Car Nicobar Island Research Articles

Seasonal distribution and upsurge of respiratory viruses among indigenous tribes with ILI and SARI in a far-flung Car Nicobar Island

BackgroundRespiratory viral illnesses among children are a prominent cause of morbidity and mortality in the developing world. The aim of this study is to understand the seasonal pattern and surge of respiratory viruses among the Nicobarese tribe.MethodsRespiratory specimens were collected from both ARI and SARI cases attended the BJR district hospital in Car Nicobar Island, India, between 2021 and 2022. Respiratory viruses were identified from the specimens by using the qRT-PCR assay. Meteorological parameters were collected and evaluated using Microsoft Excel and SPSS 21. The significant association between the surge of respiratory viruses and each climatic parameter was evaluated.ResultsIn this hospital-based cross-sectional study, 471 ILI cases were enrolled, and 209 of these were positive for respiratory viral infections. Of these respiratory virus infections, 201 (96.2%) were infected with a single respiratory virus infection, and 8 (3.8%) had mixed viral infections. Fever, cough, and chills were the most common symptoms of respiratory illness among this indigenous population. There was a significant link between respiratory viruses and influenza-like illness in children (below 5 years and 6 to 15 years).ConclusionThis prevalence study revealed that viral respiratory infections were more common in children than adults. Among these respiratory viruses, respiratory syncytial virus A (RSV) and influenza B virus were predominantly reported among tribal children up to age five years. In the year 2021, these viruses were recorded frequently during the winter season. Climate factors such as high humidity, high precipitation, moderate temperature, and moderate rainfall are found to be correlated with respiratory viral infections. This study implicates important information for preventing a further outbreak of respiratory viral infections in Car Nicobar Island.

Botanical Exploration in Car Nicobar and Nancoury Islands

The vegetation of Car Nicobar and Nancoury Islands are discussed. Car Nicobar is a flat island with an area of 126.8 square kilometres, while Nancoury is still a smaller island with hills and ridges. Evergreen forests and tidal mangrove forests are absent in Car Nicobar Island and the vegetation consists of beach forest, scrub jungle, low forest in the interior, and grass land. Unlike Car Nicobar, Nancoury Island has dense forest growth of the evergreen type. Plants growing near the shores constitute the beach forest here, while the tropical ever green forest is situated in the interior at a higher elevation. Plants of economic and medicinal importance are also described.

A New Variety of <i>Jasminum multiflorum</i> (Burm. f.) Andr. from the Nicobar Islands

Jasminum multiflorum (Burm. f.) Andr. var. nicobarium Thoth. var. nov., collected from the Car Nicobar Island is described.

On the Fore-Shore Vegetation of Malacca Coast of the Car-Nicobar Island

In this paper, an account is given of the Fore-shore Vegetation of a part of E. Coast of Car-Nicobar along the Malacca Coast. The various types of plant species found on the shore above upper tidal limits are described, and the characteristic ones being Ipomoea pes-caprae (Linn.) Sweet., Panicum repens Linn., Vigna marina Mers., Ischaemum muticum Linn., Blainvillea acmella (Linn, f.) Philipson., Pandanus furcatus Roxb., Scaevola frutescens (Mill.) Krausse., Tournefortia argentea Linn., with Cocos nucifera Linn, occur behind, followed by Hibiscus tiliaceus Linn., Erythrina variegata Linn. var. orientalis (Linn.) Merr., Calophyllum inophyllum Linn., Thespesia populnea Corr., Guettarda speciosa Linn., Syzygium aqueum (Burm f.) Alston, and other trees in jungles. The various species met with are enumerated, in which 13 species and one variety would appear to be new records for the Andamans and Nicobars.

Internal solitary waves in the central Andaman sea observed by combining mooring data and satellite remote sensing

The behavioral characteristics of internal solitary waves (ISWs) in the central Andaman Sea were revealed by analyzing multisource satellite remote sensing images combined with synchronous mooring data. The relationship between the generation time and tides of ISWs in the central Andaman Sea was analyzed and discussed. The ISWs in the central Andaman Sea exhibit a notable semidiurnal tidal cycle, primarily occurring during the spring tide. Additionally, it was observed that larger currents can generate ISWs with larger amplitudes. The propagation velocity of the ISWs initially increases and then decreases from the source, with no significant overall change in the deep areas. Based on the analysis of satellite remote sensing images that cover the source of ISWs in the central Andaman Sea, the generation time of ISWs was estimated. A comparison was made between the estimated generation time and the tidal flow predicted from the TPXO 9 global tidal model at the location of the ISW source. It was found that ISWs are generated when the westward tidal flow reaches its maximum. The ISWs in the central Andaman Sea are generated between the islands of Car Nicobar and Teresa Island. They propagate eastward into the Andaman Sea, grow in amplitude, split into multiple waves, dissipate, and vanish in the waters near the Danao Islands. The entire life cycle of these waves lasts for approximately 3∼4 days.

Biodiversity of mosquitoes (Diptera: Culicidae) in phytotelmata from Car Nicobar Island, India.

The Culicidae mosquito family breeds in various natural and artificial water bodies. Phytotelmata are plant structures that hold water and are used by many mosquito species during their life cycle. Mosquitoes are disease vectors, and phytotelmata play an important role in harbouring them. Investigating these phytotelmata will facilitate to develop appropriate site specific vector control strategy. Approximately 750 phytotelmata in 16 locations on Car Nicobar Island was examined. Mosquito larvae were collected from different habitats such as tree holes, root holes, leaf axils, and bamboo stumps. On average, the number of larvae per 10 ml of water ranged from 0.003 to 3.833. Among the 16 mosquito species identified, there were vectors of malaria (Anopheles sundaicus), dengue (Aedes aegypti and Aedes albopictus) and filariasis (Culex quinquefasciatus), belonging to seven genera. The most common phytotelmata were coconut trees (17.5%) followed by Java apple trees (10.3%) and bamboo stumps (7.1%). The most widespread mosquito species was Aedes edwardsi, followed by Aedes malayensis and Ae. albopictus, and the per cent of phytotelmata that contained these species were 42.6, 22.0, and 16.8% respectively. Anopheles mosquitoes had the highest container index (6.1%) in root holes, while Aedes and Culex mosquitoes were more frequently found in bamboo stumps. The alpha biodiversity indices indicated that the mosquito population in Car Nicobar Island was highly diverse (S = 16; DMg = 36.9). Tree holes showed the highest diversity, as all 16 species were collected from them. Assessment of phytotelmata, there is a significant relationship observed between mosquito genus, village, habitat, and tree families, on the remote island of Car Nicobar. Considering the presence of disease-transmitting mosquito vectors in the phytotelmata, these habitats should be considered when implementing control measures to eliminate mosquito-borne infections.

Burden of hypertension and associated risk factors among the Nicobarese tribe of Car Nicobar Island, India

Background: Hypertension, a significant risk factor for various non-communicable diseases, poses a preventable threat to mortality and disease burden. However, there remains a lack of data on hypertension within Indian tribes, particularly those residing in impoverished areas. Determining the prevalence of hypertension and identifying associated risk factors among the Nicobarese tribes. A cross-sectional survey was conducted, involving 2600 tribal individuals aged 18 years and above from ten randomly selected villages on Car Nicobar Island. Methods: A structured questionnaire was utilized to gather data on blood pressure (BP), anthropometric measurements, and detailed participant characteristics. Prevalence of hypertension was determined and analyzed in relation to various identified risk factors using chi-square, Karl Pearson coefficient of correlation, and generalized linear models. Prevalence ratio and adjusted risk ratio calculated, along with their corresponding confidence intervals. Results: Prevalence of hypertension was 57.9%. Several factors, including age, male gender, illiteracy, diabetes, smoking, alcohol consumption, and higher body mass index (BMI), were significantly associated with hypertension. Systolic and diastolic BP levels increased significantly with age, socio-economic scores, BMI, and weight. Conclusions: The prevalence of hypertension among the Nicobarese tribes is significantly higher compared to the general population. Adapting preventive strategies based on an understanding of the tribe's specific culture and lifestyle is important for controlling hypertension. However, it is also crucial to consider genetic and environmental influences that may contribute to the high prevalence of hypertension in this tribe.

Assessing The Prevalence, Of Hypertension And Stress Among People Living In The Car Nicobar Island, India

Assessing The Prevalence, Of Hypertension And Stress Among People Living In The Car Nicobar Island, India

Challenges in Management of Oral Cancer Cases Among the Indigenous Nicobarese Tribe of the Remote Car Nicobar Island, India during COVID19 Pandemic-A Case Report Series

The prognosis of oral cancer highly depends on early diagnosis and access to proper treatment measures.

The genus Aspidosiphon Diesing, 1851 (Sipuncula: Aspidosiphonidae): Description of a New Shell Dwelling Species, Notes on Aspidosiphon (Paraspidosiphon) Laevis De Quatrefages, 1866 and Current Status from India

Sipuncula is one of the most taxonomically neglected groups of marine invertebrates in Indian waters. Research on these worms has been stagnant for the last three decades as there are no sipunculan taxonomists in India. The current work is an attempt to resurrect taxonomic research on Indian Sipuncula fauna by describing the first new Sipuncula species from Indian seas. A new molluscan shell dwelling species, Aspidosiphon (Akrikos) carnicobarensis sp. nov., is described from Car Nicobar Island, India collected from 205 m depth. The new species is characterized by the presence of scattered unidentate hooks, a thick and well-developed anal shield with deep grooves, flattened papillae on the trunk, and warts on the posterior trunk. Aspidosiphon (Paraspidosiphon) laevis de Quatrefages, 1866 is reported along with the first colored photographs from India and notes about its taxonomic status. The paper additionally reviews the present status of all the species in the genus Aspidosiphon from India, revising them in accordance with the current classification.

The Nicobarese tribes and their coastal fishing activities during the COVID-19 pandemic-related restrictions- preliminary findings.

We interviewed the Nicobarese tribal community (N = 95) of Car Nicobar Island situated in the Andaman and Nicobar archipelago, India to analyze the impact of COVID-19-related restrictions on their coastal fishing activities. Our surveys revealed a significant reduction (p < 0.001) in the average monthly income and fish catches during pre and post-COVID-19 scenarios. Constraints faced during the pandemic-related restrictions and the possible solutions to reinforce the fishing activities were highlighted for sustainable resource management in Car Nicobar Island.

First report of marine debris in Car Nicobar, a remote oceanic Island in the Nicobar archipelago, Bay of Bengal

This study forms the first record to systematically quantify and classify the marine debris from Car Nicobar Island. Car Nicobar is a small remotely located Island in the Nicobar archipelago that is largely inhabited by Nicobarese indigenous people for ages. Considering their remote location and lack of baseline information on marine debris, we surveyed ten beaches in Car Nicobar to study the prevalence of marine debris. A total of 1438 debris items were recorded from the surveys of which plastic debris was found dominant (83.72%). Among the plastics, nets/ropes (38.87%) were found to be dominant followed by plastic bags, plastic bottles, polypropylene woven bags, plastic cans, floaters, and plastic cups. The number of debris was found to be highest in Malacca Jetty (7.2 nos/m2) and least in Mus Jetty (1.28 nos/m2). Land-based debris items from recreational and shoreline activities constituted majorly (54.52%) followed by sea-based sources such as shipping, fishing, and dumping activities (45.48%). Hierarchical Cluster Analysis (HCA) revealed that Malacca Jetty exhibited a distinct pattern of debris accumulation. Kriging interpolation was applied to understand the possible prevalence of marine debris around the coast of Car Nicobar Island. Plastic debris belonging to nearby countries such as Indonesia, Thailand, Malaysia, Myanmar, etc. was also recorded in our surveys. Shipping-based debris could be a probable source of foreign debris due to the proximity of the Nicobar archipelago to the Strait of Malacca, being one of the busiest shipping routes in the world. The baseline information generated from this study could assist the decision-makers to initiate proactive measures toward effective management of marine debris on Car Nicobar Island.

Respiratory viruses among ethnic Nicobarese during COVID-19 pandemic

BackgroundAcute respiratory infections (ARIs) and severe acute respiratory illness (SARI) are public health burdens globally. The percentage of non-SARS CoV-2 respiratory viruses among patients having ARI and SARI who visit Car Nicobar's hospital settings is undocumented. Changes in the epidemiology of other respiratory viruses during COVID19 pandemic is being reported worldwide.MethodsInpatient and outpatient settings at BJR hospital, Car Nicobar Island, India, were used to conduct prospective monitoring for ARI and SARI among Nicobarese tribal members. The patients with ARI and SARI were enlisted in BJR hospital from June 2019 to May 2021. At the ICMR-NIV in Pune, duplex RT-PCR assays were used to test the presence of respiratory viruses. The prevalence of non- SARS CoV-2 respiratory viruses was measured by comparing here between pandemic and pre-pandemic periods.ResultsDuring the COVID19 pandemic, Influenza A (H3N2) and rhinovirus were predominantly reported non-SARS CoV-2 respiratory viruses while Human metapneumovirusand influenza A (H1N1)pdm09were most commonly reported in the prepandemic period. This result indicates the altered circulation of non-SARS CoV-2 during pandemic.ConclusionsA considerable proportion of respiratory infection was correlated with respiratory viruses. Prevalence of non-SARS CoV-2 respiratory viruses was high at the time of infection when compared with pre-pandemic period, at Car Nicobar Island. This study enlightened the change in circulation of other respiratory viruses among the indigenous Nicobarese tribes. Clinicians and allied medical staff should be more prudent of these respiratory infections.

Characterization of the anopheline vector breeding habitats: Implications for elimination of malaria in tribal inhabited Car Nicobar Island.

Malaria is an important public health problem in Andaman & Nicobar archipelago. Among the three districts, Nicobar is the most endemic district where API is >2. In this district, the malaria incidence in Car Nicobar Tehsil has declined steadily over the past 10 years. A renewed initiative to consolidate this gain is being made with the ultimate objective of achieving zero indigenous transmission of malaria in Car Nicobar. So, the present study undertook a close environmental monitoring of water bodies for assessing changes in the risk potential of mosquito vector breeding habitats which can augment the elimination programme. The breeding habitats of anopheline mosquitoes were sampled in 16 areas of Car Nicobar Island for eight time periods during 2017-2020. Along with anophelines, various associated water parameters (n=60) were estimated, viz. physicochemical (n=13), and biological, which included culicine mosquito immatures, insect predators (n=5), phytoplanktons (n=31) and zooplanktons (n=10). In the 16 study sites, overall 1126 surface water stagnating bodies constituting 21 different habitat types were surveyed. Of these, 17 were positive for anopheline breeding. Water bodies from three villages were consistently found to be positive for anopheline breeding. However, early instars of anopheline larvae were more abundant compared to the late instars. Four anopheline species were recorded, including Anopheles sundaicus, A. barbirostris, A. insulaeflorum and A. subpictus, in which 48 per cent were A. sundaicus. Multivariable analysis indicated that anopheline density was significantly higher in permanent water bodies than in temporary habitats (P<0.05) (high risk of anophelines). The highest pH (≥8.2), dissolved solids (≥0.39) levels showed significantly (P<0.05) decreased larval densities (lower risk of breeding), adjusted with breeding sites and season. Nitrite levels increased (P=0.022) larval densities. The present study facilitated estimating the productive period of a larval habitat enabling target larval sources to reduce adult populations. Implementing larviciding strategy before monsoon season is presumably the most cost-effective strategy. The output can be utilized for environmental monitoring of mosquito breeding risk in other malaria endemic areas, particularly where medium/large water bodies are the predominant breeding sites for malaria vectors.

Early Pliocene Low Primary Productivity: Evidence from Car Nicobar Island, Northern Indian Ocean

Abstract Primary productivity is an important component of the ocean. Primary productivity data from Pliocene of northern Indian Ocean is lacking. Marine siliceous organisms viz., diatoms, radiolarians, silicoflagellates and siliceous sponges uptake dissolved silica (dSi) from the seawater. The biological uptake of dissolved silica (dSi) from the seawater and subsequent precipitation as biogenic silica (bSi) is a major biogeochemical cycle that has significant influence on productity. There is evidence of less silicified organisms based on micropalaeontological studies from early Pliocene (Zanclean) of Car Nicobar Island. The present study based on geochemical analyses (XRD and FTIR) from Sawai Bay Formation on Car Nicobar Island indicates that limited bSi is possibly the reason for low productivity during early Pliocene (Zanclean).

Neogene calcareous nannofossil biostratigraphy of the northern Indian Ocean: Implications for palaeoceanography and palaeoecology

Neogene sediments of the Andaman and Nicobar Islands in northern Indian Ocean, specifically the lower Miocene (Burdigalian) to lower Pliocene (Zanclean) sequences, were analysed for calcareous nannofossils that yielded well-preserved and diverse assemblages. The majority of samples contained stratigraphic marker taxa that allowed us to identify successions within the Burdigalian-Langhian (uppermost lower Miocene to lowermost middle Miocene) on the Havelock Island, Tortonian (upper Miocene) on the Neil Island and Zanclean (lower Pliocene) on the Car Nicobar Island. The nannofossil assemblages of uppermost lower Miocene to lowermost middle Miocene sediments reflect strong preference for warm tropical climate and nutricline condition i.e., depth dependent high variation of nutrient content. The presence of relatively unusual assemblage compositions, especially the presence of abundant sphenoliths and small reticulofenestrids, in conjunction with rare discoasters and alongside common diatoms, are indicative of high-productivity surface waters and probably upwelling conditions in the late Miocene. In the Tortonian (upper Miocene), low abundance of discoasters and high abundance of small reticulofenestrids (<3 μm) indicate eutrophic condition. The high-productivity surface-water environments can be linked with the intensification of the Indian Summer Monsoon. Well-preserved calcareous nannofossils have been also been recovered from the Zanclean (lower Pliocene) sediments on Car Nicobar Island. During the Zanclean warm water condition prevailed and from marginal to deep water setting i.e., transgressive event was recognised in the northern Indian Ocean.

Early Pliocene calcareous and siliceous microfossils of the Sawai Bay Formation, Car Nicobar Island, northern Indian Ocean

The present contribution provides a study of calcareous nannofossils and siliceous microfossils from the Sawai Bay Formation on Car Nicobar Island, northern Indian Ocean. Two stratigraphically short sediment intervals near Sawai Bay have been examined. Qualitative and quantitative microfossil analyses show the Sawai Bay ‘A’ Section to be devoid of siliceous microfossils, while 24 well-preserved calcareous nannofossil taxa are identified. The Sawai Bay ‘B’ Section yields 18 calcareous nannofossil, 33 radiolarian and 25 diatom taxa. The calcareous nannofossil index taxa ( Ceratolithus armatus Müller, 1974a and C. cristatus Kamptner, 1950) indicate both sections to be from zones NN12 (CN10b) and NN13 (CN10c) of early Pliocene (Zanclean) age. The radiolarian taxa, i.e., Didymocyrtis avita Riedel, 1953, Euchitonia spp., Siphocampe lineata (Ehrenberg) Nigrini, 1977, Stichocorys peregrina Riedel, 1953, Semantis spp. and Stylochlamydium sp. are common in the Sawai Bay ‘B’ Section, which is assigned to Zone RN9. Most of the diatom taxa are represented by representatives of the genera Actinocyclus Ehrenberg, 1837, Azpeitia Peragallo in Tèmpere and Peragallo, 1912, Coscinodiscus Ehrenberg, 1839a, Grammatophora Ehrenberg, 1841 and Triceratium Ehrenberg, 1839b, with the benthic diatom species Triceratium favus Ehrenberg, 1839b being predominant (~35% of the total diatom count). Siliceous microfossils are also represented by silicoflagellates dominated by Dictyocha spp. and sponge spicules dominated by astrophorids.

Diversity of native larvivorous fish fauna during pre- and post-tsunami in Car Nicobar, Andaman & Nicobar Islands, India.

Malaria is a serious public health problem in Car Nicobar Island, Andaman & Nicobar Islands, India. Using larvivorous fishes has proved to be the cheapest method for vector management approach, with long suppression of mosquito population. This study aims to scale-up the diversity of larvivorous fishes and their potential larvivoracity to evolve an appropriate biological intervention strategy against the immature stages of malaria vectors. During 2003 (pre-tsunami) and 2014-2016 (post-tsunami), an ecological descriptive survey was carried out in the water bodies around Car Nicobar Island. Fishes were captured using fishing nets and cast nets; and placed in plastic jars and preserved in formalin solution. Fishes were identified and classified according to the available keys. Their abundance and data on the current conservation status was recorded and analyzed. Their potential larvivoracity was graded according to their feeding intensity. Pre-tsunami, a total of 27 larvivorous fish species belonging to 11 orders, 23 families and 23 genera were identified. Order Perciformes and the family Cyprinidae were the most ascendant group constituting 51.9 and 11.1%, respectively. While, 80.8% of species were preferred to inhabit the freshwater region, only 37% of species were surface feeders (SF). According to the conservation, assessment and management plan (CAMP, 1998), 44.4% species were at lower risk least concern (LRlc), while 55.6% species were at least concerned (LC) as per the IUCN, 2017 categorization. However, after the tsunami, 17 fish species had gone extinct and 10 fish species were found to remain alive in the local water bodies. Post-tsunami, the larvivoracity analysis indicated that Ophiocara aporos, Ophiocara procephala, Valamugil seheli, Channa punctata, Kuhlia rupestris, Khulia mugil, and Terapon jarbua possess high-level larvivorous potentiality in nature and are recommended for vector control in the study area. These fish species were facing several anthropogenic threats, such as human interference, loss of habitat, trade, overexploitation, and fishing. Therefore, it is important to protect the water bodies from external impact and implement the conservation strategies. Further, periodic fish fauna surveys, identification of breeding sites, scale-up of the larvivorous potentiality at the field level, creating public awareness through health education on establishment of larvivorous fish ponds and planning for mass rearing of the native fish species should be adopted as part of vector management approach in the endemic malarious region of Car Nicobar Island.

Enhancing tribal farmers’ income through technological intervention: A case study from car Nicobar, Andaman &amp; Nicobar Islands

This study demonstrates the impact of customized technological intervention on the income, livelihood and dietary pattern of tribal households of Car Nicobar Island. The Krishi Vigyan Kendra, Nicobar District has adopted a Nicobari tribal farmer in 2016–17 who was practicing traditional tuhet system of subsistence farming and guided him with technological know-how and do-how of vegetable cultivation. In a span of 4 years, the farmer has brought 4,550 m2 of his hitherto fallow land of 2 ha under vegetable cultivation. By incorporating 8 to 15 vegetable crops, the diversification index of the farm increased from 0.58 to 0.77. Even as the acreage under high value vegetables increased, he simultaneously accommodated other crops in minor proportions to tide over production and marketing risks. Thus, through area expansion, technological adoption, diversified cropping pattern, efficient resource management and tactical marketing, the farmer's gross income has increased 5.5 times from ₹93,561 to ₹5,15,935 while the net income has increased almost 12 times from ₹36,711 to ₹4,28,872. Therefore, it is imperative to support the earnest efforts of tribal farmers to increase the vegetable production in this part of the Islands by lending necessary Institutional support.

Numerical Investigation of Bidirectional Mode-1 and Mode-2 Internal Solitary Wave Generation from North and South of Batti Malv Island, Nicobar Islands, India

AbstractStrong bidirectional internal solitary waves (ISWs) generate from a shallow channel between Car Nicobar and Chowra Islands of Nicobar Islands, India, and propagate toward the Andaman Sea (eastward) and Bay of Bengal (westward). Batti Malv Island separates this shallow channel into two ridges, north of Batti Malv (NBM) and south of Batti Malv (SBM). First, this study identifies the prominent mode-1 and mode-2 ISWs emerging from NBM and SBM using synthetic aperture radar images and then explores their generation mechanism(s) using a nonlinear, unstructured, and nonhydrostatic model, SUNTANS. During spring tide, flow over NBM is supercritical with respect to mode-1 internal wave. Model simulations reveal that mode-1 ISWs are generated at NBM by a “lee wave mechanism” and propagate both in the east and west directions depending on the tidal phases. However, the flow over SBM is subcritical with respect to mode-1 internal wave. The bidirectional propagating mode-1 ISWs evolve from a long-wave disturbance induced by “upstream influence.” But, during spring tide, with an increased tidal flow over SBM, it is observed that the westward propagating ISWs are formed by a dispersed hydraulic jump observed over the ridge. Moreover, the bidirectional mode-2 waves from SBM are generated by a lee wave mechanism. An energy budget comparison reveals that the region surrounding NBM is efficient in radiating low-mode baroclinic energy (0.98 GW), while SBM is highly efficient in converting barotropic to baroclinic energy (4.1 GW).