Publications by authors named "Sai Gek Lam-Phua"

Mosquito-borne flaviviruses are emerging pathogens of an increasing global public health concern because of their rapid increase in geographical range and the impact of climate change. Japanese encephalitis virus (JEV) and West Nile virus (WNV) are of concern because of the risk of reemergence and introduction by migratory birds. In Singapore, human WNV infection has never been reported and human JEV infection is rare.

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Accurate identification of mosquitoes is crucial for the management and control of vector species. Although Singapore is a tropical country with high mosquito diversity, there are no identification keys specific to its mosquito fauna. An illustrated identification key to the genera of the adult female mosquitoes of Singapore is presented.

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Article Synopsis
  • The study investigates the insecticide resistance of the mosquito vector Aedes aegypti, which is responsible for spreading diseases like dengue and Zika, across different regions.
  • Researchers sampled 33 mosquito populations from Asia, Europe, and South America to assess their resistance to the pyrethroid insecticide permethrin and identified specific resistance alleles.
  • The study found that most populations were susceptible to permethrin, but some in Italy and Vietnam showed high resistance, especially linked to the newly discovered V1016G allele, highlighting the need for ongoing monitoring of resistance in key mosquito populations.
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Prior to 1965, Singapore was part of the Malaya (now Malaysia) and was usually not mentioned when mosquito records were reported for Malaya. Consequently, many species that occurred in Singapore were not listed in the world mosquito catalog, and the available checklist for Singapore since 1986 is incomplete, with some imprecise species information. In updating this checklist, we examined and verified mosquito specimens collected from Singapore in various depositories, including a thorough review of past taxonomic literature.

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Background: Singapore has been certified malaria-free by the World Health Organization since November 1982. However, sporadic autochthonous malaria outbreaks do occur. In one of the most recent outbreaks of vivax malaria, an entomological investigation identified Anopheles sinensis as the most probable vector.

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Background: The mosquito Aedes aegypti (L.) is a major vector of viral diseases like dengue fever, Zika and chikungunya. Aedes aegypti exhibits high morphological and behavioral variation, some of which is thought to be of epidemiological significance.

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Background: Taxonomy that utilizes morphological characteristics has been the gold standard method to identify mosquito species. However, morphological identification is challenging when the expertise is limited and external characters are damaged because of improper specimen handling. Therefore, we explored the applicability of mitochondrial cytochrome C oxidase subunit 1 (COI) gene-based DNA barcoding as an alternative tool to identify mosquito species.

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We report the mosquito species and their distribution records for Ubin Island, Singapore, based on our field collections in February 2010, routine adult and larval surveys from 1993 to 2009 by Singapore operational officers, and accessioned specimens deposited in the Environmental Health Institute, Singapore, and the US National Museum of Natural History, Washington, DC. A total of 25 species and 6 unidentified species belonging to 9 genera (Aedes, Anopheles, Armigeres, Coquillettidia, Culex, Lutzia, Mansonia, Uranotaenia, and Verrallina) were identified and recorded from Ubin Island, based on specimens collected from 1993 to 2010.

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The Asian tiger mosquito, Aedes albopictus (Skuse), is the major vector of Chikungunya fever and the secondary vector of dengue fever. We collected Ae. albopictus from Singapore and performed genotyping assay to detect mutations of the voltage-gated sodium channel, which is the target site of pyrethroid insecticides.

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In August 2008, a team from the National Environmental Agency conducted an entomological investigation of a chikungunya cluster in Singapore, with the primary aim of identifying the vector responsible for the outbreak and to assess the vector control operation. A total of 173 adult mosquitoes were caught using both the sweep-net method and the BG Sentinel Traps in and around the affected workers' quarters. Of these, 120 (69.

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Background: Singapore has been certified malaria free since November 1982 by the World Health Organization and despite occasional local transmission, the country has maintained the standing. In 2009, three clusters of malaria cases were reported in Singapore.

Methods: Epidemiological, entomological and molecular studies were carried out to investigate the three clusters, namely Mandai-Sungei Kadut, Jurong Island and Sembawang.

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On the military training facility of Tekong Island, Singapore, a comprehensive vector-borne disease control program was started in end-2006 to reduce mosquito populations and negate the need for anti-malaria chemoprophylaxis. The program was based on 1) preventing importation of malaria through screening of visitors, 2) preventing human-to-mosquito transmission through early case detection and mosquito control, 3) preventing mosquito-to-human transmission through personal protection, and 4) contingency plans. Systematic environmental works were performed to reduce breeding sites, and insecticide use targeted both adult mosquitoes and larvae.

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Local transmission of chikungunya, a debilitating mosquito-borne viral disease, was first reported in Singapore in January 2008. After 3 months of absence, locally acquired Chikungunya cases resurfaced in May 2008, causing an outbreak that resulted in a total of 231 cases by September 2008. The circulating viruses were related to East, Central, and South African genotypes that emerged in the Indian Ocean region in 2005.

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