GPS observations of ionospheric TEC variations over Nepal during 22 July 2009 solar eclipse

As the study of ionospheric behavior during various solar activities is an important task, various studies of ionospheric changes during eclipse events have been widely performed in the different regions of the globe. This paper investigates the ionospheric responses to the solar eclipse on 22 July 2009 over Nepal using the total electron content (TEC) measured by dual-frequency Global Positioning System (GPS) receivers. The time-averaged Vertical TEC (vTEC) of ten GPS stations from Nepal is analyzed and it is found that the value of ionospheric TEC decreases due to the reduction of ionizing radiation. In addition, the deviation in the TEC value on eclipse day from the mean vTEC value of the top five quietest days is found to lie in the range ~1–5 TECu at those regions which were associated with the partial eclipse shadow. On the other hand, the region with the total eclipse (BRN2 and RMTE) faced ~6–7 TECu on average reduction in the TEC value. Considering that the eclipse of 22 July 2009 occurred just at sunrise in the Nepalese zone, a maximum reduction of about 5 TECu is very significant. Higher deviation in TEC is therefore linked with the path of totality and the obscuration rate. This study reveals that the ionospheric TEC over Nepal was altered by wave-like energy and momentum transport, as well as obscuration of the solar disc due to the partial and total solar eclipse. Furthermore, the cross-correlation results presented similar type signatures of the eclipse-induced ionospheric modification over Nepal. This research work serves a crucial future reference for the comparative study of change of ionospheric TEC variability over the Nepal region during Eclipse event

Variation of Total Electron Content (TEC) in the Quite and Disturbed days and their correlation with Geomagnetic Parameters of Lamjung Station in the year of 2015

Total Electron content is measured using a dual frequency GPS receiver in Lamgung (LMJG) Station located at 84.57° longitude and 28.17° latitude of the year 2015 as it is considered as geo-magnetically active year. In this study, diurnal variation of VTEC has been studied separately for quiet and disturbed days and, for the effective study of the case the PRN wise data of VTEC have been also used. The maximum VTEC is seen from 0700 LT to 1100 LT (LT=UT+5.45). PRN wise VTEC is studied taking the lower bound (LB) and upper bound (UB). The correlation of VTEC with Dst index, Kp index and Solar flux have been studied. Positive correlation has been found in disturbed days with Kp index and solar flux but negative correlation with Dst index. Dst index shows positive correlation in quiet days but Kp index shows negative correlation. BIBECHANA 17(2020) 123-13

Variation of Total Electron Content (TEC) in the Quite and Disturbed days and their correlation with Geomagnetic Parameters of Lamjung Station in the year of 2015

Total Electron content is measured using a dual frequency GPS receiver in Lamgung (LMJG) Station located at 84.57° longitude and 28.17° latitude of the year 2015 as it is considered as geo-magnetically active year. In this study, diurnal variation of VTEC has been studied separately for quiet and disturbed days and, for the effective study of the case the PRN wise data of VTEC have been also used. The maximum VTEC is seen from 0700 LT to 1100 LT (LT=UT+5.45). PRN wise VTEC is studied taking the lower bound (LB) and upper bound (UB). The correlation of VTEC with Dst index, Kp index and Solar flux have been studied. Positive correlation has been found in disturbed days with Kp index and solar flux but negative correlation with Dst index. Dst index shows positive correlation in quiet days but Kp index shows negative correlation. BIBECHANA 17(2020) 123-13

GPS TEC Scintillations and TEC depletion as seen from Hetauda and NAST, Nepal for 2016

We analyzed Global positing System Total Electron Content (GPS-TEC) data of stations Hetauda (27.414 0N and 85.051 0E) and NAST (27.656 0N and 85.327 0E), Nepal which are a part of UNAVCO.We obtained the variation of rate of TEC index (ROTI) and S4 index throughout the year 2016 for the two stations involved for the 32 all the Pseudo-Random Noise (PRN) numbers barring PRN number 4 which was inactive throughout the year. We chooses two stations data which are almost 40 km in distance and correlated the value of ROTI index with ROTI index and S4 index with S4 index and found that the ROTI index of Hetauda is well correlated with ROTI index of NAST with the highest being 94% for PRN 10 and the lowest being -13% for PRN 1. An extremely low correlation between S4 index of Hetauda and S4 index of NAST was observed with the highest correlation being 8% in PRN 3, 32 and the lowest correlation of -15% in PRN 12. BIBECHANA 18 (2) (2021) 87-9

GPS TEC Scintillations and TEC depletion as seen from Hetauda and NAST, Nepal for 2016

We analyzed Global positing System Total Electron Content (GPS-TEC) data of stations Hetauda (27.414 0N and 85.051 0E) and NAST (27.656 0N and 85.327 0E), Nepal which are a part of UNAVCO.We obtained the variation of rate of TEC index (ROTI) and S4 index throughout the year 2016 for the two stations involved for the 32 all the Pseudo-Random Noise (PRN) numbers barring PRN number 4 which was inactive throughout the year. We chooses two stations data which are almost 40 km in distance and correlated the value of ROTI index with ROTI index and S4 index with S4 index and found that the ROTI index of Hetauda is well correlated with ROTI index of NAST with the highest being 94% for PRN 10 and the lowest being -13% for PRN 1. An extremely low correlation between S4 index of Hetauda and S4 index of NAST was observed with the highest correlation being 8% in PRN 3, 32 and the lowest correlation of -15% in PRN 12. BIBECHANA 18 (2) (2021) 87-9

Co-Circulation of Dengue Virus Serotypes 1, 2, and 3 during the 2022 Dengue Outbreak in Nepal: A Cross-Sectional Study

The largest dengue outbreak in the history of Nepal occurred in 2022, with a significant number of casualties. It affected all 77 districts, with the nation’s capital, Kathmandu (altitude 1300 m), being the hardest hit. However, the molecular epidemiology of this outbreak, including the dengue virus (DENV) serotype(s) responsible for this epidemic, remain unknown. Here, we report the epidemic trends, clinico-laboratory features, and virus serotypes and their viral load profiles that are associated with this outbreak in Nepal. Dengue-suspected febrile patients were investigated by routine laboratory, serological, and molecular tools, including a real-time quantitative polymerase chain reaction (qRT-PCR). Of the 538 dengue-suspected patients enrolled, 401 (74.5%) were diagnosed with dengue. Among these dengue cases, 129 (32.2%) patients who required hospital admission had significant associations with myalgia, rash, diarrhea, retro-orbital pain, bleeding, and abdominal pain. DENV-1, -2, and -3 were identified during the 2022 epidemic, with a predominance of DENV-1 (57.1%) and DENV-3 (32.1%), exhibiting a new serotype addition. We found that multiple serotypes circulated in 2022, with a higher frequency of hospitalizations, more severe dengue, and more deaths than in the past. Therefore, precise mapping of dengue and other related infections through integrated disease surveillance, evaluation of the dynamics of population-level immunity and virus evolution should be the urgent plans of action for evidence-based policy-making for dengue control and prevention in the country

Epidemiology of dengue virus infections in Nepal, 2006-2019.

BackgroundDengue is one of the newest emerging diseases in Nepal with increasing burden and geographic spread over the years. The main objective of this study was to explore the epidemiological patterns of dengue since its first outbreak (2006) to 2019 in Nepal.MethodsThis study is a retrospective analysis that covers the last 14 years (2006-2019) of reported dengue cases from Epidemiology Diseases Control Division (EDCD), Ministry of Health and Population, Government of Nepal. Reported cases were plotted over time and maps of reported case incidence were generated (from 2016 through 2019). An ecological analysis of environmental predictors of case incidence was conducted using negative binomial regression.ResultsWhile endemic dengue has been reported in Nepal since 2006, the case load has increased over time and in 2019 a total of 17 992 dengue cases were reported from 68 districts (from all seven provinces). Compared to the case incidence in 2016, incidence was approximately five times higher in 2018 [incidence rate ratio (IRR): 4.8; 95% confidence interval (CI) 1.5-15.3] and over 140 times higher in 2019 (IRR: 141.6; 95% CI 45.8-438.4). A one standard deviation increase in elevation was associated with a 90% decrease in reported case incidence (IRR: 0.10; 95% CI 0.01-0.20). However, the association between elevation and reported cases varied across the years. In 2018 there was a cluster of cases reported from high elevation Kaski District of Gandaki Province. Our results suggest that dengue infections are increasing in magnitude and expanding out of the lowland areas to higher elevations over time.ConclusionsThere is a high risk of dengue outbreak in the lowland Terai region, with increasing spread towards the mid-mountains and beyond as seen over the last 14 years. Urgent measures are required to increase the availability of diagnostics and resources to mitigate future dengue epidemics

Evaluating active leprosy case identification methods in six districts of Nepal

Abstract Background Nepal has achieved and sustained the elimination of leprosy as a public health problem since 2009, but 17 districts and 3 provinces with 41% (10,907,128) of Nepal’s population have yet to eliminate the disease. Pediatric cases and grade-2 disabilities (G2D) indicate recent transmission and late diagnosis, respectively, which necessitate active and early case detection. This operational research was performed to identify approaches best suited for early case detection, determine community-based leprosy epidemiology, and identify hidden leprosy cases early and respond with prompt treatment. Methods Active case detection was undertaken in two Nepali provinces with the greatest burden of leprosy, Madhesh Province (40% national cases) and Lumbini Province (18%) and at-risk prison populations in Madhesh, Lumbini and Bagmati provinces. Case detection was performed by (1) house-to-house visits among vulnerable populations (n = 26,469); (2) contact examination and tracing (n = 7608); in Madhesh and Lumbini Provinces and, (3) screening prison populations (n = 4428) in Madhesh, Lumbini and Bagmati Provinces of Nepal. Per case direct medical and non-medical costs for each approach were calculated. Results New case detection rates were highest for contact tracing (250), followed by house-to-house visits (102) and prison screening (45) per 100,000 population screened. However, the cost per case identified was cheapest for house-to-house visits [Nepalese rupee (NPR) 76,500/case], followed by contact tracing (NPR 90,286/case) and prison screening (NPR 298,300/case). House-to-house and contact tracing case paucibacillary/multibacillary (PB:MB) ratios were 59:41 and 68:32; female/male ratios 63:37 and 57:43; pediatric cases 11% in both approaches; and grade-2 disabilities (G2D) 11% and 5%, respectively. Developing leprosy was not significantly different among household and neighbor contacts [odds ratios (OR) = 1.4, 95% confidence interval (CI): 0.24–5.85] and for contacts of MB versus PB cases (OR = 0.7, 95% CI 0.26–2.0). Attack rates were not significantly different among household contacts of MB cases (0.32%, 95% CI 0.07–0.94%) and PB cases (0.13%, 95% CI 0.03–0.73) (χ 2 = 0.07, df = 1, P = 0.9) and neighbor contacts of MB cases (0.23%, 0.1–0.46) and PB cases (0.48%, 0.19–0.98) (χ 2 = 0.8, df = 1, P = 0.7). BCG vaccination with scar presence had a significant protective effect against leprosy (OR = 0.42, 0.22–0.81). Conclusions The most effective case identification approach here is contact tracing, followed by house-to-house visits in vulnerable populations and screening in prisons, although house-to-house visits are cheaper. The findings suggest that hidden cases, recent transmission, and late diagnosis in the community exist and highlight the importance of early case detection

Co-Circulation of Dengue Virus Serotypes 1, 2, and 3 during the 2022 Dengue Outbreak in Nepal: A Cross-Sectional Study

The largest dengue outbreak in the history of Nepal occurred in 2022, with a significant number of casualties. It affected all 77 districts, with the nation’s capital, Kathmandu (altitude 1300 m), being the hardest hit. However, the molecular epidemiology of this outbreak, including the dengue virus (DENV) serotype(s) responsible for this epidemic, remain unknown. Here, we report the epidemic trends, clinico-laboratory features, and virus serotypes and their viral load profiles that are associated with this outbreak in Nepal. Dengue-suspected febrile patients were investigated by routine laboratory, serological, and molecular tools, including a real-time quantitative polymerase chain reaction (qRT-PCR). Of the 538 dengue-suspected patients enrolled, 401 (74.5%) were diagnosed with dengue. Among these dengue cases, 129 (32.2%) patients who required hospital admission had significant associations with myalgia, rash, diarrhea, retro-orbital pain, bleeding, and abdominal pain. DENV-1, -2, and -3 were identified during the 2022 epidemic, with a predominance of DENV-1 (57.1%) and DENV-3 (32.1%), exhibiting a new serotype addition. We found that multiple serotypes circulated in 2022, with a higher frequency of hospitalizations, more severe dengue, and more deaths than in the past. Therefore, precise mapping of dengue and other related infections through integrated disease surveillance, evaluation of the dynamics of population-level immunity and virus evolution should be the urgent plans of action for evidence-based policy-making for dengue control and prevention in the country