Northeast Region Of India Research Articles

Eco-epidemiological risk factors for Japanese encephalitis in the endemic region of North East India: a hospital-based case-control study.

Japanese encephalitis (JE) has emerged as a major public health concern in North East India due to its complex eco-epidemiological risk factors. The objective of this study was to understand the various risk factors associated with JE infection in the endemic study location. A hospital-based case-control study was conducted at Jorhat Medical College and Hospital from August 2017 to September 2018. The study participants included 49 confirmed JE cases with two control arms, one consisting of non-JE acute encephalitis syndrome (AES) patients (n = 91) and the other of non-JE non-AES patients (n = 140), admitted at the same time in the pediatric and medicine wards. A predesigned, pretested, structured questionnaire was used for data collection. Univariate analysis revealed the following to be risk factors: age at onset, sex, religion, immunization status, proximity to pigs, proximity to paddy fields (<100 m), use of a mosquito net, impregnated mosquito net, mosquito repellent, and outdoor activities. Multiple logistic regression analysis identified age at onset (adjusted odds ratio [AOR], 20.900; 95% confidence interval [CI], 2.210-31.815) and proximity to pigs (AOR, 4.190; 95% CI, 1.592-11.040) as risk factors for the first control arm and proximity to paddy fields (<100 m) (AOR, 8.470; 95% CI, 2.0251-35.438) was the only risk factor found for second control arm, whereas impregnated mosquito nets (AOR, 0.082; 95% CI, 0.009-0.725) and mosquito repellent (AOR, 0.173; 95% CI, 0.052-0.575) were found to be associated with the second control arm. Age at onset, proximity to pigs, proximity to paddy fields (<100 m), impregnated mosquito nets, and mosquito repellent were the most significant risk factors for JE in the NE region to warrant public health actions.

Epidemiological Review: Esophagus Squamous Cell Carcinoma in India

AbstractWorldwide the incidence of esophagus squamous cell carcinoma (ESCC), remains one of the most common causes of cancer death. ESCC is one of the leading types of cancer in the North and Northeast regions of India among both genders. Risk factors of ESCC include tobacco, alcohol, areca nut, hot beverages, low fruit diet, poor oral hygiene, unpiped water, and human papillomavirus infection. This review tries to elaborate on various modifiable risk factors for ESCC, which have been studied worldwide and need to be studied in India. PubMed was used as a search platform using keywords, such as “esophagus cancer,” “esophagus squamous cell carcinoma,” “epidemiology,” “India,” “incidence,” “mortality,” “risk factors,” “treatment,” “survival,” “prevention” and their corresponding Medical Subject Heading terms, were used in combination with Boolean operators “OR” and “AND.” Studies from India are mostly hospital-based case-control studies from the North region. Further research is required in India to understand the etiology, to design large-scale screening and prevention strategies.

Some of the Immediate Damages and Preliminary Observations on the 22 June, 2020 Champhai Earthquake, India

Earthquakes are amongst the worst geological hazards. There is no way to prevent earthquakes fromhappening. The devastating impacts of such event on the other hand can be greatly reduced by gaining ascientific grasp of their nature, origin, frequency, magnitude and understanding regional tectonics. In theMizoram region of North East India, the majority of the plate motion in the Indo-Burmese Wedge isaccommodated by dextral slip along the Churachandpur Mao Fault (CMF). Several great and majorearthquakes had occurred in the past in North East India. The Vaphai earthquake which occurred at 04:10am on 22 June, 2020 in Mizoram caused many immediate damages and destructions in Mizoram especiallywithin Champhai district. At least 20 aftershocks were recorded the following months and this createdwidespread panic and fear amongst the local population. Many dwelling houses, community assets, schools,government buildings, livestock and properties were damaged.

Molecular Diversity of Microbes Associated with Fermented Bamboo Shoots.

Fermented bamboo shoots are rich in high protein, carbohydrates, fibre and minerals while low in fat content. In the North-East region of India and other Asian countries, they are mostly used in various food preparations. The present study was undertaken to explore the diversity of bacteria associated with Bamboo shoots and to evaluate their antibacterial profile. Based on the results the fermented bamboo shoots showed viable counts ranging from 6.55 ± 0.91 log CFU/g to 7.86 ± 1.21 log CFU/g. The 16s rRNA sequence analysis showed that these isolates belonged to the genus Bacillus (Bacillus safensis, B. tequilensis, B. siamensis, B. nakamurai, B. subtilis) and Enterobacter. These isolates have not been reported previously from fermented bamboo shoots except B. subtilis. Surprisingly, no Lactobacillus species or molds were found in any of the samples tested. Potent antibacterial activity was recorded against Klebsiella, Staphylococcus aureus, Salmonella and B. cereus.

Impact of seasonal variation on the treatment response of constructed wetlands receiving acid mine drainage in a subtropical region

Acid mine drainage (AMD) emanating from coalfields is a severe form of water pollution with adverse ecological impacts. AMD from Makum Coalfield, Assam, India, is highly polluted and unregulated. The present study describes the influence of seasonality on the efficacy of constructed wetlands (CWs) applied for treating synthetic AMD, analogous to mine water characteristics from the Makum Coalfield. Rainfall is predominant in the northeast region of India. The effect of rainfall events on sheltered (SCW) and unsheltered (UCW) CWs was investigated under natural conditions from January to August. Acidic AMD containing Fe, Al, Mn, Zn, Co, Ni, Cr and sulfate concentrations as 100, 25, 6, 5, 1, 1, 1 and 1100 mg L−1 was continuously supplied to CWs at a hydraulic loading rate of 0.014 m3 m−2 d−1. SCW and UCW raised the pH (>5.5) and demonstrated comparable treatment performance in the dry season. Heavy rainfall imposed a highly sensitive and poor treatment response in UCW, resulting in significantly lower sulfate removal in UCW (51.34 %) than SCW (60.29 %). SCW demonstrated superior metal removal for Fe (90 %), Al (79 %), Zn (94 %), Co (92 %), Ni (91 %) and Cr (96 %), which significantly differed from UCW (85 % Fe, 70 % Al, 93 % Zn, 82 % Co, 83 % Ni and 90 % Cr), except Mn. These findings indicated possible shortening of hydraulic retention time in UCW with minimal or insignificant dilution. This experimental study underlines the limitations of wetland systems in the rainfall-affected region and recommends necessary design control measures to manage the effects of rainfall.

Satellite-Based Quantification of Methane Emissions from Wetlands and Rice Paddies Ecosystems in North and Northeast India

Methane is produced by various natural processes that directly or indirectly contribute to the entire Earth’s methane budget. If the Earth’s overall methane budget becomes imbalanced, CH4 has an impact on climate change. Wetlands, rice fields, animals, factories, and fossil fuels are major sources of methane emissions. Among all the resources, wetlands and rice fields are more prominent factors in methane emission, dependent on the water table, temperature, and vegetation. Our study employed the GIS remote sensing technique to analyze methane emissions from 2003 to 2021 in the northern part of India, East Uttar Pradesh and Bihar, and the northeast region of India that is Assam. We also predicted the water table, temperature, and vegetation as raw materials for methane creation. Water table, temperature, and vegetation are essential for wetland ecosystem life, particularly for methanogenic organisms; however, the water table and temperature are critical for rice plant growth and development. With the help of GIS remote sensing, India’s monthly rainfall pattern and the water table, vegetation, and temperature pattern over 41 years were analyzed. Our key findings highlight the importance of GIS remote-sensing-based monitoring of methane gas emissions from wetlands and rice fields for their management.

The perceived need for evidence-based COVID-19 management and Tele-education in the North-East region of India: a cross-sectional survey.

Due to the sudden rise in the cases of COVID-19 in the North-Eastern region of India, this study was conducted to survey the felt needs of the medical professionals with regards to education on the evidence-based management of COVID-19. A total of 25 North-East leaders were recruited and a baseline survey was conducted through the digital medium. Out of 25 North-East leaders, 52% were undergoing training in evidence-based medicine in the capacity-building program for evidence-based child health. Participants (48%) strongly agreed and 40% agreed on the possibility of enhanced care by capacity building in the areas of COVID-19 management through discussing cases. Out of 25 North East leaders, 48% agreed to join both as a speaker as well as a participant. Various priority topics on COVID-19 management e.g. childhood, adult, ocular manifestation, ICU management, telemedicine, vaccines, lab protocols, psychological distress, and treatment strategy have emerged. We have presented the findings of the survey which will help guide the mentoring program focusing on evidence-based management of COVID-19 in remote areas through Tele-education.

Elemental Profiling for Discrimination of Geographical Origin of Tea (Camellia sinensis) in north-east region of India by ICP-MS coupled with Chemometric techniques

The study aimed to discriminate the teas originated from eight north-east region of India using 67 elemental profiling through the use of ICP-MS and process the large data with chemometric software. Among the 67 elements, concentrations of 18 elements were significantly different in the eight regions (Darjeeling, Tripura, Upper Assam, South Bank, Terai, North Bank, Dooars and Cachar). Selected 18 elements belongs to alkali metal (Rb, Cs), alkaline earth metal (Mg, Sr, Ba), transition metal (V, Cr, Mn, Co, Ni, Zn, Mo), basic metal (Al), metalloid (B), non-metal (Se) and lanthanide (La, Ce, Nd). Multivariate chemometric analysis with PCA, LDA, SVM & OPLS DA were performed on the concentration of 18 elements on 307 authentic sample set. The correct classification rate for the training set (307) and test set (24) tea samples were 100% for SVM, LDA and OPLS DA model and confidence measure for SVM and LDA model were 99.4% and 88.97%, respectively. Variable importance in projection (VIP) values ranged between 1.04-1.51 for five elements (Cr, Mo, Rb, Mn and Ni), which can be considered as significant parameter for discrimination. The results demonstrated that ICP-MS with chemometric software could be used to discriminate the geographical origin of tea.

O047 Registry outcomes on gasless insufflation-less laparoscopic surgery in rural North-East India

Abstract Introduction Gasless insufflation-less laparoscopic surgery (GILLS) was introduced in rural northeast India as part of the NIHR Global Health Research Group - Surgical Technologies (GHRG-ST) project. The GILLS Registry aims to provide a reliable mechanism for monitoring the safe implementation of the GILLS technique in everyday clinical practice by the newly trained rural surgeons deemed competent in independent practice. Methods The GILLS Registry captured all gasless laparoscopic abdominal procedures for patients consenting to participate in the Registry and performed by trained rural surgeons. They attended the NIHR GHRG-ST TARGET training programme in March 2019 and proctorship in May 2019. Patients were recruited prospectively. Complications were reported using ISOS classification. The data were captured on REDCap from October 2019 to July 2020. Results Four rural surgeons from three regions of North-East India participated. Of 286 recorded procedures, 123 had general surgical and gynaecological GILLS procedures. Mean age was 34.51 (SD 11.17), 89% were female. Cholecystectomy (44%), tubal ligation (24%) and appendicectomy (16%) were the commonest procedures. More patients received regional (53%) over general anaesthesia (47%). Overall, 11% GILLS cases were converted to open and 9% to conventional laparoscopy. The intra and postoperative complication rates were both 5%. One patient died due to postoperative pancreatitis. Mean length of stay 3.02 (2.12) days. Conclusion GILLS procedure demonstrates favourable outcomes for patients in rural settings. This prospective Registry indicates that GILLS can be safely introduced in low resource settings and findings support wider adoption of GILLS technology in India. Take-home message Gas Insufflation-Less Laparoscopic Surgery (Gasless laparoscopy) can be safely introduced in low resource settings and the registry supports its wider adoption and implementation in India.

Recent research on the stone jars of Northeast India: Evidence from East Jaintia Hills of Meghalaya

The stone jar sites of Northeast India have been a subject of great interest since their first discovery in 1929 by James Philip Mills and John Henry Hutton in North Cachar Hills, Assam. In Southeast Asia, they were first reported by McCarthy (1900) in Laos and subsequently by the French archaeologist Madeleine Colani in 1935, who reported them in great numbers and speculated about their connections to Assam within a wider salt trade network. The present paper focuses on the stone jar sites from an unreported region of Northeast India along the Saipung Sub-division in East Jaintia Hills in the state of Meghalaya. The stone jars from the sites form the extreme westerly extension of the stone jar culture reported from Northeast India. The results of preliminary fieldwork undertaken in February 2020 across the Saipung reserved forest of Meghalaya led to the discovery and documentation of eight previously unreported sites. A small-scale excavation of four jars in the East Jaintia Hills have helped to provide key insights on the mortuary practices of the people who made and used these stone jars. Material evidences from the excavation clearly suggest that the stone jars are visible relics which were erected on top of a pit where the post-cremated cultural materials of the dead are buried. Such significant findings bear relevance to the further understanding of stone jar sites within the broader context of Northeast India and Southeast Asia.

A Study of Nodular Skin Lesions with Special Reference to the Ethnic Population of Northeast India in a Tertiary Care Hospital

Background: Nodular skin lesions vary significantly in size and colour/pigmentation. Most of these clinically resemble soft tissue lesions. Histopathology plays key role in categorizing the lesions based on which course of treatment is planned. The present study aims to find out incidence and variation of skin nodules and correlate the clinico-pathological details with special reference to ethnic population of Northeast India.&#x0D; Methods: The study is a retrospective and descriptive study conducted for a period of 2 years at a tertiary care centre. The clinical and demographic details were retrieved and H&amp;E slides are studied for histomorphology.&#x0D; Result: A total of 50 cases were studied out of which five cases were diagnosed as malignant tumours and 45 cases were diagnosed as benign tumours. Seventeen cases (34%) of tumours with follicular differentiation, eight cases (16%) of melanocytic tumours, nine cases (18%) of vascular and neural tumours, thirteen cases (26%) of tumours with apocrine and eccrine differentiation, two cases (4%) of epidermal tumors and one case (2%) of tumour with sebaceous differentiation were included under the present study. Tumors with follicular differentiation, the most commonly encountered tumor in the present study, were seen in the fourth to sixth decades of life and seen more commonly among women. A total of 18 (36%) cases belonged to ethnic tribal communities of North-east India, out of which seven were tumors of follicular differentiation, five were melanocytic tumours and six were tumors of eccrine differentiation.&#x0D; Conclusion: H&amp;E-stained sections stand as the most important tool for diagnosing and differentiating skin nodular lesions. A significant percentage (36%) of the lesions in the present study have been seen in the ethnic population of the Northeast region of India.

A study of risk factors associated with Newcastle disease and molecular characterization of genotype XIII Newcastle disease virus in backyard and commercial poultry in Assam, India

The continuous emergence of Newcastle disease virus (NDV) poses a persistent threat to the poultry industry. Recent increasing outbreaks of NDV in the North East region of India have highlighted the need to closely monitor and analyze the potential risk factors for Newcastle disease (ND) outbreaks. In the present study, an attempt was made to genotype the circulating Newcastle disease virus (NDV) in the backyard and commercial poultry flocks in Assam, India. Sera samples from unvaccinated backyard poultry flocks and tissue samples of ND suspected cases were collected and tested for the presence of NDV antibodies using the Haemagglutination inhibition (HI) test. A total of seven NDV isolates were analyzed from different districts of Assam, India, both genotypically and pathotypically. All isolates were characterized as virulent, carrying 112RRKQRF117 amino acid residues at the cleavage site. As determined by phylogenetic analysis, the isolates clustered with members of genotype XIII of class II NDV. Further analysis of risk factors of ND occurrence was conducted through a questionnaire survey. All the results indicated an occurrence of genotype XIII of NDV in the farms with inadequate biosecurity and farming practices.

Determination of focal depths of moderate earthquakes in Northeast Indian region using depth phase sPn

Determination of focal depths of moderate earthquakes in Northeast Indian region using depth phase sPn

Effect of COVID-19 epidemic-led lockdowns on aerosol black carbon concentration, sources and its radiation effect in northeast India

The COVID-19 epidemic-led lockdown (LD) from March 25 to May 31, 2020, had a different level of impact on air quality in the ecologically sensitive region of northeast India, even though the restriction on main anthropogenic activities was expected to reduce particulate matter concentration. The daily average black carbon concentration measured at 880 nm (BC880) was 1.5–15.6 μg m−3 (mean: 5.75±4.24 μg m−3) during the measurement period. It was 9.29±4.11 μg m−3 during pre-LD (February 12–March 21), 4.70±0.95 μg m−3 during LD1 (March 25–April 14), 3.41±0.56 μg m−3 during LD2 (April 15–May 3), 3.69±1.50 μg m−3 during LD3 (May 4–17), 2.94±0.93 μg m−3 during LD4 (May 18–31), and 6.56±5.35 μg m−3 during the Post-LD (June 6–July 3) of 2020. It decreased up to 68% during the lockdowns. The source apportionment based on an improved method showed a significant improvement in the contribution of BC880 sources. The radiation effect determined by Angstrom Absorption Exponent showed that brown carbon accounted for 25% of the aerosol light absorption at 370 nm during the lockdown period. Relative humidity correlates substantially with BC880, while rainfall, temperature, and solar radiation were negatively correlated. The bivariate analysis showed the dominance of local emissions in the BC880 concentrations.Research highlights Black carbon concentration decreased up to 68% during the different phases of lockdown.BC associated with fossil fuel was 51–78%, and biomass burning was 22–49%.The fraction of fossil fuel and biomass burning in whole BC fallen to 0.73 and 0.65 during the lockdowns.Air quality improved by about 47–58% on the 4th and 7th day of lockdown.Brown carbon and meteorological parameters significantly impacted aerosol light absorption in this region.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12040-022-01883-4.

Seismicity and magnitude recurrence hazard assessment in Eastern Nepal, Northeast India and Tibet Himalaya

The regions of eastern Nepal, northeast India and Tibet Himalaya (26°-30°N, 85°-97°E) are one of the most earthquake hazardous areas in the Indian subcontinent. The seismicity of this region is analyzed using Gumbel's third asymptotic distribution (GIII) method of extreme values to assess the earthquake hazard. A uniform and complete seismic data covering the time span of 120 years (i.e. 1900-2019) is used for the appraisal of earthquake magnitude recurrence in different return periods. The expected largest earthquake magnitudes during the next 20 (M20), 50 (M50) and 100 (M100) years with their 90% probability of not being exceeded (PNBE) are spatially mapped to create a brief atlas of short- and long-term regional earthquake magnitude recurrence hazard maps. The obtained results of maximum magnitude during 20, 50 and 100-years are expected to exceed the values of Mw 7.1, 7.7 and 8.2, respectively in two prominent blocks of eastern Nepal and Arunachal Himalaya in the examined region. These blocks are also more prominent for the results of 20, 50 and 100 years earthquake magnitudes with 90% PNBE i.e. return periods of 190 (M190), 475 (M475) and 950 (M950) years along with two additional blocks in the Eastern Himalayan Syntaxis (EHS) and Yadong-Gulu rift near Lhasa in the Tibet Plateau. These earthquake magnitudes are expected to exceed Mw 8.5, 8.6 and 8.9 during the next 190, 475 and 950 years, respectively in these blocks. The spatial distribution of earthquake hazards in the region reveals the complex seismotectonic setup and high crustal heterogeneity.

Role of Innate Immune Regulatory Genes, FOXP3 and FOS in Chronic Hepatitis B Infection.

Persistence of hepatitis B virus (HBV) infection leading to chronic infection and its sequalae is responsible for over half a million deaths worldwide. The reason for persistence of chronic hepatitis B (CHB) infection is still not clearly understood. An attempt was made to understand the role of immune regulatory genes in CHB in comparison to spontaneously cleared HBV infection. Relative gene expression of 26 genes involved in innate immunity were studied using Real-Time Polymerase Chain Reaction Array. A total of 679 subjects from three different geographical regions of Northeast India (Assam, Arunachal Pradesh, and Tripura) were included in this case-control study. The cases were subdivided into CHB cases with HBeAg(+)(72), CHB with HBeAg(-)(278), spontaneously cleared controls (88), and healthy controls (228). Overall, 28.3% of the subjects had previous exposure with HBV, while 28.6% had protective antibodies IgG/IgM against HBV. There was a statistically higher number of CHB in men (66.4%) compared to women (33.6%) (p = 0.0001). Proto-oncogene FOS has been found to be moderately upregulated in CHB with HBeAg +ve (2.3-fold) and significantly upregulated (4.1-fold upregulation) in hepatocellular carcinoma. Further, FOXP3 was found to be significantly upregulated (3.0-fold, p = 0.01) in CHB with HBeAg (+) compared to spontaneously cleared HBV infection. In conclusion, CHB with HBeAg positivity was found to have disrupted immune response with upregulation of FOS and FOXP3. Thus, early induction of HBeAg seroconversion with interferon-based therapy or oral nucleos(t)ide analogs along with FOS inhibitors can have important clinical implications in the management of CHB and preventing cirrhosis and HCC.

Metagenomic-Metabolomic Mining of Kinema, a Naturally Fermented Soybean Food of the Eastern Himalayas.

Kinema is a popular sticky fermented soybean food of the Eastern Himalayan regions of North East India, east Nepal, and south Bhutan. We hypothesized that some dominant bacteria in kinema may contribute to the formation of targeted and non-targeted metabolites for health benefits; hence, we studied the microbiome–metabolite mining of kinema. A total of 1,394,094,912 bp with an average of 464,698,304 ± 120,720,392 bp was generated from kinema metagenome, which resulted in the identification of 47 phyla, 331 families, 709 genera, and 1,560 species. Bacteria (97.78%) were the most abundant domain with the remaining domains of viruses, eukaryote, and archaea. Firmicutes (93.36%) was the most abundant phylum with 280 species of Bacillus, among which Bacillus subtilis was the most dominant species in kinema followed by B. glycinifermentans, B. cereus, B. licheniformis, B. thermoamylovorans, B. coagulans, B. circulans, B. paralicheniformis, and Brevibacillus borstelensis. Predictive metabolic pathways revealed the abundance of genes associated with metabolism (60.66%), resulting in 216 sub-pathways. A total of 361 metabolites were identified by metabolomic analysis (liquid chromatography-mass spectrophotometry, LC-MS). The presence of metabolites, such as chrysin, swainsonine, and 3-hydroxy-L-kynurenine (anticancer activity) and benzimidazole (antimicrobial, anticancer, and anti-HIV activities), and compounds with immunomodulatory effects in kinema supports its therapeutic potential. The correlation between the abundant species of Bacillus and primary and secondary metabolites was constructed with a bivariate result. This study proves that Bacillus spp. contribute to the formation of many targeted and untargeted metabolites in kinema for health-promoting benefits.

Evaluation of Proximate Composition, Vitamins, Amino Acids, Antioxidant activities with Minerals and Bioactive Compounds of Young Edible Bamboo (Phyllostachys mannii Gamble)

Bamboo is a plant which is lesser known as a source of food though awareness of the edible young shoots as food is increasing worldwide. Of the many known edible bamboos, shoots of Phyllostachys are popular vegetable in many South East-Asian countries. Phyllostachys mannii is one of the dominant species distributed extensively in regions of North-East India which is lesser known as compared to other species of Phyllostachys. The current study was undertaken to evaluate the proximate composition, vitamins, amino acids, minerals, bioactive components and antinutrient content of edible shoots of P. mannii Gamble. Results revealed that shoots contain adequate amount of protein (3.24 ± 0.03 g/100g FW), carbohydrate (2.73 ± 0.02 g/100g FW), vitamin C (3.23 ± 0.05 mg/100g FW) and are low in fat (0.44 ± 0.01 g/100g FW). Nineteen amino acids were detected in the shoots which includes eight essential, five conditionally essential and six non essential. Of all amino acids, the content was recorded minimum (1.05 ± 0.19 µg/mg DW) in ornithine and maximum (111.04 ± 9.59 µg/mg DW) in asparagine. WDXRF analysis detected 13 minerals in the shoots which includes eight macro and five microminerals with K (6660 ± 40 mg/kg DW) and P (930 ± 20 mg/kg DW) as dominant macromineral and Fe (9.1 ± 0.4 mg/kg DW) and Zn (10 ± 0.0 mg/kg DW) as dominant micromineral. Shoots are rich in phytosterols (265.49 ± 3.16 mg/100 g DW), phenols (382.23 ± 2.08 mg/100 g FW) and neutral detergent fiber (5.72 ± 0.03 g/100 g FW). Present results showed low cyanogen (36.22 ± 0.11 mg/kg FW) content in P. mannii compared to other bamboos and thus considered to be safe for consumption. Overall results indicate the richness of nutritional and bioactive compounds in Phyllostachys mannii which has thus potential to be used nutritious vegetable and as an ideal ingredient in functional food formulations and pharmaceuticals.

EPIDEMIOLOGY AND SEASONAL VARIATION OF APPENDICITIS – A SINGLE CENTER RETROSPECTIVE STUDY FROM NORTH-EAST INDIA

Background. Acute appendicitis is the most common surgical emergency presenting in emergency department, and appendectomy is one of the most common surgeries. There is a wide variation in the incidence of acute appendicitis reported for different countries, different regions, race, sex, age and also seasons. Objective. The aim of this study was to understand the epidemiological trend and the seasonal variation of appendicitis in the northeast region of India. Methods. It was a retrospective hospital-based study conducted in Jan 2016 – Dec 2020 at a Tertiary Care Teaching Hospital in the northeast region of India. The patient data were obtained from the Medical Record Department of the hospital and the data regarding the weather was obtained from the Indian Meteorological Department (IMD) and the website www.worldweather.com. The statistical analysis was done using SPSS software version 24.0, and the seasonal variation was studied using Kruskal Wallis test. Results. Acute appendicitis affected both the sexes equally with a marginal higher incidence in males. It also had higher peak during the second and third decade of life in both the sexes. The incidence of acute appendicitis was high in the pre-monsoon and monsoon season with peak in the monsoon season. Conclusions. Acute appendicitis is more common during the pre-monsoon and monsoon season, a period known for humidity, high incidence of bacterial and viral infections.

Analysis of crustal seismic anisotropy of the Eastern Himalayan collision zone and its adjoining regions

The crustal anisotropy of the Eastern Himalaya collision zone, Brahmaputra Valley and Shillong Plateau of Northeast India Region, is investigated by measuring the shear wave splitting of the PmS phase of teleseismic earthquakes recorded by 17 seismic stations. The anisotropic parameters are nearly stable for each tectonic regime. The mean value of delay time for the Eastern Himalaya stations is 0.45 s which indicates significant crustal anisotropy originated mostly from mid to lower crustal depth. Some stations near deep-seated fault zones exhibit fault-parallel fast polarization directions, indicating structure-induced crustal anisotropy. The fast polarization directions are mostly parallel or sub-parallel to the Himalayan arc suggesting the effect of extension tectonics predominant in the lower crustal depth owing to NW-SE compression tectonics. The maximum shearing of anisotropic minerals presents in the lower crust along the extension direction is the primary causing factor of observed anisotropy. Comparision of the PmS phase splitting with fast polarization directions from shear wave splitting of local earthquakes and stress field analysis demonstrates large angle differences at most stations, imply contrasting anisotropy properties between upper and mid-lower crust.