Salinity tolerant Aedes aegypti and Ae. albopictus—Infection with dengue virus and contribution to dengue transmission in a coastal peninsula

Surendran, Sinnathamby N.; Veluppillai, T; Eswaramohan, T.; Sivabalakrishnan, Kokila; Noordeen, F.; Ramasamy, Ranjan

doi:10.4103/0972-9062.234623

Cited by 15 publications

(25 citation statements)

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“…The first and the largest DENV transmission period occurs from June to August and corresponds with the Southwest Monsoon. The second and the smaller period occurs from October to December and coincides with the Northeast Monsoon rainfall [8].…”

Section: Introductionmentioning

confidence: 89%

“…Although the numbers decreased in the year 2018 with only 51,659 recorded DF cases, in the year 2019, 105,049 DF cases were reported to the health ministry of Sri Lanka [7]. Dengue transmission in Sri Lanka has been strongly correlated with rainfall [8]. Two distinct periods of DENV transmission occur annually, and these periods occur in association with the monsoon rains.…”

Section: Introductionmentioning

confidence: 99%

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Resistance to commonly used insecticides and underlying mechanisms of resistance in Aedes aegypti (L.) from Sri Lanka

et al. 2020

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Background: Drastic increases of dengue fever (DF) over the past few years have prompted studies on the development of resistance to insecticides in the mosquito vector, Aedes aegypti (Linnaeus). In Sri Lanka control of the vector population is essentially achieved using larvicides (temephos) and adulticides (principally pyrethroids). The present study investigates resistance to commonly used insecticides and underlying mechanisms of Ae. aegypti in selected sites in Sri Lanka. Methods: In this study, susceptibility to three commonly used adulticides (malathion, permethrin and deltamethrin) and the larvicide temephos were tested for Ae. aegypti sampled from five localities in Sri Lanka using WHO dose diagnostics tests. In addition, we performed dose-response tests for permethrin to determine lethal concentrations (LCs) with CDC bottle bioassays. An assessment of the activity of metabolic detoxifying enzymes (multifunction oxidases (MFOs), glutathione S-transferases (GSTs) and esterases) and determination of frequency of the kdr mutations (F1534C, V1016G and S989P) were also carried out to ascertain the associated resistance mechanisms. Kdr genotype frequencies were compared with samples collected from the same sites in 2015 to determine the change of allele frequencies over the years. Results: The present study revealed resistance in all Ae. aegypti populations studied, with low mortality percentages for both permethrin (10-89%) and deltamethrin (40-92%). Dose response tests revealed highest resistance ratios (RR) for permethrin and temephos from Colombo district whereas Puttalum district exhibited the lowest. High frequencies of the 1534C allele (0.052-0.802) were found in the study sites in 2017. Comparison with samples collected in 2015 revealed a substantial increase in this allele. The activity of MFOs and p-nitro phenyl-acetate esterase was significantly greater in most Sri Lankan populations in comparison to that of the New Orleans (NO) susceptible strain. In contrast, the activity of α-esterase and β-esterase was similar or lower than that in the NO strain.

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Section: Introductionmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Resistance to commonly used insecticides and underlying mechanisms of resistance in Aedes aegypti (L.) from Sri Lanka

et al. 2020

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“…, Surendran et al. ). Mosquito larvae are considered to be mostly restricted to freshwater environments, but all three major genera of medical importance ( Aedes, Anopheles , and Culex ) include both freshwater and saltwater species (Coluzzi and Sabatini , Bradley , Jude et al.…”

Section: Introductionmentioning

confidence: 99%

“…Salinity tolerance is an important trait that governs the ecology of disease-vector mosquitoes by determining the choice of larval habitat, and consequently their ecological and geographical distribution, and ultimately, the disease transmission epidemiology , Yee et al 2014, Surendran et al 2018. Mosquito larvae are considered to be mostly restricted to freshwater environments, but all three major genera of medical importance (Aedes, Anopheles, and Culex) include both freshwater and saltwater species (Coluzzi and Sabatini 1969, Bradley 1987, Jude et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Tolerance of disease‐vector mosquitoes to brackish water and their osmoregulatory ability

et al. 2019

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Salinity tolerance is an important trait that governs the ecology of disease‐vector mosquitoes by determining their choice of larval habitat, and consequently their ecological and geographical distribution. Here, we used laboratory strains to determine the osmotic responses of larvae of obligate freshwater disease‐vector mosquitoes (Aedes aegypti, Aedes albopictus, Anopheles coluzzii, An. gambiae, Culex pipiens, and Cx. quinquefasciatus) and assessed their relationship with salinity tolerance. First, we analyzed the acute dose–mortality response of fourth‐instar larvae to salinity; then, we measured their hemolymph osmolality after 24‐h exposure to varying salinities. We found that Ae. albopictus was the most tolerant species, followed by An. coluzzii, Ae. aegypti, Cx. quinquefasciatus, and An. gambiae, in decreasing order. Cx. pipiens was the least tolerant species. All mosquitoes were hyper‐iso‐osmoregulators, but with species‐specific differences. Specifically, hemolymph osmolality in deionized water varied among species, and Cx. pipiens and the two Aedes species showed the lowest and highest osmolality. Although all species were osmoconformers at higher salinity values, hemolymph osmolality approached environmental osmolality more rapidly in species of the Culex genus, compared with Aedes species where it increased slowly. Moreover, hemolymph osmolality in deionized water was significantly correlated with tolerance to salinity across species. This could allow predicting the salinity tolerance of untested species on the basis of their osmoregulatory ability. However, this correlation disappeared when considering the hemolymph osmolality of larvae exposed to salinities higher than deionized water.

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“…aegypti and Ae. albopictus because dengue and chikungunya are endemic in Jaffna [44] but can become essential also for anopheline vector control should malaria transmission recur in Jaffna.…”

Section: Discussionmentioning

confidence: 99%

Anopheline bionomics, insecticide resistance and transnational dispersion in the context of controlling a possible recurrence of malaria transmission in Jaffna city in northern Sri Lanka

et al. 2020

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Background: Malaria was eliminated from Sri Lanka in 2013. However, the influx of infected travelers and the presence of potent anopheline vectors can re-initiate transmission in Jaffna city, which is separated by a narrow strait from the malaria-endemic Indian state of Tamil Nadu. Methods: Anopheline larvae were collected from different habitats in Jaffna city and the susceptibility of emergent adults to DDT, malathion and deltamethrin investigated. Results: Anopheline larvae were found in wells, surface-exposed drains, ponds, water puddles and water storage tanks, with many containing polluted, alkaline and brackish water. Anopheles culicifacies, An. subpictus, An. stephensi and An. varuna were identified in the collections. Adults of the four anopheline species were resistant to DDT. Anopheles subpictus and An. stephensi were resistant while An. culicifacies and An. varuna were possibly resistant to deltamethrin. Anopheles stephensi was resistant, An. subpictus possibly resistant while An. varuna and An. culicifacies were susceptible to malathion. DNA sequencing showed a L1014F (TTA to TTC) mutation in the IIS6 transmembrane segment of the voltage-gated sodium channel protein in deltamethrin-resistant An. subpictus-a mutation previously observed in India but not Sri Lanka. Conclusion: Anopheles subpictus in Jaffna, like An. stephensi, may have recently originated in coastal Tamil Nadu. Besides infected overseas travelers, wind-and boat-borne carriage of Plasmodium-infected anophelines across the Palk Strait can potentially reintroduce malaria transmission to Jaffna city. Adaptation to diverse larval habitats and resistance to common insecticides in anophelines are identified as potential problems for vector control should this happen.

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Salinity tolerant Aedes aegypti and Ae. albopictus—Infection with dengue virus and contribution to dengue transmission in a coastal peninsula

Cited by 15 publications

References 1 publication

Resistance to commonly used insecticides and underlying mechanisms of resistance in Aedes aegypti (L.) from Sri Lanka

Resistance to commonly used insecticides and underlying mechanisms of resistance in Aedes aegypti (L.) from Sri Lanka

Tolerance of disease‐vector mosquitoes to brackish water and their osmoregulatory ability

Anopheline bionomics, insecticide resistance and transnational dispersion in the context of controlling a possible recurrence of malaria transmission in Jaffna city in northern Sri Lanka

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