Lectin Microarray Analysis of Salivary Gland Glycoproteins from the Arboviral Vector Aedes aegypti and the Malaria Vector Anopheles stephensi.

Background And Objectives: Salivary glands proteins but not glycoconjugates have been previously studied in mosquito vectors of human diseases. Glycoconjugates from salivary gland-derived proteins from human-feeding tick vectors can elicit hypersensitivity reactions which may also occur with mosquito bites. Protein glycoconjugate in salivary glands of the principal arboviral vector Aedes aegypti and the rapidly spreading malaria vector Anopheles stephensi were therefore investigated.

Resistance to the larvicide temephos and altered egg and larval surfaces characterize salinity-tolerant Aedes aegypti.

Aedes aegypti, the principal global vector of arboviral diseases and previously considered to oviposit and undergo preimaginal development only in fresh water, has recently been shown to be capable of developing in coastal brackish water containing up to 15 g/L salt. We investigated surface changes in eggs and larval cuticles by atomic force and scanning electron microscopy, and larval susceptibility to two widely-used larvicides, temephos and Bacillus thuringiensis, in brackish water-adapted Ae. aegypti.

Dengue Incidence and Vector Collections in Relation to COVID-19 Population Mobility Restrictions.

Contrary to expectation, dengue incidence decreased in many countries during the period when stringent population movement restrictions were imposed to combat COVID-19. Using a seasonal autoregressive integrated moving average model, we previously reported a 74% reduction in the predicted number of dengue cases from March 2020 to April 2021 in the whole of Sri Lanka, with reductions occurring in all 25 districts in the country. The reduction in dengue incidence was accompanied by an 87% reduction in larval collections of vectors in the northern city of Jaffna.

Morphological and odorant-binding protein 1 gene intron 1 sequence variations in Anopheles stephensi from Jaffna city in northern Sri Lanka.

Three Anopheles stephensi biotypes have historically been differentiated through variations in the mode numbers of egg ridges and adult spiracular indices. Anopheles stephensi odorant-binding protein 1 gene (AsteObp1) sequences in Iran and Afghanistan have been recently interpreted to suggest that the three biotypes are sibling species. AsteObp1 intron 1 sequences, mode numbers of egg ridges and spiracular indices of An.

Transcriptomic, proteomic and ultrastructural studies on salinity-tolerant Aedes aegypti in the context of rising sea levels and arboviral disease epidemiology.

Background: Aedes aegypti mosquito, the principal global vector of arboviral diseases, lays eggs and undergoes larval and pupal development to become adult mosquitoes in fresh water (FW). It has recently been observed to develop in coastal brackish water (BW) habitats of up to 50% sea water, and such salinity tolerance shown to be an inheritable trait. Genomics of salinity tolerance in Ae.

Aedes larval bionomics and implications for dengue control in the paradigmatic Jaffna peninsula, northern Sri Lanka.

Background: The larval bionomics of Aedes across the Jaffna peninsula in northern Sri Lanka was investigated to obtain information needed for developing more effective larval source reduction measures to control endemic arboviral diseases.

Methods: The habitats of preimaginal stages of Aedes mosquitoes were surveyed, and ovitrap collections were carried out in densely populated areas of the Jaffna peninsula. Aedes larval productivities were analysed against habitat characteristics, rainfall and dengue incidence.

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.

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.

Development of the major arboviral vector Aedes aegypti in urban drain-water and associated pyrethroid insecticide resistance is a potential global health challenge.

Background: Aedes aegypti were found developing in the water in open public drains (drain-water, DW) in Jaffna city in northern Sri Lanka, a location where the arboviral diseases dengue and chikungunya are endemic.

Methods: Susceptibilities to the common insecticides dichlorodiphenyltrichloroethane (DDT), malathion, propoxur, permethrin and deltamethrin and activities of the insecticide-detoxifying enzymes carboxylesterase (EST), glutathione S-transferase (GST) and monooxygenase (MO) were compared in adult Ae. aegypti developing in DW and fresh water (FW).

Anthropogenic Factors Driving Recent Range Expansion of the Malaria Vector .

The malaria vector is found in wide tracts of Asia and the Middle East. The discovery of its presence for the first time in the island of Sri Lanka in 2017, poses a threat of malaria resurgence in a country which had eliminated the disease in 2013. Morphological and genetic characterization showed that the efficient Indian urban vector form or form, has recently expanded its range to Jaffna and Mannar in northern Sri Lanka that are in proximity to Tamil Nadu state in South India.

Susceptibility to common insecticides and detoxifying enzyme activities in Anopheles sundaicus (sensu lato) after cessation of indoor residual spraying of insecticides in the Jaffna Peninsula and its surroundings in northern Sri Lanka.

Background: Sri Lanka has been malaria-free since 2013 but re-introduction of malaria transmission by infected overseas travelers is possible due to a prevalence of potent malaria vectors. Knowledge of the insecticide resistance status among Anopheles vectors is important if vector control has to be reintroduced in the island. The present study investigated the insecticide susceptibility levels and resistance mechanisms of Anopheles sundaicus (sensu lato) (previously classified as Anopheles subpictus species B) an important malaria vector in the Jaffna Peninsula and it surroundings in northern Sri Lanka after indoor residual spraying of insecticides was terminated in 2013.

Genotype and biotype of invasive Anopheles stephensi in Mannar Island of Sri Lanka.

Background: Anopheles stephensi, the major vector of urban malaria in India, was recently detected for the first time in Sri Lanka in Mannar Island on the northwestern coast. Since there are different biotypes of An. stephensi with different vector capacities in India, a study was undertaken to further characterise the genotype and biotype of An.