Membrane Feeding Research Articles

Ultrasound assisted efficient separation of lithium from brine with a composite polyether sulfone-ionic liquid membrane.

Green, selective and efficient extraction of lithium as one of the most important components for energy storages with ultrasound-assisted membrane separation of lithium from brine, which contains alkali metal chlorides, is conducted using a composite membrane. The composite membrane is formed by sealing a supported ionic liquid membrane (consisting of 1-alkyl-3-methylimidazolium hexafluorophosphate ([RMIM][PF6]) + TBP) with a polyethersulfone (PES) membrane and a PVC thin film membrane. The aim of the study is to optimize the separation process for the selective extraction of lithium from alkali metals. Various parameters, including membrane composition, feed concentration, and ultrasonic conditions, are adjusted to identify the best operating conditions. The results reveal that a membrane containing xIL = 0.5 of [MOIM][PF6] exhibits higher selectivity compared to other membranes studied. The flux of lithium initially increases with shorter sonication times, but it decreases as the duration of ultrasonic irradiation is prolonged. The optimal frequency for the ultrasonic treatment, which matches the bulk modulus of the membrane, is approximately 250 kHz. Higher frequencies result in higher flux and selectivity in lithium separation; besides, optimizing the amplitude and pulse cycle of the ultrasound at 75% leads to increased flux. Moreover, higher flux and selectivity (percentage of lithium with respect to the all of the ion flux) are achieved when separating lithium from alkali metal chlorides at higher feed concentrations, ranging from 250 ppm to 1000 ppm. The selectivity is influenced by the hydrophobicity, which depends on the behavior of the ionic liquid membrane. The process is promising for the future of the lithium mining from brine.

A Pvs25 mRNA vaccine induces complete and durable transmission-blocking immunity to Plasmodium vivax

Plasmodium vivax (P. vivax) is the major malaria parasite outside of Africa and no vaccine is available against it. A vaccine that interrupts parasite transmission (transmission-blocking vaccine, TBV) is considered highly desirable to reduce the spread of P. vivax and to accelerate its elimination. However, the development of a TBV against this pathogen has been hampered by the inability to culture the parasite as well as the low immunogenicity of the vaccines developed to date. Pvs25 is the most advanced TBV antigen candidate for P. vivax. However, in previous phase I clinical trials, TBV vaccines based on Pvs25 yielded low antibody responses or had unacceptable safety profiles. As the nucleoside-modified mRNA–lipid nanoparticle (mRNA–LNP) vaccine platform proved to be safe and effective in humans, we generated and tested mRNA–LNP vaccines encoding several versions of Pvs25 in mice. We found that in a prime-boost vaccination schedule, all Pvs25 mRNA–LNP vaccines elicited robust antigen-specific antibody responses. Furthermore, when compared with a Pvs25 recombinant protein vaccine formulated with Montanide ISA-51 adjuvant, the full-length Pvs25 mRNA–LNP vaccine induced a stronger and longer-lasting functional immunity. Seven months after the second vaccination, vaccine-induced antibodies retained the ability to fully block P. vivax transmission in direct membrane feeding assays, whereas the blocking activity induced by the protein/ISA-51 vaccine dropped significantly. Taken together, we report on mRNA vaccines targeting P. vivax and demonstrate that Pvs25 mRNA–LNP outperformed an adjuvanted Pvs25 protein vaccine suggesting that it is a promising candidate for further testing in non-human primates.

Pfs230 Domain 7 is targeted by a potent malaria transmission-blocking monoclonal antibody

Malaria transmission-blocking vaccines (TBVs) aim to induce antibodies that block Plasmodium parasite development in the mosquito midgut, thus preventing mosquitoes from becoming infectious. While the Pro-domain and first of fourteen 6-Cysteine domains (Pro-D1) of the Plasmodium gamete surface protein Pfs230 are known targets of transmission-blocking antibodies, no studies to date have discovered other Pfs230 domains that are functional targets. Here, we show that a murine monoclonal antibody (mAb), 18F25.1, targets Pfs230 Domain 7. We generated a subclass-switched complement-fixing variant, mAb 18F25.2a, using a CRISPR/Cas9-based hybridoma engineering method. This subclass-switched mAb 18F25.2a induced lysis of female gametes in vitro. Importantly, mAb 18F25.2a potently reduced P. falciparum infection of Anopheles stephensi mosquitoes in a complement-dependent manner, as assessed by standard membrane feeding assays. Together, our data identify Pfs230 Domain 7 as target for transmission-blocking antibodies and provide a strong incentive to study domains outside Pfs230Pro-D1 as TBV candidates.

Evaluation of a new fusion antigen, cd loop and HAP2-GCS1 domain (cd-HAP) of Plasmodium falciparum Generative Cell Specific 1 antigen formulated with various adjuvants, as a transmission blocking vaccine

BackgroundMalaria is a major global health challenge, and for the elimination and eradication of this disease, transmission-blocking vaccines (TBVs) are a priority. Plasmodium falciparum Generative Cell Specific 1 (PfGCS1), a promising TBV candidate, is essential for gamete fertilization. The HAP2-GCS1 domain of this antigen as well as its cd loop could induce antibodies that partially inhibit transmission of P. falciparum.MethodsIn the current study, a new synthetic fusion antigen containing cd loop and HAP2-GCS1 domain (cd-HAP) of PfGCS1 was evaluated as a transmission blocking vaccine candidate. Initially, the profile of naturally acquired IgG antibodies to the cd-HAP antigen was analysed in Iranian individuals infected with P. falciparum, to confirm that this new fusion protein has the appropriate structure containing common epitopes with the native form of PfGCS1. Then, the immunogenicity of cd-HAP was evaluated in BALB/c mice, using different adjuvant systems such as CpG, MPL, QS-21, and a combination of them (CMQ). Furthermore, the blocking efficacy of polyclonal antibodies induced against these formulations was also assessed by oocyst intensity and infection prevalence in the Standard Membrane Feeding Assay (SMFA).ResultsThe naturally acquired antibodies (dominantly IgG1 and IgG3 subclasses) induced in P. falciparum-infected individuals could recognize the cd-HAP antigen which implies that the new fusion protein has a proper conformation that mimics the native structure of PfGCS1. Concerning the immunogenicity of cd-HAP antigen, the highest IgG levels and titers, by a Th1-type immune profile, and elevated antibody avidity were induced in mice immunized with the cd-HAP antigen formulated with a combination of adjuvants (P < 0.0001). Additionally, cytokine profiling of the immunized mice displayed that a high level of IFN-γ response, a Th1-type immune response, was produced by splenocytes from immunized mice that received cd-HAP antigen in combination with CMQ adjuvants (P < 0.0001). This formulation of cd-HAP antigen with CMQ adjuvants could reduce oocyst intensity and infection prevalence by 82%, evidenced by the SMFA and hold significant implications for future malaria vaccine development.ConclusionAltogether, the results showed that cd-HAP antigen formulated with a combination of the adjuvants (CMQ), could be a promising formulation to develop a PfGCS1-based transmission-blocking vaccine.

Pervaporative Desulfurization: A Comprehensive Review of Principles, Advances, and Applications

Pervaporative desulfurization is a potential method for removing sulfur compounds from liquid hydrocarbon streams, having many advantages over existing methods. This overview covers the fundamentals, recent breakthroughs, and different applications of pervaporative desulfurization. The paper begins by explaining pervaporative desulfurization's core concepts, focusing on how polymeric membranes selectively separate sulfur molecules from liquid hydrocarbons. It explores membrane properties, operating conditions, and feed composition in pervaporative separation. It highlights how pervaporative desulfurization may reduce sulfur content to ultra-low levels and meet strict environmental and fuel quality standards. Finally, this comprehensive review paper concludes with a discussion on the future prospects and research directions in the field of pervaporative desulfurization. It highlights the need for continued innovation in membrane materials, module design, and process optimization, as well as the importance of addressing challenges related to scale-up and industrial implementation. Overall, this review paper provides valuable insights into the advancements, challenges, and potential applications of pervaporative desulfurization, offering a comprehensive understanding of this technology for researchers, engineers, and all parties involved in the development and implementation of sustainable sulfur removal processes.

Impact of spacer on membrane gas separation performance

Mixing in gas separation membranes has received much less attention than in membrane liquid separation because gas molecules have much smaller viscosity, allowing them to diffuse easily through membranes without requiring significant flow mixing. However, due to advancements in membrane fabrication technologies aimed at improving material properties, concentration polarization (CP) might become an issue in gas separation due to enhanced membrane efficiency and permeability. Consequently, a 2D CFD analysis is conducted to evaluate the impact of spacer-induced mixing on membrane gas concentration polarization for typical CO2/CH4 gas separation. Results show that spacers generally enhance flux performance while reducing CP in the membrane channel when compared to the case without spacers. Furthermore, the effectiveness of spacer-flux-to-pressure-loss-ratio (SPFP) reaches a peak for a Reynolds number in the range of 5 <Reh< 200 because of the trade-off between flux and pressure drop. This mixing-induced flux enhancement is most effective under high CP conditions (less mixing) within the membrane channel. Similarly, flux enhancement due to spacers can be observed as membrane selectivity, pressure ratio and feed gas concentration increase due to enhanced CP.

Canine Systemic Insecticides Fluralaner and Lotilaner Induce Acute Mortality of Triatoma gerstaeckeri, North American Vector of the Chagas Disease Parasite.

Chagas disease is a health concern for humans and animals across the Americas, and control options targeting the triatomine vectors of Trypanosoma cruzi, the causative agent of Chagas disease, are limited. Host-targeted interventions may be a useful and underused tool in controlling the spread of T. cruzi from vectors to hosts. Domestic dogs are known to be key bloodmeal hosts for triatomines as well as T. cruzi reservoirs and may be an effective and practical target for host-targeted insecticide deployment. We hypothesized that treating dogs with commercially available systemic insecticides (labeled for flea and tick control) would result in mortality of triatomines after consuming treated blood. We enrolled 16 privately owned dogs into five treatment groups to receive either fluralaner (Bravecto) or lotilaner (Credelio), alone or in combination with ivermectin. Blood from dogs before the initiation of treatment served as controls. Blood was collected 0, 7, 30, 45, and 90 days after the initial canine insecticide treatment and fed to 10 Triatoma gerstaeckeri nymphs through a membrane feeder, and survival was tracked daily for 7 days and weekly thereafter. All triatomines in the control and ivermectin groups survived the initial period, with no significant difference in long-term survival. In contrast, 99.7% of triatomines that fed on blood from dogs treated with either fluralaner or lotilaner died within 3 days. Although the impact of canine treatment on suppressing vector populations is unknown, fluralaner and lotilaner appear to be a compelling option for an integrated vector management approach to triatomine control.

Optimisation of adult Anopheles funestus blood-feeding on an artificial membrane feeding system

Malaria is one of the most severe vector-borne diseases caused by Plasmodium parasites and transmitted by Anopheles mosquitoes. Laboratory-reared anophelines are essential to advance research needed to reduce or eliminate malaria. The success of laboratory rearing as well as studies on parasite-mosquito transmission, is advanced by using an artificial membrane feeding systems. These require the optimisation of mosquito feeding to ensure that an optimal number of mosquitoes feed, thereby enabling successful reproduction or research sample sizes. In this study, various parameters such as the type of artificial membrane, density of adults in the feeding cup, age of the mosquito, duration of starvation, method of starvation, the volume of blood meal, duration of feeding, feeding in the light or dark and the effect of lactic acid were evaluated to determine their impact on the feeding rate of a main African malaria vector, Anopheles funestus. By optimising the artificial membrane feeding parameters, an increase in the feeding rate of the An. funestus mosquitoes was observed. The results obtained from these parameters increased the feeding rate of An. funestus above 50%. However, feeding rates were not significantly increased by the type of membrane, mosquito density, the volume of blood meal, duration of feeding and the addition of lactic acid to the cattle intestine membrane. Therefore, this study provides information on suitable conditions for adult mosquito feeding that allows for successful laboratory rearing and colony maintenance. Furthermore, it provides additional information for research studies that are dependent on blood-feeding, such as transmission blocking studies, endectocide studies etc.

Application of Seeded Membrane Distillation Crystallization for Zero Liquid Discharge

AbstractZero liquid discharge (ZLD) is a crucial requirement in industrial operations concerned with water scarcity and environmental protection. This study investigates the feasibility of using membrane distillation combined with crystallization (MDC) as a potential solution for ZLD. High‐saline NaCl solutions were used to evaluate the performance of a seeded MDC system, which demonstrated excellent recovery rates for both water (over 95 %) and salt (over 95.5 %). The presence of seeding crystals in the MDC system was found to inhibit membrane wetting. The MDC system achieved an average thermal efficiency of 61.5 %, showcasing its potential for long‐term processes. These results indicate that introducing seed crystals to the membrane's feed side enhances the MDC system's viability as a promising solution for ZLD. Additionally, the MDC system offers the prospect of high water and salt recovery, making it a sustainable approach to wastewater treatment and water reclamation.

A field bioassay for assessing ivermectin bio-efficacy in wild malaria vectors

BackgroundIvermectin (IVM) mass drug administration is a candidate complementary malaria vector control tool. Ingestion of blood from IVM treated hosts results in reduced survival in mosquitoes. Estimating bio-efficacy of IVM on wild-caught mosquitoes requires they ingest the drug in a blood meal either through a membrane or direct feeding on a treated host. The latter, has ethical implications, and the former results in low feeding rates. Therefore, there is a need to develop a safe and effective method for IVM bio-efficacy monitoring in wild mosquitoes.MethodsInsectary-reared Anopheles gambiae s.s. were exposed to four IVM doses: 85, 64, 43, 21 ng/ml, and control group (0 ng/ml) in three different solutions: (i) blood, (ii) 10% glucose, (iii) four ratios (1:1, 1:2, 1:4, 1:8) of blood in 10% glucose, and fed through filter paper. Wild-caught An. gambiae s.l. were exposed to 85, 43 and 21 ng/ml IVM in blood and 1:4 ratio of blood-10% glucose mixture. Survival was monitored for 28 days and a pool of mosquitoes from each cohort sacrificed immediately after feeding and weighed to determine mean weight of each meal type.ResultsWhen administered in glucose solution, mosquitocidal effect of IVM was not comparable to the observed effects when similar concentrations were administered in blood. Equal concentrations of IVM administered in blood resulted in pronounced reductions in mosquito survival compared to glucose solution only. However, by adding small amounts of blood to glucose solution, mosquito mortality rates increased resulting in similar effects to what was observed during blood feeding.ConclusionBio-efficacy of ivermectin is strongly dependent on mode of drug delivery to the mosquito and likely influenced by digestive processes. The assay developed in this study is a good candidate for field-based bio-efficacy monitoring: wild mosquitoes readily feed on the solution, the assay can be standardized using pre-selected concentrations and by not involving treated blood hosts (human or animal) variation in individual pharmacokinetic profiles as well as ethical issues are bypassed. Meal volumes did not explain the difference in the lethality of IVM across the different meal types necessitating further research on the underlying mechanisms.

Optimizing tick artificial membrane feeding for Ixodes scapularis

Artificial membrane feeding (AMF) is a powerful and versatile technique with a wide range of applications in the study of disease vectors species. Since its first description, AMF has been under constant optimization and standardization for different tick species and life stages. In the USA, Ixodes scapularis is the main vector of tick-borne zoonoses including the pathogens causing Lyme disease in humans and animals. Seeking to improve the overall fitness of I. scapularis adult females fed artificially, here, we have optimized the AMF technique, considerably enhancing attachment rate, engorgement success, egg laying, and egg hatching compared to those described in previous studies. Parameters such as the membrane thickness and the light/dark cycle to which the ticks were exposed were refined to more closely reflect the tick’s natural behavior and life cycle. Additionally, ticks were fed on blood only, blood + ATP or blood + ATP + gentamicin. The artificial feeding of ticks on blood only was successful and generated a progeny capable of feeding naturally on a host, i.e., mice. Adding ATP as a feeding stimulant did not improve tick attachment or engorgement. Notably, the administration of gentamicin, an antibiotic commonly used in tick AMF to prevent microbial contamination, negatively impacted Rickettsia buchneri endosymbiont levels in the progeny of artificially fed ticks. In addition, gentamicin-fed ticks showed a reduction in oviposition success compared to ticks artificially fed on blood only, discouraging the use of antibiotics in AMF. Overall, our data suggest that the AMF of adult females on blood only, in association with the natural feeding of their progeny on mice, might be used as an integrated approach in tick rearing, eliminating the use of protected species under the Animal Welfare Act (AWA). Of note, although optimized for I. scapularis adult ticks, I. scapularis nymphs, other tick species, and sand flies could also be fed using the membrane described in this study, indicating that it might be a suitable alternative for the artificial feeding of a variety of hematophagous species.

Topical, contact, and oral susceptibility of adult Culicoides biting midges (Diptera: Ceratopogonidae) to fluralaner

BackgroundCulicoides biting midges (Diptera: Ceratopogonidae) are economically important blood-feeding pests closely associated with livestock production. They are the principal vectors of two hemorrhagic disease viruses affecting both wild and domestic ruminants within the US: bluetongue virus (BTV) and epizootic hemorrhagic disease virus (EHDV). BTV impacts the US agriculture sector through direct commodity loss and strict international livestock trade restrictions. Yet, despite posing a considerable threat to US livestock, Culicoides are understudied, and management strategies are lacking. Current control tools for Culicoides are limited to synthetic chemicals, predominantly pyrethroids. With limited products available for livestock producers, proper pesticide rotation is difficult. The present study investigates the efficacy of fluralaner, an isoxazoline insecticide, beyond its current labeled use as an ectoparasiticide in anticipation of adding a new class of pesticides into rotation for use against biting midges.MethodsThe efficacy of fluralaner was evaluated by conducting contact, topical, and oral toxicity bioassays on adult female Culicoides sonorensis. Contact toxicity was assessed by using a modified WHO cone assay, which simulates exposure through landing on an insecticide-treated surface. A modified WHO topical toxicity assay, in which fluralaner dilutions were administered to the lateral thorax, was used to assess topical toxicity. For evaluation of oral toxicity, females were offered a blood meal spiked with fluralaner in an artificial membrane feeding system to simulate a systemic insecticide.ResultsContact exposure of fluralaner did not cause extensive or consistent mortality. Even the highest concentration tested (100 mg/ml) resulted in an average of only 24.3% mortality at 24 h, and mortality did not significantly differ between exposed and control midges at any concentration. One hundred percent mortality was consistently achieved at concentrations of 1 mg/ml when fluralaner was applied topically. The LC50 for topical exposure to fluralaner at 24 h was estimated to be 0.011 mg/ml. Oral exposure to fluralaner through ingestion of a spiked blood meal proved to be the most effective exposure method, significantly increasing mortality in a dose-dependent manner at 1 h post-exposure. The LC50 at 24 h following ingestion was 14.42 ng/ml.ConclusionOur results suggest that fluralaner is a viable candidate for use as an insecticide against adult biting midges if exposed orally, such as in a systemic given to livestock. As withdrawal period requirements for meat animals present unique yet definitive challenges, pharmacokinetic studies of isoxazoline drugs need to be pursued and finalized for livestock before fluralaner may be used as a management strategy in this manner. Alternatively, livestock not raised for consumption, such as hair sheep, would directly benefit from administering oral fluralaner as a component of a BTV disease management program.Graphical abstract

The effects of human and rhesus macaque blood meal sources on mosquito reproduction and adult survival under laboratory conditions

Mass rearing of mosquitoes as required to fulfil research studies is a technically challenging endeavor. Blood meal source has been recognized as a key consideration in mass rearing of mosquitoes that affects colony health and fecundity. Four species of laboratory-colonized mosquitoes from the Department of Entomology, US Army Medical Directorate – Armed Forces Research Institute of Medical Sciences (USAMD-AFRIMS); Anopheles cracens, An. dirus, An. minimus and An. sawadwongporni were fed blood meals from human and rhesus macaque sources using an artificial membrane feeder. The effects of different blood meal sources were evaluated concerning blood-feeding, survival and reproduction (fecundity and hatching rates). Adult survival was monitored at days 7, 14 and 21 post blood-feeding. Although the mosquitoes fed on human blood exhibited higher rates of engorgement, there were no significant differences in blood-feeding rates in An. cracens (P = 0.08) and An. dirus (P = 0.91) between rhesus macaque and human blood sources. Twenty-one days post-feeding, no significant differences were observed in the survival rates of mosquitoes fed on human versus rhesus macaque blood. Except for An. dirus, which had better survival rates with human blood (97.5%) than after feeding on rhesus macaque blood (95.4%). All mosquito species fed on human blood produced significantly more eggs when compared to those fed on rhesus macaque blood. However, there was no statistical difference in hatching rates between blood sources, except for An. dirus, which had better hatching rates with human blood. These results indicate that human and rhesus macaque blood may be a viable alternative for maintaining Anopheles mosquitoes in colony.

Experimental Acquisition, Maintenance, and Transmission of Methicillin-Resistant Staphylococcus aureus by the Common Bed Bug, Cimex lectularius.

Here, we fed bed bugs through a membrane contaminated with methicillin-resistant Staphylococcus aureus (MRSA) at a concentration naturally present on human skin. We then determined the amount of viable MRSA present on their surface and internally over a period of 7 days. We also determined whether bed bugs that fed through the contaminated membrane could transmit MRSA to an uncontaminated membrane when taking a second blood meal 7 days later. Bed bugs acquired MRSA both externally on the cuticle surface as well as internally when feeding. MRSA was found to persist for 7 days both externally and internally in some bed bugs. Furthermore, MRSA replicated internally but not externally. Most importantly, bed bugs were able to transmit MRSA to an uncontaminated membrane feeder in 2 of 3 trials. These findings provide the first experimental support for the hypothesis that bed bugs may contribute to the transmission of MRSA in some settings.

Assessment of the transmission blocking activity of antimalarial compounds by membrane feeding assays using natural Plasmodium falciparum gametocyte isolates from West-Africa.

Antimalarial drugs that can block the transmission of Plasmodium gametocytes to mosquito vectors would be highly beneficial for malaria elimination efforts. Identifying transmission-blocking drugs currently relies on evaluation of their activity against gametocyte-producing laboratory parasite strains and would benefit from a testing pipeline with genetically diverse field isolates. The aims of this study were to develop a pipeline to test drugs against P. falciparum gametocyte field isolates and to evaluate the transmission-blocking activity of a set of novel compounds. Two assays were designed so they could identify both the overall transmission-blocking activity of a number of marketed and experimental drugs by direct membrane feeding assays (DMFA), and then also discriminate between those that are active against the gametocytes (gametocyte killing or sterilizing) or those that block development in the mosquito (sporontocidal). These DMFA assays used venous blood samples from naturally infected Plasmodium falciparum gametocyte carriers and locally reared Anopheles gambiae s.s. mosquitoes. Overall transmission-blocking activity was assessed following a 24 hour incubation of compound with gametocyte infected blood (TB-DMFA). Sporontocidal activity was evaluated following addition of compound directly prior to feeding, without incubation (SPORO-DMFA); Gametocyte viability was retained during 24-hour incubation at 37°C when gametocyte infected red blood cells were reconstituted in RPMI/serum. Methylene-blue, MMV693183, DDD107498, atovaquone and P218 showed potent transmission-blocking activity in the TB-DMFA, and both atovaquone and the novel antifolate P218 were potent inhibitors of sporogonic development in the SPORO-DMA. This work establishes a pipeline for the integral use of field isolates to assess the transmission-blocking capacity of antimalarial drugs to block transmission that should be validated in future studies.

Fabrication of PES Modified by TiO2/Na2Ti3O7 Nanocomposite Mixed-Matrix Woven Membrane for Enhanced Performance of Forward Osmosis: Influence of Membrane Orientation and Feed Solutions.

Water treatment is regarded as one of the essential elements of sustainability. To lower the cost of treatment, the wastewater volume is reduced via the osmotic process. Here, mixed-matrix woven forward osmosis (MMWFO) PES membranes modified by a TiO2/Na2Ti3O7 (TNT) nanocomposite were fabricated for treating water from different sources. Various techniques were used to characterize the TNT nanocomposite. The crystal structure of TNT is a mix of monoclinic Na2Ti3O7 and anorthic TiO2 with a preferred orientation of (2-11). The SEM image shows that the surface morphology of the TNT nanocomposite is a forked nano-fur with varying sizes regularly distributed throughout the sample. The impact of TNT wt.% on membrane surface morphologies, functional groups, hydrophilicity, and performance was investigated. Additionally, using distilled water (DW) as the feed solution (FS), the effects of various NaCl concentrations, draw solutions, and membrane orientations on the performance of the mixed-matrix membranes were tested. Different water samples obtained from various sources were treated as the FS using the optimized PES/TNT (0.01 wt.%) MMWFO membrane. Using textile effluent as the FS, the impact of various NaCl DS concentrations on the permeated water volume was investigated. The results show that the MMWFO membrane generated with the TNT nanocomposite at a 0.01 wt.% ratio performed better in FO mode. After 30 min of use with 1 M NaCl and various sources of water as the FS, the optimized MMWFO membrane provided a steady water flow and exhibited antifouling behavior. DW performed better than other water types whenever it was used owing to its greater flow (136 LMH) and volume reduction (52%). Tap water (TW), textile industrial wastewater (TIWW), gray water (GW), and municipal wastewater (MW) showed volume reductions of 41%, 34%, 33%, and 31.9%, respectively. Additionally, when utilizing NaCl as the DS and TIWW as the FS, 1 M NaCl resulted in more permeated water than 0.25 M and 0.5 M, yet a higher volume reduction of 41% was obtained.

Do it yourself: fabricating and evaluating a mosquito (Diptera: Culicidae) blood-feeding device to replace a commercial option.

Tools for rearing hematophagous insects, such as mosquitoes (Diptera: Culicidae), in an insectary are essential for research and operational evaluations in vector biology and control. There is an abundance of low-cost options for practitioners without conventional infrastructure. However, few midrange options exist that provide a balance of efficiency and low material waste. We present here a reproducible design for an electrically powered blood-feeding device that offers long-term reusability, low material waste, and customizability for different species or experiments. The limitation is the requirement for electricity, but the gain is a simple, low-skill device that can be modified as needed. To validate the design, assessments of feeding angle and blood-feeding success were compared between the Salt Lake City Mosquito Abatement District artificial membrane feeder (SLAM) and a commercial system (Hemotek). Engorgement in Aedes aegypti (80-90%), Culex pipiens (50-80%), and Culex tarsalis (30-75%) was similar between the 2 units, resulting in nearly identical fecundity outcomes between devices. Additionally, 45° angles were more successful, generally, than presenting the feeders flat or vertical to the mosquitoes (df3,48, P = 1.014 × 10-15). This angle is simple to present with the SLAM device. Materials for in-house reproduction of the SLAM system are now widely available in regions with access to e-commerce and shipped goods. This results in a device schematic that should fit well into a relatively modular, do-it-yourself paradigm where the practitioner needs only to assemble some materials without complex engineering. This article provides schematics, cost comparison, and validation of the in-house-made SLAM system.

Malaria rapid diagnostic tests reliably detect asymptomatic Plasmodium falciparum infections in school-aged children that are infectious to mosquitoes

BackgroundAsymptomatic malaria infections (Plasmodium falciparum) are common in school-aged children and represent a disease transmission reservoir as they are potentially infectious to mosquitoes. To detect and treat such infections, convenient, rapid and reliable diagnostic tools are needed. In this study, malaria rapid diagnostic tests (mRDT), light microscopy (LM) and quantitative polymerase chain reaction (qPCR) were used to evaluate their performance detecting asymptomatic malaria infections that are infectious to mosquitoes.MethodsOne hundred seventy asymptomatic school-aged children (6–14 years old) from the Bagamoyo district in Tanzania were screened for Plasmodium spp. infections using mRDT (SD BIOLINE), LM and qPCR. In addition, gametocytes were detected using reverse transcription quantitative polymerase chain reaction (RT-qPCR) for all qPCR-positive children. Venous blood from all P. falciparum positive children was fed to female Anopheles gambiae sensu stricto mosquitoes via direct membrane feeding assays (DMFAs) after serum replacement. Mosquitoes were dissected for oocyst infections on day 8 post-infection.ResultsThe P. falciparum prevalence in study participants was 31.7% by qPCR, 18.2% by mRDT and 9.4% by LM. Approximately one-third (31.2%) of asymptomatic malaria infections were infectious to mosquitoes in DMFAs. In total, 297 infected mosquitoes were recorded after dissections, from which 94.9% (282/297) were derived from infections detected by mRDT and 5.1% (15/297) from subpatent mRDT infections.ConclusionThe mRDT can be used reliably to detect children carrying gametocyte densities sufficient to infect high numbers of mosquitoes. Subpatent mRDT infections contributed marginally to the pool of oocyts-infected mosquitoes.Graphical

Transmission-blocking activity of antimalarials for Plasmodium vivax malaria in Anopheles darlingi.

Malaria is caused by parasite of the genus Plasmodium and is still one of the most important infectious diseases in the world. Several biological characteristics of Plasmodium vivax contribute to the resilience of this species, including early gametocyte production, both of which lead to efficient malaria transmission to mosquitoes. This study evaluated the impact of currently used drugs on the transmission of P. vivax. Participants received one of the following treatments for malaria: i) chloroquine [10 mg/kg on day 1 and 7.5 mg/kg on day 2 and 3] co-administered with Primaquine [0.5 mg/kg/day for 7 days]; ii) Chloroquine [10 mg/kg on day 1 and 7.5 mg/kg on day 2 and 3] co-administered with one-dose of Tafenoquine [300 mg on day 1]; and iii) Artesunate and Mefloquine [100 mg and 200 mg on day 1, 2 and 3] co-administered with Primaquine [0.5 mg/kg/day for 14 days]. Patient blood was collected before treatment and 4 h, 24 h, 48 h and 72 h after treatment. The blood was used to perform a direct membrane feeding assay (DMFA) using Anopheles darlingi mosquitoes. The results showed 100% inhibition of the mosquito infection after 4 h using ASMQ+PQ, after 24 h for the combination of CQ+PQ and 48 h using CQ+TQ. The density of gametocytes declined over time in all treatment groups, although the decline was more rapid in the ASMQ+PQ group. In conclusion, it was possible to demonstrate the transmission-blocking efficacy of the malaria vivax treatment and that ASMQ+PQ acts faster than the two other treatments.

Evaluation of Aedes aegypti Feeding Status.

Female mosquitoes need vertebrate blood for egg development. Evaluating mosquito behavior is essential for determining the ability of a mosquito to blood feed. Blood feeding experiments are often performed using artificial membrane feeders; however, such experiments do not represent realistic scenarios in which a mosquito injects saliva into the host to prevent host hemostatic responses. Vertebrate animal models are therefore more representative of a natural blood feeding event. Here, we describe a methodology to evaluate mosquito blood feeding success that can be used to compare blood feeding between mosquito groups-for instance, wild-type versus transgenic mosquitoes lacking salivary proteins or field-collected versus laboratory-reared mosquitoes. We also include a simple procedure to measure blood meal size, allowing for a more quantitative assessment of feeding status. The volume of ingested blood directly affects mosquito fecundity and fertility, important markers of fitness. The methods described herein can be used to evaluate transmission-blocking vaccines, insecticides, or fitness costs associated with transgenic mosquitoes.