARYThirty-nine 4-to 5-week-old broiler chickens from an outbreak of Newcastle disease (ND) in Japan were examined pathologically. The causative agent was identified as a mesogenic strain of ND virus. Predominant gross lesions included haemorrhage in the lungs, congestion of the trachea, splenomegaly, atrophy of the thymus and bursa of Fabricius, and whitish discolouration of the brain. Microscopically, there was mild haemorrhagic pneumonia, catarrhal tracheitis, lymphoid necrosis in the spleen, thymus, bursa of Fabricius and caecum and diffuse non-suppurative encephalitis. Lesions associated with encephalitis were characterized by multifocal perivascular cuffing, malacia, demyelination and proliferative vasculitis. Malacic lesions occurred in the hyperstriatum, neostriatum, subleptomeningeal and periventricular regions of the cerebrum, whereas demyelination was seen mainly in the brain stem. The morphological changes that occurred in the brain in these cases were distinctive and the lesions in the lymphoid tissues were related to concurrent infection with infectious bursal disease virus.

The Maritime Continent (MC) is positioned between the Asian and Australian summer monsoons zone. The complex topography and shallow seas around it are major challenges for the climate researchers to model and understand it. It is also the centre of the tropical warm pool of Southeast Asia (SEA) and therefore the MC gets extra attention of the researchers. The monsoon in this area is affected by inter-scale ocean-atmospheric interactions such as the El-Niño Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD), and the Madden-Julian Oscillation (MJO). Monsoon rainfall in the MC (especially in Indonesia and Malaysia) profoundly exhibits its variability dependence on ocean-atmospheric phenomena in this region. This monsoon shift often introduces to dreadful events like biomass burning (BB) in Southeast Asia (SEA) in which some led to severe trans-boundary haze pollution events in the past. In this study, the BB episode of 2015 in the MC is highlighted and discussed. Observational satellite datasets are tested by performing simulations with the numerical weather prediction (NWP) model WRF-ARW (Weather Research and Forecast—Advanced research WRF). Observed and model datasets are compared to study the surface air temperature and precipitation (rainfall) anomalies influenced by ENSO, IOD, and MJO. Links amongst these influences have been recognised and the delayed precipitation of the regular monsoon in the MC due to their influence during the 2015 BB episode is explained and accounted for, which eventually led to the intensification of fire and a severe haze.

An experiment was carried out to reveal the precipitation pattern and to find out the interrelationship between precipitation and production of rice in Rangpur district. Rangpur division is more favorable for rice production. Monthly and yearly precipitation data (1983-2013) were collected from Bangladesh Meteorological department (BMD), Agargaon, Dhaka; Bangladesh Agricultural Research Council (BARC), Farmgate, Dhaka and rice production data were collected from Bangladesh Rice research Institute (BRRI); Department of Agricultural Extension (DAE), Rangpur, Bangladesh. From the analyzed precipitation data, it was clearly found that in 1984, 1985, 1987, 1999 and 2005, there were heavy precipitations and resulting flash flood. The average precipitation of Rangpur was higher (1344 mm) in 1987 than 1984, 1985, 1999 and 2005. In Rangpur district, rice production was the highest in the year of 1983, 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1995, 1996, 1997, 1998, 2001, 2002, 2003, 2004, 2007, 2008, 2009, 2010, 2011, 2012 and 2013 and lower in the year of 1984, 1985, 1987, 1994, 1999, 2000, 2005, and 2006 on the basis of total annual precipitation. Rice production reduced main two reasons such as, heavy precipitation causes flash flood and lower precipitation causes drought stress condition. Both are threat-full for higher rice production. The results show that more precipitation in the years of lowest rice production period, heavy precipitation responsible for deduction of rice production area because of flooding and drought and also shows that normal/ minimum precipitation favorable for rice production at Rangpur district. From this study, it is concluded that the irregular precipitation of period (1984, 1985, 1987, 1994, 1999, 2000, 2005, and 2006) was not satisfactory for rice production due to heavy and/or excessive lower precipitation that resulting flood and/or in part of Rangpur district of Bangladesh. The analysis exposed that precipitation was one of the most important factors for higher amount of rice production in Rangpur district.Progressive Agriculture 29 (1): 10-21, 2018

An investigation was carried out to study frequency of pesticide use during vegetable production and its impact on environment. A structured questionnaire and researcher’s observation were used for this study. The data were collected from six different villages of sixty farmers at Mymensingh sadar upazilla in Bangladesh during February to May, 2013. More than half of the respondents (51.7%) were illiterate and lack of knowledge on pesticide use. About 60% respondents had 16-20 years farming experience and showed comparative knowledge on pesticide use. About 56.7% respondents practiced monthly communication with extension worker (Block Supervisor). About 66.7% respondents spent 04-06 hours to media every day. Half of the respondents had low level knowledge on pesticide use, where only 3.3% respondent showed high level knowledge on pesticide use. About half of the respondents (51.7%) used pesticide 16-20 times during the season. About 21.7% respondent used pesticide 21-25 times during the season. For selective vegetable okra showed highest frequency, about 16.7% respondents used pesticide 26-30 times during the season, while one third respondents (33.3%) used pesticide 16-20 times. About 58.3% respondent used pesticide 16-20 times for brinjal, while 8.3% respondents used 21-25 times. About two- fifth respondents (41.7%) used pesticide 16-20 times and 21-25 times for bitter gourd, while 8.3% respondents used 05-10 times and 10-15 times. About 58.3% respondent used pesticide 16-20 times for snake gourd, while 16.3% respondents used 21-25 times. About 66.7% respondent used pesticide 16-20 times for cucumber, while 16.7% respondents used 21-25 times. It indicated farmers used pesticide to their field 1-2 times in a week during the season in some vegetable cultivation. Therefore it has a high chance of remaining pesticide residues in the vegetables and soil. Moreover, most of the respondents applied pesticides without any protection measure and faced health problem due to expose with pesticide. Routine research work with wide public awareness, government and NGO participation, and government regulation are needed for food safety and sound environment.Progressive Agriculture 26 (2): 97-102, 2015