Hay Infusion Research Articles

Hay Infusion is More Effective than The Yeast and Palm Sugar Combination as an Ovitrap Attractant of Aedes Aegypti Mosquitoes

The Aedes aegypti mosquito is widely known as a vector for Dengue Hemorrhagic Fever (DHF). Mosquito population can be controlled by using oviposition traps (ovitrap). Attractants can be used to attract mosquitoes to lay their eggs. This study aims to compare the effectiveness of Ae. aegypti mosquitoes ovitrap attractant between hay infusion, the yeast-palm sugar combination and ovitrap standard without attractant. The research method was an experimental research posttest only control group design. The results showed that the highest number of eggs during the 4 days of observation was in the hay infusion with an average number of eggs 253,44±58,445 followed by ovitrap without attractant and palm sugar with the number of eggs 31,89±25,300 and 89,78±39,499 respectively sequentially. There was a significant difference in the mean number of eggs between 10% hay infusion and 10% yeast and palm sugar combination and water with p=0.000. The conclusion of this study is that hay infusion attractant is more effective than yeast and palm sugar combination. Keywords: Aedes aegypti, Yeast, Hay Infusion, Ovitrap, Palm Sugar.

Lactic acid bacteria waste infusion as a source of attraction and oviposition stimulation of gravid female Aedes albopictus mosquitoes.

Aedes albopictus poses a public health risk in tropical countries and temperate countries in recent decades due to its capability to transmit various human arboviruses including dengue, yellow fever, and chikungunya. Vector control is the key for preventing transmission of these pathogenic viruses. Improving the effectiveness of currently utilized collection methods, such as ovitraps, is important for best species abundance monitoring, assessment of the threat of arbovirus transmission, and optimizing control activities. Therefore, this study aimed to assess the potential use of lactic acid bacteria (LAB) waste as an infusion-baited ovitrap for Aedes collection. The performance of overnight tap water, grass hay infusion and LAB waste infusion were compared for their ability in attracting gravid female Ae. albopictus. In this study, the LAB waste infusion was substantially more alluring to Ae. albopictus mosquitoes than the two controls grass hay infusion and tap water.

Oviposition responses of gravid Aedes aegypti Linn. Mosquitoes (Diptera: Culicidae) to natural organic infusions under laboratory condition

• Organic infusions of Costus igneus , Psidium guajava and Cicer arietinum were prepared. • Infusions were tested for its oviposition attractancy on gravid Ae. aegypti mosquito. • The highest oviposition in choice bioassay was 457.3 ± 22.8 in 15% insulin plant. • The highest oviposition in comparison bioassay was 475.3 ± 10.7 in 15% insulin plant. • These findings could be applied Ae. eagypti mosquito surveillance and control program. The aim of this study was to investigate the effectiveness of different concentrations of three organic infusions as an oviposition attractancy agents of gravid Ae. aegypti mosquito under laboratory condition. Three organic infusions namely, Costus igneus Nak (Insulin plant leaf), Psidium guajava Linn (Guava tree leaf), and Cicer arietinum Linn (Black chickpea) were prepared by fermentation process and bioassays such as choice bioassay and comparison bioassay were performed to assess its oviposition attractiveness. In the choice bioassay, four different concentrations namely, 5%, 10%, 15%, 50% of each infusion was tested with gravid female Ae. aegypti and the oviposition results were compared to the water control. The results showed that the oviposition attractiveness was significantly differed among the different concentrations of three infusions. The highest mean oviposition was observed to be 457.3 ± 22.9 in 15% insulin plant leave infusion and it was 192.6 ± 11.5 in water control (F = 49.64; P = <0.001; OAI = +0.40). The best resulted concentration of the infusions in the choice bioassay was further studied and compared to the positive control (10% hay infusion). The highest mean oviposition was recorded in comparison bioassay was 475.3 ± 10.7 in 15% insulin plant leaf infusion and it was 235.3 ± 9.9 in 10% hay infusion (F = 18.71; P = <0.001; OAI = +0.38). These findings suggest that the insulin plant leaf infusion could be used in ovitraps as an effective organic oviposition attractant in Ae. aegypti mosquito surveillance and control program.

Evaluation of a mosquito home system for controlling Aedes aegypti

BackgroundDengue is a significant public health issue that is caused by Aedes spp. mosquitoes. The current vector control methods are unable to effectively reduce Aedes populations and thus fail to decrease dengue transmission. Hence, there is an urgent need for new tools and strategies to reduce dengue transmission in a wide range of settings. In this study, the Mosquito Home System (MHS) and Mosquito Home Aqua (MHAQ) formulations were assessed as commercial autodissemination traps in laboratory and small-scale field trials.MethodMultiple series of laboratory and small-scale field trials were performed to assess the efficacy of MHS and MHAQ exposed to Ae. aegypti. In the laboratory trials, various parameters such as fecundity, fertility, wing size, oviposition preferences, residual effects, and MHAQ transference to other containers through controlled experiments were tested. For small-scale field trials, the efficacy of the MHS and MHAQ approaches was determined to ascertain whether wild mosquitoes could transfer the MHAQ formulation from MHS stations to ovitraps.ResultsThe data revealed that Ae. aegypti was highly susceptible to low concentrations of MHAQ formulations and had a residual effect of up to 3 months, with MHAQ exposure affecting fecundity, fertility, and mosquito wing size. In the oviposition studies, gravid females strongly preferred the hay infusion compared to tap water and MHAQ during egg-laying in the laboratory. Nevertheless, the use of commercial MHAQ by MHS was highly attractive in field settings compared to conventional ovitraps among local Aedes spp. mosquitoes. In addition, MHAQ horizontal transfer activities in the laboratory and small-scale field trials were demonstrated through larval bioassays. These findings demonstrated the potential of MHAQ to be transferred to new containers in each study site.ConclusionThis study provided proof of principle for the autodissemination of MHAQ. Through further refinement, this technique and device could become an effective oviposition trap and offer an alternative preventive tool for vector control management.Graphical abstract

EVALUATION OF MULTIPLE TRAP TYPES FOR THE CAPTURE OF VECTOR MOSQUITOES OF EASTERN EQUINE ENCEPHALITIS VIRUS IN SAINT JOHNS COUNTY, FLORIDA

Eastern equine encephalitis virus (EEEV) is a highly dangerous alphavirus vectored by multiple mosquito species in the United states. Vector surveillance and control is used to prevent the spread of EEEV, so highly efficient and attractive traps are needed to accurately assess mosquito abundance. Mosquitoes can be captured in various physiological states (host-seeking, gravid, resting, etc.), depending on what trap type is used. this study analyzed 6 trap types to determine which captured the most EEEV vectors in saint Johns county. the trap types analyzed were the biogents sentinel trap, centers for Disease control (cDc) Light trap, the sentinel Mosquito Arbovirus capture Kit, Mosquito Magnet X trap, cDc resting trap, and gravid traps. For the gravid traps, two different infusions were tested: hay infusion and cattail infusion. Aedes atlanticus Dyar and Knab was the most abundant EEEV vector captured in this study. Other EEEV vectors collected were Aedes vexans (Meigen), Culex erraticus (Dyar and Knab), and Culex nigripalpus theobald. bG traps caught the highest abundance of EEEV vectors (1520 ± 743) compared to all the other trap types analyzed. Despite capturing multiple EEEV vectors during the testing period at the chosen site, Culiseta melanura (coquillett) and Coquillettidia perturbans (Walker) were never captured.

Comparison Between Larval Survey Index and Positive Ovitrap Index in the Evaluation of Populations of Aedes (Stegomyia) aegypti (Linnaeus, 1762) North of Paraná, Brazil.

Aedes (Stegomyia) aegypti (Linnaeus, 1762) is one of the world’s most widely distributed mosquitoes and is the vector of the dengue virus, one of the most important reemerging diseases. Besides dengue, A. aegypti can also transmit urban yellow fever, chikungunya, and Zika virus, making it of great medical importance. Thus, it is of extreme importance to find reliable methods to evaluate the presence of A. aegypti in urban areas. In Brazil, rapid index surveys of Aedes aegypti by means of larval survey (LIRAa) is the official method to estimate the Breteau (BI) and property infestation (PII) indexes, which indicates how many infested containers with larvae of A. aegypti were found by the total number of properties surveyed and the proportion of houses infested, respectively. As the LIRAa requires access to private residences and trained personal to find breeding sites and do not reveal the mosquito’s presence when in low density, it has not demonstrated efficacy in determining the presence of A. aegypti. To evaluate an alternative method, the LIRAa method was compared with an oviposition trap, made with hay infusion and a hardboard pallet, to evaluate the BI and the PII. The 2 methods were carried out simultaneously through 4 surveys, sampling 60 homes per survey. To evaluate the best configuration of ovitraps for surveillance of A. aegypti, the ovitraps were installed in intradomicile and peridomicile areas, with 1 to 5 traps per residence and with 1 to 3 pallets per trap, and these different configurations were compared using the positive ovitrap index (POI) and egg density index (EDI). The ovitraps showed greater sensitivity for detecting the presence of A. aegypti, with a BI of 72.5% and PII of 54.2%, whereas the LIRAa revealed only 2.1% for the BI and 1.3% for the PII. Therefore, the use of sentinel traps can provide information in a more rapid and precise manner. As there were no differences in the ovitraps distributions patterns, the ovitraps can be installed in the peridomicile area, with 2 traps per surveillance point and 1 pallet per trap, making their installation easier and more cost-efficient, facilitating the work of health agents in future surveillances complementing LIRAa’s actions for efficient monitoring.

Behavioral responses of gravid Culex quinquefasciatus, Aedes aegypti, and Anopheles quadrimaculatus mosquitoes to aquatic macrophyte volatiles.

Mosquitoes use many cues to assess whether a habitat is conducive for reproduction, possibly including the presence of stimuli from aquatic macrophytes. The effect of water infusions of water hyacinth (Eichhornia crassipes), water lettuce (Pista stratioles), parrotfeather (Myriophyllum aquaticum), and water pennywort (Hydrocotyle umbellata) on mosquito oviposition and attraction was investigated. Gravid Culex quinquefasciatus deposited significantly more egg rafts in water hyacinth, water lettuce, or Bermuda hay (positive control) infusions compared to water, while water pennywort and parrotfeather infusions did not differ from water. In-flight attraction responses of Cx. quinquefasciatus, Aedes aegypti, and Anopheles quadrimaculatus were evaluated. The strongest attraction of gravid Cx. quinquefasciatus and Ae. aegypti occurred in the presence of volatiles from infusions of water hyacinth and water lettuce, which were equal in attractiveness to hay infusion. Water pennywort and parrotfeather infusions were not attractive. Gravid An. quadrimaculatus were not attracted to aquatic plant volatiles. The results suggest that water hyacinth and water lettuce emit volatile chemicals that attract two of three mosquito species tested and stimulate oviposition by Cx. quinquefasciatus, demonstrating that the level of attraction of aquatic plant volatiles varies among species in ways that may have relevance to bait-based detection and control methods.

Comparing Effectiveness of Hay Infusion and Sugar Fermentation Solution as Ovitrap's Attractans to Aedes aegypti

Dengue Hemorrhagic Fever (DHF) is still one of the major public health problems in the world and Indonesia. There are several methods of mosquito vector control, one of them is the use of ovitrap and the addition of attractants which is a compound that may attract gravid mosquitoes to lay eggs. Some examples of attractants are hay infusion and sugar fermentation solution. This research aimed to compare effectiveness of hay infusion and sugar fermentation solution as Aedes aegypti attractants. This research type was true experimental laboratory with complete randomized design which is divided into 3 groups of ovitrap containing aquades as control, 20% hay infusion and 20% sugar fermentation solution. Ovitraps with those attractants were put into a mosquito coop containing 25 gravid female mosquitoes. Mosquito’s eggs counting was done after 2 days with 9 times repetition. The data were then analyzed using Kruskal-Wallis and Mann-Whitney test. It was found that the difference of mosquito’s eggs number in the ovitrap containing the fermentation solution of sugar and hay infusion had a significance value of 0.000 (p&gt; 0,05). It means that hay infusion is more effective compared with sugar fermentation. Keywords : DHF, ovitrap, attractant, hay infusion, sugar fermentation solution

Fauna, Ecological Characteristics, and Checklist of the Mosquitoes in Mazandaran Province, Northern Iran.

Mosquitoes are important vectors of human and animal diseases. This study updates current knowledge on fauna, dominance, and distribution of mosquitoes in Mazandaran Province, Northern Iran, to inform disease control effort. Larval collections, using standard dippers or droppers, and adult collections, using total catches, shelter pits, CDC light traps, and human landing catches, were performed monthly in 30 villages across 16 counties, from May to December 2014. Ovitraps, baited with hay infusion as oviposition attractants or stimulants for Aedes (Stegomyia) mosquitoes, were installed in each village and inspected weekly for eggs. Lactophenol and Berlese media were used for preserving and mounting specimens. Overall, 36,024 mosquito specimens (19,840 larvae and 16,184 adults) belonging to 4 genera and 20 species were morphologically identified. The dominance and distribution indices showed that Culex pipiens s.s. was the eudominant species with a constant distribution of larvae (D = 69.07%, C = 100%) and adults (D = 31.86%, C = 100%), followed by Cx tritaeniorhynchus (D = 38.14%, C = 100%) and Anopheles maculipennis s.l. (D = 11.05%, C = 100%) as adults. Aedes vexans was the dominant (7.85%) species, but it had a sporadic (20%) distribution. Culex torrentium and Culiseta morsitans were added as the new species to the checklist of mosquitoes in Mazandaran Province. Due to the potential role, Cx. pipiens s.s. as a vector of various pathogens, further ecological studies are recommended.

Collagen degradation as a possibility to determine the post-mortem interval (PMI) of animal bones: a validation study referring to an original study of Boaks et al. (2014).

Estimation of the post-mortem interval (PMI) of unknown skeletal remains is a common forensic task. Boaks and colleagues demonstrated a new method for PMI estimation in showing a reduction of the collagen to non-collagen content (Co/NCo ratio) in porcine bones after a PMI of 12months using the Sirius Red/Fast Green Collagen Staining Kit from Chondrex in 2014 (Boaks et al. Forensic Sci Int 240: 104-110, 2014). The aim of our study was to reproduce this method and to investigate if the method could be used for forensic issues. Sixteen fresh porcine bones were placed in prepared boxes where they were treated regularly with distilled water or with water from hay infusions. For determining the Co/NCo ratio, we used the Sirius Red/Fast Green Collagen Staining Kit from Chondrex, which stains collagenous (Co) proteins red and non-collagenous (NCo) proteins green Chondrex Inc. (2008). After a PMI of 1-3months, an analysis of porcine bone thin sections was performed on the one hand with spectrophotometry, on the other hand with stereomicroscopy. Using spectrophotometry, we go low and partially negative Co/NCo ratios which were up to 100-fold lower than the results we expected to get. The data we got by stereomicroscopy and calculating the Co/NCo ratio from extracting the red and green content with the software MATLAB and so calculating the Co/NCo ratio showed a correlation between PMI and the Co/NCo ratio in the porcine bone samples. Regular addition of distilled water or water from a hay infusion did not produce any significant differences so that an increased presence of microorganisms had obviously no influence on collagen degradation.

The Phytochemical Analysis of Hay Infusions and Papaya Leaf Juice as an Attractant Containing Insecticide for Aedes Aegypti

Aedes aegypti mosquito population could be controlled by using lethal ovitrap. The addition of hay infusions as a attractant greatly enhance Aedes aegypti eggs trapped, and papaya leaf juice may inhibit Aedes aegypti eggs evolve to larvae or a larvae to pupae stage. This study was conducted to find out the chemical compounds in hay infusion and papaya leaf juice. We used phytochemical test using UV-Vis Spectrophotometry, Thin Layer Chromatography, and High Performance Liquid Chromatoraphy (HPLC) method. The results showed that hay infusion contains 12,75 mg/L ammonium and &lt;1,20 ppm (g/mL) lactic acid and papaya leaf juice contains 0,25% alkaloid, 0,14% flavonoid, 0,30% saponin, ?68 mg/L steroid and 11,34% tannin, but negative terpenoid. We concluded that hay infusion and papaya leaf juice contains chemical compounds that could be use as attractant and bioinsecticide to Aedes aegypti, respectively.

Differences in Effectiveness between Well Water and Hay Infusion Water as Ovitrap of Mosquitoes Larvae

Abstract Background: Prevention efforts have been made to eradicate mosquito breeding, larvae examination but the results have not been optimal. Therefore, larval source reduction program and mobilize the health sector participation is critical. The Objective: The purpose of research to determine the effectiveness of the prevention of Dengue Hemorrhagic Fever (DHF) by utilizing the waste for ovitrap in Semarang City Elementary School. Method: This research was a quasy experiment with the design of a post-test study design. The subjects were 75 elementary schools in the District Tembalang, Gajah Mungkur, and Semarang. Result: The results showed that there was no difference in the rate of House Index, Container Index, Breteau Index and Free-Larva Numbers on modified fresh water, hay infusion ovitrap placed indoor and outdoor. The results of the post-hoc test found a significant difference between the modified ovitrap consist of fresh water and hay infusion on the number of larvae that were caught. Conclusion: It is recommended that communities should play an active role in eradicating the mosquito by breaking the cycle of life of the mosquito. Keywords: Well water, Hay infusion water, Ovitrap, Mosquito larvae

Efficacy of ULV and thermal aerosols of deltamethrin for control of Aedes albopictus in nice, France.

BackgroundUltra-low volume (ULV) insecticidal aerosols dispensed from vehicle-mounted cold-foggers are widely considered the method of choice for control of Aedes aegypti and Ae. albopictus during outbreaks of dengue and chikungunya and, more recently, Zika. Nevertheless, their effectiveness has been poorly studied, particularly in Europe. Nearly all published studies of ULV efficacy are bio-assays based on the mortality of caged mosquitoes. In our study we preferred to monitor the direct impact of treatments on the wild mosquito populations. This study was undertaken to evaluate the efficiency of the two widely used space spraying methods to control Ae. albopictus and Ae. aegypti.MethodsWe determined the susceptibility of local Ae. albopictus to deltamethrin by two methods: topical application and the “WHO Tube Test”. We used ovitraps baited with hay infusion and adult traps (B-G Sentinel) baited with a patented attractant to monitor the mosquitoes in four residential areas in Nice, southern France. The impact of deltamethrin applied from vehicle-mounted ULV fogging-machines was assessed by comparing trap results in treated vs untreated areas for 5 days before and 5 days after treatment. Four trials were conducted at the maximum permitted application rate (1 g.ha-1). We also made two small-scale tests of the impact of the same insecticide dispensed from a hand-held thermal fogger.ResultsSusceptibility to the insecticide was high but there was no discernable change in the oviposition rate or the catch of adult female mosquitoes, nor was there any change in the parous rate. In contrast, hand-held thermal foggers were highly effective, with more than 90% reduction of both laid eggs and females.ConclusionsWe believe that direct monitoring of the wild mosquito populations gives a realistic assessment of the impact of treatments and suggest that the lack of efficacy is due to lack of interaction between the target mosquitoes and the ULV aerosol. We discuss the factors that influence the effectiveness of both methods of spraying in the context of epidemic situations.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1881-y) contains supplementary material, which is available to authorized users.

Gravid Anopheles gambiae sensu stricto avoid ovipositing in Bermuda grass hay infusion and it's volatiles in two choice egg-count bioassays.

BackgroundA number of mosquito species in the Culex and Aedes genera prefer to lay eggs in Bermuda grass (Cynodon dactylon) hay infusions compared to water alone. These mosquitoes are attracted to volatile compounds from the hay infusions making the infusions effective baits in gravid traps used for monitoring vectors of arboviral and filarial pathogens. Since Bermuda grass is abundant and widespread, it is plausible to explore infusions made from it as a potential low cost bait for outdoor monitoring of the elusive malaria vector Anopheles gambiae s.s.MethodsThis study investigated preferential egg laying of individual An. gambiae s.s. in hay infusion or in tap water treated with volatiles detected in hay infusion headspace compared to tap water alone, using two-choice egg-count bioassays. Infusions were prepared by mixing 90 g of dried Bermuda grass (hay) with 24 L of unchlorinated tap water in a bucket, and leaving it for 3 days at ambient temperature and humidity. The volatiles in the headspace of the hay infusion were sampled with Tenax TA traps for 20 h and analysed using gas chromatography coupled to mass spectrometry.ResultsIn total, 18 volatiles were detected in the infusion headspace. Nine of the detected compounds and nonanal were selected for bioassays. Eight of the selected compounds have previously been suggested to attract/stimulate egg laying in An. gambiaes.s. Gravid females were significantly (p < 0.05) less likely to lay eggs in hay infusion dilutions of 25, 50 and 100 % and in tap water containing any of six compounds (3-methylbutanol, phenol, 4-methylphenol, nonanal, indole, and 3-methylindole) compared to tap water alone. The oviposition response to 10 % hay infusion or any one of the remaining four volatiles (4-hepten-1-ol, phenylmethanol, 2-phenylethanol, or 4-ethylphenol) did not differ from that in tap water.ConclusionsAnopheles gambiae s.s. prefers to lay eggs in tap water rather than Bermuda grass hay infusion. This avoidance of the hay infusion appears to be mediated by volatile organic compounds from the infusion. It is, therefore, unlikely that Bermuda grass hay infusion as formulated and used in gravid traps for Culex and Aedes mosquitoes will be suitable baits for monitoring gravid An. gambiae s.s.

Trapping biases ofCulex torrentiumandCulex pipiensrevealed by comparison of captures in CDC traps, ovitraps, and gravid traps

We evaluate three trapping methods for their effectiveness at capturing Culex pipiens and Culex torrentium, both enzootic vectors of bird-associated viruses in Europe. The comparisons, performed in two regions in Sweden, were among CDC traps baited with carbon dioxide, gravid traps, and ovitraps baited with hay infusion. The proportions of the two Culex species in a catch differed between trap types, with CDC traps catching a lower proportion of Cx. torrentium than both gravid traps and ovitraps. Between gravid traps and ovitraps, there was no difference in the proportions of the two species. The results indicate that Cx. torrentium may go undetected or underestimated compared to Cx. pipiens when using carbon dioxide baited CDC traps. The new insight of trap bias presented here adds an important dimension to consider when investigating these vectors of bird-associated viruses in the field.

Evaluación de ovitrampas letales como estrategia para el control de Aedes aegypti

Introduction: Dengue fever is a vector-borne viral disease of major public health importance. In the absence of a vaccine, control measures are primarily focused on reducing the mosquito vector. However, these strategies are very expensive, and the use of lethal ovitraps could contribute, in a practical manner, to the design of cost-effective strategies for vector control.Objective: To determine the most efficient type of lethal ovitrap for Ae. aegypti vector control by combining different types of insecticides, oviposition substrates and attractant infusions.Materials and methods: The study was conducted in two stages. In the first, 18 different ovitraps resulting from the combination of insecticides (deltamethrin and permethrin), oviposition substrates (towel, dacron and flannel), and attractant infusion (10 and 20% hay infusion, and dechlorinated water) were evaluated in the laboratory. For this evaluation, ovitraps were placed into a mosquito holding cage, and 100 gravid Ae. aegypti females were released. The top six ovitraps were selected based on the higher number of registered eggs, and the lower hatched eggs percentage. In the second, the top six ovitraps were evaluated in field conditions.Results: In laboratory conditions, statistical differences were observed between the 18 ovitraps. The ovitraps with deltamethrin were the most efficient showing the best results. In field conditions, the ovitraps with the highest vector reduction were those combining deltamethrin/towel/10% hay infusion.Conclusions: The ovitrap combining deltamethrin, towel as oviposition substrate, and 10% hay infusion as attractant was the most efficient Ae. aegypti vector control.

Isolation and Biochemical Characterization of a Glucose Dehydrogenase from a Hay Infusion Metagenome

Glucose hydrolyzing enzymes are essential to determine blood glucose level. A high-throughput screening approach was established to identify NAD(P)-dependent glucose dehydrogenases for the application in test stripes and the respective blood glucose meters. In the current report a glucose hydrolyzing enzyme, derived from a metagenomic library by expressing recombinant DNA fragments isolated from hay infusion, was characterized. The recombinant clone showing activity on glucose as substrate exhibited an open reading frame of 987 bp encoding for a peptide of 328 amino acids. The isolated enzyme showed typical sequence motifs of short-chain-dehydrogenases using NAD(P) as a co-factor and had a sequence similarity between 33 and 35% to characterized glucose dehydrogenases from different Bacillus species. The identified glucose dehydrogenase gene was expressed in E. coli, purified and subsequently characterized. The enzyme, belonging to the superfamily of short-chain dehydrogenases, shows a broad substrate range with a high affinity to glucose, xylose and glucose-6-phosphate. Due to its ability to be strongly associated with its cofactor NAD(P), the enzyme is able to directly transfer electrons from glucose oxidation to external electron acceptors by regenerating the cofactor while being still associated to the protein.

A Novel Autocidal Ovitrap for the Surveillance and Control of Aedes aegypti

We describe an inexpensive autocidal ovitrap for Aedes aegypti that uses cross-linked polyacrylamide (PAM) gel as the oviposition substrate. Aedes aegypti females readily laid eggs on PAM gel that had been hydrated with either hay infusion or water. Aedes aegypti larvae that hatched from their eggs desiccated on the surface of the PAM gel. We tested the effects of gel hydration, texture, and type of attractant on trap performance, and compared the capture rates of standard ovitraps with those of PAM gel ovitraps in the field. The results showed that the number of eggs did not vary over a range of gel hydration levels (40-100%) and that more eggs were recovered from ovitraps containing coarse gel than from those containing homogenized gel. The PAM gel hydrated with hay infusion was more attractive to gravid female mosquitoes than gel hydrated with water. In the field, the number of eggs recovered from autocidal ovitraps with PAM gel was similar to that recovered from standard ovitraps with hay infusion.

An improved autocidal gravid ovitrap for the control and surveillance of Aedes aegypti

BackgroundLimited success has been achieved using traditional vector control methods to prevent the transmission of dengue viruses. Integrated control programs incorporating alternative tools, such as gravid ovitraps (lethal ovitraps and sticky ovitraps) may provide greater potential for monitoring and reducing vector populations and dengue virus transmission. We had developed an autocidal gravid ovitrap (AGO) as a simple, low-cost device for surveillance and control of Ae. aegypti without the use of pesticides that does not require servicing for an extended period of time. The purpose of our study was to improve the efficacy and efficiency of this device.MethodsCompetitive assays were performed in the laboratory and an outdoor cage to evaluate whether modifications to the structure and appearance of our original trap design (AGO-A), and the addition of an olfactory bait (hay infusion), improve trap function. The performance of a modified trap design (AGO-B) was then assessed and compared with conventional ovitraps in a series of field tests in San Juan City, Puerto Rico. Generalized linear mixed models were used to analyze adult Ae. aegypti capture data from the laboratory, outdoor cage and field experiments.ResultsIncreasing the size of the trap entrance, altering the color of trap components, and increasing the volume/surface area of the aqueous bait significantly improved the performance of the AGO in the outdoor cage. In a subsequent field comparison, captures of Ae. aegypti females were 3.7 fold greater in the improved trap (AGO-B), compared with the original design (AGO-A). An infusion bait produced “in situ” significantly improved capture rates of the improved trap under both semi-natural and field conditions. Semi-weekly collections of Ae. aegypti females in the AGO-B were significantly correlated with cumulative rainfall 8 to 28 days prior to sampling, whereas egg collections in paired conventional ovitraps were not. When vector abundance was low, the AGO-B provided greater sensitivity and precision as a surveillance device, compared with paired conventional ovitraps.ConclusionsThe AGO-B can be used to efficiently attract and capture gravid Ae. aegypti females for more than 8 weeks without the need for trap maintenance.

&lt;i&gt;Paramecium caudatum&lt;/i&gt; Avoids from Naloxone

Protozoa aggregate to or avoid from chemical substances. We aimed to show the significance of nitric oxide (NO) in the performance of the eukaryotes to misuse drug exposure. The micro-organism Paramecium caudatum was collected from natural sources and properly isolated by repeatedly sub-cultivation in hay infusion. Number of cells per 1ml of pure medium culture was counted using Sedgwick-Rafter cell chamber. Doses of naloxone (0.05-0.4µg/µl) solely or jointly with the NO agents were infused into the chamber. Cell response was recorded after drug infusion with intervals (0-180 sec). Negative control received distilled water (1µl) instead of naloxone (legend 0). Along with, the Ca channels or cGMP pathway was banded to discuss the mechanism. According to the results, the Paramecia showed negative chemo-taxis to the naloxone, the response which is comparable with signs of withdrawal from abused drugs. This response was potentiated by activation of NO system, but, reversed after usage of the system blocker. The inhibition of Ca channels or cGMP signaling pathway markedly enhanced the avoidance. In conclusion, this study may clearly contribute the signal molecule NO in the dependence of the eukaryotes on sedative misuse drugs.