Lack of kdr mutations in a population of Asian tiger mosquitoes from Costa Rica

Use of insecticides has led to the fixation of alleles for single amino acid changes in the voltage gated sodium channel (VGSC) associated with knockdown resistance (kdr) in insects of agricultural or medical importance. In this short note, we study allele frequencies of 5 kdr loci, S989, I1011, L1014, V1016 and F1534 in a population of the Asian tiger mosquito, Aedes albopictus (Skuse) (Diptera Culicidae), collected in the only identified location with persistent infestations in Costa Rica. We found no mutant alleles associated with kdr resistance, and a synonymous point mutation was observed at loci V1016. Our results likely reflect the recent invasion of the Asian tiger mosquito in Costa Rica, and also provide a baseline for future studies looking at the global distribution of kdr mutations in this important vector of dengue and chikungunya viruses

Interaction Rating Scale (IRS) as an Evidence-Based Practical Index of Children’s Social Skills and Parenting

Background: The purpose of this paper is to describe the features of the Interaction Rating Scale (IRS) as an evidence-based practical index of children’s social skills and parenting.Methods: The participants in our study, which was conducted as part of a Japan Science and Technology Agency (JST) project, were 370 dyads of children (aged 18, 30, and 42 month) and 81 dyads of 7-year-old children with their caregivers. The participants completed the five minute interaction session and were observed using the IRS.Results: The results indicated that the IRS can measure children’s social skill development and parenting with high validity. Along with the discriminate validity for pervasive development disorder (PDD), attention-deficit/hyperactivity disorder (ADHD), abuse and maltreatment, a high correlation with the SDQ (Strength and Difficulties Questionnaire), and high reliability, the IRS is effective in describing features of social skill development.Conclusions: The IRS provides further evidence of the fact that in order to study children’s social skill development, it is important to evaluate various features of the caregiver-child interaction as a predictor of social skills

A Small-Scale Field Trial of Pyriproxyfen-Impregnated Bed Nets against Pyrethroid-Resistant Anopheles gambiae s.s. in Western Kenya

Pyrethroid resistance is becoming a major problem for vector control programs, because at present, there are few suitable chemical substitutes for pyrethroids, as when used on bed nets the insecticide must have low mammalian toxicity as well as high activity to mosquitoes. Pyriproxyfen (PPF) is one of the most active chemicals among the juvenile hormone mimic (JHM) group. Sterilizing mosquitoes by using PPF could be a potential control measure for pyrethroid-resistant malaria vectors. We investigated the sterilizing effects of two types of PPF-impregnated bed nets - a 1% PPF-impregnated net and a 1% PPF +2% permethrin-impregnated net (Olyset Duo) - to pyrethroid-resistant wild population of Anopheles gambiae s.s. in western Kenya. High mortality of blood-fed mosquitos was observed 3 days post-collection, in the houses where PPF-impregnated nets were used, indicating the effect of PPF on the longevity of mosquitos that came in contact with the net. Reduction in the number of ovipositing females, number of eggs, and number of progeny per female were also observed in the houses in which both Olyset Duo and PPF-impregnated nets were used. This is the first field study showing the high sterilizing efficacy of PPF against wild pyrethroid-resistant An. gambiae s.s. population. In addition, we recognized the necessity of combined use of permethrin with PPF, in order to reduce the risk of mosquito bites and provide a level of personal protection. Further studies on wild pyrethroid-resistant mosquito populations such as An. arabiensis and An. funestus s.s. would provide more information on the practical use of the PPF-impregnated bed nets

Co-occurrence of Point Mutations in the Voltage-Gated Sodium Channel of Pyrethroid-Resistant Aedes aegypti Populations in Myanmar

Background:Single amino acid substitutions in the voltage-gated sodium channel associated with pyrethroid resistance constitute one of the main causative factors of knockdown resistance in insects. The kdr gene has been observed in several mosquito species; however, point mutations in the para gene of Aedes aegypti populations in Myanmar have not been fully characterized. The aim of the present study was to determine the types and frequencies of mutations in the para gene of Aedes aegypti collected from used tires in Yangon City, Myanmar.Methodology/Principal Findings:We determined high pyrethroid resistance in Aedes aegypti larvae at all collection sites in Yangon City, by using a simplified knockdown bioassay. We showed that V1016G and S989P mutations were widely distributed, with high frequencies (84.4% and 78.8%, respectively). By contrast, we were unable to detect I1011M (or I1011V) or L1014F mutations. F1534C mutations were also widely distributed, but with a lower frequency than the V1016G mutation (21.2%). High percentage of co-occurrence of the homozygous V1016G/S989P mutations was detected (65.7%). Additionally, co-occurrence of homozygous V1016G/F1534C mutations (2.9%) and homozygous V1016G/F1534C/S989P mutations (0.98%) were detected in the present study.Conclusions/Significance:Pyrethroid insecticides were first used for malaria control in 1992, and have since been constantly used in Myanmar. This intensive use may explain the strong selection pressure toward Aedes aegypti, because this mosquito is generally a domestic and endophagic species with a preference for indoor breeding. Extensive use of DDT for malaria control before the use of this chemical was banned may also explain the development of pyrethroid resistance in Aedes aegypti

The Relationship of Energy Malnutrition, Skeletal Muscle and Physical Functional Performance in Patients with Stable Chronic Obstructive Pulmonary Disease

Weight loss is a factor that affects prognosis in patients with chronic obstructive pulmonary disease (COPD) independent of lung function. One of the major factors for weight loss is energy malnutrition. There have been no reports on the factors related to energy malnutrition in COPD patients. This retrospective observational study aimed to investigate these factors. We included 163 male subjects with COPD. Respiratory quotient (RQ), an index of energy malnutrition, was calculated by expiratory gas analysis using an indirect calorimeter. RQ 2). Energy malnutrition was observed in 43%. The independent factors associated with energy malnutrition were tidal volume (VT) (OR 0.99; 95% CI 0.985–0.998; p = 0.015) and Th12 erector spinae muscle cross-sectional area SMI (Th12ESMSMI) (OR 0.71; 95% CI 0.535–0.946; p = 0.019). In decision-tree profiling of energy malnutrition, VT was extracted as the first distinguishable factor, and Th12ESMSMI as the second. In ROC analysis, VT SMI < 10.1 (AUC, 0.70) was the cutoff value for energy malnutrition. Energy malnutrition may be an early warning sign of nutritional disorders

Analysis of a cellular structure observed in the compound eyes of Drosophila white; yata mutants and white mutants

We previously identified the Drosophila yata mutant, which showed phenotypes including progressive vacuolization of the white-coloured compound eye, progressive shrinkage of the brain and a shortened lifespan. The yata gene was shown to be involved in controlling intracellular trafficking of the Amyloid precursor protein-like protein, which is an orthologue of Amyloid precursor protein, which is a causative molecule of Alzheimer's disease. In this study, we examined the phenotype of the compound eye of the yata mutant using electron microscopy and confocal microscopy. We found that abnormal cellular structures that seemed to originate from bleb-like structures and contained vesicles and organelles, such as multivesicular bodies and autophagosomes, were observed in aged white; yata mutants and aged white mutants. These structures were not observed in newly eclosed flies and the presence of the structures was suppressed in flies grown under constant dark conditions after eclosion. The structures were not observed in newly eclosed red-eyed yata mutants or wild-type flies, but were observed in very aged red-eyed wild-type flies. Thus, our data suggest that the observed structures are formed as a result of changes associated with exposure to light after eclosion in white mutants, white; yata mutants and aged flies