Prevalence of dengue and diversity of cultivable bacteria in vector Aedes aegypti (L.) from two dengue endemic districts, Kanchanpur and Parsa of Nepal

Background: Dengue fever, an endemic arboviral disease, represents one of the major public health concerns in Nepal. It is transmitted by bites of infected Aedes aegypti and Aedes albopictus , the former being primary vector. The bacterial community plays a significant role in biology of mosquitoes; however, the bacterial communities of primary vector A. aegypti remain unstudied in Nepal. The study was designed to determine the rate of dengue seropositivity and to explore the bacterial diversity of A. aegypti from dengue endemic districts, Kanchanpur and Parsa of Nepal. Methods: A cross-sectional study was conducted between June 2013 and November 2013 at two hospitals of Kanchanpur and Parsa. A total of 221 serum samples were collected from patients (inpatients and outpatients) suspected of suffering from dengue fever and attending Mahakali Zonal Hospital, Mahendranagar, Kanchanpur, and Narayani Zonal Hospital, Birgunj, Parsa. Detection of anti-dengue IgM was performed by using human dengue IgM capture ELISA. The larvae and pupae of mosquitoes (A. aegypti) were collected, reared, and emerged. Then, the bacteria were isolated and identified from the gut of identified mosquitoes by using standard methods. Results: Out of total 221 serum samples collected from patients suspected of suffering from dengue fever, 34 (15.38%) were positive for anti-dengue IgM. Gram-negative bacteria were isolated in largest proportion (63%) followed by gram-positive cocci (23.27%) and gram-positive rods (13.73%). The most common cultivable bacteria isolated were Staphylococcus spp., Pseudomonas spp., and Acinetobacter spp. The average bacterial load in the vectors was 3.91 7 104 cfu/ml. Conclusions: High rate of anti-dengue IgM seropositivity was reported in our study. The environmental bacteria were predominantly isolated and identified in A. aegypti. The paratransgenic approach to control vector might be possible by spreading the genetically modified bacteria in larval habitat or shelter of adult mosquitoes

Spatio-temporal distribution of dengue and lymphatic filariasis vectors along an altitudinal transect in Central Nepal

Background: Rapidly increasing temperatures in the mountain region of Nepal and recent reports of dengue fever and lymphatic filariasis cases from mountainous areas of central Nepal prompted us to study the spatio-temporal distribution of the vectors of these two diseases along an altitudinal transect in central Nepal. Methodology/Principal Findings: We conducted a longitudinal study in four distinct physiographical regions of central Nepal from September 2011 to February 2012. We used BG-Sentinel and CDC light traps to capture adult mosquitoes. We found the geographical distribution of the dengue virus vectors Aedes aegypti and Aedes albopictus along our study transect to extend up to 1,310 m altitude in the Middle Mountain region (Kathmandu). The distribution of the lymphatic filariasis vector Culex quinquefasciatus extended up to at least 2,100 m in the High Mountain region (Dhunche). Statistical analysis showed a significant effect of the physiographical region and month of collection on the abundance of A. aegypti and C. quinquefasciatus only. BG-Sentinel traps captured significantly higher numbers of A. aegypti than CDC light traps. The meteorological factors temperature, rainfall and relative humidity had significant effects on the mean number of A. aegypti per BG-Sentinel trap. Temperature and relative humidity were significant predictors of the number of C. quinquefasciatus per CDC light trap. Dengue fever and lymphatic filariasis cases had previously been reported from all vector positive areas except Dhunche which was free of known lymphatic filariasis cases. Conclusions/Significance: We conclude that dengue virus vectors have already established stable populations up to the Middle Mountains of Nepal, supporting previous studies, and report for the first time the distribution of lymphatic filariasis vectors up to the High Mountain region of this country. The findings of our study should contribute to a better planning and scaling-up of mosquito-borne disease control programmes in the mountainous areas of Nepal

ManufactSim: Manufacturing Line Simulation Using Heterogeneous Distributed Robots

International audienceThe creation of current assembly lines can benefit from the new advances made in the fields of Computer Science and the Internet of Things (IoT) to increase their flexibility and improve their reliability. There are assembly line simulators developed for this purpose. However, these simulators have been designed to model every detail of the line and take hours to be done. The aim of this paper is to introduce a faster and more accurate computer-based solution - ManufactSim- allowing the simulation of a real production system. This implementation derives from a behavioral modular robots simulator enhanced with a 3D display option. The results show that ManufactSim ’s performances are above the standards with an execution time less than 11 s for 8 h shift running on a CAD computer. Our developed solution is able to face this challenge with an highly accurate and efficient simulator without compromise. The performed benchmarks show that we obtain a robust and agile tool needed for a global future solution based on Machine Learning. The benefits of this contribution will permit to automate the generation of industrial assembly lines while caring on multiple optimization criteria

Risk factors for the presence of chikungunya and dengue vectors (Aedes aegypti and Aedes albopictus), their altitudinal distribution and climatic determinants of their abundance in central Nepal

Background: The presence of the recently introduced primary dengue virus vector mosquito Aedes aegypti in Nepal, in association with the likely indigenous secondary vector Aedes albopictus, raises public health concerns. Chikungunya fever cases have also been reported in Nepal, and the virus causing this disease is also transmitted by these mosquito species. Here we report the results of a study on the risk factors for the presence of chikungunya and dengue virus vectors, their elevational ceiling of distribution, and climatic determinants of their abundance in central Nepal. Methodology/Principal findings: We collected immature stages of mosquitoes during six monthly cross-sectional surveys covering six administrative districts along an altitudinal transect in central Nepal that extended from Birgunj (80 m above sea level [asl]) to Dhunche (highest altitude sampled: 2,100 m asl). The dengue vectors Ae. aegypti and Ae. albopictus were commonly found up to 1,350 m asl in Kathmandu valley and were present but rarely found from 1,750 to 2,100 m asl in Dhunche. The lymphatic filariasis vector Culex quinquefasciatus was commonly found throughout the study transect. Physiographic region, month of collection, collection station and container type were significant predictors of the occurrence and co-occurrence of Ae. aegypti and Ae. albopictus. The climatic variables rainfall, temperature, and relative humidity were significant predictors of chikungunya and dengue virus vectors abundance. Conclusions/Significance: We conclude that chikungunya and dengue virus vectors have already established their populations up to the High Mountain region of Nepal and that this may be attributed to the environmental and climate change that has been observed over the decades in Nepal. The rapid expansion of the distribution of these important disease vectors in the High Mountain region, previously considered to be non-endemic for dengue and chikungunya fever, calls for urgent actions to protect the health of local people and tourists travelling in the central Himalayas

Map of the study areas.

<p>The map shows physiographic regions, development regions and study sites along an altitudinal transect from the lowlands (Birgunj; 80 m above sea level) to the High Mountain region (Dhunche; 2,100 m above sea level) in central Nepal.</p

Relative abundance of collected female <i>Aedes aegypti</i>, <i>Aedes albopictus</i> and <i>Culex quinquefasciatus</i> in central Nepal.

<p>Each pie-chart represents positive traps for mosquitoes captured either by BG-Sentinel traps or CDC light traps.</p

Effect plots of meteorological factors for <i>Aedes aegypti</i> and <i>Culex quinquefasciatus</i> mean abundance in central Nepal.

<p>Panels A, B and C show the effects of adjusted mean temperature (°C), adjusted relative humidity (%) and adjusted rainfall (mm), respectively, on the number of female <i>Aedes aegypti</i> per BG-Sentinel trap. Panels D, E and F show the effects of adjusted mean temperature (°C), adjusted relative humidity (%) and adjusted rainfall (mm), respectively, on the number of female <i>Culex quinquefasciatus</i> per CDC light trap. Mosquito numbers are displayed in log scale. The effect of adjusted rainfall on <i>C. quinquefasciatus</i> abundance was not significant but remained in the final model.</p

Effect plots for <i>Aedes aegypti</i> and <i>Culex quinquefasciatus</i> mean abundance in central Nepal.

<p>Panels A and B show the effect of physiographic regions and months of collection, respectively, on the mean abundance of female <i>A. aegypti</i>; panels C and D show the effect of physiographic region and month of collection on the mean abundance of female <i>C. quinquefasciatus</i> (pooled data from both trap types). Mosquito abundance is displayed in log scale. <i>Aedes aegypti</i> was not recorded in the High Mountain region and not determined (n.d).</p

Species and sex composition and abundance of mosquitoes collected in BG-sentinel and CDC light trap in central Nepal.

<p>ND means not determined.</p

Number of female mosquitoes [mean ± SEM] collected in central Nepal with different trap types.

<p>The number of females per trap was square root transformed to visualize the data more clearly. BGST - BG-Sentinel trap, CDCLT - CDC light trap, n _{(BG-Sentinel trap)} = 59, n_{(CDC light trap)} = 30. The symbol *** indicates significant different from each other at a family error rate of p<0.001.</p