Editorial: World Malaria Day 2023 - ending malaria transmission: reaching the last mile to zero malaria

The effect of an external magnetic field on the isotopic selectivity in a two-color three-step polarization-based isotope-selective photoionization of atomic samarium has been studied. Isotope-selective photoionization of samarium is realized through a level scheme having total angular momentum (J) sequence 0-1-1-continuum by using two lasers linearly polarized in the same direction and the isotopic selectivity is measured by varying the magnetic field strength perpendicular to the laser polarization axis while keeping the delay between the laser pulses fixed and vice versa. The experimental data have been analyzed and compared with the results of the numerical calculations. The magnetic field perpendicular to the laser polarization axis present in the laser-atom interaction region has been found to degrade the isotopic selectivity. Further, the Lande factor ( g J ) of the excited energy level 16 690.76 cm−1 (J = 1) of samarium has been determined from the observed oscillation in the isotopic selectivity. The value of g J , thus obtained, is in good agreement with that reported in the literature.

India is a malaria endemic country which is targeting malaria elimination by 2027. Transmission intensities are low-to-moderate depending on the region supported by multiple disease vectors. Among these, comparatively North-East India contributes to high proportions of malaria cases annually, the majority of which are due to Plasmodium falciparum (90%). Anopheles minimus and An. baimaii (sibling species in the An. dirus complex) are widely prevalent and incriminated as vectors of malaria. Number of intervention tools were field-evaluated beginning 1988 to date against disease vectors and causative parasites to contain the spread of malaria. These included (i) insecticide-treated netting materials (ITNs) for vector control, (ii) rapid diagnostic tests (RDTs) for in situ diagnosis, and (iii) therapeutic efficacy of artemisinin-based combination therapies (ACTs) for improved drug-policy; all of which were incorporated in healthcare services resulting in substantial disease transmission reduction. Populations of both An. minimus and An. baimaii were observed depleting, instead An. culicifacies s.l. recorded to be fast invading degraded forests and assessed to be resistant to multiple insecticides. Of the two prevalent Plasmodium species, while P. vivax continued to be susceptible to chloroquine therapy, P. falciparum had emerged resistant to most available antimalarial drugs except ACTs over space and time and spreading to peninsular India threatening elimination efforts. Disease transmission trends were observed to be declining for which the state of Assam has made huge strides reporting steady fall in cases each passing year vis-à-vis Meghalaya, Mizoram and Tripura (all sharing international border with Bangladesh), in which malaria transmission remained uninterrupted. Consequently, control of malaria in the North-East region of India is of immediate importance and needs prioritization for intensified disease surveillance and control interventions coupled with improved access to healthcare services mitigating risk of disease outbreaks and spread of drug-resistant malaria helping realize the goal of malaria elimination in the country.

Three-color three-step laser resonance ionization spectroscopy has been employed to investigate the au-toionization spectra of atomic samarium in the energy region 50,330 -51,160 cm(-1). The measurements were carried out in an atomic beam coupled to a linear time of flight mass spectrometer. Fifty-five odd-parity autoionization levels of atomic samarium in the above-mentioned energy region have been ob-served using three excitation schemes. Among these, fifty autoionization levels are new. The total angular momenta of eighteen odd-parity autoionization levels have been assigned uniquely. (c) 2021 Elsevier Ltd. All rights reserved.

Akin to classical taxonomy (based on comparative morphology), investigations on cytology of biological species related to chromosome studies are getting into oblivion and considered low priority, an expertise that is fast waning for everyone riding bandwagon in the era of molecular biology.

Malarial threat is receding in India and for achieving malaria-free status, vector biology is regaining its due importance for targeting species-specific interventions in place and time. Anopheles minimus, the major vector of malaria in north-east India, is disappearing fast evidenced by reduced levels of malaria transmission and morbidity. An. minimus is a species complex comprising three sibling species of which An. minimus s.s., formally named as An. minimus, is recorded to occur in east and north-east India. It is highly anthropophilic and responsible for fulminating outbreaks of malaria evidenced by incrimination records in range of its distribution. For its control, DDT continues to be the insecticide of choice for indoor residual spraying; however, populations are highly resilient in response to residual insecticides for paradigm shift in vector behaviour from indoor resting to outdoors resulting in continued transmission. Extra-domiciliary transmission of malaria is a challenge for which newer interventions, viz., attractive toxic sugar bait, eave-tube technology, nano-synthesized pesticides, new adult repellents, oviposition deterrents need to be field-evaluated under local geo-epidemiological conditions. To keep vector populations at bay, it is advocated to upscale interventions for 'universal coverage' of human populations at risk to check malaria transmission and spread of drug-resistant malaria.

We have investigated high-lying even-parity energy levels of atomic samarium in the energy region 32,156.3-32,886.4 cm(-1) using two-color three-step photoionization technique. The experiments have been carried out in an atomic beam coupled to a linear time of flight mass spectrometer. The analysis of the photoionization spectra has resulted in the identification of twenty-five high-lying even-parity energy levels of atomic samarium. These include the confirmation of fifteen energy levels reported earlier while the remaining ten energy levels are new. The observed relative photoionization signal intensities of the corresponding transitions are also reported. The possible total angular momenta of the newly discovered energy levels have been assigned by the total angular momentum selection rules. Further, the radiative lifetimes of twenty high-lying even-parity energy levels of atomic samarium were measured for the first time by delayed three-color three-photon resonance ionization spectroscopy via a pump-probe method. (C) 2019 Elsevier Ltd. All rights reserved.

Anopheles culicifacies s.l. is a predominant mosquito vector in rural India generating bulk of malaria cases (>60%) annually and maintains endemic malaria in areas of its influence. It is the most studied species complex for its sibling-species composition, distribution and their bionomical characteristics having implications in vector control. It is a highly adaptive and robust mosquito virtually resistant to all available insecticides including pyrethroids in large tracts of mainland India and fast invading new territories thwarting malaria elimination efforts. Control of An. culicifacies is a formidable challenge and containing its spread and transmission of drug-resistant malaria deserves utmost priority. Innovative technologies are warranted for sustained control of this vector species for achieving malaria elimination.Vector surveillance and monitoring insecticide resistance should be the continuing activity for formulating evidence-based and doable intervention strategies for effective vector management.

Due to the importance of Sm-149 isotope in the nuclear industry, isotope-selective photoionization of the odd isotopes of samarium has been studied using multi-color photoionization technique. The present work has been carried out in an atomic beam coupled to a linear time-of-flight mass spectrometer using multimode dye lasers. A new photoionization scheme: 292.58 cm(-1)-> 17,769.71 cm(-1)-> 34,929.9 cm(-1)-> continuum with the J-value sequence 1-1-0-continuum has been identified for the enrichment of only odd isotopes using linearly polarized lasers in the same direction. This photoionization scheme in combination with the first-step transition: 0 cm(-1)-> 17,769.71 cm(-1) (I=0 -> J=1) has been utilized to realize a common level excitation scheme which has significantly increased the photoionization yield of the odd isotopes and suppressed the ionization of the even isotopes of samarium using suitable choice of laser polarization. To enhance the photoionization yield further, a search for the third-step transition terminating into an autoionization level has been carried out. A strong autoionization resonance at the third-step laser wavelength 644.14 nm, corresponding to the transition 34,929.9 cm(-1)-> 50,450.3 cm(-1) has been identified. The J-value of the newly discovered autoionization level at 50,450.3 (+/- 0.5) cm(-1) has been uniquely assigned as J=1. Finally, the photoexcitation/photoionization cross sections of all the transitions involved in the common level excitation scheme including that of the third-step transition terminating into the autoionization level have been measured by saturation method. (C) 2019 Elsevier Ltd. All rights reserved.

Towards Malaria Elimination - A Leap Forward was started to mark the occasion for renewed commitment to end malaria transmission for good (the WHO's call for "Malaria Free World" by 2030). This book is dedicated for the benefit of researchers, scientists, program and policy managers, students and anyone interested in malaria and other mosquito-borne diseases with the goal of sharing recent information on success stories, innovative control approaches and challenges in different regions of the world. Some main issues that emerged included multidrug-resistant malaria and pandemic risk, vaccines, cross-border malaria, asymptomatic parasite reservoir, the threat of Plasmodium vivax and Plasmodium knowlesi, insecticide resistance in Anopheles vectors and outdoor malaria transmission. This book is one little step forward to bring together in 17 chapters the experiences of malaria-expert researchers from five continents to present updated information on disease epidemiology and control at the national/regional level, highlighting the constraints, challenges, accomplishments and prospects of malaria elimination.

In this work, we address the issue of the suitability of blue fluorescent light as a frequency offset reference during the ladder-level excitation 5S1/2→5P3/2→5D3/2 of Rb85 atoms. A simple pump-probe spectroscopy experiment is performed to generate non-degenerate blue light emission produced by the spontaneous decay route 5D3/2→6P3/2→5S1/2. By varying the relative intensity of the pump-probe combination, we can hover between regimes dominated by mechanisms such as double resonance optical pumping (DROP) and Autler-Townes splitting. The efficacy of the blue fluorescence (420 nm) as a frequency offset reference is pronounced under the DROP regime due to its narrow (∼natural) linewidth. To provide further insight into the stability performance, the pump laser connecting the 5P3/2→5D3/2 transition is stabilized to the peak of the blue light with the help of a probe stabilized to the saturation absorption signal of the 5S1/2→5P3/2 transition. For this purpose, we used the coherence-induced modulation transfer technique. The error frequency noise power spectra and the subsequent Allan variance calculation clearly show that probe fluctuations are transferred to the pump laser because of an existing two-photon coherent coupling.

India is ecologically vast and has close to a billion-population living at risk of malaria. Given the evidence-based present-day intervention tools and large-scale implementation, India has recorded declining trends in disease transmission from 2 million cases in 2001 to close to a million cases in 2017 and embarked upon malaria elimination in keeping with the Global Technical Strategy by 2030. India is malaria endemic, but transmission intensities varied across its landscape with just few States of the east, central and northeast contributing bulk (80%) of total positive cases. Plasmodium falciparum and P. vivax are the predominant infections of which there has been steady increase in proportions of the former for constituting >60% of total cases what was 50:50 in 2001, a phenomenon attributed to emerging drug resistance. With the rolling out of the available intervention tools, malaria elimination is foreseeable yet there are multiple challenges which must be addressed to overcome the constraints. We strongly advocate continued disease surveillance and monitoring, universal coverage and intensification of coreinterventions for prevention and treatment prioritizing high-risk States, strengthening cross-border collaborations for information sharing and coordinated activities, and above all sustained allocation of resources, creating the enabling environment to end malaria transmission.

Radiative lifetimes of fifteen even-parity high-lying levels of atomic samarium in the energy range 34,000-34,815 cm(-1) have been measured systematically. The measurements were carried out by detecting time-resolved delayed three-colour photoionization signal using pump-probe technique in an atomic beam coupled to a time-of-flight mass spectrometer. The measured values are in the range of 35 to 349 ns. Accuracy of the measurements was validated by measuring the lifetime of the first excited level used in the excitation scheme by employing two-colour pump-probe photoionization spectroscopy and comparing the measured value with that reported in the literature. (C) 2018 Elsevier Ltd. All rights reserved.

Employing three-colour three-step resonance ionization spectroscopy, photoionization spectra of atomic uranium have been investigated extensively in the energy region 49,959–51,504 cm−1. A detailed analysis of the photoionization spectra has resulted in the observation of 346 even-parity autoionizing levels including 199 new levels and a Rydberg series converging to the second-lowest ionic level (\({}^{6}{\text{L}}_{11/2}^{\text{o}}\)) of uranium. Using the method of laser polarization combinations as well as the method of total angular momentum (J) selection rules, the J values of 72 of these autoionizing levels have been assigned unambiguously. Out of these 72 levels, the unique J values of 56 autoionizing levels have been determined for the first time, while it has been confirmed for the remaining 16 reported previously.

Long-lasting insecticidal nets (LLINs) are being promoted for malaria vector control in the northeastern Indian state of Assam. A cross-sectional study was conducted to assess the current residual bio-efficacy and durability of both the Olyset(®) and PermaNet(®)2.0 LLINs that were distributed earlier in 2009, 2011 and 2013 to help formulate informed policy regarding net procurement, supplies and replacement. The study was undertaken in three different malaria endemic blocks of Assam during the period of June to October of 2014. The residual bio-efficacies were ascertained using the WHO cone-bioassay method for mosquito mortality post-exposure and corroborated with the ring-net assay for the median knockdown times of both types of LLINs in use by these communities. Cross-sectional community surveys were distributed to assess net ownership, utilization, community practices and the physical conditions of the nets in terms of being torn and the numbers of holes per position. Both the Olyset(®) and PermaNet(®)2.0 LLINs that were distributed in 2009 (i.e., nearly after five years of community usage) were completely torn, worn out and obsolete. However, the LLINs distributed in 2011 (i.e., three years of community usage) retained their residual bio-efficacies in susceptibility ranges that varied from 57% to 79%. However, for the LLINs that were distributed in 2013, the observed residual efficacy was adequate and resulted in a mosquito mortality rate >80 percent. Of the two types of LLINs inspected, the Olyset(®)nets were more durable and robust in terms of being torn less frequently (37.1%, 39/105) compared with the PermaNet(®)2.0 nets (51.8%, 204/394). Regarding the LLINs that were distributed in 2013, all were physically intact and in good condition. The majority of the distributed LLINs (99.2%, 639/644) were still in the possession of the householders of the surveyed populations. This study revealed that the serviceable life of the nets was slightly less than three years in terms of waning residual bio-efficacy and durability that warranted replacement. The communities were aware of the benefits of the use of mosquito net for personal protection and regularly used the nets; thus, LLIN-based interventions for sustained vector control should be scaled up.

The malaria situation in India is complex as a result of diverse socio-environmental conditions. India contributes a substantial burden of malaria outside sub-Saharan Africa, with the third highest Plasmodium vivax prevalence in the world. Successful malaria control in India is likely to enhance malaria elimination efforts in the region. Despite modest gains, there are many challenges for malaria elimination in India, including: varied patterns of malaria transmission in different parts of the country demanding area-specific control measures; intense malaria transmission fuelled by favourable climatic and environment factors; varying degrees of insecticide resistance of vectors; antimalarial drug resistance; a weak surveillance system; and poor national coordination of state programmes. Prevention and protection against malaria are low as a result of a weak health-care system, as well as financial and socioeconomic constraints. Additionally, the open borders of India provide a potential route of entry for artesunate-resistant parasites from southeast Asia. This situation calls for urgent dialogue around tackling malaria across borders-between India's states and neighbouring countries-through sharing of information and coordinated control and preventive measures, if we are to achieve the aim of malaria elimination in the region.