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Insecticide susceptibility status of field-collected Aedes (Stegomyia) aegypti (L.) at a dengue endemic site in Shah Alam, Selangor, Malaysia

Rong LS, Ann AT, Ahmad NW, Lim LH, Azirun MS

Southeast Asian J Trop Med Public Health, 2012 Jan;43(1):34-47.
PMID: 23082552

Biweekly ovitrap surveillance (OS) was conducted for a year (August 2007 - September 2008) at two different dengue endemic sites in Shah Alam, Selangor, Malaysia, 50 km from Kuala Lumpur. Aedes aegypti collected from these 2 locations were raised to the F3 stage and subjected to a WHO standard bioassay method to determine lethal time (LT) against pyrethroids (permethrin 0.75%, cyfluthrin 0.15%), organophosphates (malathion 5.0%, fenitrothion 1.0%), carbamates (propoxur 0.1%, bendiocarb 0.1%) and organochlorine (DDT 4.0%). Insecticide susceptibilities were analyzed for one year. Aedes aegypti were resistant to DDT with a mortality range of 0 - 13.3% throughout the year at both sites. Susceptibilities to pyrethroids and carbamates varied throughout the year. In contrast, susceptibilities to pyrethroids and carbamates varied throughout the year: resistant to propoxur, bendiocarb and permethrin with mortality of < 80% in most months; but, showed incipient resistant to cyfluthrin in most months. Mosquitoes were consistently susceptible to malathion and fenitrothion, with complete mortality during most months. They were especially susceptible to malathion with LT50 values of 21.32 - 36.37 minutes, suggesting effectiveness of malathion for control of dengue.

Matched MeSH terms: Aedes/drug effects*
Spray application of Bacillus thuringiensis israelensis (Bti strain AM65-52) against Aedes aegypti (L.) and Ae. albopictus Skuse populations and impact on dengue transmission in a dengue endemic residential site in Malaysia

Tan AW, Loke SR, Benjamin S, Lee HL, Chooi KH, Sofian-Azirun M

Southeast Asian J Trop Med Public Health, 2012 Mar;43(2):296-310.
PMID: 23082582

A one year study was conducted to evaluate the impact of spray application of Bacillus thuringiensis israelensis (Bti), strain AM65-52 on vector populations and dengue transmission in a dengue endemic state in Malaysia. Residential sites with similar populations of Aedes aegypti (L.) and Aedes albopictus Skuse were studied. One site was treated with spray application of Bti into all outdoor target vector habitats, which consisted of natural and artificial containers. The other site was not treated. The impact of spray application was measured with an indoor and outdoor ovitrap index (OI) and epidemiologic data. Significant reductions in both Ae. aegypti and Ae. albopictus, OI were observed both indoors and outdoors, in treated sites compared to untreated sites (p < 0.05). OI reduction was achieved over time in the treated area. The OI was suppressed to below 10%. This was maintained for 4 weeks into the post-treatment phase. The outdoor OI at the untreated site remained at more than 40% for 38 weeks during the evaluation period. One dengue case occurred at the Bti treatment site at the beginning of the treatment phase, but no further cases were detected during the remainder of the treatment phase. However, there was an ongoing dengue outbreak in the untreated area with 15 serologically confirmed cases during weeks 37-54. Intensive fogging operations with pyrethroids at the untreated (Bti) site had a positive impact on Ae. albopictus, but not on Ae. aegypti.

Matched MeSH terms: Aedes*
Effect of ten chlorophytes on larval survival, development and adult body size of the mosquito Aedes aegypti

Ahmad R, Chu WL, Ismail Z, Lee HL, Phang SM

Southeast Asian J Trop Med Public Health, 2004 Mar;35(1):79-87.
PMID: 15272748

The effect of ten microalgal chlorophytes isolated from mosquito breeding containers on the survival, larval development and adult body size of the mosquito Aedes aegypti was investigated. All larvae fed with six of the microalgal isolates died after 7 days. These isolates were found to be resistant to digestion by mosquito larvae. Delayed pupation and body size reduction of the mosquitos fed with Chlorococcum UMACC 218 and Scenedesmus UMACC 220 were observed. In contrast, larvae fed with Ankistrodesmus convolutus UMACC 101 and Chlorococcum UMACC 213 were bigger in size than those fed with normal insectory feed. The present study showed that microalgal chlorophytes have the potential to be used as larvicidal agents for mosquitos.

Matched MeSH terms: Aedes/physiology*
Fulltext Effect of sublethal dosages of malathion on the oral susceptibility of Aedes aegypti to dengue-2 virus infection

Lee HL, Argubano RA, Ahmad R

Southeast Asian J Trop Med Public Health, 1997 Sep;28(3):664-5.
PMID: 9561626
Matched MeSH terms: Aedes/virology*
Fulltext Does transovarial transmission of dengue virus occur in Malaysian Aedes aegypti and Aedes albopictus?

Lee HL, Mustafakamal I, Rohani A

Southeast Asian J Trop Med Public Health, 1997 Mar;28(1):230-2.
PMID: 9322311
Matched MeSH terms: Aedes/virology*
Fulltext Detection of dengue virus from field Aedes aegypti and Aedes albopictus adults and larvae

Ahmad R, Ismail A, Saat Z, Lim LH

Southeast Asian J Trop Med Public Health, 1997 Mar;28(1):138-42.
PMID: 9322296

Mosquito adults and larvae were collected from dengue high risk areas and transported to the laboratory for identification. Identified mosquitos were pooled according to the species, date and locality and stored at -70 degrees C. A total of 1,385 pools of Aedes albopictus and 267 pools of Ae. Aegypti were collected from major towns in 12 states in Peninsular Malaysia. Virus isolation was carried out using cell culture (C6/36 clone) of Ae. albopictus and detection of dengue virus by the peroxidase anti-peroxidase staining. All positive isolations were further re-confirmed by the reverse transcriptase-polymerase chain reaction (RT-PCR). Most of the pools were negative with PAP staining and RT-PCR. However, 11 mosquito pools were positive with PAP staining. On the other hand, samples from Terengganu, Pulau Pinang and Johor were positive using both methods.

Matched MeSH terms: Aedes/virology*
Mosquito fauna of the Bengkoka Peninsula, Sabah, Malaysia

Cheong WH, Loong KP, Mahadevan S, Mak JW, Kan SK

Southeast Asian J Trop Med Public Health, 1984 Mar;15(1):19-26.
PMID: 6146203

A total of 37 species of mosquitoes from seven genera were collected in six villages in the Bengkoka Peninsula, Sabah State, during two visits in 1981 in connection with studies on malaria and filariasis. Fifty-five per cent of the total mosquitoes collected were Mansonia. An. collessi constituted a new record of the species from Sabah. An. balabacensis was found to be naturally infected with sporozoites. Ma. bonneae was found to be naturally infected with Brugia, probably B. malayi. Parous rates of An. balabacensis and Ma. bonneae were very high with consequent high probability of survival ideally suiting transmission of malaria and filariasis.

Matched MeSH terms: Aedes/microbiology
Fulltext Refractoriness of Aedes aegypti (Linnaeus) to dual infection with dengue and chikungunya virus

Rohani A, Potiwat R, Zamree I, Lee HL

Southeast Asian J Trop Med Public Health, 2009 May;40(3):443-8.
PMID: 19842428

In this study, artificial membrane feeding technique was used to orally feed Aedes aegypti with dengue and chikungunya viruses. Virus detection was carried out by reverse transcriptase polymerase chain reaction. The study did not detect dual infection of Ae. aegypti with dengue and chikungunya virus from the same pool or from individual mosquitoes. Oral receptivity of Ae. aegypti to chikungunya virus was higher than that of dengue virus.

Matched MeSH terms: Aedes/virology*
The risk of dengue hemorrhagic fever (DHF) outbreak based on vector density in Kurau, Riau province, Indonesia

Mangara SG, Sukmono, Kusumadiharja J, Suroso T, Sutjipto H

Southeast Asian J Trop Med Public Health, 2000;31 Suppl 1:134-9.
PMID: 11414442

It is known that in Padang, Rantau, Rangsang, Merbau and Bengkalis islands, Riau Province, the deposit of oil was found in a huge quantity. The drilling concession belongs to Kondur Petroleum Company. To operate an exploitation, hundreds of workers not only Indonesian but also the workers from foreign countries come and go to that area. It was recorded that the workers from foreign countries come from Singapore, Malaysia, Thailand, The Philippines, Taiwan, Japan, Korea. United States of America and from France, Britain, Australia and Germany. These workers have a close interaction with about 50,00 local population distributed with a high concentration in some places. The high risk of DHF was determined since the significant density of Aedes aregypti larvae, the main vector of DHF, were found in Lukit, Mengkikip and Melibur, three locations of survey. Of 104 (53.3%) of 195 houses in these three survey locations were found positive for the larvae. Even though there were no positive of larvae in 65 houses in Lukit, in Melibur and Mengkikip, the House Index (HI) was 61.7% and 95.7%. Outside the houses 521 containers were examined in three locations of survey and 329 (63.1%) were positive for Ae. aegypti larvae. The highest number of containers positive for Ae. aegypti larvae were 213 (94.7%) out of 225 and found in Mengkikip. In Melibur, 114 (68.3%) out of 167 of containers were positive and in Lukit only 2 (1.56%) out of 129 containers were positive of Ae. aegypti larvae. These larvae density constitute a high risk of DHF outbreak, and unfortunately is supported by the rainfall situation recorded in Kurau and BZ Climatology Stations. It was recorded that all along the year, at least one day in a month there was the rain which the rainfall volume was 30 ml.

Matched MeSH terms: Aedes/growth & development*
Studies on the effect of translocation of chemical insecticides in Eicchornia host plant on Mansonia mosquitos--a potential control method

Lee HL, Singh KI

Southeast Asian J Trop Med Public Health, 1993;24 Suppl 2:105-9.
PMID: 7526473

A novel method for the control of Mansonia larvae was developed and tested. In this method, foliar absorption and translocation of a chemical insecticide, monocrotophos, a known systemic insecticide was studied in the Eicchornia plant. Acetone solution of the insecticide was painted onto leaves of the plant. At daily intervals, stems were severed and divided into equal sections which were introduced into bowls. Larvae of Aedes aegypti were tested for the presence of monocrotophos. It was found that translocation of the insecticide occurred at different rates in the stems and in some plants the chemical was also released into the surrounding water. Based on these results, 2 insecticides namely, monocrotophos and temephos were painted onto leaves of the host plant and their translocation to the root and water environment was examined by testing with Mansonia and Aedes aegypti larvae. The results again confirmed the translocation process and it was found that the insecticides were secreted into the surrounding water, thereby killing the larvae. However, in leaves painted with permethrin (synthetic pyrethroid) or flufenoxuron (chitin synthesis inhibitor), such a process was not detected. The potential of this new concept in Mansonia larval control is examined.

Matched MeSH terms: Aedes/metabolism
Relative potency of lambdacyhalothrin and cypermethrin applied as thermal fogs for the control of houseflies (Musca domestica) and mosquitos (Aedes aegypti)

Lim JL, Visvalingam M

Southeast Asian J Trop Med Public Health, 1990 Mar;21(1):77-84.
PMID: 2402678

Two highly active synthetic pyrethroid insecticides, lambdacyhalothrin and cypermethrin, were evaluated as thermal fogs against houseflies (Musca domestica Linnaeus) and mosquitos (Aedes aegypti Linnaeus). Lambdacyhalothrin (OMS 3021) showed an average of 2.5 times more knockdown activity and over 5 times more adulticidal activity than cypermethrin against Musca domestica and Aedes aegypti. These results demonstrate that lambdacyhalothrin is highly effective at very low rates as a thermal fog against Ae. aegypti and M. domestica. Commercially available formulations of 2.5% and 5% lambdacyhalothrin can be diluted either with water for ULV cold aerosol space-spraying or with diesel/kerosene for thermal fogging at recommended application rates of 0.5-1 g ai/ha for mosquito control and 2 g ai/ha for housefly control. Due to the very low rates of application, formulated products of lambdacyhalothrin are unlikely to present any acute hazards in normal use. The low dosages required to bring about rapid control of houseflies and mosquitos make this new pyrethroid insecticide particularly cost-effective. Coupled with its good residual activity (Jutsum et al, 1984), lambdacyhalothrin can be adopted as a powerful tool in integrated pest management program for the control of medically important pests and vectors.

Matched MeSH terms: Aedes*
Distribution and ecological consideration of Breinlia booliati infecting wild rodents in Malaysia

Liat LB, Wah MJ, Singh M, Ho BC, Hian YE

Southeast Asian J Trop Med Public Health, 1975 Jun;6(2):241-6.
PMID: 1166352

Seven of the 18 species of lowland forest terrestrial and semi-arboreal murids were found naturally infected with Breinlia booliati. Of these, two species, Rattus sabanus and R. cremoriventer, were found to be the most preferred hosts. None of the murids from the highland, field or human-inhabited areas was infected. This could have been due more to the greater scarcity of the vectors in these habitats than to the susceptibility of the hosts. The absence of this parasite in the squirrels examined may be attributed either to host specificity or to the normal activity cycles or vertical stratification of the vectors, separating them in space and/or time from the squirrels. The pattern of dispersion of the parasite is influenced by the wide distribution of suitable hosts, and the hypothesis that the parasite is of forest origin is discussed.

Matched MeSH terms: Aedes/parasitology
Knowledge, attitudes, and practices related to control of Dengue haemorrhagic fever in an urban Malay kampung

Dobbins JG, Else JG

Southeast Asian J Trop Med Public Health, 1975 Mar;6(1):120-6.
PMID: 1170643
Matched MeSH terms: Aedes/growth & development*
Fulltext Chikungunya virus in macaques, Malaysia

Sam IC, Chua CL, Rovie-Ryan JJ, Fu JY, Tong C, Sitam FT, et al.

Emerg Infect Dis, 2015 Sep;21(9):1683-5.
PMID: 26291585 DOI: 10.3201/eid2109.150439
Matched MeSH terms: Aedes/virology
Fulltext Insecticide resistance in dengue vectors from hotspots in Selangor, Malaysia

Rasli R, Cheong YL, Che Ibrahim MK, Farahininajua Fikri SF, Norzali RN, Nazarudin NA, et al.

PLoS Negl Trop Dis, 2021 Mar;15(3):e0009205.
PMID: 33755661 DOI: 10.1371/journal.pntd.0009205

BACKGROUND: In Malaysia, dengue remains a top priority disease and usage of insecticides is the main method for dengue vector control. Limited baseline insecticide resistance data in dengue hotspots has prompted us to conduct this study. The present study reports the use of a map on the insecticide susceptibility status of Aedes aegypti and Aedes albopictus to provide a quick visualization and overview of the distribution of insecticide resistance.
METHOD AND RESULTS: The insecticide resistance status of Aedes populations collected from 24 dengue hotspot areas from the period of December 2018 until June 2019 was proactively monitored using the World Health Organization standard protocol for adult and larval susceptibility testing was conducted, together with elucidation of the mechanisms involved in observed resistance. For resistance monitoring, susceptibility to three adulticides (permethrin, deltamethrin, and malathion) was tested, as well as susceptibility to the larvicide, temephos. Data showed significant resistance to both deltamethrin and permethrin (pyrethroid insecticides), and to malathion (organophosphate insecticide) in all sampled Aedes aegypti populations, while variable resistance patterns were found in the sampled Aedes albopictus populations. Temephos resistance was observed when larvae were tested using the diagnostic dosage of 0.012mg/L but not at the operational dosage of 1mg/L for both species.
CONCLUSION: The present study highlights evidence of a potential threat to the effectiveness of insecticides currently used in dengue vector control, and the urgent requirement for insecticide resistance management to be integrated into the National Dengue Control Program.

Matched MeSH terms: Aedes/drug effects*
Field Worker Evaluation of Dengue Vector Surveillance Methods: Factors That Determine Perceived Ease, Difficulty, Value, and Time Effectiveness in Australia and Malaysia

Azil AH, Ritchie SA, Williams CR

Asia Pac J Public Health, 2015 Oct;27(7):705-14.
PMID: 25186807 DOI: 10.1177/1010539514548760

This qualitative study aimed to describe field worker perceptions, evaluations of worth, and time costs of routine dengue vector surveillance methods in Cairns (Australia), Kuala Lumpur and Petaling District (Malaysia). In Cairns, the BG-Sentinel trap is a favored method for field workers because of its user-friendliness, but is not as cost-efficient as the sticky ovitrap. In Kuala Lumpur, the Mosquito Larvae Trapping Device is perceived as a solution for the inaccessibility of premises to larval surveys. Nonetheless, the larval survey method is retained in Malaysia for prompt detection of dengue vectors. For dengue vector surveillance to be successful, there needs to be not only technical, quantitative evaluations of method performance but also an appreciation of how amenable field workers are to using particular methods. Here, we report novel field worker perceptions of dengue vector surveillance methods in addition to time analysis for each method.

Matched MeSH terms: Aedes*
Fulltext Entomological Surveillance Associated with Human Zika Cases in Miri Sarawak, Malaysia

Ali R, Azmi RA, Wasi Ahmad N, Abd Hadi A, Muhamed KA, Rasli R, et al.

Am J Trop Med Hyg, 2020 May;102(5):964-970.
PMID: 32228777 DOI: 10.4269/ajtmh.19-0339

Two confirmed human cases of Zika virus (ZIKV) were reported in the district of Miri, Sarawak, in 2016. Following that, a mosquito-based ZIKV surveillance study was conducted within 200-m radius from the case houses. Mosquito surveillance was conducted using five different methods, that is, biogents sentinel mosquito (BG) sentinel trap, modified sticky ovitrap, resting catch, larval surveillance, and conventional ovitrap. A total of 527 and 390 mosquito samples were obtained from the case houses in two localities, namely, Kampung Lopeng and Taman Shang Ri La, Miri, Sarawak, respectively. All mosquitoes collected were identified, which consisted of 11 species. Aedes albopictus, both the adult and larval stages, was the dominant species. Resting catch method obtained the highest number of adult mosquitoes (67%), whereas ovitrap showed the highest catch for larval mosquitoes (84%). Zika virus was detected in both adults and larvae of Ae. albopictus together with adults of Culex gelidus, and Culex quinquefasciatus using the real-time reverse transcriptase polymerase chain reaction (PCR) technique. It was noteworthy that Ae. albopictus positive with ZIKV were caught and obtained from four types of collection method. By contrast, Cx. gelidus and Culex quinquefasciatus adults collected from sticky ovitraps were also found positive with ZIKV. This study reveals vital information regarding the potential vectors of ZIKV and the possibility of transovarian transmission of the virus in Malaysia. These findings will be essentials for vector control program managers to devise preparedness and contingency plans of prevention and control of the arboviral disease.

Matched MeSH terms: Aedes/virology
Detection of Persistent Chikungunya Virus RNA but not Infectious Virus in Experimental Vertical Transmission in Aedes aegypti from Malaysia

Wong HV, Vythilingam I, Sulaiman WY, Lulla A, Merits A, Chan YF, et al.

Am J Trop Med Hyg, 2016 Jan;94(1):182-6.
PMID: 26598564 DOI: 10.4269/ajtmh.15-0318

Vertical transmission may contribute to the maintenance of arthropod-borne viruses, but its existence in chikungunya virus (CHIKV) is unclear. Experimental vertical transmission of infectious clones of CHIKV in Aedes aegypti mosquitoes from Malaysia was investigated. Eggs and adult progeny from the second gonotrophic cycles of infected parental mosquitoes were tested. Using polymerase chain reaction (PCR), 56.3% of pooled eggs and 10% of adult progeny had detectable CHIKV RNA, but no samples had detectable infectious virus by plaque assay. Transfected CHIKV RNA from PCR-positive eggs did not yield infectious virus in BHK-21 cells. Thus, vertical transmission of viable CHIKV was not demonstrated. Noninfectious CHIKV RNA persists in eggs and progeny of infected Ae. aegypti, but the mechanism and significance are unknown. There is insufficient evidence to conclude that vertical transmission exists in CHIKV, as positive results reported in previous studies were almost exclusively based only on viral RNA detection.

Matched MeSH terms: Aedes/virology*
Isolation of Zika virus from Aedes aegypti mosquitoes in Malaysia

Marchette NJ, Garcia R, Rudnick A

Am J Trop Med Hyg, 1969 May;18(3):411-5.
PMID: 4976739
Matched MeSH terms: Aedes/virology*
Fulltext Cost of Dengue Vector Control Activities in Malaysia

Packierisamy PR, Ng CW, Dahlui M, Inbaraj J, Balan VK, Halasa YA, et al.

Am J Trop Med Hyg, 2015 Nov;93(5):1020-1027.
PMID: 26416116 DOI: 10.4269/ajtmh.14-0667

Dengue fever, an arbovirus disease transmitted by Aedes mosquitoes, has recently spread rapidly, especially in the tropical countries of the Americas and Asia-Pacific regions. It is endemic in Malaysia, with an annual average of 37,937 reported dengue cases from 2007 to 2012. This study measured the overall economic impact of dengue in Malaysia, and estimated the costs of dengue prevention. In 2010, Malaysia spent US$73.5 million or 0.03% of the country's GDP on its National Dengue Vector Control Program. This spending represented US$1,591 per reported dengue case and US$2.68 per capita population. Most (92.2%) of this spending occurred in districts, primarily for fogging. A previous paper estimated the annual cost of dengue illness in the country at US$102.2 million. Thus, the inclusion of preventive activities increases the substantial estimated cost of dengue to US$175.7 million, or 72% above illness costs alone. If innovative technologies for dengue vector control prove efficacious, and a dengue vaccine was introduced, substantial existing spending could be rechanneled to fund them.

Matched MeSH terms: Aedes/virology*

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