Southwest India Research Articles

Recurrence in Plasmodium vivax malaria: a prospective cohort study with long follow-up from a coastal region in South-West India.

Background: India is endemic for Plasmodium vivax(Pv) malaria. Despite a decrease in incidence, its elimination is hampered by recurrences. This study aimed to characterize recurrences in Pv malaria and study its association with primaquine (PQ) usage. Methods: Symptomatic adult Pv patients were followed-up for up to 23 months for recurrences. The time to recurrence was compared by the PQ dosage they received using a log-rank test. Results: Of the 294 malaria patients, 206 (70%) patients had Pv infection during the study period. A total of 20 (9.7%) recurrences were seen in 17 (8.2%) patients of Pv. The percentage of first-time recurrences were highest in the no PQ group (25%), followed by the weekly PQ group (20%), low dose daily PQ (8.2%) group, and high dose daily PQ group (3.1%). Conclusions: Recurrence in Pv malaria is common, especially in those who receive an inappropriate prescription of primaquine.

Streptococcus agalactiae-associated Urinary Tract Infections amongst Male Patients at a Tertiary Care Setting in Southwest India

Streptococcus agalactiae-associated Urinary Tract Infections amongst Male Patients at a Tertiary Care Setting in Southwest India

Spatio-temporal distribution of heavy metals in sediments of Biyyam Backwater, Kerala, Southwest India; its environmental implications

Biyyam backwater is a developing eco-tourism hub and prone to increased pollution due to urbanization and agricultural waste disposal. This study investigates the distribution, temporal variation, enrichment and accumulation of heavy metals in the surface sediments from Biyyam backwaters. Samples were collected from four locations during post-monsoon (December 2017), pre-monsoon (March 2018) and monsoon (July 2018) seasons. Sediment texture, organic matter and heavy metals such as Mn, Co, Zn, Ni, Cr, Pb, Sc, Cd, and As were analyzed. The metal concentration in surface sediments decreased in the following order, i.e., Mn > Cr > Zn > Ni > Pb > As > Co > Sc > Cd. Spatio-temporal variability in distribution pattern of heavy metals show higher concentrations in upstream region. Heavy metal concentrations in surface sediments show relatively higher Igeo factors indicating contribution of heavy metals from agricultural and urban waste disposal. These relatively high values indicate that the Biyyam backwater is threatened by metal contamination, specifically by As, Cd, Cr and Ni. Biyyam backwater is an eco-tourism hub and a beautiful aquatic ecosystem, thus our results would help the local environmental managers to develop strategies to conserve the natural state of the kayal via managing the sources of pollution and sediment remediation in the area.

Response of sea surface temperature, chlorophyll and particulate organic carbon to a tropical cyclonic storm over the Arabian Sea, Southwest India

The response of sea surface temperature (SST), chlorophyll (Chl) and particulate organic carbon (POC) to the tropical cyclonic storm Ockhi between 29th November and 6th December 2017 over the Arabian Sea, Southwest coast of India was studied. The unique observation is that the cyclone overturned northeastwards (clockwise), the wind speed in north-northwestwards (8–12 m s−1) which caused cold patches (< 28.5 °C) in the northwestern Arabian Sea compared to the southwest coast of India. Sea surface cooling (3–4 °C) was observed in concurrence with significant Chl response (0.5–7.5 mg m−3) along the Ockhi cyclone path. The post cyclonic low SST and high Chl from cyclone centre to farther areas suggested the extent of upwelled nutrient rich cold waters for plankton proliferation. POC levels showed a 3-fold increase, affected by significant biomass production due to subsurface phytoplankton and nutrient sources evidenced by deepening of mixed layer depth. The cyclone induced contrasting surface Chl (< 1 mg m−3) and POC (80–160 mg m−3) concentration substantiated the dominance of less labile refractory organic particulates in the offshore waters. The sub surface cooling and Chl bloom was noticed up to 50 m indicating the strong relation of vertical bio-physical structure during tropical cyclones. This study revealed that the tropical cyclones can act in such a way that it improves the positive magnitude of Chl and POC whereas reverses the SST behavior, on either side of the cyclone path within a short period in the oligotrophic waters of Arabian Sea.

Genesis and Trends in Marine Heatwaves Over the Tropical Indian Ocean and Their Interaction With the Indian Summer Monsoon

AbstractMarine heatwaves (MHWs) are extreme oceanic warm water events (above 90th percentile threshold) that significantly impact the marine environment. Recent studies have explored the genesis and impacts of MHWs in the global oceans though they are least understood in the tropical Indian Ocean. Here we investigate the genesis and trend of MHWs in the Indian Ocean during 1982–2018 and their role in modulating the Indian summer monsoon. We find that the rapid warming in the Indian Ocean plays a critical role in increasing the number of MHWs. Meanwhile, the El Niño has a prominent influence on the occurrence of MHWs during the monsoon. The Indian Ocean warming and the El Niño variability have synergistically resulted in some of the strongest and long‐lasting MHWs in the Indian Ocean. The western Indian Ocean region experienced the largest increase in MHWs at a rate of 1.2–1.5 events per decade, followed by the north Bay of Bengal at a rate of 0.4–0.5 events per decade. Locally, the MHWs are induced by increased solar radiation, relaxation of winds, and reduced evaporative cooling. In the western Indian Ocean, the decreased winds further restrict the heat transport by ocean currents from the near‐equatorial regions toward the north. Our analysis indicates that the MHWs in the western Indian Ocean and the north Bay of Bengal lead to a reduction in monsoon rainfall over the central Indian subcontinent. On the other hand, there is an enhancement of monsoon rainfall over southwest India due to the MHWs in the Bay of Bengal.

The Evolution of Lighting in South-West India from Night-Time Lights: 2012–2020

Human-induced alterations of the landscape and the same driven climate changes are seriously making drastic changes in the processes on the Earth's surface, regionally and globally. Visible Infrared Imaging Radiometer Suite (VIIRS) night-time light datasets can precisely detect the intensity and scope of human activities. Accurate and temporal monitoring of urban areas and urban sprawls is highly imperative to the detection and assessment of regional development of a region. This study quantitatively assessed and mapped the light extents and urban region in Kerala, one of the southwest Indian states from 2012 to 2020 with the help of low light imaging day/night band data collected from the VIIRS and utilised VIIRS night time Lights V.2 time series from the monthly averages with filtering to eliminate extraneous features such as aurora, biomass burning, and background. ISOCLUSTER based classification and the threshold methods are used for the light extent and urban region extraction respectively. The result indicated that the Kerala State experienced very high urbanization from 2012 to 2019. But in the case of 2020, there was a decrement in the radiance due to the lockdown and night curfews followed by the COVID-19 global pandemic. Normal life including transportation, industries, and business, etc. was affected much before the national lockdown in Kerala. It was proved with the help of time series data generated from mid-2019 to the end of 2020. The time-series data was generated with 580 night light datasets of NASA’s Black Marble VNP46A2 from 1st June 2019 to 31st December 2020 on daily basis.Graphical abstract

THILAFUSHI A TOXIC BOMB: LEARNING FROM AN ISLAND’S SWM PRACTICE

The Republic of Maldives, an archipelago of 26 atolls situated in the Indian Ocean, southwest of India is one of the paramount vacation destinations for the tourists. The vast panorama of esteem verdure and vast Indian oceans. Being a major sea destination attracts a large number of seafarings. The inception of tourism and locals in Maldives tend to generate a considerable amount of municipal solid waste, which in due period became one of the major concerns of the Central Government of Maldives. This paper deals with the study of the solid waste generation, transfer and end disposal characteristics and the involvement of various stakeholders in the process of decentralizing the waste management process and imposing various techniques and initiatives in waste generation and implementation of the 3R of Waste management. In the due process of Waste management, the role of Thilafushi, an inhabitant island has played a considerable role in the processing and the reclamation of the Lagoon of Thilafushi into a landfill has become a major issue for the fragile ecosystem and thus the term “Toxic Bomb” was associated with the island’s name. The involvement of stakeholders such as the World Bank and the Asian Development Bank has considerably put serious effort with the active support of the Government and the people are covered in the paper.

Aerosol Opto-physical Properties: Temporal Variation, Aerosol Type Discrimination and Source Identification

Atmospheric aerosol characterization experiments were conducted, for the first time, over AC-Ahmednagar, a semi-urban location in south-west India, using a multi-spectral solar radiometer from January 2016 to May 2018. The MODIS/Terra retrieved Level-2 daily swath AOD550 nm data sets during 2011-2021 were also used to infer long-term behaviour of columnar aerosols at AC-Ahmednagar. The daily-averaged, Microtops II Sun photometer measured AOD500 nm and AOD1020 nm and MODIS retrieved AOD550 nm reveal a discernible wide spectrum of variability in their magnitudes. Magnitude-wise, AODs at both the wavelengths depict an increasing trend of about 0.05 year–1 (AOD500 nm) and 0.03 year–1 (AOD1020 nm). However, MODIS AOD550 nm illustrates statistically insignificant increasing trend of about 0.007 year–1. Microtops II Sun photometer derived Angstrom exponent (AE) depicts a noticeable day-to-day variability with respect to its overall mean value (1.06 ± 0.30) indicating the presence of diverse-sized aerosols. The AOD500 nm against AE440-870 nm contour density map analysis qualitatively characterizes different aerosol types prevalent in the atmospheric column. The weighted PSCF (WPSCF) analysis for AOD performed on a seasonal basis reveals the presence of possible contribution of long-range transported plumes of varied aerosols on different scales and types from a variety of emission sources from different regions.

Intensive Teaching: Examining Teachers’ Professional Pressures and Pedagogical Practices at an Elite School

This article asks the following questions: What pressures do teachers face from parents and senior administrators? How do the pressures teachers face from parents and senior administrators affect how they teach students? Specifically, how does this affect the methods they engage in to generate ‘good’ student outcomes? It answers these questions by analysing interviews with 24 high school teachers at an elite international school in Bangalore, a city in southwest India. This article argues that the pressures teachers face from senior administrators and parents to produce high-achieving students result in them engaging in intensive teaching practices. These practices represent teachers’ attempts to produce students capable of earning high grades and entrance into competitive colleges and universities. This article extends our understanding of the factors that shape teachers’ pedagogical practices by making explicit connections between affluent parenting practices and the professional roles of teachers at elite schools. As such, this article makes important contributions to the literature on the sociology of education and teaching.

A pigtailed macaque model of Kyasanur Forest disease virus and Alkhurma hemorrhagic disease virus pathogenesis.

Kyasanur Forest disease virus (KFDV) and the closely related Alkhurma hemorrhagic disease virus (AHFV) are emerging flaviviruses that cause severe viral hemorrhagic fevers in humans. Increasing geographical expansion and case numbers, particularly of KFDV in southwest India, class these viruses as a public health threat. Viral pathogenesis is not well understood and additional vaccines and antivirals are needed to effectively counter the impact of these viruses. However, current animal models of KFDV pathogenesis do not accurately reproduce viral tissue tropism or clinical outcomes observed in humans. Here, we show that pigtailed macaques (Macaca nemestrina) infected with KFDV or AHFV develop viremia that peaks 2 to 4 days following inoculation. Over the course of infection, animals developed lymphocytopenia, thrombocytopenia, and elevated liver enzymes. Infected animals exhibited hallmark signs of human disease characterized by a flushed appearance, piloerection, dehydration, loss of appetite, weakness, and hemorrhagic signs including epistaxis. Virus was commonly present in the gastrointestinal tract, consistent with human disease caused by KFDV and AHFV where gastrointestinal symptoms (hemorrhage, vomiting, diarrhea) are common. Importantly, RNAseq of whole blood revealed that KFDV downregulated gene expression of key clotting factors that was not observed during AHFV infection, consistent with increased severity of KFDV disease observed in this model. This work characterizes a nonhuman primate model for KFDV and AHFV that closely resembles human disease for further utilization in understanding host immunity and development of antiviral countermeasures.

Evaluating spatial variability of subsurface carbon stock and free-phase gas using ground-penetrating radar and direct measurements in coastal landforms of South-West Indian peatlands

Organic rich soils (peat) store significant amount of global soil carbon (C) in the form of methane (CH4) and carbon dioxide (CO2). Peat soils act as sinks and are a source of greenhouse gases (GHG) which occur in the form of Free Phase Gas in coastal landforms. South-West India has an extensive wetland system and is the primary source of GHG emissions, and CH4, in particular, has high potential to contribute to global climate change. In this scenario, this study sheds light on how SW Indian peatlands contribute to the global carbon cycle. The soil C stock and GHG spatial distribution in three distinct topographic coastal landforms within the peatland region were investigated: site 1, Muthukulam in the wetland boundary; site 2, Ramapuram in the paleo-sand ridge, and site 3, Eruva in the paleo-drainage channel. The combination of non-destructive Ground Penetrating Radar (GPR) and direct measurement (coring) in conjunction with the C core analysis helped in building the relationship between the GHG storage in the landforms of varying C stocks. Moreover, Common offset GPR has the ability to image subsurface features, lithological boundaries, coastal landforms, and peat-forming environments. The result from this study depicts the importance of different landforms in the storage of C and GHG in SW Indian peatlands.

Fimbristylis sunilii (Cyperaceae): A new species from Southern Western Ghats, Kerala, India

Fimbristylis sunilii, a new species of Cyperaceae, from Western Ghats of Kerala, Southwest India is described and illustrated with photographs. The paper provides distribution and phenology of the new species along with comparison of its allied species.

Pest categorisation of Leucinodes orbonalis.

The EFSA Panel on Plant Health performed a pest categorisation of the eggplant fruit and shoot borer, Leucinodes orbonalis Guenée, (Lepidoptera: Crambidae), for the territory of the EU. L. orbonalis is a tropical and sub‐tropical species native to Asia and Australia with India considered its centre of origin. Following taxonomic revision, literature reporting L. orbonalis from sub‐Saharan Africa should be regarded as referring to members of a complex of other species of Leucinodes native to Africa and not as referring to L. orbonalis. L. orbonalis is not present in the EU and is not a regulated EU pest. L. orbonalis is a major pest of Solanum melongena (eggplant) in Asia where larvae feed within leaves, stems, shoots and fruits. Larvae can also feed on a range of other plants, mostly within Solanaceae although L. orbonalis is generally not reported as a pest of crops other than S. melongena. However, in recent years L. orbonalis has emerged as a pest of Solanum tuberosum in south‐west India. In tropical areas there can be 10 generations per year if conditions are suitable. L. orbonalis has been intercepted 350 times in the EU from a range of Asian countries on a range of produce, mostly larvae in fruits of S. melongena. Biotic factors (host availability) and abiotic factors (climate suitability) suggest that some small areas of the EU could be suitable for establishment. Adult L. orbonalis can fly and the species could spread within the EU. The introduction of L. orbonalis into the EU would have an economic impact, most likely on S. melongena production, the magnitude of which is uncertain. Measures are available to prevent the entry of L. orbonalis into the EU. L. orbonalis satisfies the criteria that are within the remit of EFSA to assess for this species to be regarded as a potential Union quarantine pest.

Phytoplankton Diversity and Environmental Drivers in a Backwater Inlet of Central Kerala, Southwest India

Phytoplankton Diversity and Environmental Drivers in a Backwater Inlet of Central Kerala, Southwest India

Parental aspirations, schools, and the limits of flexible citizenship: Examining elite return migrants’ schooling decisions

This article investigates how return migrant parents navigate primary and secondary education options in Bangalore, a city in southwest India, by addressing the following question: What factors do return migrant parents consider when making schooling decisions? Through analyzing interviews with return migrant parents from 37 different families, the author argues that parents ultimately want to give their children the skills necessary to pursue their educational and professional interests anywhere in the world. To do so, parents select the ‘best’ school for their child, taking into consideration its demographics, curriculum, and reputation. However, in the process of crafting their children’s transnational futures, parents encounter stumbling blocks as they prepare for the transition from high school to college.

Loss of marine fish stock in south west India: Examining the causes from the perspective of indigenous fishermen

The study area is a potent biodiversity spot and the indigenous coastal livelihood heavily depends upon the region’s fish resources in the south-west coast of India. They are spread around 35 indigenous fishing villages and having a reef enriched coast of about 80 kilometres. Data were collected through focus group discussions and key informant interviews. All of the discussants were indigenous community members and citizen scientists in the region. The collected indigenous data were validated using the available literature and reports. The result showed the rich marine biodiversity knowledge persists among indigenous fishers, specifically regarding the importance of seabed ecosystems. These are considered as natural assets with respect to the ecosystem services provided by them and the respective livelihood practices possible for the indigenous fishing community. This also indicates a very strong traditional livelihood practice which conserves biodiversity of the ocean and their sustainable use for generations. However, the results also indicated with visual and followed literature evidences, currently, these biodiversity were at a risk of getting extinct and/or endangered. Consequently, this also led to the loss of livelihood in the study areas. Coupled with them, there are various natural and anthropogenic pressures such as Climate Change, Overfishing, Pollution and destructive developmental practices in the area.

Population Dynamics of Commercial Fish, Gerres filamentosus Cuvier, 1829 (Family: Gerreidae) along the Coast of South West India

Population Dynamics of Commercial Fish, Gerres filamentosus Cuvier, 1829 (Family: Gerreidae) along the Coast of South West India

Spatiotemporal variability in groundwater chemistry of a mountainous catchment with complex geologic and climate gradients in south west India

Mountainous catchments are one of the world’s important water sources that sustains a major portion of global population and a rich biodiversity. The groundwater quantity and quality of mountainous watersheds depend generally on the geologic characteristics and climate gradients. Although many groundwater studies have been carried out in the midlands and lowlands of many river basins, not enough focus has been paid to the mountainous catchments of tropical watersheds. Here we report a case study on groundwater quality and controlling factors of a mountainous catchments of the Western Ghats mountain ranges of peninsular India—the Bhavani river basin, which is identified as a testbed for long-term monitoring of the Critical Zone process. A total of 88 water samples were collected seasonally for assessing various physico-chemical parameters, solute contents and scaling properties. Standard methods were followed for the estimation of various hydrochemical parameters in the open and borewell samples. The results of the study revealed that higher pH and Total Dissolved Solids (TDS) are noticed in the talc-tremolite dominated central zone whereas low values are recorded in the charnockite dominated areas. The major cations in the water samples are of the order Ca2+ > Mg2+ > Na+ > K+ and the anions are of the order HCO3− > Cl− > SO42−. The content of Cl− shows higher values in areas close to agricultural/settlement areas. An overall evaluation shows that the hydrochemistry of groundwater in the study area is influenced by both silicate and carbonate weathering. Mineral stability indices computed for the groundwater reveal that about 52% of the samples are supersaturated with carbonate minerals and often exhibit scaling due to solute overloading. Saturation Index and mineral stability diagram also support that the incongruent dissolution of aluminosilicate minerals (silicate weathering) is an important hydrochemical process controlling the chemistry of groundwater. Langelier saturation index (LSI) and Puckorius scaling index (PSI) show that a significant number of open well and borewell samples exhibit scaling tendency. Among the contributing factors that determine water quality of groundwaters, chemical weathering and anthropogenic activities play a significant role.

Controls on rare earth elements distribution from Kerala coast, southwest India over the past 2000 years

Climate changes on the Southwest coast of India have essential impacts on social and economic development, and the ecosystem of Southern India. Here, we present the last 2000 cal yr AD rare earth elemental records of the sediment core from the Cherai, Kerala coast, southwest India. The light rare earth elements (LREE) were the most abundant fraction in the core sediment, followed by medium rare earth elements (MREE) and heavy rare earth elements (HREE). Total REE (ΣREE) showed a significant correlation with fine fractions and Y, Al, Ti, Fe and total organic carbon content of the sediments, suggesting an intrinsic relationship between REE, total organic carbon and fine grain-size fraction. The LREE and MREE were enriched over the MREE due to their high adsorption with the fine fraction. The lack of correlation between terrigenous elements and low Y/Ho elemental ratio suggests a minor shift in the source materials. High ΣREE values during warm (Medieval Warm Period/ Medieval Climate Anomaly (MWP/MCA) and cold Little Ice Age (LIA) periods indicate a high influx of lithogenous materials during these intervals. The negative δCe values except MCA suggest a suboxic condition and the δEu values suggest feldspar-rich source rock material derived from moderately weathered sediments. It also indicates that the REE variations are controlled by factors like river supply, biological productivity and redox condition. A close link between monsoonal precipitation and REE records existed on the southwest coast of India. During the Dark Age Cold Period (DACP)/MWP transition, a sudden increase in monsoon is documented and the monsoon precipitation was further decreased during LIA and Current Warming Period. The Cherai core REE records synchronize with the episodes of centennial-scale warm/cool events and essentially follow the northern hemispheric climate cycles.

Increasing antimicrobial resistance is not inevitable: in reply to microbiological and antibiotic profile of osteomyelitis tertiary care hospital

It was with interest and alarm that we read the report by Vijakumar et al regarding antimicrobial susceptibility patterns of pathogens isolated from patients with chronic osteomyelitis.1 The authors reviewed 132 isolates from 100 patients managed in Davangere, Karnataka, South West India between January 2017-December 2019.