... Prof. Gyula Huszenicza Dr. Zoltán Demeter Page 3. 3 Contents ... multifocal gray matter necro... more ... Prof. Gyula Huszenicza Dr. Zoltán Demeter Page 3. 3 Contents ... multifocal gray matter necrosis, perivascular lymphocytic inflammation and cytoplasmic and intranuclear inclusionbodies are observed (Amude et al., 2007; Greene & Appel, 2006) ...
In India, DDT is still the insecticide of choice for public health programmes against vector born... more In India, DDT is still the insecticide of choice for public health programmes against vector borne diseases. But recent information on susceptibility status of DDT against mosquitoes in Northeast India is scarce. Continued monitoring of insecticide resistance status, underlying mechanisms and establishment of a data base are of prime importance in the development of insecticide resistance management programme. In the present study status of DDT resistance and underneath biochemical mechanisms were investigated against vector of bancroftian filariasis, Culex quinquefasciatus Say (Diptera: Culicidae), in Assam. The locations were selected for mosquito collection on the basis of use of insecticide and / or eco-environmental settings. Insecticide susceptibility assays were performed on wild caught adult female mosquitoes to DDT (4%). The percent mortality against DDT in all the study sites ranges between 11.875 and 50.0 whereas percent mortality in susceptible laboratory strain (S–Lab) ...
Appropriate monitoring of vector resistance to insecticides is an integral component of planning ... more Appropriate monitoring of vector resistance to insecticides is an integral component of planning and evaluation of insecticide use in vector borne disease control programmes. Culex quinquefasciatus is the principal vector of bancroftian filariasis in Indian subcontinent. This mosquito has developed resistance to DDT and some pyrethroid insecticides because of a mechanism conferring reduced nervous system sensitivity, termed knockdown resistance (kdr). Knockdown resistance is mainly caused by a single nucleotide polymorphism (SNP) in para-type voltage-gated sodium channel (TTA/TTT), which resulted a L1014F substitution. There are different established methods for detection of kdr mutation. However, all methods have some limitations and complexity. We developed a new high-throughput assay for the detection of knockdown resistance and real-time genotyping of kdr polymorphism in individual Culex quinquefasciatus. We designed a single-labeled probe, known as SimpleProbe® consist of a sin...
Aedes mosquitoes are highly invasive and can survive almost any climatic conditions. They transmi... more Aedes mosquitoes are highly invasive and can survive almost any climatic conditions. They transmit a number of major world's deadly diseases. Therefore, a study was undertaken during December 2010 to evaluate the entomo-epidemiological risk of Aedes mosquito borne diseases (VBD) in Mumbai international seaport areas to minimize potential global health risks and prevent introduction of new VBD in India. Surveys were undertaken in operational and residential areas of Mumbai Port Trust (MPT). All the entomological indices were found to be above the critical level, prescribed for seaports by International Health Regulations Act, 2005. The operational areas where large goods are handled from cargo ships were found to be more prone to mosquito breeding comparing to residential areas. High insecticide tolerance of Aedes aegypti population against temephos and fenthion from Mumbai port area is reported for the first time. A careful and regular invigilation of the international seaports to prevent building up of vector density of dengue/chikungunya and yellow fever is recommended.
Aedes mosquitoes are highly invasive and can survive almost any climatic conditions. They transmi... more Aedes mosquitoes are highly invasive and can survive almost any climatic conditions. They transmit a number of major world's deadly diseases. Therefore, a study was undertaken during December 2010 to evaluate the entomo-epidemiological risk of Aedes mosquito borne diseases (VBD) in Mumbai international seaport areas to minimize potential global health risks and prevent introduction of new VBD in India. Surveys were undertaken in operational and residential areas of Mumbai Port Trust (MPT). All the entomological indices were found to be above the critical level, prescribed for seaports by International Health Regulations Act, 2005. The operational areas where large goods are handled from cargo ships were found to be more prone to mosquito breeding comparing to residential areas. High insecticide tolerance of Aedes aegypti population against temephos and fenthion from Mumbai port area is reported for the first time. A careful and regular invigilation of the international seaports to prevent building up of vector density of dengue/chikungunya and yellow fever is recommended.
OBJECTIVES: Dengue/Dengue Hemorrhagic Fever (DHF) is the most rapidly spreading vector-borne infe... more OBJECTIVES: Dengue/Dengue Hemorrhagic Fever (DHF) is the most rapidly spreading vector-borne infection all over the world. Uttarakhand (India) is the prime destination for national and international tourists. Here we assessed the epidemiological characteristics and entomological parameters of dengue/DHF in Uttarakhand (India) using in-depth statistical methods to measure risk of dengue epidemics.
Asian Pacific Journal of Tropical Medicine, Jan 1, 2011
To understand the insecticide resistance status of Culex quinquefasciatus Say (Diptera: Culicidae... more To understand the insecticide resistance status of Culex quinquefasciatus Say (Diptera: Culicidae) (Cx. Quinquefasciatus) to deltamethrin, cyfluthrin, permethrin, lambdacyhalothrin, DDT and malathion in filarial endemic areas of Uttar Pradesh, India.Insecticide susceptibility assays were performed on wild-caught adult female Cx. quinquefasciatus mosquitoes to deltamethrin (0.05%), cyfluthrin (0.15%), permethrin (0.75%), lambdacyhalothrin (0.05%), malathion (5.0%) and DDT (4.0%), the discriminating doses recommended by the World Health Organisation (WHO).The data showed that Cx. quinquefasciatus is highly resistant to DDT and malathion; the mortality was 28.33% and 27.5%, respectively and incipient resistance to synthetic pyrethroids (deltamethrin, cyfluthrin, permethrin, and lambdacyhalothrin), where mortality ranged from 95.83% in permethrin to 98.33% in cyfluthrin and lambdacyhalothrin. Knockdown times (KDT50) in response to synthetic pyrethroids varied significantly between different insecticides (P<0.01) from 31.480 min for permethrin to 21.650 for cyfluthrin.The results presents here provide the status report of the insecticide resistance/susceptibility of Cx. quinquefasciatus in major filaria endemic areas of northern India.
We determined the fatty acid compositions of six species of freshwater microalgae belonging to th... more We determined the fatty acid compositions of six species of freshwater microalgae belonging to the Chlorophyta, which were isolated from freshwater bodies in Assam, India. All six microalgae – Desmodesmus sp. DRLMA7, Desmodesmus elegans DRLMA13, Scenedesmus sp. DRLMA5, Scenedesmus sp. DRLMA9 Chlorella sp. DRLMA3 and Chlorococcum macrostigmatum DRLMA12-showed similar fatty acid profiles 16:0, 16:4, 18:1, 18:2, and 18:3 as major components. We also compared fatty acid compositions during the late exponential and stationary growth phases of D. elegans DRLMA13 and Scenedesmus sp. DRLMA9 in BG11 medium. We observed enhanced percentages of total saturated and monounsaturated fatty acids with a concomitant decrease in polyunsaturated fatty acid content upon the prolonged cultivation of both microalgae. Distinct morphological features of microalgal isolates were determined by scanning electron microscopic (SEM) studies. An ornamented cell wall was found in D. elegans DRLMA13, which is characteristic of small spineless species of Desmodesmus. The isolated microalgae were further distinguished through analysis of internal transcribed spacer 2 (ITS2) secondary structures and compensatory base changes (CBCs). Analysis of CBCs showed the relatedness of Chlorella sp. DRLMA3 with other Chlorella-like organisms, but it does not belong to the clade comprising Chlorella sensu stricto, which includes Chlorella vulgaris. The CBC count between Scenedesmus sp. DRLMA9 and other species of Scenedesmus provides evidence that this isolate represents a new species.► We isolated six different species of freshwater microalgae and studied their fatty acid compositions. ► We compared the changes in fatty acid composition during exponential and stationary phase in two microalgal species. ► Prolonged cultivation of microalgae increase total saturated and monounsaturated fatty acids. ► Palmitic, oleic, linoleic and linolenic acids are the major fatty acids synthesized by the six freshwater microalgae studied. ► Compensatory base changes in the secondary structures of the rDNA-ITS2 are compared to understand their phylogenetic relationships.
Abstract: The Voltage Gated Sodium Channel (VGSC) is critical for binding of different insecticid... more Abstract: The Voltage Gated Sodium Channel (VGSC) is critical for binding of different insecticides and plays a key role in insecticide resistance. The insect sodium channel consists of four homologous domains (I to IV), each containing six transmembrane segments (S1 to S6). An important mechanism of resistance to DDT and pyrethroids is termed knockdown resistance (kdr), caused by a single nucleotide polymorphism in the IIS6 domain of sodium channels. We analyzed the polymorphisms, nucleotide diversity, and phylogenies in the vgsc-IIS6 gene in Culex quinquefasciatus from India. We analyzed the neutral model/hypothesis to infer if natural selection is acting upon the vgsc s Fs test were performed to determine whether the distribution of nucleotide variation within the samples was consistent with the neutral model. We theorized that the evolutionary pattern of intra-population distribution of variability in vgsc gene is consistent with the neutral expectation.
The study investigated the development and stage specificity of physiological resistance to insec... more The study investigated the development and stage specificity of physiological resistance to insecticides in a colony of Culex quinquefasciatus Say (Diptera: Culicidae) mosquitoes, which are vectors of bancroftian filariasis in India, after selection with deltamethrin. Resistance was selected by exposing the larvae to the concentration of deltamethrin that caused 50% mortality in the tested population (i.e., LC50). Under continuous selection pressure, the LC50 increased steadily in subsequent generations. The estimated LC50 for the F0 generation was 0.409 μg/L; the LC50 first displayed a substantial increase in the F5 generation (5.616 μg/L) and reached 121.902 μg/L in the F10 generation. The objective of this study was to establish a deltamethrin-resistant colony to develop a research programme that will study the evolution of physiological resistance patterns and stage-specific resistance responses in Cx. quinquefasciatus larvae and adults under laboratory conditions. An approximately 298-fold increase in resistance was recorded after 10 generations, as evidenced by the resistance ratio (RR50). The progress and effect of the selection pressure in the adult stage was monitored with the World Health Organisation (WHO) diagnostic test. The mortality, as observed using the WHO diagnostic test, declined significantly from the F5 generation (85%) onwards and the highest rate of survival (65%) was observed in the F10 generation.
... Prof. Gyula Huszenicza Dr. Zoltán Demeter Page 3. 3 Contents ... multifocal gray matter necro... more ... Prof. Gyula Huszenicza Dr. Zoltán Demeter Page 3. 3 Contents ... multifocal gray matter necrosis, perivascular lymphocytic inflammation and cytoplasmic and intranuclear inclusionbodies are observed (Amude et al., 2007; Greene & Appel, 2006) ...
In India, DDT is still the insecticide of choice for public health programmes against vector born... more In India, DDT is still the insecticide of choice for public health programmes against vector borne diseases. But recent information on susceptibility status of DDT against mosquitoes in Northeast India is scarce. Continued monitoring of insecticide resistance status, underlying mechanisms and establishment of a data base are of prime importance in the development of insecticide resistance management programme. In the present study status of DDT resistance and underneath biochemical mechanisms were investigated against vector of bancroftian filariasis, Culex quinquefasciatus Say (Diptera: Culicidae), in Assam. The locations were selected for mosquito collection on the basis of use of insecticide and / or eco-environmental settings. Insecticide susceptibility assays were performed on wild caught adult female mosquitoes to DDT (4%). The percent mortality against DDT in all the study sites ranges between 11.875 and 50.0 whereas percent mortality in susceptible laboratory strain (S–Lab) ...
Appropriate monitoring of vector resistance to insecticides is an integral component of planning ... more Appropriate monitoring of vector resistance to insecticides is an integral component of planning and evaluation of insecticide use in vector borne disease control programmes. Culex quinquefasciatus is the principal vector of bancroftian filariasis in Indian subcontinent. This mosquito has developed resistance to DDT and some pyrethroid insecticides because of a mechanism conferring reduced nervous system sensitivity, termed knockdown resistance (kdr). Knockdown resistance is mainly caused by a single nucleotide polymorphism (SNP) in para-type voltage-gated sodium channel (TTA/TTT), which resulted a L1014F substitution. There are different established methods for detection of kdr mutation. However, all methods have some limitations and complexity. We developed a new high-throughput assay for the detection of knockdown resistance and real-time genotyping of kdr polymorphism in individual Culex quinquefasciatus. We designed a single-labeled probe, known as SimpleProbe® consist of a sin...
Aedes mosquitoes are highly invasive and can survive almost any climatic conditions. They transmi... more Aedes mosquitoes are highly invasive and can survive almost any climatic conditions. They transmit a number of major world's deadly diseases. Therefore, a study was undertaken during December 2010 to evaluate the entomo-epidemiological risk of Aedes mosquito borne diseases (VBD) in Mumbai international seaport areas to minimize potential global health risks and prevent introduction of new VBD in India. Surveys were undertaken in operational and residential areas of Mumbai Port Trust (MPT). All the entomological indices were found to be above the critical level, prescribed for seaports by International Health Regulations Act, 2005. The operational areas where large goods are handled from cargo ships were found to be more prone to mosquito breeding comparing to residential areas. High insecticide tolerance of Aedes aegypti population against temephos and fenthion from Mumbai port area is reported for the first time. A careful and regular invigilation of the international seaports to prevent building up of vector density of dengue/chikungunya and yellow fever is recommended.
Aedes mosquitoes are highly invasive and can survive almost any climatic conditions. They transmi... more Aedes mosquitoes are highly invasive and can survive almost any climatic conditions. They transmit a number of major world's deadly diseases. Therefore, a study was undertaken during December 2010 to evaluate the entomo-epidemiological risk of Aedes mosquito borne diseases (VBD) in Mumbai international seaport areas to minimize potential global health risks and prevent introduction of new VBD in India. Surveys were undertaken in operational and residential areas of Mumbai Port Trust (MPT). All the entomological indices were found to be above the critical level, prescribed for seaports by International Health Regulations Act, 2005. The operational areas where large goods are handled from cargo ships were found to be more prone to mosquito breeding comparing to residential areas. High insecticide tolerance of Aedes aegypti population against temephos and fenthion from Mumbai port area is reported for the first time. A careful and regular invigilation of the international seaports to prevent building up of vector density of dengue/chikungunya and yellow fever is recommended.
OBJECTIVES: Dengue/Dengue Hemorrhagic Fever (DHF) is the most rapidly spreading vector-borne infe... more OBJECTIVES: Dengue/Dengue Hemorrhagic Fever (DHF) is the most rapidly spreading vector-borne infection all over the world. Uttarakhand (India) is the prime destination for national and international tourists. Here we assessed the epidemiological characteristics and entomological parameters of dengue/DHF in Uttarakhand (India) using in-depth statistical methods to measure risk of dengue epidemics.
Asian Pacific Journal of Tropical Medicine, Jan 1, 2011
To understand the insecticide resistance status of Culex quinquefasciatus Say (Diptera: Culicidae... more To understand the insecticide resistance status of Culex quinquefasciatus Say (Diptera: Culicidae) (Cx. Quinquefasciatus) to deltamethrin, cyfluthrin, permethrin, lambdacyhalothrin, DDT and malathion in filarial endemic areas of Uttar Pradesh, India.Insecticide susceptibility assays were performed on wild-caught adult female Cx. quinquefasciatus mosquitoes to deltamethrin (0.05%), cyfluthrin (0.15%), permethrin (0.75%), lambdacyhalothrin (0.05%), malathion (5.0%) and DDT (4.0%), the discriminating doses recommended by the World Health Organisation (WHO).The data showed that Cx. quinquefasciatus is highly resistant to DDT and malathion; the mortality was 28.33% and 27.5%, respectively and incipient resistance to synthetic pyrethroids (deltamethrin, cyfluthrin, permethrin, and lambdacyhalothrin), where mortality ranged from 95.83% in permethrin to 98.33% in cyfluthrin and lambdacyhalothrin. Knockdown times (KDT50) in response to synthetic pyrethroids varied significantly between different insecticides (P<0.01) from 31.480 min for permethrin to 21.650 for cyfluthrin.The results presents here provide the status report of the insecticide resistance/susceptibility of Cx. quinquefasciatus in major filaria endemic areas of northern India.
We determined the fatty acid compositions of six species of freshwater microalgae belonging to th... more We determined the fatty acid compositions of six species of freshwater microalgae belonging to the Chlorophyta, which were isolated from freshwater bodies in Assam, India. All six microalgae – Desmodesmus sp. DRLMA7, Desmodesmus elegans DRLMA13, Scenedesmus sp. DRLMA5, Scenedesmus sp. DRLMA9 Chlorella sp. DRLMA3 and Chlorococcum macrostigmatum DRLMA12-showed similar fatty acid profiles 16:0, 16:4, 18:1, 18:2, and 18:3 as major components. We also compared fatty acid compositions during the late exponential and stationary growth phases of D. elegans DRLMA13 and Scenedesmus sp. DRLMA9 in BG11 medium. We observed enhanced percentages of total saturated and monounsaturated fatty acids with a concomitant decrease in polyunsaturated fatty acid content upon the prolonged cultivation of both microalgae. Distinct morphological features of microalgal isolates were determined by scanning electron microscopic (SEM) studies. An ornamented cell wall was found in D. elegans DRLMA13, which is characteristic of small spineless species of Desmodesmus. The isolated microalgae were further distinguished through analysis of internal transcribed spacer 2 (ITS2) secondary structures and compensatory base changes (CBCs). Analysis of CBCs showed the relatedness of Chlorella sp. DRLMA3 with other Chlorella-like organisms, but it does not belong to the clade comprising Chlorella sensu stricto, which includes Chlorella vulgaris. The CBC count between Scenedesmus sp. DRLMA9 and other species of Scenedesmus provides evidence that this isolate represents a new species.► We isolated six different species of freshwater microalgae and studied their fatty acid compositions. ► We compared the changes in fatty acid composition during exponential and stationary phase in two microalgal species. ► Prolonged cultivation of microalgae increase total saturated and monounsaturated fatty acids. ► Palmitic, oleic, linoleic and linolenic acids are the major fatty acids synthesized by the six freshwater microalgae studied. ► Compensatory base changes in the secondary structures of the rDNA-ITS2 are compared to understand their phylogenetic relationships.
Abstract: The Voltage Gated Sodium Channel (VGSC) is critical for binding of different insecticid... more Abstract: The Voltage Gated Sodium Channel (VGSC) is critical for binding of different insecticides and plays a key role in insecticide resistance. The insect sodium channel consists of four homologous domains (I to IV), each containing six transmembrane segments (S1 to S6). An important mechanism of resistance to DDT and pyrethroids is termed knockdown resistance (kdr), caused by a single nucleotide polymorphism in the IIS6 domain of sodium channels. We analyzed the polymorphisms, nucleotide diversity, and phylogenies in the vgsc-IIS6 gene in Culex quinquefasciatus from India. We analyzed the neutral model/hypothesis to infer if natural selection is acting upon the vgsc s Fs test were performed to determine whether the distribution of nucleotide variation within the samples was consistent with the neutral model. We theorized that the evolutionary pattern of intra-population distribution of variability in vgsc gene is consistent with the neutral expectation.
The study investigated the development and stage specificity of physiological resistance to insec... more The study investigated the development and stage specificity of physiological resistance to insecticides in a colony of Culex quinquefasciatus Say (Diptera: Culicidae) mosquitoes, which are vectors of bancroftian filariasis in India, after selection with deltamethrin. Resistance was selected by exposing the larvae to the concentration of deltamethrin that caused 50% mortality in the tested population (i.e., LC50). Under continuous selection pressure, the LC50 increased steadily in subsequent generations. The estimated LC50 for the F0 generation was 0.409 μg/L; the LC50 first displayed a substantial increase in the F5 generation (5.616 μg/L) and reached 121.902 μg/L in the F10 generation. The objective of this study was to establish a deltamethrin-resistant colony to develop a research programme that will study the evolution of physiological resistance patterns and stage-specific resistance responses in Cx. quinquefasciatus larvae and adults under laboratory conditions. An approximately 298-fold increase in resistance was recorded after 10 generations, as evidenced by the resistance ratio (RR50). The progress and effect of the selection pressure in the adult stage was monitored with the World Health Organisation (WHO) diagnostic test. The mortality, as observed using the WHO diagnostic test, declined significantly from the F5 generation (85%) onwards and the highest rate of survival (65%) was observed in the F10 generation.
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