Isolation and characterization of emerging Mpox virus from India.

Mpox (previously known as Monkeypox) has recently re-emerged, primarily through human-to-human transmission in non-endemic countries including India. Virus isolation is still considered as the gold standard for diagnosis of viral infections. Here, the qPCR positive skin lesion sample from a patient was inoculated in Vero E6 cell monolayer. Characteristic cytopathic effect exhibiting typical cell rounding and detachment was observed at passage-02. The virus isolation was confirmed by qPCR. The replication kinetics of the isolate was determined that revealed maximum viral titre of log 6.3 PFU/mL at 72 h postinfection. Further, whole genome analysis through next generation sequencing revealed that the Mpox virus (MPXV) isolate is characterized by several unique SNPs and INDELs. Phylogenetically, it belonged to A.2 lineage of clade IIb, forming a close group with all other Indian MPXV along with few from USA, UK, Portugal, Thailand and Nigeria. This study reports the first successful isolation and phenotypic and genotypic characterization of MPXV from India.

Morphometric and morphological appraisal of the eggs of Anopheles stephensi (Diptera: Culicidae) from India.

BACKGROUND & OBJECTIVES: Anopheles stephensi is one of the most important urban malaria vectors in India and contribute about 12% of total malaria cases. An. stephensi has three ecological variants; type, intermediate and mysorensis that can be differentiated on the basis of differences in number of ridges on egg float and on the basis of spiracular indices. Because of its anthropophilic nature the 'type' form is an efficient malaria vector. In the present study, the egg surface morphometry and morphology of An. stephensi 'type' form was studied and detail distinguish- ing characters were recorded for its correct identification. METHODS: Eggs of An. stephensi 'type' form were studied by scanning electron microscopy (SEM) after sputter- coating with gold. In total 23 egg characters were analysed morphologically and morphometrically, which included egg attributes, deck attributes, ventral tubercles, micropyle and float attributes. RESULTS: The dorsal surface of the egg of 'type' form was curved while the ventral surface was concave and both anterior and posterior ends were blunt. The average length and width of egg was 473.94 + 11.18 and 154.69 + 2.66 µm respectively. The number of float ribs observed was 20.33 ± 0.33. The maximum length of float was found to be 246.57 + 15.27 µm, whereas maximum width was 87.16 + 3.83 µm. INTERPRETATION & CONCLUSION: The present study has generated some important data which is specific to An. Stephensi 'type' form and provided significant morphological and morphometric standards for its correct identification. This information could be useful in differentiation of An. stephensi 'type' form from other ecological forms of the same species as well as other species of Anopheles.

Absence of asymptomatic malaria in a cohort of 133 individuals in a malaria endemic area of Assam, India.

BACKGROUND: Malaria in northeast India affects children and adults annually. The number of malaria cases reported has declined over the past few years. Nevertheless, it is not clear whether there is an actual decline in parasitaemia or whether asymptomatic malaria infections are on the rise, especially in forested and forest-fringed areas. Asymptomatic malaria forms a parasite reservoir that acts as an epicentre for malaria spread during high-transmission season. Therefore it is important to understand the quantum of asymptomatic malaria infections among the vulnerable population. METHOD: Four forest fringed historically malaria endemic villages were selected for the study. A total of 133 individuals without a fever history in the past four weeks were tested for malaria parasite using rapid diagnostic test (RDT), microscopy and polymerase chain reaction (PCR) assay during January - February 2014. Indoor resting Anopheles vectors were collected, identified and tested for sporozoite using VectorTest™ panel assay during October 2013 to March 2014, which is a low transmission season for malaria. Social and demographic data were recorded during the study. RESULTS: Mean age (± SEM) of the participants was 16.1 ± 1.2 years (95 % CI: 13.8-18.4). All participants (100 %) reported to use mosquito nets. Altogether, 43.6 % of participants had education below primary level and only 9 % reported a travel history during the past four weeks. All RDT, microscopy and PCR assays were found negative indicating no asymptomatic malaria parasitaemia. Seven known malaria vector species namely, Anopheles nivipes, An. minimus, An. annularis, An. vagus, An. aconitus, An. philippinensis and An. culicifacies, were recorded in the present study. VectorTest™ sporozoite panel assay conducted on 45 pools (N = 224) of vector mosquitoes were found negative for Plasmodium sporozoite. DISCUSSION: Northeastern states of India report asymptomatic malaria parasitemia along with high malaria transmission. An. minimus and An. dirus are recognised as efficient vectors, but An. culicifacies, An. philippinensis and An. annularis also play role in malaria transmission. Currently all participants were found negative for asymptomatic malaria, however the small sample size may restrict the scope of present results to the population living in more remote areas. CONCLUSION: No cases of asymptomatic malaria infections parasitaemia was found in the present study conducted during a low transmission season indicating that asymptomatic malaria parasitaemia may not be prevalent in the region. Mosquito specimens were tested negative for the malaria sporozoites. Study findings encourage the ongoing malaria intervention efforts and recommends similar investigations in different ecological areas involving large populations.

Genetic polymorphism and amino acid sequence variation in Plasmodium falciparum GLURP R2 repeat region in Assam, India, at an interval of five years.

BACKGROUND: The R2 repeat region of GLURP has been reported as a good genetic marker for Plasmodium falciparum genotyping. Proper knowledge of the extent and nature of P. falciparum genetic diversity using highly immunogenic R2 repeat region in malaria-endemic areas is a crucial element to understand various aspects related to immunity acquisition and disease pathogenesis. METHODS: Population diversity of P. falciparum GLURP and amino acid sequence repeats in GLURP R2 region was studied in malaria-endemic Assam state, northeast India and compared at an interval of five years during 2005 (Group-A) and 2011 (Group-B). RESULTS: Of the 66 samples, a total of 55 samples showed positive PCR bands for GLURP R2 region and altogether ten types of alleles with size ranging from 501 bp to 1,050 bp (50 bp bin) were observed and coded as genotypes I-X. In Group-A (n = 29), 24 samples were found infected with single, four with double and one with triple P. falciparum genotype, while in Group-B (n = 26), single genotype was found in 23 samples, double in two samples and triple in one sample. Genotype IV showed significant increase (p = 0.002) during 2011 (Group-B). Genotypes I to V were more common in Group-B (62%), however genotypes VI to X were more frequently distributed in Group-A. The expected heterozygosity was found slightly higher in Group-A (HE = 0.87) than Group-B (HE = 0.85), whereas multiplicity of infection (MOI) in Group-A (MOI = 1.21 ± 0.49) and Group-B (MOI = 1.12 ± 0.43) did not display significant variation. The amino acid repeat sequence unit (AAU) DKNEKGQHEIVEVEEILPE (called 'a') was more frequent in the well-conserved part of R2 repeat region. CONCLUSION: The present study is the first extensive study in India which has generated substantial data for understanding the type and distribution of naturally evolved genetic polymorphism at amino acid sequence level in GLURP R2 repeat region in P. falciparum. There was decrease in the PCR amplicon size as well as the number of AAU [amino acid repeat unit] in Group-B displaying the bottleneck effect. The present study described a new type of AAU 'd' which varied from the other previous known AAUs.

Acute and subchronic dermal toxicity of Vitex negundo essential oil.

Vitex negundo is a common herb in different herbal formulation. The potential acute and sub-chronic dermal toxicities were evaluated as per OECD (Organization for Economic Cooperation and Development) guidelines 402 and 411, respectively. Both sexes of Wistar rats were exposed to Vitex negundo oil of 2000 mg/kg body weight for acute dermal toxicity, whereas in the dermal sub-chronic toxicity study, rats were exposed to Vitex negundo oil 250, 500 and 1000 mg/kg body weight, respectively, for five times a week for 90 d. In acute and sub-chronic toxicity studies, all animals were normal without any behavioral, serum biochemistry, hematology, necroscopical and histopathological changes. The no observed effect level (NOEL) and no observed adverse effect level (NOAEL) of Vitex negundo oil were 250 and 1000 mg/kg/day, respectively. Vitex negundo oil is under the category 5 (Unclassified) according to the Globally Harmonized System, with an LD50 value of over 2000 mg/kg.

Black fly (Simulium sp) composition, daytime biting activity and possible onchocerciasis infection in north-east, India.

Pupal stages of Simulium were collected and identified from various breeding habitats of twelve locations in northeastern India. Simulium flies, while attempting to land on human were collected between 07:00-17:00 hrs to understand the biting pattern. Seven species belonging to three sub-genera, Eusimulium (1), Gomphostilbia (1) and Simulium (5) belonging genus Simulium were encountered. Out of total seven species recorded, S. (E) aureohirtum, S. (G) tenuistylum and S. (S) rufibasis were predominant and shared 30.3%, 29.9% and 27.6% of total collection. Stream breeding habitat contributed 47.3% of total catch and was found to be preferred breeding habitat (p < 0.0001). S. (S) christophersi and S. (G) tenuistylum were recorded for the first time from the northeastern region of India. Simuliids biting rhythm showed bimodal pattern and were more active during sunny day (p < 0.0001). Microscopic dissection of simuliids (n = 266) did not incriminate simuliids as vector of onchocerciasis.

DDT & deltamethrin resistance status of known Japanese encephalitis vectors in Assam, India.

BACKGROUND & OBJECTIVE: Japanese encephalitis (JE) outbreaks are common in Assam, northeastern State of India. Information on resistance in known JE vectors in the affected area is important for effective control measures. This study was undertaken to determine the species abundance of JE vectors endemic to Sibsagar district of Assam, and their susceptibility against DDT and deltamethrin. METHODS: Adult mosquitoes were collected using CDC light trap and aspirators from human dwellings from 13 endemic villages falling under three Primary Health Centres. Collected mosquitoes were identified and unfed female mosquitoes were used for DDT and deltamethrin sensitivity bioassay. The bioassay was performed following WHO protocol using standard susceptibility test kit. Knockdown time (KDT) was monitored at every 10 minutes intervals, whereas mortalities were recorded 24 h post-exposure. Vector density and resistance status were mapped using geographic information system (GIS) technique. RESULTS: A total of 7655 mosquitoes were sampled under three genera, i.e. Anopheles, Culex and Mansonia, and nine species, the JE vector Cx. vishnui group (31.78%) was the most predominant species, followed by Ma. uniformis (16.81%) and Ma. indiana (16.45%). All vector species were suspected to be resistant to DDT and sensitive to deltamethrin, except Ma. indiana, which was suspected to deltamethrin resistant. The KDT50 and KDT95 values of vector mosquitoes for DDT were significantly higher as compared to deltamethrin. The probit model used to estimate KDT50 and KDT95 values did not display normal distribution of percentage knockdown with time for all the vectors tested for DDT and deltamethrin, except for Ma. indiana for deltamethrin assay and Cx. gelidus for the DDT assay. INTERPRETATION & CONCLUSION: Differences in insecticide resistance status were observed between insecticides and vector species. The results of this study provided baseline data on insecticide resistance in known JE vectors of Sibsagar, Assam. The maps generated may allow better communication in control operations and comparison of changes in susceptibility status of these vectors over time.

Nested PCR detection of Plasmodium malariae from microscopy confirmed P. falciparum samples in endemic area of NE India.

The present study evaluates the performance of OptiMAL-IT test and nested PCR assay in detection of malaria parasites. A total of 76 randomly selected blood samples collected from two malaria endemic areas were tested for malaria parasites using microscopy and OptiMAL-IT test in the field. PCR assays were performed in the laboratory using DNA extracted from blood spots of the same samples collected on the FTA classic cards. Of the total of 61 field confirmed malaria positive samples, only 58 (95%) were detected positive using microscopy in the laboratory. Sensitivity, specificity, positive predictive value, negative predictive value and false discovery rate of OptiMal-IT in comparison to the microscopy were 93%, 83%, 95%, 79% and 5%, respectively. On the other hand, the sensitivity and specificity of PCR assay were 97% and 100%, respectively, whereas positive predictive value, negative predictive value and false discovery rate were 100%, 90% and 0%, respectively. The overall performance of OptiMal-IT and PCR assays for malaria diagnosis was 76% and 97%, respectively. PCR assay enabled the identification of infection with Plasmodium malariae Laveran, 1881 in four samples misidentified by microscopy and Plasmodium-specific antigen (PAN) identified by the OptiMAL-IT test. In addition to the standard methods, such PCR assay could be useful to obtain the real incidence of each malaria parasite species for epidemiological perspectives.

Influence of water physicochemical characteristics on Simuliidae (Diptera) prevalence in some streams of Meghalaya, India.

BACKGROUND & OBJECTIVES: Simuliids (Diptera) are one of the medically important biting insects group and have worldwide distribution. Their immature stages proliferate in fast flowing river or stream water and have been considered as important ecological indicator. METHODS: Aquatic stages of simuliids were collected and speciated from 16 different fresh water rivers and streams. Water flow rate was determined and water samples were analysed for various water variables such as water temperature, pH, dissolved oxygen concentration (DOC), dissolved oxygen saturation (DOS), conductivity, total dissolved solute (TDS), turbidity, resistivity and salinity. Linear regression was used to determine relationship between simuliid density and water variables, whereas multiple regression was used to determine the fitness for the presence of simuliid species. Principal component analysis (PCA) was used to determine the water parameters association with simuliid distribution. RESULTS: Total 565 specimens comprising of three species namely, Simulium (S) barraudi Puri, S. (S) striatum Brunetti, and S. (S) himalayense Puri were recorded in the present study. Simulium barraudi was the most abundant (56.8%) and its density was high (χ2 = 289.3; df = 2; p <0.0001) as compared to the others. The average population size of each species was 188.3, whereas Simpson and Shannon-Wiener diversity indices were 0.4466 and 1.306 respectively. Linear regression showed that simuliid density was associated with the water flow rate. Principal component analysis indicated that the water parameters accounted for 42.25% variation along D1 axis, while 24.1% variation along D2 axis. Atleast two principal components have eigenvalue >1 and accounted for 32.6% of variation. INTERPRETATION & CONCLUSION: Our study provides new information on simuliid species association with breeding water parameters in a little studied region of high biological interest. Turbidity, water flow and pH are important water parameters affecting the simuliid species prevalence. Each simuliid species preferred different sets of physicochemical parameters of breeding habitat, which are specific to that particular species. Therefore, simuliid species community as a whole cannot be considered as a suitable indicator of the streams water quality. In addition to describing simuliids, the information provided herein will be useful for the conservation of aquatic ecology and environment in Meghalaya state of India.

Effects of weak static magnetic fields on the development of seedlings of Arabidopsis thaliana.

To study magnetoreception of Arabidopsis thaliana, we analysed several developmental responses including cryptochrome-independent seed germination and the phytochrome- and cryptochrome-dependent hypocotyl elongation and photo-accumulation of anthocyanins and chlorophylls in weak static magnetic fields ranging from near null to 122 µT. A field of 50 µT accelerated seed germination by about 20 h relative to samples maintained in a near-null field. The double mutant, cry1cry2, lacking cryptochromes 1 and 2 displayed the same magnetic field-induced germination acceleration under blue light as the wild-type strain. Magnetic field-induced germination acceleration was masked in the presence of exogenous sucrose. Stimulus-response curves for hypocotyl elongation in a range between near-null to 122 µT indicated maxima near 9 and 60 µT for the wild-type strain as well as mutant cry1cry2. The photo-accumulation of anthocyanins and chlorophylls could be effectively modulated by magnetic fields in the presence of low-irradiance red and blue light, respectively. The findings indicate that Arabidopsis thaliana possesses light-independent mechanisms of magnetic field reception, which remain presently unidentified. Our results are in better agreement with predictions of the level crossing mechanism (LCM) of magnetoreception rather than those of the cryptochrome-associated radical-pair mechanism (RPM).

Repellent activity of some essential oils against Simulium species in India.

Use of repellents seems to be most reliable method of personal protection against annoyance and infections associated with haematophagous insects. We have investigated the biting activity of Simulium and tested the repellency of five essential oils extracted from Homalomena aromatica Schott (Alismatales: Araceae), Pogostemon heyneanus Bentham (Lamiales: Lamiaceae), Citrus aurantifolia Swingle (Sapindales: Rutaceae), Vitex negundo L. (Lamiales: Lamiaceae), and Ageratum conzoides L. (Asterales: Asteraceae) on the human volunteers against Simulium (blackflies) in three locations of Arunachal Pradesh, India. Blackflies preferred biting legs (> 79%) as compared to hand and face with profound biting activity during 1000-1100 h (> 23%) and 1500 - 1600 h (> 28%). The essential oil extracted from Homalomena aromatica, Vitex negundo and Ageratum conizoides provided > 2 h protection at 5% concentration and > 5 h protection at 10% concentration in all the three testing locations. The repellency of Homalomena aromatica, Vitex negundo and Ageratum conizoides essential oils after 6 h application was > 50% at 5% concentration and > 90% at 10% concentration. The study provides evidence for the potential of these essential oils in developing new repellents against blackflies.

Deltamethrin Contact Exposure Mediated Toxicity and Histopathological Aberrations in Tissue Systems of Public Health Importance Cockroach Species Periplaneta americana and Blattella germanica.

Cockroach species Periplaneta americana and Blattella germanica potentially survive in locations close to human activity. Besides spoiling food material, cockroaches also transfer pathogens of different diseases among human beings. Since the insecticides have been used extensively to control cockroaches, information on their insecticide susceptibility and toxicity at the cellular level may be crucial. In the study, deltamethrin toxicity as well as the deltamethrin-mediated cytomorphological changes in the brain, ovary and midgut of the two important cockroach species have been assessed. Different concentrations [0.00025% (0.0025 mg/ml), 0.0025% (0.025 mg/ml), 0.025% (0.25 mg/ml), 0.25% (2.5 mg/ml), 0.5% (5 mg/ml), 1% (10 mg/ml)] of deltamethrin in acetone were used to expose test species in WHO bottle assay. Knockdown was recorded after 5 min interval while delayed mortality was observed after 24 h. Brain, ovary and gut were dissected post 1 h exposure and 24 h holding (for 0.25, 0.5 and 1% concentration), and tissues were processed for microscopic analysis. Deltamethrin exposed cockroaches and dissected tissues were used to estimate deltamethrin using HPLC. At 0.00025% (lowest concentration), the percentage knock-down observed was 66.7% for P. americana and 80% B. germanica respectively (R 2 = 0.78; p = 0.0001) in 1 h. KDT50 value was found to be 8.7 min (95% CI: 7.3-10.2), while KDT99 was 20.7 min (95% CI: 16.0-35.7) in P. americana at 1% concentration. Whereas, the KDT50 and KDT99 values for B. germanica were 7.4 min (95% CI: 5.4-9.1) and 27.4 min (95% CI: 18.2-80.0) at a similar concentration. LD50 and LD95 values (for 60 min standard exposure) were 0.0006% (95% CI: 0.00-0.001) and 0.034% (95% CI: 0.013-0.49) respectively for P. americana, while these values were 0.0005 (95% CI: 0.00-0.001) and 0.04 (95% CI: 0.01-0.23) for B. germanica. Exposure to 1% deltamethrin induced a considerable toxic effect in the epithelial cells in the midgut. HPLC estimated 0.21 ± 0.05 mg (95% CI: 0.18-0.25; CoV 23.9%) deltamethrin in P. americana post 1% exposure. Even short term exposure to a low concentration of synthetic pyrethroid deltamethrin displayed immediate knockdown and delayed mortality in both the test species. Considerable histological damage was observed in both the insects at 1% exposure. In India, resistance to deltamethrin may have been reported among different insects due to its extensive use. However, the formulations such as insecticide paints, attractant baits etc. developed using deltamethrin as an active ingredient could be useful in cockroach control operations.

Harnessing heterosis and male sterility in soybean [Glycine max (L.) Merrill]: A critical revisit.

Soybean is a predominantly self-pollinated crop. It is also one of the important oilseed legumes. Soybean is an excellent crop having industrial, traditional, culinary, feeding, and cultural roles. Genetic diversity in breeding programs is of prime importance as it ensures the success of any breeding by enhancing the outcomes and results of the plants. The phenomenon wherein the progeny exhibits greater biomass (yield) and a faster rate of development and fertility than its parents is referred to as heterosis. As of now, heterosis is mainly limited to the trait of seed yield and is considered the basis for the development of better (superior) varieties. Male sterility (MS) is extensively used for the production of seeds and the improvement of crops coupled with the traditional breeding programs and molecular technology. Therefore, deployment of MS and heterosis in breeding soybean could yield better outcomes. This review aims to focus on two aspects, namely, MS and heterosis in soybean with its scope for crop improvement.

Malaria incidence among paramilitary personnel in an endemic area of Tripura.

BACKGROUND & OBJECTIVES: Paramilitary operations along the Indo-Bangladesh border are adversely affected by malaria induced morbidity and mortality. Villages surrounding the paramilitary installations often serve as disease reservoirs. Malaria incidence in Tripura State Rifles (TSR) units in Dhalai District of Tripura was studied and the role of the village population in disease transmission was also assessed. METHODS: Mass blood surveys were carried out among TSR personnel and villagers during 2007 to 2009. Malaria diagnosis through blood smear examination and rapid detection kits was done, and percentage parasitaemia was determined. Activity of malaria vectors was monitored using CDC light traps. RESULTS: Slide positivity rates (SPR) in the neighbouring villages (51.4%) was significantly higher than that in TSR (27.7%) (P<0.0001). Malaria incidence in villages did not show seasonal variability while it was lowest during post-monsoon season in TSR (P<0.325; OR = 0.74). Per cent Pf parasitaemia was high in TSR (0.29) as compared to villagers (0.20) (P<0.0001). Anopheles minimus and An. dirus were the major malaria vectors observed. INTERPRETATION & CONCLUSIONS: Paramilitary and public health authorities should adopt targeted measures to reduce the malaria incidence in the villages surrounding the paramilitary installations as the village populations play a major role in disease transmission.

Deltamethrin Microencapsulation in Emulsion Paint Binder and Its Long-Term Efficacy Against Dengue Vector Aedes aegypti.

Various control interventions have been effective in the control of arthropod vectors to a certain extent; still, sustained vector control is an existing problem globally. Insecticide-based formulations have been found to be useful, however the proper delivery of active molecules to target vectors is important. Currently, synthetic pyrethroid deltamethrin (DM) has been microencapsulated in the emulsion paint binder and evaluated for long-term effectiveness against dengue vector Aedes aegypti. Different compositions of emulsion binder were prepared by varying the content of monomer and DM. A selection was made for the composition yielding the best combination of properties like solid content, intrinsic viscosity, and DM content. Developed formulation was tested against laboratory-reared and pathogen-free Ae. aegypti mosquitoes. Encapsulation of DM in emulsion binder during polymerization showed a uniform distribution. The optimized formulation was stable and did not have a considerable plasticizing effect. Scanning electron microscopy revealed that grain-like micro crystals of DM and surfactant sodium lauryl sulfate (SDS) were uniformly distributed on the formulation surface. The best optimized formulation was highly effective against dengue vector Ae. aegypti and found to provide efficacy for up to 18 months of application. The knockdown time (KDT) values KDT10 and KDT50 were 7.4 min (95% CI: 5.6-9.1) and 22.1 min (95% CI: 19.7-24.3) respectively, whereas 24 h corrected mortality was 90% (95% CI: 82.5-97.5) after 18 months of application (T18). The probit model used to determine knockdown values did not deviate from the linearity and displayed normal distribution of knockdown % with time for different formulations (p ≥ 0.1). Presently developed DM microencapsulated emulsion binder was stable, smooth, and uniform. The binder displayed excellent anti-insect property and was capable of providing long-term effectiveness against dengue vectors Ae. aegypti. Such a formulation after field-scale evaluation could be very useful in attaining long-term protection from arthropod vectors.

Behavioural response of mosquito vectors Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus to synthetic pyrethroid and organophosphorus-based slow-release insecticidal paint.

BACKGROUND: The direct toxicological impact of insecticides on vector mosquitoes has been well emphasized; however, behavioural responses such as excito-repellency and physical avoidance as a result of insecticide exposure have not been much studied. We have demonstrated the excito-repellency and behavioural avoidance in certain vector mosquito species on exposure to a slow-release insecticidal paint (SRIP) formulation in addition to direct toxicity. METHODS: A SRIP formulation developed by the Defence Research and Development Establishment, Gwalior, contains chlorpyriphos, deltamethrin and pyriproxyfen as active insecticides. Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti mosquitoes were used to study the excito-repellency response of the formulation. The experiments were performed in a specially designed dual-choice exposure and escape chamber made of transparent polymethyl methacrylate. For the experiments, the SRIP formulation was applied undiluted at a rate of 8 m2 per kg on 15 cm2 metallic surfaces. Mosquitoes were introduced into the exposure chamber, and observations of the movement of mosquitoes into the escape chamber through the exit portal were taken at 1-min intervals for up to 30 min. RESULTS: The evaluated formulation displayed strong excito-repellency against all three tested vector mosquito species. Results showed that the ET50 (escape time 50%) for Ae. aegypti, An. stephensi and Cx. quinquefasciatus was 20.9 min, 14.5 min and 17.9 min for contact exposure (CE) respectively. Altogether in CE, the escape rates were stronger in An. stephensi mosquitoes at different time intervals compared to Ae. aegypti and Cx. quinquefasciatus mosquitoes. The probit analysis revealed that the determined ET did not deviate from linearity for both non-contact exposure (NCE) and placebo exposure (PE) (χ2 ≤ 7.9; p = 1.0) for Ae. aegypti mosquitoes and for NCE (χ2 = 8.3; p = 1.0) and PE (χ2 = 1.7; p = 1.0) treatments in Cx. quinquefasciatus. Mortality (24 h) was found to be statistically higher (F = 6.4; p = 0.02) in An. stephensi for CE but did not vary for NCE (p ≥ 0.3) and PE (p = 0.6) treatments among the tested mosquito species. Survival probability response suggested that all the three tested species displayed similar survival responses for similar exposures (χ2 ≤ 2.3; p ≥ 0.1). CONCLUSION: The study demonstrates the toxicity and strong behavioural avoidance in known vector mosquito species on exposure to an insecticide-based paint formulation. The combination of insecticides in the present formulation will broaden the overall impact spectrum for protecting users from mosquito bites. The efficacy data generated in the study provide crucial information on the effectiveness of the tested formulation and could be useful in reducing the transmission intensity and disease risk in endemic countries.

Malaria epidemiology along Indo-Bangladesh border in Tripura State, India.

Malaria epidemiological surveys were conducted in 16 villages along the Indo-Bangladesh border in Tripura, northeastern India. Insecticide resistance among malaria vectors and chloroquine resistance in the parasite were also studied along with monitoring of vector density using light traps. The epidemiological data indicated that malaria incidence was highest during June-July and lowest during November. Examination of blood smears collected through door to door surveys indicated slide positivity rate (SPR) of 25.2% and that Plasmodium falciparum was the predominant parasite (slide falciparum rate of 22.3%). The incidence rates of falciparum malaria varied significantly among the age groups (p<0.001) and 2-4 year olds were the most affected. Major malaria vectors recorded in light trap collections were An. dirus, An. minimus and An. philippinensis/nivipes. Chloroquine resistance studies indicated that treatment failure occurred in 35% of the cases and hence the use of artesunate combination therapy (ACT) was recommended for treatment of malaria in the area.

Correction to: Are malaria elimination efforts on right track? An analysis of gains achieved and challenges ahead.

AbstractIn the original publication of this article [1], the legends in Fig. 9 are missing during the process of typesetting.

Are malaria elimination efforts on right track? An analysis of gains achieved and challenges ahead.

BACKGROUND: Malaria causes significant morbidity and mortality each year. In the past few years, the global malaria cases have been declining and many endemic countries are heading towards malaria elimination. Nevertheless, reducing the number of cases seems to be easy than sustained elimination. Therefore to achieve the objective of complete elimination and maintaining the elimination status, it is necessary to assess the gains made during the recent years. MAIN TEXT: With inclining global support and World Health Organisation (WHO) efforts, the control programmes have been implemented effectively in many endemic countries. Given the aroused interest and investments into malaria elimination programmes at global level, the ambitious goal of elimination appears feasible. Sustainable interventions have played a pivotal role in malaria contraction, however drug and insecticide resistance, social, demographic, cultural and behavioural beliefs and practices, and unreformed health infrastructure could drift back the progress attained so far. Ignoring such impeding factors coupled with certain region specific factors may jeopardise our ability to abide righteous track to achieve global elimination of malaria parasite. Although support beyond the territories is important, but well managed integrated vector management approach at regional and country level using scrupulously selected area specific interventions targeting both vector and parasite along with the community involvement is necessary. A brief incline in malaria during 2016 has raised fresh perturbation on whether elimination could be achieved on time or not. CONCLUSIONS: The intervention tools available currently can most likely reduce transmission but clearing of malaria epicentres from where the disease can flare up any time, is not possible without involving local population. Nevertheless maintaining zero malaria transmission and checks on malaria import in declared malaria free countries, and further speeding up of interventions to stop transmission in elimination countries is most desirable. Strong collaboration backed by adequate political and financial support among the countries with a common objective to eliminate malaria must be on top priority. The present review attempts to assess the progress gained in malaria elimination during the past few years and highlights some issues that could be important in successful malaria elimination.