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Field efficacy of fipronil 3G, lambda-cyhalothrin 10%CS, and sumithion 50EC against the dengue vector Aedes albopictus in discarded tires

Sulaiman S, Pawanchee ZA, Wahab A, Jamal J, Sohadi AR

J Vector Ecol, 1999 Dec;24(2):154-7.
PMID: 10672544

The efficacy of three insecticides, fipronil 3G, lambda-cyhalothrin 10%CS, and sumithion 50EC were evaluated against the dengue vector Aedes albopictus in discarded tires in Kuala Lumpur, Malaysia. The dosage given for each insecticide was 0.01 g of active ingredient/m2. Fipronil 3G was the most effective larvicide with a residual activity of up to two weeks, causing 88% mortality in Aedes albopictus. Lambda-cyhalothrin 10%CS was effective for one week causing 92% larval mortality and two weeks with 63% larval mortality. Sumithion 50EC had a residual efficacy of one week with 79% larval mortality.

Matched MeSH terms: Larva/physiology
Occurrence of sweet refuse at disposal sites: rainwater retention capacity and potential breeding opportunities for Aedes aegypti

Dieng H, Satho T, Meli NKKB, Abang F, Nolasco-Hipolito C, Hakim H, et al.

Environ Sci Pollut Res Int, 2018 May;25(14):13833-13843.
PMID: 29512008 DOI: 10.1007/s11356-017-1078-8

Nectar is the staple diet of adult mosquitoes in the wild, but its availability is inconsistent and can be affected by rainfall. In urban centers, Aedes vectors commonly use man-made containers as their major habitat; however, they can colonize any items replenished by rainfall. Garbage output has increased significantly in recent years, at a time when collection frequency is reducing. Such garbage usually includes organic components, some of which are sweet and can be fed upon by other animals or become can containers for rainwater. Despite evidence that Aedes larvae can thrive in containers comprised of organic waste material, which can be produced by rodents gnawing on fruits or vegetables, and that adults can survive on sweet waste fluids, the capacity of organic waste materials to accumulate rainwater and act as egg deposition sites has not been examined. It is also unknown for how long sweet extracts can sustain the life of adult vectors. Here, we investigated the abundance of sweet leftovers at garbage sites and the rainwater retention capacity of some organic materials through a field survey and laboratory bioassays. We also examined whether sweet waste fluids impact egg hatching success and longevity of Aedes aegypti. The results of this study indicated that sweet products with leftovers are highly prevalent in garbage. When exposed to rain, food items (BAFrc, banana fruit resembling container; and BSPrc, boiled sweet potato resembling container) and the packaging of sweet foods (SMIc, sweetened condensed milk can) retained water. When provided an opportunity to oviposit in cups containing BAF extract (BAFex), BSP extract (BSPex), and SMI extract (SMIex), eggs were deposited in all media. Egg maturation in the BAFex environment resulted in similar larval eclosion success to that resulting from embryo development in a water milieu. Adults maintained on sweet waste extracts had long lifespans, although shorter than that of their sugar solution (SUS)-fed counterparts. Taken together, these results indicated that sweet waste materials are useful to dengue mosquitoes, acting both as oviposition sites and energy sources.

Matched MeSH terms: Larva/physiology
Fulltext Distribution pattern of black fly (Diptera: Simuliidae) assemblages along an altitudinal gradient in Peninsular Malaysia

Ya'cob Z, Takaoka H, Pramual P, Low VL, Sofian-Azirun M

Parasit Vectors, 2016 Apr 19;9:219.
PMID: 27094088 DOI: 10.1186/s13071-016-1492-7

BACKGROUND: Preimaginal black flies (Diptera: Simuliidae) are important components of the stream ecosystem. However, there has been limited research undertaken on the vertical distribution of preimaginal black flies and their associated ecological factors. Stream conditions are generally variable along the altitudinal gradient. Therefore, we conducted an in-depth entomological survey to investigate the simuliid distribution pattern along an altitudinal gradient in Peninsular Malaysia.
METHODS: A total of 432 collections were performed in this study (24 samplings at each of 18 fixed-streams at monthly intervals) from February 2012 to January 2014. Larvae and pupae attached on aquatic substrates such as grasses, leaves and stems, twigs, plant roots and rocks were collected by hand using fine forceps. Stream depth (m), width (m), velocity (m/s), water temperature (°C), acidity (pH), conductivity (mS/cm) and dissolved oxygen (mg/L) were measured at the time of each collection.
RESULTS: A total of 35 black fly species were recorded in the present study. The most frequently collected species were Simulium tani (31.7%) and S. whartoni (21.5%), while the relatively common species were Simulium sp. (nr. feuerborni) (16.2%), S. decuplum (15.5%), S. angulistylum (14.8%), S. bishopi (13.2%) and S. izuae (11.8%). Total estimated species richness ranged between 39.8 and 41.3, which yielded more than 80% of sampling efficiency. Six simuliid species were distributed below 500 m, whereas eight species were distributed above 1400 m. Simulium sp. (nr. feuerborni) and S. asakoae were found from middle to high altitudes (711-1813 m). Simulium whartoni, S. brevipar and S. bishopi were distributed widely from low to high altitudes (159-1813 m). Regression analysis between species richness and PCs revealed that the species richness was significantly associated with wider, deeper and faster streams at low altitude, normal water temperature (23-25 °C), low conductivity, higher discharge, more canopy cover and riparian vegetation and with larger streambed particles (F = 20.8, df = 1, 422, P

Matched MeSH terms: Larva/physiology
Fulltext Malaria and Anopheles mosquitos in Malaysia

Rahman WA, Che'Rus A, Ahmad AH

Southeast Asian J. Trop. Med. Public Health, 1997 Sep;28(3):599-605.
PMID: 9561615

Until today, malaria is still one of the most important diseases in Malaysia. This is because Malaysia is located within the equatorial zone with high temperatures and humidities, usually important for the transmission of malaria. The number of malaria cases were estimated to be around 300,000 before the launching of the Malaria Eradication Program (MEP). The program was successful in reducing the numbers progressively during the 1967-1982 period. During the period 1980-1991, the highest number of malaria cases recorded for the country was 65,283 in 1989 (16,902 in Peninsular Malaysia, 47,545 in Sabah and 836 in Sarawak) whilst the lowest was 22,218 (10,069 in Peninsular Malaysia, 11,290 in Sabah and 859 in Sarawak) in 1983. In Malaysia, there are 434 species of mosquitos, representing 20 genera. Of these, 75 species are Anopheles that comprise of 2 subgenus, i.e. Anopheles and Cellia. Of the 75 species, only 9 have been reported as vectors: An. maculatus, An balabacensis, An. dirus, An. letifer An. campestris, An. sundaicus, An. donaldi, An. leucophyrus and An. flavirostris. The behavior, seasonal abundance, biting activities and breeding sites of these species are discussed.

Matched MeSH terms: Larva/physiology
Update on temporal and spatial abundance of dengue vectors in Penang, Malaysia

Saifur RG, Hassan AA, Dieng H, Ahmad H, Salmah MR, Satho T, et al.

J Am Mosq Control Assoc, 2012 Jun;28(2):84-92.
PMID: 22894118

It is important to obtain frequent measurements of the abundance, distribution, and seasonality of mosquito vectors to determine the risk of disease transmission. The number of cases of dengue infection has increased in recent years on Penang Island, Malaysia, with recurring epidemics. However, ongoing control attempts are being critically hampered by the lack of up-to-date information regarding the vectors. To overcome this problem, we examined the current situation and distribution of dengue vectors on the island. Residences throughout the urban, suburban, and rural areas were inspected through wet and dry seasons between February 2009 and February 2010. Two vectors were encountered in the survey, with Aedes aegypti present in especially high numbers mostly in urban areas. Similar observations were noted for Ae. albopictus in rural areas. The former species was more abundant in outdoor containers, while the latter showed almost equivalent abundance both outdoors and indoors. The dengue virus was active in both urban and rural areas, and the number of cases of infection was higher in areas where Ae. aegypti was predominant. The abundance of immature Ae. albopictus was positively correlated with rainfall (r2 = 0.461; P < 0.05), but this was not the case for Ae. aegypti. For both species, the size of immature populations tended to increase with increasing intensity of rain, but heavy rains resulted in population loss. In addition to updating data regarding the larval habitats and locations (outdoors and indoors), this study highlighted the importance of spatial vector control stratification, which has the potential to reduce costs in control programs.

Matched MeSH terms: Larva/physiology
Fulltext Food Consumption, Developmental Time, and Protein Profile of the Digestive System of the Red Palm Weevil, Rhynchophorus ferrugineus (Coleptera: Dryophthoridae) Larvae Reared on Three Different Diets

Zulkifli AN, Zakeri HA, Azmi WA

J Insect Sci, 2018 Sep 01;18(5).
PMID: 30285257 DOI: 10.1093/jisesa/iey093

The red palm weevil (RPW), Rhynchophorus ferrugineus Olivier (Coleoptera: Dryophthoridae) is one of the most dangerous pests of major cultivated palms including coconut, oil palm, and sago. The larval stage of the weevil causes the most destruction of the palms as it completely destroys the palm cabbage. In this study, the larvae were given three different diets-coconut cabbage, oil palm cabbage, and sago stem, under laboratory conditions for food consumption and developmental time experiment. The protein profiles of the digestive systems of the larvae fed on these three diets were also determined. Although the coconut diet was the most consumed by RPW larvae compared to oil palm and sago diets, the growth rate of RPW larvae on oil palm diet was however significantly shorter than those on the coconut and sago diets: the RPW only need 1 mo and 9 d to complete the larval duration. Proteins profiling of eight 2-DE gel protein spots that range 50-20 kDa were identified by mass spectrometry sequence analysis. Based on the Matrix Science Software, the most dominant protein was cationic trypsin. However, based on the NCBI BLAST tool, aminopeptidase N was the most dominant enzyme. This finding can lead to the development of pest control strategies based on the antinutritional protease inhibitors as potential biocontrol agents. Urgent action to find effective control methods should be taken seriously as this weevil is presumed to be one of the serious pests of oil palm industry in Malaysia.

Matched MeSH terms: Larva/physiology
Fulltext Analysis of chemical compositions and larvicidal activity of nut extracts from Areca catechu Linn against Aedes (Diptera: Culicidae)

Bharathithasan M, Ravindran DR, Rajendran D, Chun SK, Abbas SA, Sugathan S, et al.

PLoS One, 2021;16(11):e0260281.
PMID: 34843539 DOI: 10.1371/journal.pone.0260281

BACKGROUND: There is a growing need to use green alternative larvicidal control for Aedes larvae compared to chemical insecticides. Substantial reliance on chemical insecticides caused insecticide resistance in mosquito populations. Thus, research for alternate chemical compounds from natural products is necessary to control Aedes larvae. This study explores the analysis of chemical compositions from Areca catechu nut as a potential larvicide for Aedes (Diptera: Culicidae).
METHODS: The Areca catechu nut collected from Ipoh, Perak, Malaysia was grounded into powder and used for Soxhlet extraction. The chemical analysis of the extracts and their structures were identified using the GCMS-QP2010 Ultra (Shimadzu) system. National Institute of Standards and Technology (NIST) Chemistry WebBook, Standard Reference Database 69 (https://webbook.nist.gov/chemistry/) and PubChem (https://pubchem.ncbi.nlm.nih.gov/), the two databases used to retrieve the synonyms, molecular formula, molecular weight, and 2-dimensional (2D) structure of chemical compounds. Next, following WHO procedures for larval bioassays, the extracts were used to asses larvicidal activity against early 4th instar larvae of Aedes aegypti and Aedes albopictus.
RESULTS: The larvicidal activities were observed against early 4th stage larvae with different concentrations in the range from 200 mg/L to 1600 mg/L. The LC50 and LC95 of Aedes aegypti were 621 mg/L and 2264 mg/L respectively; whereas the LC50 and LC95 of Aedes albopictus were 636 mg/L and 2268 mg/L respectively. Mortality was not observed in the non-target organism test. The analysis using gas chromatography and mass spectrometer recovered several chemical compounds such as Arecaidine, Dodecanoic acid, Methyl tetradecanoate, Tetradecanoic acid , and n-Hexadecanoic acid bioactive components. These chemical constituents were used as additive formulations in pesticides, pest control, insect repellent, and insecticidal agents.
CONCLUSIONS: Our study showed significant outcomes from the extract of Areca catechu nut and it deserves further investigation in relation to chemical components and larvicidal actions between different species of Aedes mosquitoes. Even though all these findings are fundamental, it may have some interesting potentials to be developed as natural bio-larvicidal products.

Matched MeSH terms: Larva/physiology
Genetic diversity of infective larvae of Gnathostoma spinigerum (Nematoda: Gnathostomatidae) in freshwater swamp eels from Thailand

Eamsobhana P, Wanachiwanawin D, Roongruangchai K, Song SL, Yong HS

J Helminthol, 2017 Nov;91(6):767-771.
PMID: 27890039 DOI: 10.1017/S0022149X16000857

Human gnathostomiasis is a food-borne zoonosis caused by a tissue nematode of the genus Gnathostoma. The disease is highly endemic in Asia, including Thailand. The freshwater swamp eel (Monopterus albus), the second intermediate host of the gnathostome nematode, has an important role in transmitting the infection in Thailand. Surveys on the infective larvae of Gnathostoma spinigerum based on morphological features in freshwater swamp eels have been performed continuously and reported in Thailand. However, there is still limited molecular data on intra-species variations of the parasite. In this study, a total of 19 third-stage larvae of morphologically identified G. spinigerum were collected from 437 liver samples of freshwater swamp eels purchased from a large wholesale market in Bangkok, Thailand. Molecular characterization based on mitochondrial cytochrome c oxidase subunit I (COI) sequences was performed to elucidate their genetic variations and phylogenetic relationship. Among the 19 infective larvae recovered from these eels, 16 were sequenced successfully. Phylogenetic analyses inferred from the partial COI gene showed the presence of three distinct COI haplotypes. Our findings confirm the presence of G. spinigerum as the main species in Thailand.

Matched MeSH terms: Larva/physiology
Feeding Artemia franciscana (Kellogg) larvae with bacterial heat shock protein, protects from Vibrio campbellii infection

Sung YY, Ashame MF, Chen S, Macrae TH, Sorgeloos P, Bossier P

J Fish Dis, 2009 Aug;32(8):675-85.
PMID: 19515074 DOI: 10.1111/j.1365-2761.2009.01046.x

Among their numerous physiological effects, heat shock proteins (Hsps) are potent immunomodulators, a characteristic reflecting their potential as therapeutic agents and which led to their application in combating infection. As an example, the up-regulation of endogenous Hsp70 in the branchiopod crustacean Artemia franciscana (Kellogg) is concurrent with shielding against bacterial infection. To better understand this protective mechanism, gnotobiotic Artemia were fed with Escherichia coli treated to over-produce different prokaryotic Hsps. This was shown to increase larval resistance to experimental Vibrio campbellii exposure. Immunoprobing of Western blots showed that the enhanced resistance to V. campbellii correlated with DnaK production in E coli. A definitive role for DnaK was then demonstrated by feeding Artemia larvae with transformed bacteria over-producing only this protein, although other Hsps such as DnaJ and grpE also provided tolerance against Vibrio infection. Feeding of bacteria synthesizing selected Hsps is therefore suggested as an alternative to antibiotic use as a means of enhancing resistance of Artemia larvae to bacterial infection, which may have potential applications in aquaculture.

Matched MeSH terms: Larva/physiology
The molecular prevalence, distribution and risk factors associated with Babesia bigemina infection in Peninsular Malaysia

Ola-Fadunsin SD, Sharma RSK, Abdullah DA, Gimba FI, Abdullah FFJ, Sani RA

Ticks Tick Borne Dis, 2021 05;12(3):101653.
PMID: 33465661 DOI: 10.1016/j.ttbdis.2021.101653

Babesia bigemina is a tick-borne protozoan that affects cattle in almost all regions of the world. Despite its importance, there is no report of its prevalence in cattle using molecular detection methods in Peninsular Malaysia. This study describes the prevalence, distribution, and risk factors associated with B. bigemina infection using molecular diagnostic methods. Also, the species of ticks infesting cattle and the attitude of cattle farmers towards tick control in Peninsular Malaysia were studied. Blood samples were collected from 1045 cattle from 43 herds throughout the country, and were subjected to molecular studies to detect B. bigemina. Tick samples for entomological studies were also collected and identified. Epidemiological information of each cattle and farm were obtained using a well-structured questionnaire containing open-ended and closed-ended questions. Data were statistically analyzed using Univariate and Multivariate models. The 211-base pair of AMA-1 gene of B. bigemina was amplified and confirmed in 30.5 % (319/1045; 95 % CI = 27.8-33.4) of the sampled population, with the haemoprotozoan detected in all the sampled herds. Breed, age, physiological status, management type, rate of de-ticking, and closeness to human settlement were the risk factors significantly (p < 0.05) associated with the prevalence of B. bigemina in cattle. Rhipicephalus (Boophilus) microplus and Haemaphysalis bispinosa were the species of ticks collected from cattle, with the former been more prevalent. A large number of cattle farmers (12/43; 28 %) do not control ticks in their herds. The findings of this study will create baseline data on the epidemiology of the haemoprotozoan and control patterns of its tick vectors that will guide the government in enacting policies that will improve food security and the economy of the nation.

Matched MeSH terms: Larva/physiology
Relationship between population growth of the red flour beetle Tribolium castaneum and protein and carbohydrate content in flour and starch

Wong N, Lee CY

J Econ Entomol, 2011 Dec;104(6):2087-94.
PMID: 22299375

The effects of eight diets (atta flour, wheat flour, self-rising flour, rice flour, custard powder, corn flour, tapioca starch, and potato starch) on the development of the red flour beetle, Tribolium castaneum (Herbst), reared at 29-31 degrees C and 66-70% RH were assessed. Five pairs of male and female T. castaneum were reared on the respective diets for 28 d before the experimental setup was dismantled and adult counts were recorded. In another experiment, the insects were allowed to mate and oviposit in each flour or starch type over a period of 7 d before being removed. The counting of pupae and adult emergence began on the day of emergence and was continued on a daily basis until day 140. Proximate analysis was performed for chemical composition of each diet, and the numbers of new adults that developed were found to be positively correlated (r2 = 0.97; P < 0.05) with the protein content and negatively correlated (r2 = 0.93; P < 0.05) with the carbohydrate content. For T. castaneum, the suitable diets were ranked as follows: atta flour > wheat flour > self-rising flour > rice flour > custard powder > corn flour > tapioca starch > potato starch. T. castaneum larval development to the pupal and adult stages developed significantly faster in atta flour (P < 0.05) than in the other diets, and the greatest number of progeny was produced from beetles reared on atta flour. Fewer adults emerged from wheat flour, self-rising flour, and rice flour, and no new emergences were recorded for the remaining diets. Developmental rate was much slower in beetles reared on diets in which a low number in progeny was produced. These data illustrate that different diets can influence the sustainability of these insects and affect their development and growth.

Matched MeSH terms: Larva/physiology
Fulltext Ingestion of bacteria overproducing DnaK attenuates Vibrio infection of Artemia franciscana larvae

Sung YY, Dhaene T, Defoirdt T, Boon N, MacRae TH, Sorgeloos P, et al.

Cell Stress Chaperones, 2009 Nov;14(6):603-9.
PMID: 19373565 DOI: 10.1007/s12192-009-0112-2

Feeding of bacterially encapsulated heat shock proteins (Hsps) to invertebrates is a novel way to limit Vibrio infection. As an example, ingestion of Escherichia coli overproducing prokaryotic Hsps significantly improves survival of gnotobiotically cultured Artemia larvae upon challenge with pathogenic Vibrio campbellii. The relationship between Hsp accumulation and enhanced resistance to infection may involve DnaK, the prokaryotic equivalent to Hsp70, a major molecular chaperone in eukaryotic cells. In support of this proposal, heat-stressed bacterial strains LVS 2 (Bacillus sp.), LVS 3 (Aeromonas hydrophila), LVS 8 (Vibrio sp.), GR 8 (Cytophaga sp.), and GR 10 (Roseobacter sp.) were shown in this work to be more effective than nonheated bacteria in protecting gnotobiotic Artemia larvae against V. campbellii challenge. Immunoprobing of Western blots and quantification by enzyme-linked immunosorbent assay revealed that the amount of DnaK in bacteria and their ability to enhance larval resistance to infection by V. campbellii are correlated. Although the function of DnaK is uncertain, it may improve tolerance to V. campbellii via immune stimulation, a possibility of significance from a fundamental perspective and also because it could be applied in aquaculture, a major method of food production.

Matched MeSH terms: Larva/physiology
Fulltext Eco-friendly synthesis of silver nanoparticles and its larvicidal property against fourth instar larvae of Aedes aegypti

Ali ZA, Roslan MA, Yahya R, Wan Sulaiman WY, Puteh R

IET Nanobiotechnol, 2017 Mar;11(2):152-156.
PMID: 28476997 DOI: 10.1049/iet-nbt.2015.0123

In this study, larvicidal activity of silver nanoparticles (AgNPs) synthesised using apple extract against fourth instar larvae of Aedes aegypti was determined. As a result, the AgNPs showed moderate larvicidal effects against Ae. aegypti larvae (LC50 = 15.76 ppm and LC90 = 27.7 ppm). In addition, comparison of larvicidal activity performance of AgNPs at high concentration prepared using two different methods showed that Ae. aegypti larvae was fully eliminated within the duration of 2.5 h. From X-ray diffraction, the AgNP crystallites were found to exhibit face centred cubic structure. The average size of these AgNPs as estimated by particle size distribution was in the range of 50-120 nm. The absorption maxima of the synthesised Ag showed characteristic Ag surface plasmon resonance peak. This green synthesis provides an economic, eco-friendly and clean synthesis route to Ag.

Matched MeSH terms: Larva/physiology
Regulation of gene expression mediating indeterminate muscle growth in teleosts

Ahammad AK, Asaduzzaman M, Asakawa S, Watabe S, Kinoshita S

Mech. Dev., 2015 Aug;137:53-65.
PMID: 25842264 DOI: 10.1016/j.mod.2015.02.006

Teleosts are unique among vertebrates due to their indeterminate muscle growth, i.e., continued production of neonatal muscle fibers until death. However, the molecular mechanism(s) underlying this property is unknown. Here, we focused on the torafugu (Takifugu rubripes) myosin heavy chain gene, MYHM2528-1, which is specifically expressed in neonatal muscle fibers produced by indeterminate muscle growth. We examined the flanking region of MYHM2528-1 through an in vivo reporter assay using zebrafish (Danio rerio) and identified a 2100 bp 5'-flanking sequence that contained sufficient promoter activity to allow specific gene expression. The effects of enhanced promoter activity were observed at the outer region of the fast muscle and the dorsal edge of slow muscle in zebrafish larvae. At the juvenile stage, the promoter was specifically activated in small diameter muscle fibers scattered throughout fast muscle and in slow muscle near the septum separating slow and fast muscles. This spatio-temporal promoter activity overlapped with known myogenic zones involved in teleost indeterminate muscle growth. A deletion mutant analysis revealed that the -2100 to -600 bp 5'flanking sequence of MYHM2528-1 is essential for promoter activity. This region contains putative binding sites for several representative myogenesis-related transcription factors and nuclear factor of activated T-cell (NFAT), a transcription activator involved in regeneration of mammalian adult skeletal muscle. A significant reduction in the promoter activity of the MYHM2528-1 deletion constructs was observed in accordance with a reduction in the number of these binding sites, suggesting the involvement of specific transcription factors in indeterminate muscle growth.

Matched MeSH terms: Larva/physiology

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