Even with continuous vector control, dengue is still a growing threat to public health in Southeast Asia. Main causes comprise difficulties in identifying productive breeding sites and inappropriate targeted chemical interventions. In this region, rural families keep live birds in backyards and dengue mosquitoes have been reported in containers in the cages. To focus on this particular breeding site, we examined the capacity of bird fecal matter (BFM) from the spotted dove, to support Aedes albopictus larval growth. The impact of BFM larval uptake on some adult fitness traits influencing vectorial capacity was also investigated. In serial bioassays involving a high and low larval density (HD and LD), BFM and larval standard food (LSF) affected differently larval development. At HD, development was longer in the BFM environment. There were no appreciable mortality differences between the two treatments, which resulted in similar pupation and adult emergence successes. BFM treatment produced a better gender balance. There were comparable levels of blood uptake and egg production in BFM and LSF females at LD; that was not the case for the HD one, which resulted in bigger adults. BFM and LSF females displayed equivalent lifespans; in males, this parameter was shorter in those derived from the BFM/LD treatment. Taken together these results suggest that bird defecations successfully support the development of Ae. albopictus. Due to their cryptic aspects, containers used to supply water to encaged birds may not have been targeted by chemical interventions.
We describe a gall midge Macarangamyia itiokai Elsayed Tokuda gen. n., sp. n. belonging to the subtribe Schizomyiina (Diptera: Cecidomyiidae: Asphondyliini) inducing petiole galls on Macaranga bancana (Miq.) in Lambir Hills National Park, Borneo, Malaysia. The new genus is distinguishable from all known genera of Schizomyiina by the unique dorsally-placed aedeagus slit, the short, membranous, protrusible ovipositor, with scattered strong setae ventrally and dorsally, and the presence of spiracles on all larval thoracic segments. It is compared and separated from its closely related Oriental genera of Schizomyiina.
Precipitating antibodies to an insect pathogenic RNA virus of Darna trima from East Malaysia have been found in a small percentage of human sera from several different groups of persons in West Malaysia and the United Kingdom. No associated illness was identified. The results suggest that an antigenically related virus or viruses are present in the environment that may be associated with symptomless or inapparent infections in man.
The levels of susceptibility of C. p. fatigans larvae from four different localities in Malaya to DDT, dieldrin, malathion, fenthion, diazinon and Sevin have been studied; their toxicity was: diazinon > fenthion > malathion > dieldrin > DDT > Sevin.Larvae from different localities showed a wide range of susceptibility to the chlorinated hydrocarbon insecticides, dieldrin (40x) and DDT (10x), but the organophosphorus compounds and the carbamate compound, Sevin, gave consistent results from all localities. One strain from a rural area (Lamir) was the most susceptible to all insecticides and has been used as a reference strain for related studies on the development of resistance.
Hookworm-related cutaneous larva migrans (HrCLM) is a zoonosis which is endemic in many sub-tropic and tropical countries including Malaysia. We report a case of a 40-year old plantation worker who presented with a pruritic rash on his abdomen. It is important for clinicians to diagnose and treat HrCLM promptly as this condition results in considerable morbidity when treatment is delayed.
Gastrointestinal nematode infections can cause great losses in revenue due to decrease livestock production and animal death. The use of anthelmintic to control gastrointestinal nematode put a selection pressure on nematode populations which led to emergence of anthelmintic resistance. Because of that, this study was carried out to investigate the efficacy of aqueous and methanol extract of Cassia siamea against the motility of C. elegans Bristol N2 and C. elegans DA1316. Caenorhabditis elegans Bristol N2 is a susceptible strain and C. elegans DA1316 is an ivermectin resistant strain. In vitro bioassay of various concentrations of (0.2, 0.6, 0.8, 1.0 and 2.0 mg mL-1) aqueous and methanol extracts of C. siamea was conducted against the motility of L4 larvae of C. elegans Bristol N2 and C. elegans DA1316. The L4 larvae were treated with 0.02 μg mL-1 of ivermectin served as positive control while those in M9 solution served as negative control. The activity of the extracts was observed after 24 h and 48 h. A significant difference was recorded in the extract performance compared to control at (P < 0.001) after 48 h against the motility of the larvae of both strains. The methanol extracts inhibited the motility of C. elegans Bristol N2 by 86.7% as well as DA1316 up to 84.9% at 2.0 mg mL-1 after 48 h. The methanol extract was more efficient than aqueous extract (P < 0.05) against the motility of both strains of C. elegans. Cassia siamea may be used as a natural source of lead compounds for the development of alternative anthelmintic against parasitic nematodes as well ivermectin resistant strains of nematodes.
Two new species of black flies, Simulium mainitense and S. tukurongense, are described from Palawan, the Philippines. Both species are placed in the Simulium nitidithorax subgroup of the Simulium tuberosum species-group of Simulium (Simulium). They are characterized by the female sensory vesicle of medium length, pupal thorax covered with round tubercles, and anterodorsal trichomes on the pupal thorax longer than frontal trichomes. This combination of characters separates these two new species from S. quasifrenum Delfinado, the only previously known member of the S. nitidithorax subgroup from Palawan, and nine other related species from Sabah, Sarawak, Peninsular Malaysia and India. Simulium mainitense sp. nov. is distinguished from S. tukurongense sp. nov. in the female by the somewhat larger body size, and greater length ratio of the labrum against the clypeus; and in the pupa by the much longer gill filaments.
Dengue is a serious mosquito borne disease common in tropical and sub-tropical countries including Malaysia. There is at present a lack of specific treatment and an effective tetravalent vaccine against dengue. The control of dengue depends solely on the suppression of the two most important vectors namely, Aedes aegypti and Ae albopictus. Despite intensive and extensive control efforts by health agencies, the disease continues to spread. This paper updates various innovations on control of dengue vectors. Gene-based sterile insect technique using the RIDL technology for both Aedes aegypti & Ae albopictus control has now been actively researched and field trials are pursued to evaluate the effectiveness of the technology. The release of Wolbachia-infected Ae aegypti is another dengue control innovation. The infected mosquito cannot support development of dengue virus and has shorter life span. Other innovations include: auto-dissemination of insect control agents using ovitrap, autocidal adult and larva trap, outdoor residual spraying, insecticidal paint and biocontrol agent. In other innovation, outbreak prediction capability is enhanced by developing model based on environmental data and analysis utilising neural network.
Tarsubulura perarmata (Ratzel, 1868) is described from a primate Tarsius bancanus and from Tupaidae: Tupaia glis and T. minor in Malaysia (Kuala Lumpur). Its biological cycle is done by the experimental infestation of crickets belonging to the genera Valanga and Oxya. The infective larvae are obtained after three weeks of development of 28 degrees C in the intermediate host. They differ from third stage larvae obtained from Subulurinae by the development of cuticular pharyngeal lobes. The early apparition of this ontogenetic character confirms the isolation of the genus Tarsubulura as compared to the general evolution of the Subuluridae.
Morphological and host-plant relationship studies were conducted to differentiate two sympatric populations of brown planthopper (BPH), Nilaparvata lugens, one from rice (Oryza sativa) and the other from Leersia hexandra, a weed grass. In morphometric studies based on esterase activities, an UPGMA dendrogram using 17 quantitative morphological characters, including stridulatory organs (courtship signal-producing organs) between two sympatric populations of N. lugens, one from rice and the other from L. hexandra, a weed grass revealed that both populations were separated from each other. An out-group, N. bakeri, was found to be completely different from the two sympatric populations of N. lugens. Rice plants were best suited for the establishment of the rice-infesting population, and L. hexandra was a favourable host for the Leersia-infesting population. The individuals derived from one host did not thrive on the other host, as shown by a significant reduction in survival and nymphal development, ovipositional preferences, ovipositional response, and egg hatchability. Therefore, morphological and host-plant relationship studies indicate that rice-associated population with high esterase activities and L. heaxandra-associated population with low esterase activities are two closely related sibling species.
Galleria mellonella larvae have been increasingly used in research, including microbial infection studies. They act as suitable preliminary infection models to study host-pathogen interactions due to their advantages, such as the ability to survive at 37°C mimicking human body temperature, their immune system shares similarities with mammalian immune systems, and their short life cycle allowing large-scale studies. Here, we present a protocol for simple rearing and maintenance of G. mellonella without requiring special instruments and specialized training. This allows the continuous supply of healthy G. mellonella for research purposes. Besides, this protocol also provides detailed procedures on the (i) G. mellonella infection assays (killing assay and bacterial burden assay) for virulence studies and (ii) bacterial cell harvesting from infected larvae and RNA extraction for bacterial gene expression studies during infection. Our protocol could not only be used in the studies of A. baumannii virulence but can also be modified according to different bacterial strains.
Megaselia scalaris (Loew) is one of the best-known diets for the swiftlet. Previous studies have addressed the problem of some mass rearing conditions for this insect; unfortunately, the details of the nutritional composition of the life stages and cost of the breeding materials were insufficiently reported, even though this information is crucial for farming the edible-nest swiftlet. We aimed to investigate the nutritional composition of the life stages of M scalaris on a cost basis using 3 common commercial breeding materials: chicken pellets (CPs), fish pellets (FPs), and mouse pellets (MPs). Modified Association of Official Analytical Chemists (AOAC) proximate and mineral analyses were carried out on the insect's third instar larvae, pupal, and adult stages to determine the nutritional composition. Regardless of the breeding materials, the adult stage of M scalaris had significantly higher crude protein than the other stages; the pupae were rich in calcium, which is required for egg production; and the third instar larvae had the highest amount of crude fat compared with the other stages. Regarding the energy content, there were no significant differences among the stages according to the breeding materials. In terms of nutritional cost, CP was the most economic breeding material and generated the highest amount of nutrients per US dollar (US $). Different life stages of M scalaris were used by the swiftlets by supplying the required nutrients, and future studies should focus on effective diet feeding methods.
Megaselia scalaris (Loew) (Diptera: Phoridae) provides great evidential value in estimating the postmortem interval (PMI) compared with other dipterans due to its common occurrence on human corpses both indoors and in concealed environments. Studies have focused on the effect of temperature, larval diet, and photoperiod on the development of the species; however, knowledge of M. scalaris development at different moisture levels is insufficient. This study aimed to investigate the effects of substrate moisture on the larval development time, pupal recovery, pupal weight, adult emergence, and adult head width of M. scalaris. The larvae were reared in five replicates on substrates with six moisture levels ranging from 50 to 90%. Larvae and puparia were sampled daily, and the collection time, number, and weight were recorded, measured, and then compared using multivariate analysis of variance with a post hoc least significant difference test. Larvae developed most quickly (3.75 ± 0.04 d) at 50% substrate moisture; the larvae were able to survive in extremely wet substrates (90% moisture), but the development time was significantly longer (6.48 ± 0.19 d). Moisture greatly influenced the pupation rate and adult emergence but showed a weak effect on the pupae weight and adult head width. Due to the significance of moisture on the development of M. scalaris, PMI estimation using M. scalaris with cadavers of different moisture content must be carefully conducted to avoid inaccuracy.
Hermetia illucens larvae by nature are a decomposer which fed on organic wastes. This study explores the potential of producing biodiesel using lipids from H. illucens larvae. Three types of organic wastes (sewage sludge, fruit waste and palm decanter cake from oil palm mill) were selected based on considerable generation and disposal concern in the area of study as well as lack of investigations as feed for Hermetia illucens larvae in current literatures. Growth rate of the larvae was determined with studying the changes in the biomass per day. H. illucens larvae fed with fruit waste and palm decanter cake have shown growth rates of 0.52±0.02 and 0.23±0.09 g d(-1), respectively. No positive sign of growth were observed in the larvae fed with treated sewage sludge (-0.04±0.01 g d(-1)). Biodiesel as fatty acid methyl ester (FAME) was synthesized by transesterification of the larvae lipid using sulphuric acid as catalyst in methanol. FAME produced was ascertained using ATR-FTIR spectroscopy and GC-MS. The main compositions of fatty acid were found to be C12:0, C16:0 and C18:1n9c. Fatty acid composition of C12:0 fed with fruit waste, sewage sludge and palm decanter was found to be most abundant in the larvae lipid. The amount of C12:0 obtained was 76.13%, 58.31% and 48.06%, respectively. In addition, fatty acid of C16:0 was attained at 16.48% and 25.48% fed with sewage sludge and palm decanter, respectively. Based on the findings, FAME derived from larvae lipids is feasible to be used for biodiesel production.
To determine the geographic origin of the black fly Simulium suzukii on Okinawa Island, Japan, macrogenomic profiles derived from its polytene chromosomes were compared with those of mainland and other insular populations of S. suzukii and of the isomorphic Simulium tani species complex. The Okinawan population is a chromosomally unique cytoform, designated 'D,' which is essentially monomorphic and differs by about 27 fixed rearrangements from the chromosomal standard sequence for the subgenus Simulium and by two fixed differences from its nearest known relative, representing the type of S. suzukii, on the main islands of Japan. Chromosomal band sequences revealed two additional, sympatric cytoforms of S. suzukii, designated 'A' and 'B,' each with species status, in Korea, and a third cytoform, designated 'C,' on Hokkaido, Japan. A new cytoform, 'K,' of S. tani from Malaysia, representing the type of S. tani, is more closely related to cytoforms in Thailand, as are populations from Taiwan previously treated as S. suzukii but more closely aligned with S. tani and newly recognized as cytoform 'L' of the latter nominal species. Rooting of chromosomal band sequences by outgroup comparisons allowed directionality of chromosomal rearrangements to be established, enabling phylogenetic inference of cytoforms. Of 41 macrogenomic rearrangements discovered in the five new cytoforms, four provide evidence for a stepwise origin of the Okinawan population from populations characteristic of the main islands of Japan. The macrogenomic approach applied to black flies on Okinawa Island illustrates its potential utility in defining source areas for other species of flies including those that might pose medical and veterinary risks.