Metabolic Processes Are Differentially Regulated During Wild-Type and Attenuated Dengue Virus Infection in Aedes aegypti

Successful completion of the dengue virus (DENV) life cycle in its mosquito vectors is important for efficient human–mosquito–human cycle of transmission, but the virus–mosquito interactions that underpin this critical event are poorly defined. To understand the virus–host interactions that determine viral infection by Aedes aegypti, the principal DENV vector, the authors compared transcriptomic changes in the head/thorax of the mosquito after intrathoracic infection with the wild-type DENV2 16681 strain and its attenuated derivative, PDK53. Using high-throughput RNA-sequencing, the authors identified 1,629 differentially expressed genes (DEGs) during 16681 infection, compared with only 22 DEGs identified during PDK53 infection, indicating that 16681 infection triggers a more robust host transcriptomic response compared with PDK53 infection. The authors further found that 16681 infection, but not PDK53 infection, altered metabolism in these heads/thoraces. Altogether, our findings reveal differential regulation of metabolic processes during wild-type and attenuated DENV infection, and suggest the need for future work to study the role of metabolic processes in determining DENV infection and replication in its mosquito vectors.

TIR-Domain-Containing Adapter-Inducing Interferon-β (TRIF)-Dependent Antiviral Responses Protect Mice against Ross River Virus Disease

RRV has been prevalent in the South Pacific region for decades and causes substantial economic and social costs. Though RRV is geographically restricted, a number of other alphaviruses have spread globally due to expansion of the mosquito vectors and increased international travel.

Potensi Culex quinquefasciatus sebagai Vektor Filariasis dan Kondisi Lingkungan di Kota Pekalongan

Pekalongan City was still an endemic area of Lymphatic Filariasis (LF). Twice cycles ofMass Drug Administration (MDA) had been implemented, but the Microfi laria rate (Mf rate) wasstill more than 1%. This observational research aimed to study the potential of Culex quinquefasciatusas a vector of LF in Pekalongan City. A Cross-sectional design was chosen as an approach in compilinginformation related to environmental factors and mosquitoes. The population of this research washouses located in Jenggot and Kertoharjo village with thirty-one houses, located around fi lariasiscases, purposively selected as samples. Variables studied in this research were environmental factorsand mosquito vectors. Data collection using observation, and laboratory examination throughmosquito dissection. Data would be analyzed descriptively. This study found that there were 8 Culexquinquefasciatus tested positive L3 fi larial worm (infective rate 4.39%). There were 74.2% of houseshad mosquitoes’ breeding sites around them. The breeding sites were found at domestic waste disposal,drainage in front of the house, and infi ltration well for liquid waste. As much as 86.2% of the breedingsites contained mosquito larvae. This research concluded that Cx. quinquefasciatus was confi rmedpositive fi laria worm thus establish as mosquito vector for Lymphatic Filariasis in Pekalongan City.The breeding sites related to the mosquito development were small water bodies, drainage in front ofand around the house.

Histomorohological Studies on Ovary of Guppy (Poecilia Reticulata) And Development of Follicular Placenta

The larvivorous fish Poecilia reticulata was propagated prolifically in the garden for control of mosquito vectors and later redistributed in a number of water reservoirs, in different villages nearby Dapoli. The gravid live bearing females were quickly dissected for their ovaries and embryos. The developed embryo with yellow rounded yolk sac, the remnants of the follicular placental tissue and thick vascular network of connective tissue was also observed.

Evaluation of Pyriproxyfen Effects on Aedes aegypti and Predatory Mosquito Toxorhynchites rutilus (Diptera: Culicidae)

Control of mosquito vectors of pathogens remains heavily dependent on the application of conventional insecticides. Pyriproxyfen (PPF) is a novel insecticide that has been proposed for use in autodissemination techniques to control mosquito vectors. The use of PPF can inhibit adult emergence but does not inhibit larval development. This feature is favorable for controlling Aedes aegypti because PPF has the potential to work in combination with natural sources of mortality (competition, predation) during the immature stages, and other control methods, including biocontrol agents that further suppress recruitment of adult mosquitoes. However, the PPF effects on life-history traits of Ae. aegypti in comparison to predatory mosquito Toxorhynchites rutilus, a source of mortality, are not fully understood. Here, we show that larval exposure to PPF concentrations that inhibit 50–90% of adult emergence in Ae. aegypti had a negligible effect on adult emergence and lifespan of Tx. rutilus. Weights of adult Ae. aegypti and Tx. rutilus were not influenced by PPF. These findings suggest that the use of PPF to control mosquito vectors may have low effects on mosquito biocontrol agents. Our results extend and confirm earlier data showing that PPF has potential to implement with Tx. rutilus to suppress Ae. aegypti and provide an additional advantage of PPF use in autodissemination control strategies.

Hyper-prevalence of submicroscopic Plasmodium falciparum infections in a rural area of western Kenya with declining malaria cases

Background The gold standard for diagnosing Plasmodium falciparum infection is microscopic examination of Giemsa-stained peripheral blood smears. The effectiveness of this procedure for infection surveillance and malaria control may be limited by a relatively high parasitaemia detection threshold. Persons with microscopically undetectable infections may go untreated, contributing to ongoing transmission to mosquito vectors. The purpose of this study was to determine the magnitude and determinants of undiagnosed submicroscopic P. falciparum infections in a rural area of western Kenya. Methods A health facility-based survey was conducted, and 367 patients seeking treatment for symptoms consistent with uncomplicated malaria in Homa Bay County were enrolled. The frequency of submicroscopic P. falciparum infection was measured by comparing the prevalence of infection based on light microscopic inspection of thick blood smears versus real-time polymerase chain reaction (RT-PCR) targeting P. falciparum 18S rRNA gene. Long-lasting insecticidal net (LLIN) use, participation in nocturnal outdoor activities, and gender were considered as potential determinants of submicroscopic infections. Results Microscopic inspection of blood smears was positive for asexual P. falciparum parasites in 14.7% (54/367) of cases. All of these samples were confirmed by RT-PCR. 35.8% (112/313) of blood smear negative cases were positive by RT-PCR, i.e., submicroscopic infection, resulting in an overall prevalence by RT-PCR alone of 45.2% compared to 14.7% for blood smear alone. Females had a higher prevalence of submicroscopic infections (35.6% or 72 out of 202 individuals, 95% CI 28.9–42.3) compared to males (24.2%, 40 of 165 individuals, 95% CI 17.6–30.8). The risk of submicroscopic infections in LLIN users was about half that of non-LLIN users (OR = 0.59). There was no difference in the prevalence of submicroscopic infections of study participants who were active in nocturnal outdoor activities versus those who were not active (OR = 0.91). Patients who participated in nocturnal outdoor activities and use LLINs while indoors had a slightly higher risk of submicroscopic infection than those who did not use LLINs (OR = 1.48). Conclusion Microscopic inspection of blood smears from persons with malaria symptoms for asexual stage P. falciparum should be supplemented by more sensitive diagnostic tests in order to reduce ongoing transmission of P. falciparum parasites to local mosquito vectors.

Characterization of the reproductive tract bacterial microbiota of virgin, mated, and blood-fed Aedes aegypti and Aedes albopictus females

Background Aedes aegypti and Ae. albopictus are vectors of numerous arboviruses that adversely affect human health. In mosquito vectors of disease, the bacterial microbiota influence several physiological processes, including fertility and vector competence, making manipulation of the bacterial community a promising method to control mosquito vectors. In this study, we describe the reproductive tract tissue microbiota of lab-reared virgin Ae. aegypti and Ae. albopictus males, and virgin, mated, and mated + blood-fed females of each species, comparing the bacterial composition found there to the well-described gut microbiota. Methods We performed metabarcoding of the 16S rRNA isolated from the gut, upper reproductive tract (URT; testes or ovaries), and lower reproductive tract (LRT; males: seminal vesicles and accessory glands; females: oviduct, spermathecae, and bursa) for each species, and evaluated the influence of host species, tissue, nutritional status, and reproductive status on microbiota composition. Finally, based on the identified taxonomic profiles of the tissues assessed, bacterial metabolic pathway abundance was predicted. Results The community structure of the reproductive tract is unique compared to the gut. Asaia is the most prevalent OTU in the LRTs of both Ae. aegypti and Ae. albopictus. In the URT, we observed differences between species, with Wolbachia OTUs being dominant in the Ae. albopictus URT, while Enterobacter and Serratia were dominant in Ae. aegypti URT. Host species and tissue were the best predictors of the community composition compared to reproductive status (i.e., virgin or mated) and nutritional status (i.e., sugar or blood-fed). The predicted functional profile shows changes in the abundance of specific microbial pathways that are associated with mating and blood-feeding, like energy production in mated tissues and siderophore synthesis in blood-fed female tissues. Conclusions Aedes aegypti and Ae. albopictus have distinct differences in the composition of microbiota found in the reproductive tract. The distribution of the bacterial taxonomic groups indicates that some bacteria have tissue-specific tropism for reproductive tract tissue, such as Asaia and Wolbachia. No significant differences in the taxonomic composition were observed in the reproductive tract between virgin, mated, and mated + blood-fed females, but changes in the abundance of specific metabolic pathways were found in the predicted microbial functional profiles in mated and blood-fed females. Graphical Abstract

Revisiting dengue virus-mosquito interactions: molecular insights into viral fitness

Dengue virus (DENV), like other viruses, closely interacts with the host cell machinery to complete its life cycle. Over the course of infection, DENV interacts with several host factors with pro-viral activities to support its infection. Meanwhile, it has to evade or counteract host factors with anti-viral activities which inhibit its infection. These molecular virus-host interactions play a crucial role in determining the success of DENV infection. Deciphering such interactions is thus paramount to understanding viral fitness in its natural hosts. While DENV-mammalian host interactions have been extensively studied, not much has been done to characterize DENV-mosquito host interactions despite its importance in controlling DENV transmission. Here, to provide a snapshot of our current understanding of DENV-mosquito interactions, we review the literature that identified host factors and cellular processes related to DENV infection in its mosquito vectors, Aedes aegypti and Aedes albopictus, with a particular focus on DENV-mosquito omics studies. This knowledge provides fundamental insights into the DENV life cycle, and could contribute to the development of novel antiviral strategies.