Global genomics of Aedes aegypti unveils widespread and novel infectious viruses capable of triggering a small RNA response

The mosquito Aedes aegypti is a prominent vector for arboviruses, but the breadth of mosquito viruses that infects this specie is not fully understood. In the broadest global survey to date of over 200 Ae. aegypti small RNA samples, we detected viral small interfering RNAs (siRNAs) and Piwi interacting RNAs (piRNAs) arising from mosquito viruses. We confirmed that most academic laboratory colonies of Ae. aegypti lack persisting viruses, yet two commercial strains were infected by a novel tombus-like virus. Ae. aegypti from North to South American locations were also teeming with multiple insect viruses, with Anphevirus and a bunyavirus displaying geographical boundaries from the viral small RNA patterns. Asian Ae. aegypti small RNA patterns indicate infections by similar mosquito viruses from the Americas and reveal the first wild example of dengue virus infection generating viral small RNAs. African Ae. aegypti also contained various viral small RNAs including novel viruses only found in these African substrains. Intriguingly, viral long RNA patterns can differ from small RNA patterns, indicative of viral transcripts evading the mosquitoes' RNA interference (RNAi) machinery. To determine whether the viruses we discovered via small RNA sequencing were replicating and transmissible, we infected C6/36 and Aag2 cells with Ae. aegypti homogenates. Through blind passaging, we generated cell lines stably infected by these mosquito viruses which then generated abundant viral siRNAs and piRNAs that resemble the native mosquito viral small RNA patterns. This mosquito small RNA genomics approach augments surveillance approaches for emerging infectious diseases.

Isolation, identification, and tolerance analysis of yeast during the natural fermentation process of Sidamo coffee beans

Yeast, which plays a pivotal role in the brewing, food, and medical industries, exhibits a close relationship with human beings. In this study, we isolated and purified 60 yeast strains from the natural fermentation broth of Sidamo coffee beans to screen for indigenous beneficial yeasts. Among them, 25 strains were obtained through morphological characterization on nutritional agar medium from Wallerstein Laboratory (WL), with molecular biology identifying Saccharomyces cerevisiae strain YBB-47 and the remaining 24 yeast strains identified as Pichia kudriavzevii. We investigated the fermentation performance, alcohol tolerance, SO2 tolerance, pH tolerance, sugar tolerance, temperature tolerance, ester production capacity, ethanol production capacity, H2S production capacity, and other brewing characteristics of YBB-33 and YBB-47. The results demonstrated that both strains could tolerate up to 3% alcohol by volume at a high sucrose mass concentration (400 g/L) under elevated temperature conditions (40 ℃), while also exhibiting a remarkable ability to withstand an SO2 mass concentration of 300 g/L at pH 3.2. Moreover, S. cerevisiae YBB-47 displayed a rapid gas production rate and strong ethanol productivity. whereas P. kudriavzevii YBB-33 exhibited excellent alcohol tolerance. Furthermore, this systematic classification and characterization of coffee bean yeast strains from the Sidamo region can potentially uncover additional yeasts that offer high-quality resources for industrial-scale coffee bean production.

Effect of C-type lectin 16 on dengue virus infection in Aedes aegypti salivary glands

C-type lectins (CTLs) are a family of carbohydrate-binding proteins and an important component of mosquito saliva. Although CTLs play key roles in immune activation and viral pathogenesis, little is known about their role in regulating dengue virus (DENV) infection and transmission. In this study, we established a homozygous CTL16 knockout Aedes aegypti mutant line using CRISPR/Cas9 to study the interaction between CTL16 and viruses in mosquito vectors. Furthermore, mouse experiments were conducted to confirm the transmission of DENV by CTL16-/- A. aegypti mutants. We found that CTL16 was mainly expressed in the medial lobe of the salivary glands (SGs) in female A. aegypti. CTL16 knockout increased DENV replication and accumulation in the SGs of female A. aegypti, suggesting that CTL16 plays an important role in DENV transmission. We also found a reduced expression of immunodeficiency and Janus kinase/signal transducer and activator of transcription pathway components correlated with increased DENV viral titer, infection rate, and transmission efficiency in the CTL16 mutant strain. The findings of this study provide insights not only for guiding future investigations on the influence of CTLs on immune responses in mosquitoes but also for developing novel mutants that can be used as vector control tools.

[A study on the dual use of e-cigarettes and cigarettes among adolescents in Shandong Province]

Objective: To understand the current status and its associated factors of dual use of e-cigarettes and cigarettes among adolescents in Shandong Province and explore the reasons for dual use behavior. Methods: A self-administered survey was conducted among 7 999 middle school students who were selected by stratified multi-stage cluster sample method. Data were weighted and analyzed by the SPSS 25.0 complex program. Results: In Shandong Province, the prevalence rates of attempting and current dual use of e-cigarettes and cigarettes among adolescents appeared as 7.7% and 1.3%, respectively. Male, friends smoking, and secondhand smoke exposure in the past 7 days were risk factors for dual use. Compared with cigarette smokers, dual users have no differences in cognition and behavior in quitting smoking (P>0.05). The main reason for dual users to smoke e-cigarettes was curiosity. Conclusions: Dual use of e-cigarettes and cigarettes is common among adolescents in Shandong Province, and its influencing factors are similar to traditional cigarettes. Dual use is not a transitional stage for smoking cessation. Dual users are more likely to continue smoking in the future, which should be paid attention and concern.

Micro-scale urbanization-based risk factors for dengue epidemics

Dengue is one of the world's most rapidly spreading mosquito-borne viral diseases. As it is found mostly in urban and semi-urban areas, urbanization and associated human activities that affect the environment and larval habitats could become risk factors (e.g., lane width, conditions of street ditches) for the spread of dengue. However, there are currently no systematic studies of micro-scale urbanization-based risk factors for the spread of dengue epidemics. We describe the study area, two micro-scale environmental risk factors associated with urbanization, and meteorological data. Since the observations involve spatial and temporal correlations, we also use some statistical methods for the analysis of spatial and spatial-temporal data for the relationship between urbanization and dengue. In this study, we analyzed data from Kaohsiung, a densely populated city in southern Taiwan, and found a positive correlation between environmental risk factors associated with urbanization (ditches positive for mosquito larvae and closely packed streets termed "dengue lanes") and clustering effects in dengue cases. The statistical analysis also revealed that the occurrence of positive ditches was significantly associated with that of dengue lanes in the study area. The relationship between climate variables and positive ditches was also analyzed in this paper, indicating a relationship between dengue and both rainfall and temperature, with temperature having a greater effect. Overall, this work is immediately relevant and applicable for policymakers in government, who will need to reduce these favorable habitats for vector-born disease spreaders and implement regulations for new urban constructions to thus reduce dengue spread in future outbreaks.

Extraction of genomic DNA for sequencing from snail Helix lucorum

In the past, there were no easily distinct and recognizable features as a guide for precise clinical and genetic diagnosis of cases with chromosome microdeletions involving 15q26 including CHD2,. The present study analysed the clinical data and collected venous blood samples from a pediatric patient and his healthy family members for DNA testing. The whole-exome sequencing was performed by the next-generation sequencing (NGS). Chromosomal copy-number variations were tested based on NGS. We present a review of all cases with chromosome microdeletions affecting CHD2. A novel de novo 5.82-Mb deletion at 15q25.3-15q26.1 including CHD2 was identified in our patient who is an 11.6-year-old boy. We first found surprising efficacy of lamotrigine in controlling intractable drop seizures in the individual. These cases have development delay, behavioural problems, epilepsy, variable multiple anomalies, etc. Phenotypes of individuals with deletions involving 15q26 including CHD2 are highly variable with regard to facial features and multiple developmental anomalies. We first found the special clinical entity of development delay, behavioural problems, epilepsy, variable skeletal and muscular anomalies, abnormalities of variable multiple systems and characteristic craniofacial phenotypes in patients with chromosome microdeletions involving CHD2. The larger deletions involving 15q26 including CHD2 tend to cause the classical phenotype. A distinctive craniofacial appearance of the classical phenotype is midface hypoplasia and perifacial protrusion.

[Efficacy of adjuvant programmed cell death 1 (PD-1) monoclonal antibody immunotherapy in Chinese patients with resected stage Ⅱ-Ⅲ melanoma]

Objective: To explore the efficacy of adjuvant programmed cell death 1 (PD-1) monoclonal antibody immunotherapy in Chinese patients with resected stage Ⅱ-Ⅲ melanoma. Methods: A total of 296 patients who underwent radical surgery for stage Ⅱ-Ⅲ cutaneous orlimb melanoma at Fudan University Shanghai Cancer Center and Shanghai Electric Power Hospital between 2017 and 2021 and received adjuvant PD-1 monoclonal antibody immunotherapy, low-dose interferon (IFN), or observational follow-up were enrolled in this study. Patients were divided into the PD-1 monoclonal antibody group (164 cases) and the IFN or observation group (IFN/OBS group, 132 cases) based on postoperative adjuvant treatment methods. Patients' disease recurrence and survival were observed. Results: Among the 296 patients, 77 had cutaneous melanoma and 219 had limb melanoma; 110 were stage Ⅱ and 186 were stage Ⅲ. Among stage Ⅱ patients, the median recurrence-free survival (RFS) in the PD-1 monoclonal antibody group (46 cases) did not reach, while the median RFS in the IFN/OBS group (64 cases) was 36 months. The 1-year RFS rates were 85.3% and 92.1% and the 2-year RFS rates were 71.9% and 63.7% in the PD-1 monoclonal antibody group and the IFN/OBS group, respectively, with no statistically significant difference (P=0.394). Among stage Ⅲ patients, the median RFS rates in the PD-1 monoclonal antibody group (118 cases) and the IFN/OBS group (68 cases) were 23 and 13 months, respectively. The 1-year RFS rates were 70.0% and 51.8% and the 2-year RFS rates were 51.8% and 35.1%in the PD-1 monoclonal antibody group and the IFN/OBS group, respectively, with a statistically significant difference (P=0.010). Stratified analysis showed that the advantage of PD-1 monoclonal antibody adjuvant therapy in improving RFS persisted in the subgroups of primary ulceration (HR=0.558, 95% CI: 0.348-0.893), lymph node macroscopic metastasis (HR=0.486, 95% CI: 0.285-0.828), stage ⅢC (HR=0.389, 95% CI: 0.24-0.63), and the subgroup without BRAF/c-Kit/NRAS gene mutations (HR=0.347, 95% CI: 0.171-0.706). In terms of recurrence patterns, in stage Ⅱ patients, the recurrence and metastasis rate was 15.2% (7/46) in the PD-1 monoclonal antibody group, significantly lower than the IFN/OBS group [43.8% (28/64), P=0.002]. In stage Ⅲ melanoma patients, the recurrence and metastasis rate was 42.4% (50/118) in the PD-1 monoclonal antibody group, also lower than the IFN/OBS group [63.2% (43/68), P=0.006]. Conclusions: In real-world settings, compared with patients receiving low-dose IFN adjuvant therapy or observational follow-up, PD-1 monoclonal antibody immunotherapy can reduce the recurrence and metastasis rate of cutaneous and limb melanoma, and prolong the postoperative RFS of stage Ⅲ cutaneous and limb melanoma patients. Patients with a heavier tumor burden benefit more from immunotherapy.

Short-chain fatty acids ameliorate allergic airway inflammation via sequential induction of PMN-MDSCs and Treg cells

Background

Reinforcement of the immune-regulatory pathway is a feasible strategy for prevention and therapy of allergic asthma. The short-chain fatty acids (SCFAs) acetate, propionate, and butyrate are pleiotropic microbial fermentation products known to induce regulatory T (Treg) cells and exert an immune-regulatory effect. The cellular mechanism underlying SCFA immune regulation in asthma is not fully understood.

Objective

We investigated the role of myeloid-derived suppressor cells (MDSCs) and Treg cells, the immune-regulatory cells of innate and adaptive origin, respectively, in SCFA-elicited protection against allergic airway inflammation.

Methods

BALB/c mice were given SCFA-containing drinking water before being rendered asthmatic in response to ovalbumen. When indicated, mice were given a GR1-depleting antibody to investigate the function of MDSCs in allergic inflammation of the airways. MDSCs were sorted to examine their immunosuppressive function and interaction with T cells.

Results

The mice receiving SCFAs developed less severe asthma that was accompanied by expansion of PMN-MDSCs and Treg cells. Mice depleted of PMN-MDSCs exhibited aggravated asthma, and the protective effect of SCFAs was abrogated after PMN-MDSC depletion. SCFAs were able to directly induce T-cell differentiation toward Treg cells. Additionally, we found that PMN-MDSCs enhanced Treg cell expansion in a cell contact-dependent manner. Whilst membrane-bound TGF-β has been shown to induce Treg cell differentiation, we found that MDSCs upregulated surface expression of TGF-β after coculture with T-cells and that MDSC-induced Treg cell differentiation was partially inhibited by TGF-β blockage.

Conclusions

Although previous studies revealed Treg cells as the effector mechanism of SCFA immune regulation, we found that SCFAs ameliorate allergic airway inflammation by relaying immune regulation, with sequential induction of PMN-MDSCs and Treg cells.

"Liu-Liang-Chung" syndrome with multiple congenital anomalies and the distinctive craniofacial features caused by dominant ZEB2 gene gain mutation

BACKGROUND

Contiguous gene gain syndrome including entire ZEB2 may be a novel syndrome. In the past, there were no easily distinct and recognizable features as a guide for precise clinical and genetic diagnosis of the syndrome.

CASE PRESENTATION

We report a novel case with the syndrome with a novel de novo 22.16 Mb duplication at 2q21.2-q24.1. The syndrome is characterized by multiple anomalies including the same typical craniofacial phenotype that is entirely different from Mowat-Wilson syndrome (MWS), and other quite similar features of MWS consisting of development delay, congenital heart disease, abdominal abnormalities, urogenital abnormalities, behavioral problems and so on, in which the distinctive craniofacial features can be more easily recognized.

CONCLUSIONS

Contiguous gene gain syndrome including entire ZEB2 characterized with similar multiple congenital anomalies of MWS and the distinctive craniofacial features is mainly caused by large 2q22 repeats including ZEB2 leading to dominant singe ZEB2 gene gain mutation, which is recommended to be named "Liu-Liang-Chung" syndrome. We diagnose this novel syndrome to distinguish it from MWS. Some variable additional features in the syndrome including remarkable growth and development retardation and protruding ears were recognized for the first time.

Use of unmanned ground vehicle systems in urbanized zones: A study of vector Mosquito surveillance in Kaohsiung

Dengue fever is a vector-borne disease that has become a serious global public health problem over the past decade. An essential aspect of controlling and preventing mosquito-borne diseases is reduction of mosquito density. Through the process of urbanization, sewers (ditches) have become easy breeding sources of vector mosquitoes. In this study, we, for the first time, used unmanned ground vehicle systems (UGVs) to enter ditches in urban areas to observe vector mosquito ecology. We found traces of vector mosquitoes in ~20.7% of inspected ditches, suggesting that these constitute viable breeding sources of vector mosquitoes in urban areas. We also analyzed the average gravitrap catch of five administrative districts in Kaohsiung city from May to August 2018. The gravitrap indices of Nanzi and Fengshan districts were above the expected average (3.26), indicating that the vector mosquitoes density in these areas is high. Using the UGVs to detect positive ditches within the five districts followed by insecticide application generally yielded good control results. Further improving the high-resolution digital camera and spraying system of the UGVs may be able to effectively and instantly monitor vector mosquitoes and implement spraying controls. This approach may be suitable to solve the complex and difficult task of detecting mosquito breeding sources in urban ditches.

CLEC5A mediates Zika virus-induced testicular damage

BACKGROUND

Zika virus (ZIKV) infection is clinically known to induce testicular swelling, termed orchitis, and potentially impact male sterility, but the underlying mechanisms remain unclear. Previous reports suggested that C-type lectins play important roles in mediating virus-induced inflammatory reactions and pathogenesis. We thus investigated whether C-type lectins modulate ZIKV-induced testicular damage.

METHODS

C-type lectin domain family 5 member A (CLEC5A) knockout mice were generated in a STAT1-deficient immunocompromised background (denoted clec5a^-/-stat1^-/-) to enable testing of the role played by CLEC5A after ZIKV infection in a mosquito-to-mouse disease model. Following ZIKV infection, mice were subjected to an array of analyses to evaluate testicular damage, including ZIKV infectivity and neutrophil infiltration estimation via quantitative RT-PCR or histology and immunohistochemistry, inflammatory cytokine and testosterone detection, and spermatozoon counting. Furthermore, DNAX-activating proteins for 12 kDa (DAP12) knockout mice (dap12^-/-stat1^-/-) were generated and used to evaluate ZIKV infectivity, inflammation, and spermatozoa function in order to investigate the potential mechanisms engaged by CLEC5A.

RESULTS

Compared to experiments conducted in ZIKV-infected stat1^-/- mice, infected clec5a^-/-stat1^-/- mice showed reductions in testicular ZIKV titer, local inflammation and apoptosis in testis and epididymis, neutrophil invasion, and sperm count and motility. CLEC5A, a myeloid pattern recognition receptor, therefore appears involved in the pathogenesis of ZIKV-induced orchitis and oligospermia. Furthermore, DAP12 expression was found to be decreased in the testis and epididymis tissues of clec5a^-/-stat1^-/- mice. As for CLEC5A deficient mice, ZIKV-infected DAP12-deficient mice also showed reductions in testicular ZIKV titer and local inflammation, as well as improved spermatozoa function, as compared to controls. CLEC5A-associated DAP12 signaling appears to in part regulate ZIKV-induced testicular damage.

CONCLUSIONS

Our analyses reveal a critical role for CLEC5A in ZIKV-induced proinflammatory responses, as CLEC5A enables leukocytes to infiltrate past the blood-testis barrier and induce testicular and epididymal tissue damage. CLEC5A is thus a potential therapeutic target for the prevention of injuries to male reproductive organs in ZIKV patients.

An IoT-based smart mosquito trap system embedded with real-time mosquito image processing by neural networks for mosquito surveillance

An essential aspect of controlling and preventing mosquito-borne diseases is to reduce mosquitoes that carry viruses. We designed a smart mosquito trap system to reduce the density of mosquito vectors and the spread of mosquito-borne diseases. This smart trap uses computer vision technology and deep learning networks to identify features of live Aedes aegypti and Culex quinquefasciatus in real-time. A unique mechanical design based on the rotation concept is also proposed and implemented to capture specific living mosquitoes into the corresponding chambers successfully. Moreover, this system is equipped with sensors to detect environmental data, such as CO₂ concentration, temperature, and humidity. We successfully demonstrated the implementation of such a tool and paired it with a reliable capture mechanism for live mosquitos without destroying important morphological features. The neural network achieved 91.57% accuracy with test set images. When the trap prototype was applied in a tent, the accuracy rate in distinguishing live Ae. aegypti was 92%, with a capture rate reaching 44%. When the prototype was placed into a BG trap to produce a smart mosquito trap, it achieved a 97% recognition rate and a 67% catch rate when placed in the tent. In a simulated living room, the recognition and capture rates were 90% and 49%, respectively. This smart trap correctly differentiated between Cx. quinquefasciatus and Ae. aegypti mosquitoes, and may also help control mosquito-borne diseases and predict their possible outbreak.

Hypoxia-induced upregulation of matrix metalloproteinase 9 increases basement membrane degradation by downregulating collagen type IV alpha 1 chain

Hypoxia can cause basement membrane (BM) degradation in tissues. Matrix metalloproteinase 9 (MMP-9) is involved in various human cancers as well as BM degradation by downregulating type IV collagen (COL4). This study investigated the role of MMP-9 in hypoxia-mediated BM degradation in rat bone marrow based on its regulation of collagen type IV alpha 1 chain (COL4A1). Eighty male rats were randomly divided into four groups based on exposure to hypoxic conditions at a simulated altitude of 7,000 m, control (normoxia) and 3, 7, and 10 days of hypoxia exposure. BM degradation in bone marrow was determined by transmission electron microscopy. MMP-9 levels were assessed by western blot and real-time PCR, and COL4A1 levels were assessed by western blot and immunohistochemistry. Microvessels BMs in bone marrow exposed to acute hypoxia were observed by electron microscopy. MMP-9 expression increased, COL4A1 protein expression decreased, and BM degradation occurred in the 10-, 7-, and 3-day hypoxia groups compared with that in the control group (all P < 0.05). Hypoxia increased MMP-9 levels, which in turn downregulated COL4A1, thereby increasing BM degradation. MMP-9 upregulation significantly promoted BM degradation and COL4A1 downregulation. Our results suggest that MMP-9 is related to acute hypoxia-induced BM degradation in bone marrow by regulating COL4A1.

Moringa oleifera seed ethanol extract and its active component kaempferol potentiate pentobarbital-induced sleeping behaviours in mice via a GABAergic mechanism

CONTEXT

Moringa oleifera Lam. (Moringaceae) (MO) is an important food plant that has high nutritional and medical value. However, there is limited information on whether its seeds can improve sleep.

OBJECTIVE

This study investigated the effects of MO seed ethanol extracts (EEMOS) on sleep activity improvement and examined the underlying mechanisms.

MATERIALS AND METHODS

Male ICR mice were placed into six groups (n = 12) and treated as follows: Control (sodium carboxymethyl cellulose, 20 mL/kg), estazolam tablets (2 mg/kg), EEMOS (1, 2 g/kg) and kaempferol (1, 2 mg/kg). These samples were successively given intragastric for 14 d. Locomotor activity assay, pentobarbital-induced sleeping and pentetrazol-induced seizures tests were utilized to examine the sedative-hypnotic effects (SHE) of EEMOS.

RESULTS

Compared with the control group, the results revealed that EEMOS (2 g/kg) and KA (2 mg/kg) possessed good SHE and could significantly elevate the levels of γ-aminobutyric acid and reduce the levels of glutamic acid in the mouse hypothalamus (p < 0.05). Moreover, SHE was blocked by picrotoxin, flumazenil and bicuculline (p < 0.05). EEMOS (2 g/kg) and KA (2 mg/kg) significantly upregulated the protein expression levels of glutamic acid decarboxylase-65 (GAD₆₅) and α₁-subunit of GABA_A receptors in the hypothalamus of mice (p < 0.05), not affecting glutamic acid decarboxylase-67 (GAD₆₇) and γ₂-subunit expression levels (p > 0.05). Additionally, they cause a significant increase in Cl^- influx in human cerebellar granule cells at a concentration of 8 µg/mL (p  <  0.05).

DISCUSSION AND CONCLUSIONS

These findings demonstrated that EEMOS could improve sleep by regulating GABA_A-ergic systems, and encourage further clinical trials to treat insomnia.

Spontaneous Ferromagnetism Induced Topological Transition in EuB_{6}

The interplay between various symmetries and electronic bands topology is one of the core issues for topological quantum materials. Spontaneous magnetism, which leads to the breaking of time-reversal symmetry, has been proven to be a powerful approach to trigger various exotic topological phases. In this Letter, utilizing the combination of angle-resolved photoemission spectroscopy, magneto-optical Kerr effect microscopy, and first-principles calculations, we present the direct evidence on the realization of the long-sought spontaneous ferromagnetism induced topological transition in soft ferromagnetic EuB_{6}. Explicitly, we reveal the topological transition is from Z_{2}=1 topological insulator in paramagnetic state to χ=1 magnetic topological semimetal in low temperature ferromagnetic state. Our results demonstrate that the simple band structure near the Fermi level and rich topological phases make EuB_{6} an ideal platform to study the topological phase physics.

Prohemocytes are the main cells infected by dengue virus in Aedes aegypti and Aedes albopictus

Background

The primary disease vectors for dengue virus (DENV) transmission between humans are the mosquitoes Aedes aegypti and Aedes albopictus, with Ae. aegypti population size strongly correlated with DENV outbreaks. When a mosquito is infected with DENV, the virus migrates from the midgut to the salivary glands to complete the transmission cycle. How the virus crosses the hemocoel, resulting in systemic infection, is still unclear however. During viral infection and migration, the innate immune system is activated in defense. As part of cellular-mediated immunity, hemocytes are known to defend against bacteria and Plasmodium infection and may also participate in defending against DENV infection. Hemocytes are categorized into three cell types: prohemocytes, granulocytes, and oenocytoids. Here, we investigated which hemocytes can be infected by DENV and compare hemocyte infection between Ae. aegypti and Ae. albopictus.

Methods

Hemocytes were collected from Ae. aegypti and Ae. albopictus mosquitoes that were intrathoracically infected with DENV2-GFP. The collected hemocytes were then identified via Giemsa staining and examined microscopically for morphological differences and viral infection.

Results

All three types of hemocytes were infected by DENV, though the predominantly infected cell type was prohemocytes. In Ae. aegypti, the highest and lowest infection rates at 7 days post infection occurred in prohemocytes and granulocytes, respectively. Prohemocytes were also the primary infection target of DENV in Ae. albopictus, with similar infection rates across the other two hemocyte groups. The ratios of hemocyte composition did not differ significantly between non-infected and infected mosquitoes for either species.

Conclusions

In this study, we showed that prohemocytes were the major type of hemocyte infected by DENV in both Ae. aegypti and Ae. albopictus. The infection rate of prohemocytes in Ae. albopictus was lower than that in Ae. aegypti, which may explain why systemic DENV infection in Ae. albopictus is less efficient than in Ae. aegypti and why Ae. albopictus is less correlated to dengue fever outbreaks. Future work in understanding the mechanisms behind these phenomena may help reduce arbovirus infection prevalence.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05276-w.

[Combined application of field epidemiology and laboratory etiology analysis in the investigation of a foodborne disease outbreak in Xinjiang uygur Autonomous Region, 2016]

Objectives: To analyze the causes of a foodborne outbreak in rural areas of Xinjiang between April 2 and April 5 in 2016. Methods: Cases and the relevant background information were obtained by consulting outpatient records of local health centers and regional people's hospitals and interviewing doctors and residents. All samples were collected by the laboratory test through epidemiological and food hygiene investigations. The χ² test (Fisher's exact probability method) was used to compare differences in incidence rates. Molecular typing, virulence genes and single nucleotide polymorphisms (SNPS) were analyzed by using Pulsed Field Gel Electrophoresis (PFGE) and Whole Genome Sequencing (WGS). Results: A total of 142 cases were found in this study, with incidence rate at 5.7‰ (142/24 979). Among all cases, the main symptoms were nausea (94%), vomiting (92%) and abdominal pain (67%), and the incubation period was about 2 h (1-7.5 h). There were 16 Staphylococcus aureus isolates identified and all of them could produce A+C+E mixed enterotoxin. PFGE showed 100% homology. WGS further revealed that there were 9 and 1 strains contained by Sequence Type 1 (ST1) and ST5405, respectively. All ST1 strains were in the same clade on the genome tree. Among these, 7 strains shared close proximity (74 SNPs) and 2 strains shared close relationships as well (127 SNPs). The S. aureus isolates that caused the outbreak were introduced by a mutant isolate from the milk supply station. Conclusions: This foodborne outbreak was mainly caused by Staphylococcus aureus contamination.

Comparison of Fan-Traps and Gravitraps for Aedes Mosquito Surveillance in Taiwan

A key component of integrated vector management strategies is the efficient implementation of mosquito traps for surveillance and control. Numerous trap types have been created with distinct designs and capture mechanisms, but identification of the most effective trap type is critical for effective implementation. For dengue vector surveillance, previous studies have demonstrated that active traps utilizing CO₂ attractant are more effective than passive traps for capturing Aedes mosquitoes. However, maintaining CO₂ supply in traps is so labor intensive as to be likely unfeasible in crowded residential areas, and it is unclear how much more effective active traps lacking attractants are than purely passive traps. In this study, we analyzed Aedes capture data collected in 2019 from six urban areas in Kaohsiung City to compare Aedes mosquito catch rates between (passive) gravitraps and (active) fan-traps. The average gravitrap index (GI) and fan-trap index (FI) values were 0.68 and 3.39 respectively at peak catch times from June to August 2019, with consistently higher FI values calculated in all areas studied. We compared trap indices to reported cases of dengue fever and correlated them with weekly fluctuations in temperature and rainfall. We found that FI trends aligned more closely with case numbers and rainfall than GI values, supporting the use of fan-traps for Aedes mosquito surveillance and control as part of broader vector management strategies. Furthermore, combining fan-trap catch data with rapid testing for dengue infections may improve the early identification and prevention of future disease outbreaks.

Geolocation Inference of Forensic Individual Origin by Soil Metagenomic Analysis

Abstract

Objective To preliminarily discuss the feasibility of geolocation inference of forensic individual origin by soil metagenomic analysis. Methods The 33 soil samples from Heilongjiang, Qinghai and Tibet were collected, total bacterial DNA in the samples were extracted, and universal primers were used to amplify the V3 and V4 hypervariable region of bacterial 16S rDNA. The region was sequenced by high-throughput sequencing （HTS） with the MiSeq sequencer. Bioinformatics analysis such as species composition and sample comparison was performed on sequencing data. The richness index and diversity index were calculated based on operational taxonomic unit （OTU） results. Results A total of 2 720 149 sequences were generated by sequencing. Those sequences were clustered into 114 848 OTUs. The Chao1 indexes of soil microorganisms in Heilongjiang, Qinghai, and Tibet were 797.45, 745.11 and 535.98, respectively, and Shannon indexes were 6.46, 6.36 and 6.25, respectively. The number of bacterial species and the community diversity in the soil from high to low were Heilongjiang > Qinghai > Tibet. The composition of soil bacteria in three provinces at various classification levels were obtained, the dominant genuses in Heilongjiang were Chthoniobacteraceae DA101 and an unannotated genus of Thermogemmatisporaceae; the dominant genuses in Qinghai were an unannotated genus of Cytophagaceae and an unannotated genus of Nocardioidaceae; the dominant genuses in Tibet were an unannotated genus of Comamonadaceae and Verrucomicrobiaceae Luteolibacter. The results of principal co-ordinates analysis demonstrated that, according to the weighted UniFrac analysis, the three principle components represented 56.36% of the total variable, and according to the unweighted UniFrac analysis, the three principle components represented 34.81% of the total variable. The samples from the same province could be clustered together, and the species and content of soil microorganisms from different provinces were significantly different. Conclusion Based on the metagenomic analysis method, soil samples from different regions can be effectively distinguished, which has potential application value in geolocation inference of forensic individual origin in the future.

A Thioester-Containing Protein Controls Dengue Virus Infection in Aedes aegypti Through Modulating Immune Response

Complement-like proteins in arthropods defend against invading pathogens in the early phases of infection. Thioester-containing proteins (TEPs), which exhibit high similarity to mammalian complement C3, are thought to play a key role in the innate immunity of arthropods. We identified and characterized anti-dengue virus (DENV) host factors, in particular complement-like proteins, in the mosquito Aedes aegypti. Our results indicate that TEP1 limits DENV infection in Ae. aegypti. We showed that TEP1 transcription is highly induced in mosquitoes following DENV infection. Silencing TEP1 resulted in the up-regulation of viral RNA and proteins. In addition, the production of infectious virus particles increased in the absence of TEP1. We generated a transgenic mosquito line with a TEP1 loss-of-function phenotype under a blood meal-inducible promoter. We showed that viral protein and titers increased in transgenic mosquitoes after an infectious blood meal. Interestingly, expression of transcription factor Rel2 and certain anti-microbial peptides (AMPs) were inhibited in transgenic mosquitoes. Overall, our results suggest that TEP1 regulates the immune response and consequently controls the replication of dengue virus in mosquitoes. This finding provides new insight into the molecular mechanisms of mosquito host factors in the regulation of DENV replication.