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1.
Article in English | MEDLINE | ID: mdl-38965027

ABSTRACT

The Spanish Society of Tropical Medicine and International Health (SEMTSI), the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), the Spanish Society of Emergency Medicine (SEMES), the Spanish Society of Primary Care Physicians (SEMERGEN) and the Spanish Society of Family and Community Medicine (SEMFYC) have prepared a consensus statement on the diagnosis and management of patients with imported febrile illnesses. Twenty authors with different backgrounds and representing different healthcare perspectives (ambulatory primary care, travel and tropical medicine specialists, emergency medicine, hospital care, microbiology and parasitology and public health), identified 39 relevant questions, which were organised in 7 thematic blocks. After a systematic review of the literature and a thoughtful discussion, the authors prepared 125 recommendations, as well as several tables and figures to be used as a consulting tool. The present executive summary shows a selection of some of the most relevant questions and recommendations included in the guidelines.

2.
Article in English | MEDLINE | ID: mdl-38961045

ABSTRACT

Cervus nippon (sika deer) are widely distributed throughout eastern Asia. Deer possess a variety of antibodies against several zoonotic pathogens, indicating that they act as reservoir of zoonoses. In this study, we reported the characterization of cultured cells derived from sika deer and evaluated their susceptibility to arthropod-borne viruses to clarify their usefulness in virological studies. Cells derived from testicular tissue in Dulbecco's modified eagle medium with 16% fetal bovine serum started growing as primary cultured cells. The diploid cells consisted of 68 chromosomes, consistent with those of Japanese sika deer previously reported. The phylogenetic analysis showed the cells formed a robust clade with Japanese population of C. nippon, indicating that the cultured cells established in this study were originated from the Japanese sika deer. The cells immortalized by the simian virus 40 T-antigen were predominantly spindle-shaped cells exhibiting adhesive properties, and cultivated at 37°C and 5% CO2, which are common culture conditions for many mammalian cell lines. Western blotting analysis indicated that the cultured cells were multiple types of cells that coexist, including at least epithelial, fibroblast, and also Leydig cells. We confirmed that the cells have susceptibility to several arboviruses distributed in Japan: Getah virus, Japanese encephalitis virus, Oz virus, and severe fever with thrombocytopenia syndrome virus, but not to Tarumiz tick virus. From these results, the cells contribute to clarify the role of sika deer as a reservoir of zoonoses in nature and deer-associated experimental research at the cellular and molecular levels.

3.
Parasit Vectors ; 17(1): 285, 2024 Jul 02.
Article in English | MEDLINE | ID: mdl-38956650

ABSTRACT

Usutu virus is an emerging pathogen transmitted by mosquitoes. Culex modestus mosquitoes are widespread in Europe, but their role in disease transmission is poorly understood. Recent data from a single infectious mosquito suggested that Culex modestus could be an unrecognized vector for Usutu virus. In this study, our aim was to corroborate this finding using a larger sample size. We collected immature Culex modestus from a reedbed pond in Flemish Brabant, Belgium, and reared them in the laboratory until the third generation. Adult females were then experimentally infected with Usutu virus in a blood meal and incubated at 25 °C for 14 days. The presence of Usutu virus in the saliva, head and body of each female was determined by plaque assay and quantitative real-time reverse-transcription polymerase chain reaction (qRT-PCR). The transmission efficiency was 54% (n = 15/28), confirming that Belgian Culex modestus can experimentally transmit Usutu virus.


Subject(s)
Culex , Flavivirus Infections , Flavivirus , Mosquito Vectors , Animals , Culex/virology , Female , Mosquito Vectors/virology , Flavivirus/genetics , Flavivirus/physiology , Belgium , Flavivirus Infections/transmission , Flavivirus Infections/virology , Saliva/virology
4.
Int J Health Geogr ; 23(1): 18, 2024 Jul 07.
Article in English | MEDLINE | ID: mdl-38972982

ABSTRACT

BACKGROUND: The spread of mosquito-transmitted diseases such as dengue is a major public health issue worldwide. The Aedes aegypti mosquito, a primary vector for dengue, thrives in urban environments and breeds mainly in artificial or natural water containers. While the relationship between urban landscapes and potential breeding sites remains poorly understood, such a knowledge could help mitigate the risks associated with these diseases. This study aimed to analyze the relationships between urban landscape characteristics and potential breeding site abundance and type in cities of French Guiana (South America), and to evaluate the potential of such variables to be used in predictive models. METHODS: We use Multifactorial Analysis to explore the relationship between urban landscape characteristics derived from very high resolution satellite imagery, and potential breeding sites recorded from in-situ surveys. We then applied Random Forest models with different sets of urban variables to predict the number of potential breeding sites where entomological data are not available. RESULTS: Landscape analyses applied to satellite images showed that urban types can be clearly identified using texture indices. The Multiple Factor Analysis helped identify variables related to the distribution of potential breeding sites, such as buildings class area, landscape shape index, building number, and the first component of texture indices. Models predicting the number of potential breeding sites using the entire dataset provided an R² of 0.90, possibly influenced by overfitting, but allowing the prediction over all the study sites. Predictions of potential breeding sites varied highly depending on their type, with better results on breeding sites types commonly found in urban landscapes, such as containers of less than 200 L, large volumes and barrels. The study also outlined the limitation offered by the entomological data, whose sampling was not specifically designed for this study. Model outputs could be used as input to a mosquito dynamics model when no accurate field data are available. CONCLUSION: This study offers a first use of routinely collected data on potential breeding sites in a research study. It highlights the potential benefits of including satellite-based characterizations of the urban environment to improve vector control strategies.


Subject(s)
Aedes , Cities , Satellite Imagery , Animals , Satellite Imagery/methods , Mosquito Vectors , French Guiana/epidemiology , Dengue/epidemiology , Dengue/transmission , Dengue/prevention & control , Humans , Breeding/methods
5.
Animal Model Exp Med ; 2024 Jul 10.
Article in English | MEDLINE | ID: mdl-38987937

ABSTRACT

Vector-borne diseases caused by arthropod-borne viruses (arboviruses) are a considerable challenge to public health globally. Mosquito-borne arboviruses, such as Chikungunya, Dengue, and Zika viruses, cause a range of human illnesses and may be fatal. Currently, efforts to control these diseases still face challenges due to growing vector resistance towards insecticides, urbanization, and limited effective antiviral treatments and vaccines. Animal models are crucial in antiviral research on mosquito-borne arboviruses, playing a role in understanding disease mechanisms, vaccine development, and toxicity testing, but the application of animal models still faces the challenges of ethical considerations and animal-to-human translational success. Genetically engineered mouse models, hamster models and non-human primate (NHP) are currently used in arbovirus research, but new models such as tree shrews and novel humanized mice are emerging. In the context of Malaysian research, the use of long-tailed macaques as potential NHP models for arbovirus research is possible; however, it faces the ethical dilemma of using an endangered species for scientific purposes. Overall, animal models play a crucial role in advancing infectious disease research, but a balance between medical research and species conservation must be upheld.

6.
Ticks Tick Borne Dis ; 15(6): 102380, 2024 Jul 11.
Article in English | MEDLINE | ID: mdl-38996644

ABSTRACT

Beiji nairovirus (BJNV), in the family Nairoviridae, the order Bunyavirales, was recently reported as a causative agent of an emerging tick-borne zoonotic infection in China. This study investigated the prevalence of BJNV in ticks in Japan. Screening of over 2,000 ticks from multiple regions revealed a widespread distribution of BJNV and BJNV-related viruses in Japan, particularly in the northern island, and in other high altitude areas with exclusive occurrence of Ixodes ticks. Phylogenetic analysis identified three distinct groups of nairoviruses in ticks in Japan: BJNV, Yichun nairovirus (YCNV) and a newly identified Mikuni nairovirus (MKNV). BJNV and YCNV variants identified in ticks in Japan exhibited high nucleotide sequence identities to those in China and Russia with evidence of non-monophyletic evolution among BJNVs, suggesting multiple cross-border transmission events of BJNV between the Eurasian continent and Japan. Whole genome sequencing of BJNV and MKNV revealed a unique GA-rich region in the S segment, the significance of which remains to be determined. In conclusion, the present study has shown a wide distribution and diversity of BJNV-related nairoviruses in Ixodes ticks in Japan and has identified unique genomic structures. The findings demonstrate the significance of BJNV as well as related viruses in Japan and highlight the necessity of monitoring emerging nairovirus infections and their potential risks to public health.

7.
J Med Entomol ; 2024 Jul 12.
Article in English | MEDLINE | ID: mdl-39001615

ABSTRACT

Directly involved in the "suck-and-spit" physiology, female mosquito salivary glands (SGs) primarily imbibe blood for egg development and release anticoagulants to keep blood flowing. Indirectly involved, mosquitoes can uptake arboviruses during blood feeding from a viremic host. This research examined the presence of the filamentous cytoplasmic contractile protein (F-actin) and heparan sulfate proteoglycan (HSPG), in the female mosquito SGs. Immunofluorescent antibody labeling of actin molecules or HSPG combined with anatomy suggests that F-actin forms a network in the SG lobe parenchymal cells attached to intralobar ducts by HSPG. In addition, F-actin twists around intralobar SG ducts in a beaded manner, altogether involved in the expulsion of SG secretions. This arrangement in female Aedes aegypti SGs, suggests that F-actin structures are integrally involved in transmitting infectious agents into hosts.

8.
Integr Zool ; 2024 Jul 17.
Article in English | MEDLINE | ID: mdl-39016029

ABSTRACT

Ticks can transmit many pathogens, including arboviruses, to their vertebrate hosts. Arboviruses must overcome or evade defense mechanisms during their passage from the tick gut to the hemolymph, salivary glands, and the feeding site in the host skin. This review summarizes current knowledge of defense mechanisms in specific tick tissues and at the feeding site in the host skin. We discuss the possible roles of these defense mechanisms in viral infection and transmission. The responses of tick salivary proteins to arbovirus infection are also discussed. This review provides information that may help accelerate research on virus-tick interactions.

9.
RECIIS (Online) ; 18(2)abr.-jun. 2024.
Article in Portuguese | LILACS, Coleciona SUS | ID: biblio-1561903

ABSTRACT

Chikungunya, arbovirose que provoca febre e artralgia debilitante, demonstra potencial crônico e incapacitante por longos períodos, não havendo vacinas ou terapias específicas. Recentemente, a doença evoluiu da condição negligenciada para uma ameaça à saúde pública, impactando milhões de pessoas em regiões tropicais e subtropicais. Este estudo analisa a produção do conhecimento sobre a Chikungunya, na perspectiva da Vigilância em Saúde. Trata-se de metodologia exploratória-descritiva, com análise bibliométrica. Realizou-se a coleta nas bases Scopus e Web of Science para artigos de 2008 a 2022. A análise revelou uma série temporal de produção destacando a contribuição de Estados Unidos, Brasil e França. Identificaram-se como áreas mais produtivas: doenças transmissíveis, medicina tropical e parasitologia, fundamentais à Vigilância em Saúde e ao planejamento de políticas públicas. Quanto aos pesquisadores, Weaver, Scott C., Failloux, Anna-Bella e De Lamballerie, Xavier foram relevantes no cenário global, indicando a importância da colaboração e da abordagem interdisciplinar.


Chikungunya, an arbovirus that causes fever and debilitating arthralgia, has potential to be chronic and incapacitating for long periods, and there are no vaccines or therapies available for it. Recently, the disease has evolved from a neglected condition to public health threat, impacting millions in tropical and subtropical regions. This study analyzed the knowledge production about chikungunya, from the perspective of Health Surveillance, using an exploratory-descriptive methodology and bibliometric analysis. Articles from 2008 to 2022 were collected from Scopus and Web of Science databases. The analysis showed a production time series, highlighting the contribution of United States, Brazil, and France. The most productive areas were identified as: communicable diseases, tropical medicine and parasitology, which are fundamental to Health Surveillance and public policy planning. Regarding researchers, Weaver, Scott C., Failloux, Anna-Bella, and De Lamballerie, Xavier were relevant in the global scenario, indicating the importance of collaboration and of the interdisciplinary approach.


El chikungunya, arbovirus que causa fiebre y artralgia debilitante, tiene potencial de ser crónico e incapacitante por largos periodos, todavía no hay vacunas ni terapias. Recientemente, la enfermedad ha pasado de afección desatendida a amenaza para la salud pública, afectando a millones en regiones tropicales y subtropicales. Este estudio analiza la producción de conocimientos sobre chikungunya, desde la perspectiva de la Vigilancia Sanitaria. Se utilizó una metodología exploratoria-descriptiva con análisis bibliométrico. Se recompilaron artículos de Scopus y Web of Science, 2008-2022. El análisis reveló una serie temporal de producción, destacando la contribución de EEUU, Brasil y Francia. Se identificaron como áreas más productivas: enfermedades transmisibles, medicina tropical y parasitología, fundamentales para la Vigilancia Sanitaria y la planificación de políticas públicas. En cuanto a los investigadores, Weaver, Scott C., Failloux, Anna-Bella y De Lamballeire, Xavier fueron relevantes en el escenario global, indicando la importancia de la colaboración y del enfoque interdisciplinario.


Subject(s)
Epidemiology , Bibliometrics , Chikungunya virus , Scientific and Technical Activities , Health Communication , Health Policy , Arbovirus Infections , Health Surveillance , Public Health , Communicable Diseases , Public Health Surveillance
10.
Viruses ; 16(6)2024 Jun 14.
Article in English | MEDLINE | ID: mdl-38932252

ABSTRACT

Brazil has earned the moniker "arbovirus hotspot", providing an ideal breeding ground for a multitude of arboviruses thriving in various zoonotic and urban cycles. As the planet warms and vectors expand their habitat range, a nuanced understanding of lesser-known arboviruses and the factors that could drive their emergence becomes imperative. Among these viruses is the Iguape virus (IGUV), a member of the Orthoflavivirus aroaense species, which was first isolated in 1979 from a sentinel mouse in the municipality of Iguape, within the Vale do Ribeira region of São Paulo State. While evidence suggests that IGUV circulates among birds, wild rodents, marsupials, bats, and domestic birds, there is no information available on its pathogenesis in both humans and animals. The existing literature on IGUV spans decades, is outdated, and is often challenging to access. In this review, we have curated information from the known literature, clarifying its elusive nature and investigating the factors that may influence its emergence. As an orthoflavivirus, IGUV poses a potential threat, which demands our attention and vigilance, considering the serious outbreaks that the Zika virus, another neglected orthoflavivirus, has unleashed in the recent past.


Subject(s)
Flavivirus , Animals , Brazil/epidemiology , Flavivirus/physiology , Humans , Flavivirus Infections/virology , Flavivirus Infections/epidemiology , Flavivirus Infections/veterinary , Phylogeny , Mice , Birds/virology
11.
Acta Trop ; 257: 107272, 2024 Jun 15.
Article in English | MEDLINE | ID: mdl-38885823

ABSTRACT

The Orthoflavivirus ilheusense (ILHV) is an arbovirus that was first isolated in Brazil in 1944 during an epidemiologic investigation of yellow fever. Is a member of the Flaviviridae family and it belongs to the antigenic complex of the Ntaya virus group. Psorophora ferox is the primary vector of ILHV and this study presents the isolation and phylogenetic analysis of ILHV in a pool of Ps. ferox collected in the state of Goiás in 2021. Viral isolation tests were performed on Vero cells and C6/36 clones. The indirect immunofluorescence test (IFI) was used to confirm the positivity of the sample. The positive sample underwent RT-qPCR, sequencing, and phylogenetic analysis. This is the first report of ILHV circulation in this municipality and presented close relationship between this isolate and another ILHV isolate collected in the city of Belém (PA).

12.
Pathogens ; 13(6)2024 May 28.
Article in English | MEDLINE | ID: mdl-38921757

ABSTRACT

The Chikungunya virus (CHIKV) presents global health challenges, with Brazil experiencing outbreaks since its introduction in 2014. In 2023, following a CHIKV outbreak in Minas Gerais (MG), social media was used to optimize an entomological survey aimed at identifying vectors and viral lineages and assessing insecticide resistance. Following Instagram posts, residents with suspected CHIKV infection were able to schedule mosquito aspirations. In total, 421 mosquitoes (165 Aedes aegypti and 256 Culex quinquefasciatus) were captured from 40 households in Salinas city (MG) and tested for the Dengue, Zika, and Chikungunya viruses through RT-qPCR. Twelve of 57 pools (10 Ae. aegypti and two Cx. quinquefasciatus) tested positive for CHIKV RNA. Viral RNA was also detected in the heads of nine Ae. aegypti, indicating viral dissemination but not in Cx. quinquefasciatus. Genome sequencing yielded the first near-complete genome from the 2023 outbreak, unveiling that the CHIKV strain belonged to the East/Central/South African (ECSA) genotype. Additionally, genetic analyses revealed high frequencies of kdr alleles, including in CHIKV-infected mosquitoes, suggesting resistance to pyrethroid insecticides in this Ae. aegypti population. Social media was important for guiding mosquito-capture efforts in CHIKV transmission hotspots, thus optimizing the opportunity for viral detection. These findings emphasize the urgent need for innovative vector studies and control strategies, as well as interdisciplinary approaches in public health interventions.

13.
Pathogens ; 13(6)2024 Jun 03.
Article in English | MEDLINE | ID: mdl-38921767

ABSTRACT

Oropouche orthobunyavirus (OROV) is an arbovirus transmitted by midges that has been involved in outbreaks throughout Central and South America. In Brazil, human cases have been historically concentrated in the northern region of the country. Oropouche fever in humans range from mild clinical signs to rare neurological events, and is considered a neglected tropical disease in Brazil. Due to the clinical similarities to other arboviruses, such as chikungunya and dengue viruses, OROV infections are likely to be underreported. Chikungunya virus (CHIKV) cases in Brazil were first recognized in 2014 in the states of Amapá and Bahia in the north and northeast regions, respectively. Both OROV and CHIKV cause nonspecific symptoms, making clinical diagnosis difficult in a scenario of arbovirus cocirculation. Aiming to investigate OROV transmission during the CHIKV introduction in the state of Amapá located in the Brazilian Amazon, we conducted a retrospective molecular (RT-qPCR) and serological investigation in febrile cases (N = 166) collected between August 2014 and May 2015. All acute serum samples were negative for OROV RNA using RT-qPCR. However, neutralizing antibodies for OROV were detected using a plaque reduction neutralization test (PRNT90) in 10.24% (17/166) of the patients, with neutralizing antibody titers ranging from 20 to ≥640, suggesting the previous exposure of patients to OROV. Regarding CHIKV, recent exposure was confirmed by the detection of CHIKV RNA in 20.25% (33/163) of the patients and by the detection of anti-CHIKV IgM in 28.57% (44/154) of the patients. The additional detection of anti-CHIKV IgG in 12.58% (19/151) of the febrile patients suggests that some individuals had been previously exposed to CHIKV. Whether the OROV exposure reported here occurred prior or during the CHIKV circulation in Amapá, is unknown, but because those arboviral infections share similar clinical signs and symptoms, a silent circulation of enzootic arboviruses during the introduction of exotic arboviruses may occur, and highlights the importance of syndromic cases' surveillance to arboviruses in Brazil.

14.
J Gen Virol ; 105(6)2024 Jun.
Article in English | MEDLINE | ID: mdl-38921821

ABSTRACT

Schmallenberg virus (SBV) belongs to the Simbu serogroup within the family Peribunyaviridae, genus Orthobunyavirus and is transmitted by Culicoides biting midges. Infection of naïve ruminants in a critical phase of gestation may lead to severe congenital malformations. Sequence analysis from viremic animals revealed a very high genome stability. In contrast, sequence variations are frequently described for SBV from malformed fetuses. In addition to S segment mutations, especially within the M segment encoding the major immunogen Gc, point mutations or genomic deletions are also observed. Analysis of the SBV_D281/12 isolate from a malformed fetus revealed multiple point mutations in all three genome segments. It also has a large genomic deletion in the antigenic domain encoded by the M segment compared to the original SBV reference strain 'BH80/11' isolated from viremic blood in 2011. Interestingly, SBV_D281/12 showed a marked replication deficiency in vitro in Culicoides sonorensis cells (KC cells), but not in standard baby hamster kidney cells (BHK-21). We therefore generated a set of chimeric viruses of rSBV_D281/12 and wild-type rSBV_BH80/11 by reverse genetics, which were characterized in both KC and BHK-21 cells. It could be shown that the S segment of SBV_D281/12 is responsible for the replication deficit and that it acts independently from the large deletion within Gc. In addition, a single point mutation at position 111 (S to N) of the nucleoprotein was identified as the critical mutation. Our results suggest that virus variants found in malformed fetuses and carrying characteristic genomic mutations may have a clear 'loss of fitness' for their insect hosts in vitro. It can also be concluded that such mutations lead to virus variants that are no longer part of the natural transmission cycle between mammalian and insect hosts. Interestingly, analysis of a series of SBV sequences confirmed the S111N mutation exclusively in samples of malformed fetuses and not in blood from viremic animals. The characterization of these changes will allow the definition of protein functions that are critical for only one group of hosts.


Subject(s)
Bunyaviridae Infections , Ceratopogonidae , Genome, Viral , Orthobunyavirus , Animals , Orthobunyavirus/genetics , Orthobunyavirus/classification , Orthobunyavirus/isolation & purification , Bunyaviridae Infections/virology , Bunyaviridae Infections/veterinary , Ceratopogonidae/virology , Cricetinae , Cell Line , Virus Replication , Point Mutation , Cattle , Sheep , Phylogeny , RNA, Viral/genetics
15.
Front Microbiol ; 15: 1394661, 2024.
Article in English | MEDLINE | ID: mdl-38863760

ABSTRACT

Our knowledge of alphavirus genetic diversity is mainly based on viruses isolated from anthropophilic mosquito species, humans, and livestock during outbreaks. Studies on alphaviruses from sylvatic amplification cycles in sub-Saharan Africa have been conducted less often than from epizootic environments. To gain insight into alphavirus diversity in enzootic transmission cycles, we collected over 23,000 mosquitoes in lowland rainforest and savannah gallery forest in southwestern Uganda and tested them for alphavirus infections. We detected Sindbis virus (SINV) in a Culex Culex sp. mosquito and Middelburg virus (MIDV) in Eretmapodites intermedius and Mansonia africana. MIDV is a mosquito-borne alphavirus that causes febrile illness in sheep, goats, and horses and was previously not known to occur in Uganda. SINV, also a mosquito-borne alphavirus, causes mild infections in humans. Full genomes of SINV and MIDV were sequenced, showing a nucleotide identity of 99% to related strains. Both isolates replicated to high titres in a wide variety of vertebrate cells. Our data suggest endemic circulation of SINV and MIDV in Uganda.

16.
Euro Surveill ; 29(26)2024 Jun.
Article in English | MEDLINE | ID: mdl-38940002

ABSTRACT

Oropouche fever is caused by Oropouche virus (OROV), transmitted primarily through the bite of infected midges, particularly of the genus Culicoides. The virus is mainly circulating in Central and South America where several countries reported an ongoing outbreak. We report here two imported cases of OROV infection identified in Italy, late May-early June 2024. These cases indicate that in the shadow of a massive dengue outbreak in the Americas, the Oropouche outbreak might be more widespread than previously estimated.


Subject(s)
Travel , Humans , Italy/epidemiology , Male , Cuba/epidemiology , Adult , Orthobunyavirus/isolation & purification , Animals , Disease Outbreaks , Bunyaviridae Infections/diagnosis , Bunyaviridae Infections/epidemiology , Middle Aged , Female
17.
One Health Outlook ; 6(1): 12, 2024 Jul 01.
Article in English | MEDLINE | ID: mdl-38946009

ABSTRACT

Oropouche and Mayaro viruses are enzootic arboviruses of public health concern throughout Latin America. Recent outbreaks of OROV in northern region and sporadic autochthonous cases in western region of Brazil, suggest a silent circulation of these neglected viruses. Aiming to investigate the exposure of different species of domestic animals to MAYV and OROV in urban and peri-urban areas of West-Central Brazil, we performed a cross-sectional serosurvey by plaque reduction neutralization test (PRNT). Our findings included neutralizing antibodies for both arboviruses in cattle, dogs and horses, suggesting eventual role of domestic animals in enzootic arbovirus surveillance in Brazil.

18.
Parasit Vectors ; 17(1): 255, 2024 Jun 11.
Article in English | MEDLINE | ID: mdl-38863029

ABSTRACT

BACKGROUND: RNA interference (RNAi) is a target-specific gene silencing method that can be used to determine gene functions and investigate host-pathogen interactions, as well as facilitating the development of ecofriendly pesticides. Commercially available transfection reagents (TRs) can improve the efficacy of RNAi. However, we currently lack a product and protocol for the transfection of insect cell lines with long double-stranded RNA (dsRNA). METHODS: We used agarose gel electrophoresis to determine the capacity of eight TRs to form complexes with long dsRNA. A CellTiter-Glo assay was then used to assess the cytotoxicity of the resulting lipoplexes. We also measured the cellular uptake of dsRNA by fluorescence microscopy using the fluorophore Cy3 as a label. Finally, we analyzed the TRs based on their transfection efficacy and compared the RNAi responses of Aedes albopictus C6/36 and U4.4 cells by knocking down an mCherry reporter Semliki Forest virus in both cell lines. RESULTS: The TRs from Biontex (K4, Metafectene Pro, and Metafectene SI+) showed the best complexing capacity and the lowest dsRNA:TR ratio needed for complete complex formation. Only HiPerFect was unable to complex the dsRNA completely, even at a ratio of 1:9. Most of the complexes containing mCherry-dsRNA were nontoxic at 2 ng/µL, but Lipofectamine 2000 was toxic at 1 ng/µL in U4.4 cells and at 2 ng/µL in C6/36 cells. The transfection of U4.4 cells with mCherry-dsRNA/TR complexes achieved significant knockdown of the virus reporter. Comparison of the RNAi response in C6/36 and U4.4 cells suggested that C6/36 cells lack the antiviral RNAi response because there was no significant knockdown of the virus reporter in any of the treatments. CONCLUSIONS: C6/36 cells have an impaired RNAi response as previously reported. This investigation provides valuable information for future RNAi experiments by showing how to mitigate the adverse effects attributed to TRs. This will facilitate the judicious selection of TRs and transfection conditions conducive to RNAi research in mosquitoes.


Subject(s)
Aedes , RNA Interference , RNA, Double-Stranded , Transfection , RNA, Double-Stranded/genetics , RNA, Double-Stranded/metabolism , Animals , Cell Line , Aedes/genetics , Gene Silencing , Semliki forest virus/genetics , Semliki forest virus/drug effects
19.
Biol Proced Online ; 26(1): 17, 2024 Jun 18.
Article in English | MEDLINE | ID: mdl-38890570

ABSTRACT

BACKGROUND: Culex pipiens L. is a principal vector of zoonotic arboviruses in Europe, acting in both an amplification role in enzootic transmission between avian hosts and as a bridge vector between avian hosts and mammals. The species consists of two forms which are indistinguishable using morphological methods but possess varying ecological and physiological traits that influence their vector capacity. In this study we validate methods that can be used to extract trace DNA from single pupal exuviae of Cx. pipiens for use in molecular speciation of samples. These DNA extraction methods are compared using measurement of the total yield and successful identification using a real-time polymerase chain reaction (PCR) assay. RESULTS: Genomic DNA was initially extracted from colony-derived individuals using an ethanol precipitation method, two commercially available DNA extraction kits: DNeasy® Blood & Tissue Kit (Qiagen, UK) and Wizard® SV Genomic DNA Purification System (Promega, UK) and a direct real-time PCR method. Time elapsed between eclosion and processing of pupae significantly influenced Cx. pipiens form identification as nucleic acid concentration and PCR amplification success decreased with increased time elapsed. Real-time PCR amplification success, however, was not shown to vary significantly between the three extraction methods, with all methods successfully identifying all samples, but the direct real-time PCR method achieved a lesser amplification success rate of 70% (n = 20 for each treatment). More variable results were produced when field-derived exuviae were used, with no significant difference in real-time PCR amplification success found across the four methods and a lower overall rate of successful identification of 55-80%. CONCLUSIONS: This study shows that both colony and field derived Cx. pipiens pupal exuviae can be a useful non-invasive source of trace DNA permitting accurate biotype differentiation for at least twenty-four hours post-eclosion. The significance and utility of this technique in ecological and behavioural studies of Cx. pipiens is discussed and recommendations made for use according to experimental scenario.

20.
Cad. Ibero-Am. Direito Sanit. (Online) ; 13(2): 78-92, abr.-jun.2024.
Article in Portuguese | LILACS | ID: biblio-1560972

ABSTRACT

O estudo analisa uma formação em Iniciação Científica sobre arboviroses, a partir da percepção de jovens estudantes, em Ceilândia ­ Distrito Federal. Objetivo: compreender em que medida a Iniciação Científica mobiliza esses jovens a participarem de ações de vigilância e promoção da saúde no território, e entender sua motivação para participar do projeto. Metodologia: abrangeu-se a análise das redações escritas para a seleção ao Curso de Formação para Iniciação Científica na Educação Básica e as Arboviroses; a administração desse curso e; posteriormente, um grupo focal com estudantes para análise do processo educativo da Iniciação Científica que vivenciaram. Resultados: a análise de conteúdo evidenciou a percepção dos alunos sobre a Iniciação Científica, centrada em seis categorias analíticas: motivação dos alunos para Iniciação Científica; processo de formação do saber; formação de jovens cientistas; saúde e meio ambiente; participação e empoderamento juvenil e percepções acerca do Sistema Público de Saúde. Conclusão: o enfrentamento às arboviroses exige políticas e intervenções de amplo espectro, e a Iniciação Científica fortaleceu esses jovens estudantes enquanto sujeitos de direitos, ampliou sua percepção sobre ciência, saúde, relação com o ambiente, com o Sistema Único de Saúde e estimulou o interesse em ações preventivas no combate às arboviroses nesses territórios.


This study analyzes a Scientific Initiation (SI) program on arboviroses, from the perception of young high school students in Ceilândia ­ Distrito Federal. Objective: It aims to understand to what extent the SI mobilizes these young people to participate in surveillance and health promotion actions in the territory and understand their motivation to participate in this project. Methodology: The methodology included the analysis of the essays written for the selection to the Training Course for Scientific Initiation in Basic Education and the Arboviroses, the administration of this course, and later a focus group with students to analyze the SI educational process they experienced. Results: The result of the Content Analysis showed that the students' perception about the SI could be grouped into six categories: students' motivation for the scientific initiation; the learning process; the training of young scientists; health and environment; youth participation and empowerment, and perceptions of the Public health system in Brazil (SUS). Conclusion: Confronting arboviroses requires broad-spectrum policies and interventions, and the SI strengthened these young students as subjects of rights, broadened their perception of science, health, relationship with the environment, with the Sistema Único de Saúde and stimulated interest in preventive actions to combat arboviroses in these territories. Keywords: Health education; Arbovirus infections; Adolescents; Public health.


Analiza una formación en Iniciación Científica (IC) sobre arbovirus, desde la percepción de jóvenes estudiantes de secundaria en Ceilândia, Distrito Federal. Objetivo: el objetivo es comprender en qué medida la IC moviliza a estos jóvenes a participar en acciones de vigilancia y promoción de la salud en el territorio, así como entender su motivación para participar en proyectos de IC. Metodología: la metodología incluyó el análisis de las redacciones escritas para la selección al Curso de Formación para Iniciación Científica en Educación Básica y Arbovirus, la administración de este curso y, posteriormente, un grupo focal con los estudiantes para analizar el proceso educativo de IC que vivieron. Resultados: los resultados del Análisis de Contenido mostraron la percepción de los estudiantes sobre la IC enfocada en seis categorías analíticas: motivación de los estudiantes por la iniciación científica; proceso de formación de conocimientos; formación de jóvenes científicos; salud y medio ambiente; participación y empoderamiento de los jóvenes y percepciones sobre el Sistema Público de Salud (SUS). Conclusiones: Enfrentar los arbovirus requiere políticas e intervenciones de amplio espectro, y la IC fortaleció a estos jóvenes estudiantes como sujetos de derechos, ampliando su percepción sobre ciencia, salud, relación con el entorno, con el Sistema Único de Salud y estimuló el interés en acciones preventivas en la lucha contra los arbovirus en estos territorios.


Subject(s)
Health Law
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