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3.
Sci Rep ; 12(1): 6550, 2022 04 21.
Article in English | MEDLINE | ID: covidwho-1815594

ABSTRACT

Dengue is recognized as a health problem that causes significant socioeconomic impacts throughout the world, affecting millions of people each year. A commonly used method for monitoring the dengue vector is to count the eggs that Aedes aegypti mosquitoes have laid in spatially distributed ovitraps. Given this approach, the present study uses a database collected from 397 ovitraps allocated across the city of Natal, RN-Brazil. The Egg Density Index for each neighborhood was computed weekly, over four complete years (from 2016 to 2019), and simultaneously analyzed with the dengue case incidence. Our results illustrate that the incidence of dengue is related to the socioeconomic level of the neighborhoods in the city of Natal. A deep learning algorithm was used to predict future dengue case incidence, either based on the previous weeks of dengue incidence or the number of eggs present in the ovitraps. The analysis reveals that ovitrap data allows earlier prediction (four to six weeks) compared to dengue incidence itself (one week). Therefore, the results validate that the quantification of Aedes aegypti eggs can be valuable for the early planning of public health interventions.


Subject(s)
Aedes , Dengue , Animals , Artificial Intelligence , Brazil/epidemiology , Dengue/epidemiology , Humans , Mosquito Vectors
4.
J Med Entomol ; 59(1): 301-307, 2022 01 12.
Article in English | MEDLINE | ID: covidwho-1784366

ABSTRACT

The efficacy of three groups of insect growth regulators, namely juvenile hormone mimics (methoprene and pyriproxyfen), chitin synthesis inhibitors (diflubenzuron and novaluron), and molting disruptor (cyromazine) was evaluated for the first time, against Aedes albopictus Skuse (Diptera: Culicidae) larvae from 14 districts in Sabah, Malaysia. The results showed that all field populations of Ae. albopictus were susceptible towards methoprene, pyriproxyfen, diflubenzuron, novaluron, and cyromazine, with resistance ratio values ranging from 0.50-0.90, 0.60-1.00, 0.67-1.17, 0.71-1.29, and 0.74-1.07, respectively. Overall, the efficacy assessment of insect growth regulators in this study showed promising outcomes and they could be further explored as an alternative to conventional insecticides.


Subject(s)
Aedes , Juvenile Hormones/pharmacology , Mosquito Control/methods , Aedes/drug effects , Aedes/growth & development , Animals , Diflubenzuron/pharmacology , Insect Vectors/drug effects , Insect Vectors/growth & development , Insecticides/pharmacology , Larva/drug effects , Larva/growth & development , Malaysia , Methoprene/pharmacology , Phenylurea Compounds/pharmacology , Pyridines/pharmacology
5.
Front Public Health ; 10: 778736, 2022.
Article in English | MEDLINE | ID: covidwho-1775985

ABSTRACT

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.


Subject(s)
Aedes , Mosquito Control , Animals , Mosquito Vectors , Taiwan
6.
Infect Genet Evol ; 99: 105243, 2022 04.
Article in English | MEDLINE | ID: covidwho-1763893

ABSTRACT

Mayaro Virus is an emerging arbovirus which can be responsible of important outbreaks in tropical regions. A retrospective study was performed in French Guiana, an ultraperipheral region of Europe in Amazonia. We identified 17 human cases between 2003 and 2019. The clinical and biological picture was close to Chikungunya with fever and arthralgia. One patient had acute meningo-encephalitis, and 4 had persistent arthralgia. Physicians should be aware of this virus, as imported cases in Europe have already occurred. AUTHOR SUMMARY: Latin America has experienced several epidemics of arboviruses in recent years, some known for a long time, such as the dengue virus, and others of more recent introduction such as the chikungunya or Zika viruses. There are other arboviruses for the moment more discreet which are rife with low noise in several countries of the continent, such as the Mayaro virus. This alphavirus, with a presentation similar to that of the chikungunya virus, is currently confined to transmission by forest mosquitoes, but its potential to be transmitted by coastal mosquitoes such as Aedes aegypti, make it a potential candidate for a continent-wide epidemic. It therefore seems necessary to know this virus as well as possible in order to anticipate the occurrence of a possible new epidemic. We present here a both demographic and clinical study of this endemic arbovirus disease in French Guiana.


Subject(s)
Aedes , Arboviruses , Chikungunya Fever , Chikungunya virus , Zika Virus Infection , Zika Virus , Animals , Arthralgia , Cross-Sectional Studies , French Guiana/epidemiology , Humans , Mosquito Vectors , Retrospective Studies , Zika Virus Infection/epidemiology
7.
Molecules ; 27(5)2022 Feb 28.
Article in English | MEDLINE | ID: covidwho-1760782

ABSTRACT

Dengue is a neglected disease, present mainly in tropical countries, with more than 5.2 million cases reported in 2019. Vector control remains the most effective protective measure against dengue and other arboviruses. Synthetic insecticides based on organophosphates, pyrethroids, carbamates, neonicotinoids and oxadiazines are unattractive due to their high degree of toxicity to humans, animals and the environment. Conversely, natural-product-based larvicides/insecticides, such as essential oils, present high efficiency, low environmental toxicity and can be easily scaled up for industrial processes. However, essential oils are highly complex and require modern analytical and computational approaches to streamline the identification of bioactive substances. This study combined the GC-MS spectral similarity network approach with larvicidal assays as a new strategy for the discovery of potential bioactive substances in complex biological samples, enabling the systematic and simultaneous annotation of substances in 20 essential oils through LC50 larvicidal assays. This strategy allowed rapid intuitive discovery of distribution patterns between families and metabolic classes in clusters, and the prediction of larvicidal properties of acyclic monoterpene derivatives, including citral, neral, citronellal and citronellol, and their acetate forms (LC50 < 50 µg/mL).


Subject(s)
Aedes , Insecticides , Oils, Volatile , Animals , Gas Chromatography-Mass Spectrometry , Humans , Insecticides/pharmacology , Larva , Mosquito Vectors , Oils, Volatile/pharmacology
8.
Int J Mol Sci ; 23(6)2022 Mar 17.
Article in English | MEDLINE | ID: covidwho-1760648

ABSTRACT

Rift Valley fever virus (RVFV) is a mosquito-borne bunyavirus endemic to Africa and the Arabian Peninsula, which causes diseases in humans and livestock. C-type lectin receptors (CLRs) represent a superfamily of pattern recognition receptors that were reported to interact with diverse viruses and contribute to antiviral immune responses but may also act as attachment factors or entry receptors in diverse species. Human DC-SIGN and L-SIGN are known to interact with RVFV and to facilitate viral host cell entry, but the roles of further host and vector CLRs are still unknown. In this study, we present a CLR-Fc fusion protein library to screen RVFV-CLR interaction in a cross-species approach and identified novel murine, ovine, and Aedes aegypti RVFV candidate receptors. Furthermore, cross-species CLR binding studies enabled observations of the differences and similarities in binding preferences of RVFV between mammalian CLR homologues, as well as more distant vector/host CLRs.


Subject(s)
Aedes , Rift Valley Fever , Rift Valley fever virus , Animals , Humans , Lectins, C-Type/genetics , Mammals , Mice , Mosquito Vectors/genetics , Sheep
9.
Acta Trop ; 227: 106269, 2022 Mar.
Article in English | MEDLINE | ID: covidwho-1729465

ABSTRACT

Monte Verde, a peri­urban squatter community near San Pedro Sula, virtually eliminated Aedes aegypti production in all known larval habitats: wells; water storage containers including pilas (open concrete water tanks used for laundry), 200-liter drums, 1000-liter plastic "cisterns," buckets; and objects collecting rainwater. The project began in 2016 when Monte Verde was overrun with dengue, Zika, and chikungunya. During more than a year of experimentation, Monte Verde residents crafted an effective, sustainable, and environmentally friendly toolkit that was inexpensive but required full community participation. Biological control with copepods, turtles, and tilapia was at the core of the toolkit, along with a mix of other methods such as getting rid of unnecessary containers, scrubbing them to remove Ae. aegypti eggs, and covering them to exclude mosquitoes or rainwater. Environmentally friendly larvicides also had a limited but crucial role. Key design features: (1) toolkit components known to be nearly 100% effective at preventing Ae. aegypti production when fitted to appropriate larval habitats; (2) using Ae. aegypti larval habitats as a resource by transforming them into "egg sinks" to drive Ae. aegypti population decline; (3) dedicated community volunteers who worked with their neighbors, targeting 100% coverage of all known Ae. aegypti larval habitats with an appropriate control method; (4) monthly monitoring in which the volunteers visited every house to assess progress and improve coverage as an ongoing learning experience for both volunteers and residents. Taking pupae as an indicator of Ae. aegypti production, from September 2018 to the end of the record in December 2021 (except for a brief lapse during COVID lockdown in 2020), the monthly count of pupae fluctuated between zero and 0.6% of the 22,984 pupae counted in the baseline survey at the beginning of the project. Adult Ae. aegypti declined to low numbers but did not disappear completely. There were no recognizable cases of dengue, Zika, or chikungunya after June 2018, though the study design based on a single site did not provide a basis for rigorous confirmation that Monte Verde's Ae. aegypti control program was responsible. Nonetheless, Monte Verde's success at eliminating Ae. aegypti production can serve as a model for extending this approach to other communities. Key ingredients for success were outside stimulation and facilitation to foster shared community awareness and commitment regarding the problem and its solution, enduring commitment of local leadership, compatibility of the toolkit with the local community, overcoming social obstacles, rapid results with "success breeding success," and building resilience.


Subject(s)
Aedes , COVID-19 , Copepoda , Dengue , Tilapia , Turtles , Zika Virus Infection , Zika Virus , Aedes/physiology , Animals , Communicable Disease Control , Community Participation , Dengue/epidemiology , Dengue/prevention & control , Honduras , Humans , Larva , Mosquito Control/methods , SARS-CoV-2
10.
BMC Public Health ; 22(1): 388, 2022 02 24.
Article in English | MEDLINE | ID: covidwho-1700631

ABSTRACT

BACKGROUND: Dengue is the major mosquito-borne disease in Sri Lanka. After its first detection in January 2020, COVID-19 has become the major health issue in Sri Lanka. The impact of public health measures, notably restrictions on movement of people to curb COVID-19 transmission, on the incidence of dengue during the period March 2020 to April 2021 was investigated. METHODS: The incidence of dengue and COVID-19, rainfall and the public movement restrictions implemented to contain COVID-19 transmission were obtained from Sri Lanka government sources. A Seasonal Autoregressive Integrated Moving Average (SARIMA) model was used to predict the monthly dengue incidence from March 2020 to April 2021 for each of the country's 25 districts based on five years of pre-pandemic data, and compared with the actual recorded incidence of dengue during this period. Ovitrap collections of Aedes larvae were performed in Jaffna city in the Jaffna district from August 2020 to April 2021 and the findings compared with similar collections made in the pre-pandemic period from March 2019 to December 2019. RESULTS: The recorded numbers of dengue cases for every month from March 2020 to April 2021 in the whole country and for all 25 districts over the same period were lower than the numbers of dengue cases predicted from data for the five years (2015-2019) immediately preceding the COVID-19 pandemic. The number of dengue cases recorded nationwide represented a 74% reduction from the predicted number of dengue cases for the March 2020 to April 2021 period. The numbers of Aedes larvae collected from ovitraps per month were reduced by 88.6% with a lower proportion of Ae. aegypti than Ae. albopictus in Jaffna city from August 2020 until April 2021 compared with March 2019 to December 2019. CONCLUSION: Public health measures that restricted movement of people, closed schools, universities and offices to contain COVID-19 transmission unexpectedly led to a significant reduction in the reported numbers of dengue cases in Sri Lanka. This contrasts with findings reported from Singapore. The differences between the two tropical islands have significant implications for the epidemiology of dengue. Reduced access to blood meals and lower vector densities, particularly of Ae. aegypti, resulting from the restrictions on movement of people, are suggested to have contributed to the lower dengue incidence in Sri Lanka.


Subject(s)
Aedes , COVID-19 , Dengue , Animals , COVID-19/epidemiology , Dengue/epidemiology , Dengue/prevention & control , Humans , Incidence , Mosquito Vectors , Pandemics/prevention & control , SARS-CoV-2 , Sri Lanka/epidemiology
11.
Parasit Vectors ; 15(1): 23, 2022 Jan 10.
Article in English | MEDLINE | ID: covidwho-1627901

ABSTRACT

BACKGROUND: Yellow fever virus (YFV) is an arbovirus that, despite the existence of a safe and effective vaccine, continues to cause outbreaks of varying dimensions in the Americas and Africa. Between 2017 and 2019, Brazil registered un unprecedented sylvatic YFV outbreak whose severity was the result of its spread into zones of the Atlantic Forest with no signals of viral circulation for nearly 80 years. METHODS: To investigate the influence of climatic, environmental, and ecological factors governing the dispersion and force of infection of YFV in a naïve area such as the landscape mosaic of Rio de Janeiro (RJ), we combined the analyses of a large set of data including entomological sampling performed before and during the 2017-2019 outbreak, with the geolocation of human and nonhuman primates (NHP) and mosquito infections. RESULTS: A greater abundance of Haemagogus mosquitoes combined with lower richness and diversity of mosquito fauna increased the probability of finding a YFV-infected mosquito. Furthermore, the analysis of functional traits showed that certain functional groups, composed mainly of Aedini mosquitoes which includes Aedes and Haemagogus mosquitoes, are also more representative in areas where infected mosquitoes were found. Human and NHP infections were more common in two types of landscapes: large and continuous forest, capable of harboring many YFV hosts, and patches of small forest fragments, where environmental imbalance can lead to a greater density of the primary vectors and high human exposure. In both, we show that most human infections (~ 62%) occurred within an 11-km radius of the finding of an infected NHP, which is in line with the flight range of the primary vectors. CONCLUSIONS: Together, our data suggest that entomological data and landscape composition analyses may help to predict areas permissive to yellow fever outbreaks, allowing protective measures to be taken to avoid human cases.


Subject(s)
Brazil , Culicidae , Disease Outbreaks , Mosquito Vectors , Yellow Fever/transmission , Aedes/growth & development , Aedes/virology , Animals , Biodiversity , Brazil/epidemiology , Climate , Culicidae/growth & development , Culicidae/virology , Forests , Humans , Mosquito Vectors/classification , Mosquito Vectors/growth & development , Mosquito Vectors/virology , Risk Factors , Yellow Fever/epidemiology
12.
PLoS Negl Trop Dis ; 15(12): e0010001, 2021 12.
Article in English | MEDLINE | ID: covidwho-1627325

ABSTRACT

INTRODUCTION: In Colombia, organochloride, organophosphate, carbamate, and pyrethroid insecticides are broadly used to control Aedes aegypti populations. However, Colombian mosquito populations have shown variability in their susceptibility profiles to these insecticides, with some expressing high resistance levels. MATERIALS AND METHODS: In this study, we analyzed the susceptibility status of ten Colombian field populations of Ae. aegypti to two pyrethroids; permethrin (type-I pyrethroid) and lambda-cyhalothrin (type-II pyrethroid). In addition, we evaluated if mosquitoes pressured with increasing lambda-cyhalothrin concentrations during some filial generations exhibited altered allelic frequency of these kdr mutations and the activity levels of some metabolic enzymes. RESULTS: Mosquitoes from all field populations showed resistance to lambda-cyhalothrin and permethrin. We found that resistance profiles could only be partially explained by kdr mutations and altered enzymatic activities such as esterases and mixed-function oxidases, indicating that other yet unknown mechanisms could be involved. The molecular and biochemical analyses of the most pyrethroid-resistant mosquito population (Acacías) indicated that kdr mutations and altered metabolic enzyme activity are involved in the resistance phenotype expression. CONCLUSIONS: In this context, we propose genetic surveillance of the mosquito populations to monitor the emergence of resistance as an excellent initiative to improve mosquito-borne disease control measures.


Subject(s)
Aedes/drug effects , Aedes/genetics , Insecticide Resistance , Insecticides/pharmacology , Animals , Colombia , Insect Proteins/genetics , Mutation , Nitriles/pharmacology , Permethrin/pharmacology , Pyrethrins/pharmacology
13.
J Theor Biol ; 535: 110987, 2022 02 21.
Article in English | MEDLINE | ID: covidwho-1620894

ABSTRACT

The annual death statistics due to vector-borne diseases transmitted by Aedes mosquitoes cause a still growing concern for the public health in the affected regions. An improved understanding of how climatic and population changes impact the spread of Aedes aegypti will help estimate the future populations exposure and vulnerability, and is essential to the improvement of public health preparedness. We apply an empirically well-investigated process-based mathematical model based on the life cycle of the mosquito to assess how climate scenarios (Representative Concentration Pathways (RCP)) and population scenarios (Shared Socioeconomic Pathways (SSP)) will affect the growth and potential distribution of this mosquito in China. Our results show that the risk area is predicted to expand considerably, increasing up to 21.46% and 24.75% of China's land area in 2050 and 2070, respectively, and the new added area lies mainly in the east and center of China. The population in the risk area grows substantially up to 2050 and then drops down steadily. However, these predicted changes vary noticeably among different combinations between RCPs and SSPs with the RCP2.6*SSP4 yielding the most favorable scenario in 2070, representing approximately 14.11% of China's land area and 113 cities at risk, which is slightly lower compared to 2019. Our results further reveal that there is a significant trade-off between climatic and human population impacts on the spreading of Aedes aegypti, possibly leading to an overestimation (underestimation) in sparsely (densely) populated areas if the populations impact on the mosquito's life history is unaccounted for. These results suggest that both climate and population changes are crucial factors in the formation of the populations exposure to Aedes-borne virus transmission in China, however, a reduced population growth rate may slow down the spread of this mosquito by effectively counteracting the climate warming impacts.


Subject(s)
Aedes , Animals , Cities , Climate Change , Humans , Models, Theoretical , Mosquito Vectors
14.
PLoS One ; 16(11): e0260281, 2021.
Article in English | MEDLINE | ID: covidwho-1546951

ABSTRACT

BACKGROUND: There is a growing need to use green alternative larvicidal control for Aedes larvae compared to chemical insecticides. Substantial reliance on chemical insecticides caused insecticide resistance in mosquito populations. Thus, research for alternate chemical compounds from natural products is necessary to control Aedes larvae. This study explores the analysis of chemical compositions from Areca catechu nut as a potential larvicide for Aedes (Diptera: Culicidae). METHODS: The Areca catechu nut collected from Ipoh, Perak, Malaysia was grounded into powder and used for Soxhlet extraction. The chemical analysis of the extracts and their structures were identified using the GCMS-QP2010 Ultra (Shimadzu) system. National Institute of Standards and Technology (NIST) Chemistry WebBook, Standard Reference Database 69 (https://webbook.nist.gov/chemistry/) and PubChem (https://pubchem.ncbi.nlm.nih.gov/), the two databases used to retrieve the synonyms, molecular formula, molecular weight, and 2-dimensional (2D) structure of chemical compounds. Next, following WHO procedures for larval bioassays, the extracts were used to asses larvicidal activity against early 4th instar larvae of Aedes aegypti and Aedes albopictus. RESULTS: The larvicidal activities were observed against early 4th stage larvae with different concentrations in the range from 200 mg/L to 1600 mg/L. The LC50 and LC95 of Aedes aegypti were 621 mg/L and 2264 mg/L respectively; whereas the LC50 and LC95 of Aedes albopictus were 636 mg/L and 2268 mg/L respectively. Mortality was not observed in the non-target organism test. The analysis using gas chromatography and mass spectrometer recovered several chemical compounds such as Arecaidine, Dodecanoic acid, Methyl tetradecanoate, Tetradecanoic acid , and n-Hexadecanoic acid bioactive components. These chemical constituents were used as additive formulations in pesticides, pest control, insect repellent, and insecticidal agents. CONCLUSIONS: Our study showed significant outcomes from the extract of Areca catechu nut and it deserves further investigation in relation to chemical components and larvicidal actions between different species of Aedes mosquitoes. Even though all these findings are fundamental, it may have some interesting potentials to be developed as natural bio-larvicidal products.


Subject(s)
Aedes/drug effects , Areca/chemistry , Insecticides/toxicity , Nuts/chemistry , Plant Extracts/toxicity , Aedes/physiology , Animals , Insect Control , Insect Repellents/chemistry , Insect Repellents/isolation & purification , Insect Repellents/toxicity , Insecticides/chemistry , Insecticides/isolation & purification , Larva/drug effects , Larva/physiology , Plant Extracts/chemistry , Plant Extracts/isolation & purification
15.
J Immunol Res ; 2021: 8214656, 2021.
Article in English | MEDLINE | ID: covidwho-1546598

ABSTRACT

Dengue fever is an infection by the dengue virus (DENV) transmitted by vector mosquitoes. It causes many infections in tropical and subtropical countries every year, thus posing a severe disease threat. Cytokine storms, one condition where many proinflammatory cytokines are mass-produced, might lead to cellular dysfunction in tissue/organ failures and often facilitate severe dengue disease in patients. Interleukin- (IL-) 18, similar to IL-1ß, is a proinflammatory cytokine produced during inflammation following inflammasome activation. Inflammatory stimuli, including microbial infections, damage signals, and cytokines, all induce the production of IL-18. High serum IL-18 is remarkably correlated with severely ill dengue patients; however, its possible roles have been less explored. Based on the clinical and basic findings, this review discusses the potential immunopathogenic role of IL-18 when it participates in DENV infection and dengue disease progression based on existing findings and related past studies.


Subject(s)
Dengue Virus/physiology , Dengue/immunology , Inflammasomes/metabolism , Inflammation/immunology , Interleukin-18/immunology , Aedes , Animals , Disease Vectors , Humans , Interleukin-1beta/immunology
16.
Vector Borne Zoonotic Dis ; 21(11): 900-909, 2021 11.
Article in English | MEDLINE | ID: covidwho-1532426

ABSTRACT

Background: A wide range of insect-specific viruses (ISVs) have been reported worldwide. There are no studies from India that have reported ISVs. The current study describes the identification of Phasi Charoen-like virus (PCLV) from Aedes aegypti mosquito-pools from six districts of Karnataka state, India. Materials and Methods: During the Chikungunya virus (CHIKV) outbreak in the Bangalore Urban district in 2019, using conventional PCR, it was found that both human and mosquito samples were positive for CHIKV. For retrieve the complete genome sequence, mosquito samples were subjected to next generation sequencing (NGS) analysis and PCLV was also found. During 2019, as part of a vector-borne disease surveillance, we received 50 mosquito pool samples from 6 districts of the state, all of them were subjected to NGS to identify PCLV. Results: The A. aegypti mosquito-pools samples were subjected to the NGS platform that led to identification of an ISV, PCLV. PCLV was identified in 26 A. aegypti mosquito-pools collected from 6 districts. We also found mixed infection of PCLV with the Dengue virus (DENV; genotypes 1 and 3) and CHIKV from five pools. The nucleotide identity for the L gene of Indian PCLV sequences ranged between 97.1% and 98.3% in comparison with the Thailand sequences. Conclusions: To the best of our knowledge, this is the first report of PCLV dual infection with DENV and CHIKV in India. The present study confirms the presence of PCLV in A. aegypti mosquitoes from Karnataka state. The study adds India in the global geographical distribution of PCLV.


Subject(s)
Aedes , Chikungunya virus , RNA Viruses , Animals , Chikungunya virus/genetics , India/epidemiology , Mosquito Vectors
17.
J Med Entomol ; 58(5): 2006-2011, 2021 09 07.
Article in English | MEDLINE | ID: covidwho-1493864

ABSTRACT

Medical Entomology as a field is inherently global - thriving on international and interdisciplinary collaborations and affected dramatically by arthropod and pathogen invasions and introductions. This past year also will be remembered as the year in which the SARS-CoV-2 COVID-19 pandemic affected every part of our lives and professional activities and impacted (or changed, sometimes in good ways) our ability to collaborate and detect or respond to invasions. This incredible year is the backdrop for the 2020 Highlights in Medical Entomology. This article highlights the broad scope of approaches and disciplines represented in the 2020 published literature, ranging from sensory and chemical ecology, population genetics, impacts of human-mediated environmental change on vector ecology, life history and the evolution of vector behaviors, to the latest developments in vector surveillance and control.


Subject(s)
Entomology , Aedes , Animals , COVID-19/epidemiology , Environment , Humans , Insect Control , Insect Vectors , Tick-Borne Diseases/epidemiology , Ticks
18.
Molecules ; 26(20)2021 Oct 15.
Article in English | MEDLINE | ID: covidwho-1480884

ABSTRACT

Mosquito-borne viruses including dengue, Zika, and Chikungunya viruses, and parasites such as malaria and Onchocerca volvulus endanger health and economic security around the globe, and emerging mosquito-borne pathogens have pandemic potential. However, the rapid spread of insecticide resistance threatens our ability to control mosquito vectors. Larvae of Aedes aegypti were screened with the Medicines for Malaria Venture Pandemic Response Box, an open-source compound library, using INVAPP, an invertebrate automated phenotyping platform suited to high-throughput chemical screening of larval motility. We identified rubitecan (a synthetic derivative of camptothecin) as a hit compound that reduced A. aegypti larval motility. Both rubitecan and camptothecin displayed concentration dependent reduction in larval motility with estimated EC50 of 25.5 ± 5.0 µM and 22.3 ± 5.4 µM, respectively. We extended our investigation to adult mosquitoes and found that camptothecin increased lethality when delivered in a blood meal to A. aegypti adults at 100 µM and 10 µM, and completely blocked egg laying when fed at 100 µM. Camptothecin and its derivatives are inhibitors of topoisomerase I, have known activity against several agricultural pests, and are also approved for the treatment of several cancers. Crucially, they can inhibit Zika virus replication in human cells, so there is potential for dual targeting of both the vector and an important arbovirus that it carries.


Subject(s)
Aedes/drug effects , Aedes/virology , Camptothecin/analogs & derivatives , Insecticides/pharmacology , Mosquito Vectors/drug effects , Mosquito Vectors/virology , Aedes/physiology , Animals , Antiviral Agents/pharmacology , Camptothecin/pharmacology , Drug Discovery , Female , High-Throughput Screening Assays , Humans , Insecticide Resistance , Larva/drug effects , Larva/physiology , Motor Activity/drug effects , Pandemics/prevention & control , Topoisomerase I Inhibitors/pharmacology , Vector Borne Diseases/epidemiology , Vector Borne Diseases/prevention & control , Virus Replication/drug effects , Zika Virus/drug effects
19.
J Virol ; 95(24): e0059621, 2021 11 23.
Article in English | MEDLINE | ID: covidwho-1443352

ABSTRACT

Cellular factors have important roles in all facets of the flavivirus replication cycle. Deciphering viral-host protein interactions is essential for understanding the flavivirus life cycle as well as development of effective antiviral strategies. To uncover novel host factors that are co-opted by multiple flaviviruses, a CRISPR/Cas9 genome wide knockout (KO) screen was employed to identify genes required for replication of Zika virus (ZIKV). Receptor for Activated Protein C Kinase 1 (RACK1) was identified as a novel host factor required for ZIKV replication, which was confirmed via complementary experiments. Depletion of RACK1 via siRNA demonstrated that RACK1 is important for replication of a wide range of mosquito- and tick-borne flaviviruses, including West Nile Virus (WNV), Dengue Virus (DENV), Powassan Virus (POWV) and Langat Virus (LGTV) as well as the coronavirus SARS-CoV-2, but not for YFV, EBOV, VSV or HSV. Notably, flavivirus replication was only abrogated when RACK1 expression was dampened prior to infection. Utilising a non-replicative flavivirus model, we show altered morphology of viral replication factories and reduced formation of vesicle packets (VPs) in cells lacking RACK1 expression. In addition, RACK1 interacted with NS1 protein from multiple flaviviruses; a key protein for replication complex formation. Overall, these findings reveal RACK1's crucial role to the biogenesis of pan-flavivirus replication organelles. IMPORTANCE Cellular factors are critical in all facets of viral lifecycles, where overlapping interactions between the virus and host can be exploited as possible avenues for the development of antiviral therapeutics. Using a genome-wide CRISPR knockout screening approach to identify novel cellular factors important for flavivirus replication we identified RACK1 as a pro-viral host factor for both mosquito- and tick-borne flaviviruses in addition to SARS-CoV-2. Using an innovative flavivirus protein expression system, we demonstrate for the first time the impact of the loss of RACK1 on the formation of viral replication factories known as 'vesicle packets' (VPs). In addition, we show that RACK1 can interact with numerous flavivirus NS1 proteins as a potential mechanism by which VP formation can be induced by the former.


Subject(s)
CRISPR-Cas Systems , Flavivirus/genetics , Neoplasm Proteins/genetics , Receptors for Activated C Kinase/genetics , Virus Replication , A549 Cells , Aedes , Animals , COVID-19 , Chlorocebus aethiops , Culicidae , Dengue Virus/genetics , Genome-Wide Association Study , HEK293 Cells , Host-Pathogen Interactions/genetics , Humans , RNA, Small Interfering/metabolism , RNA, Viral/metabolism , SARS-CoV-2 , Vero Cells , West Nile virus/genetics , Zika Virus/genetics , Zika Virus Infection/virology
20.
J Gen Virol ; 102(4)2021 04.
Article in English | MEDLINE | ID: covidwho-1393559

ABSTRACT

Reactive oxygen species (ROS) are chemically active species which are involved in maintaining cellular and signalling processes at physiological concentrations. Therefore, cellular components that regulate redox balance are likely to play a crucial role in viral life-cycle either as promoters of viral replication or with antiviral functions. Zinc is an essential micronutrient associated with anti-oxidative systems and helps in maintaining a balanced cellular redox state. Here, we show that zinc chelation leads to induction of reactive oxygen species (ROS) in epithelial cells and addition of zinc restores ROS levels to basal state. Addition of ROS (H2O2) inhibited dengue virus (DENV) infection in a dose-dependent manner indicating that oxidative stress has adverse effects on DENV infection. ROS affects early stages of DENV replication as observed by quantitation of positive and negative strand viral RNA. We observed that addition of ROS specifically affected viral titres of positive strand RNA viruses. We further demonstrate that ROS specifically altered SEC31A expression at the ER suggesting a role for SEC31A-mediated pathways in the life-cycle of positive strand RNA viruses and provides an opportunity to identify drug targets regulating oxidative stress responses for antiviral development.


Subject(s)
Dengue Virus/drug effects , Hydrogen Peroxide/pharmacology , Reactive Oxygen Species/pharmacology , Virus Replication , Zinc/pharmacology , Adolescent , Aedes , Animals , Caco-2 Cells , Child , Child, Preschool , Chlorocebus aethiops , Cricetinae , Dengue/virology , Dengue Virus/physiology , Humans , Oxidative Stress , RNA, Viral
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