scholarly journals Chikungunya (Togaviridae) and Dengue 2 (Flaviviridae) Viruses Isolated from Aedes aegypti Mosquitoes by qRT-PCR Technique: Xenosurveillance for Arboviruses Circulating in Burkina Faso

2021 ◽  
Author(s):  
Aristide Sawdetuo Hien ◽  
Ibrahim Sangaré ◽  
Eric L. Parfait Ouattara ◽  
Simon P. Sawadogo ◽  
Diloma D. Soma ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Burkina Faso ◽  
Disease Surveillance ◽  
Adult Stage ◽  
Public Health Importance ◽  
Control Programs ◽  
Qrt Pcr ◽  
One Step ◽  
Study Sites ◽  
And Control

Abstract: In 2016, we conducted an entomological survey in a railway transect between Banfora and Ouagadougou, Burkina Faso. The aim was to evaluate the risk factors for arbovirus epidemics, including vector infection status, in areas representative of the country. Aedes aegypti mosquitoes were collected at larval stage from four study sites and reared until adult stage and kept in RNAlater for detection of arbovirus RNA. In the laboratory, the mosquito specimens were screened for dengue virus (DENV) and chikungunya virus (CHIKV) using one step real-time qRT-PCR. We detected one DENV-2 positive pool from Ouagadougou, giving a minimum infec-tion rate (MIR) of 16.67, and 6 CHIKV positive pools, giving a MIR of 66.67 from Ouagadougou, but also in Banfora and Boromo. The qRT-PCR is a useful tool for the surveillance of arboviruses of public health importance in Burkina Faso and may be incorporated into disease surveillance and control programs in Burkina Faso.

Health Lessons Learned from the Recent Earthquakes and Tsunami in Asia

2007 ◽  
Vol 22 (1) ◽  
pp. 15-21 ◽  
Author(s):  
Claude de Ville de Goyet
Keyword(s):  
Disease Surveillance ◽  
Lessons Learned ◽  
World Health ◽  
Material Support ◽  
Control Programs ◽  
Needs Assessments ◽  
Life Saving ◽  
Health Organization ◽  
Recent Earthquakes ◽  
And Control

AbstractThe evaluations following the Tsunami that affected 12 countries (December 2004) and the earthquakes in Bam, Iran (2003), and in Pakistan (2005) offered valuable lessons for public health preparedness against all types of risks (natural, complex, or technological) in all countries (regardless their level of development).The lessons learned, needs assessments, effectiveness of external life-saving assistance, disease surveillance and control, as well as donations management, were reviewed.Although hundreds of surveys or studies were conducted, the needs assessments were partial and uncoordinated. The findings often were not shared by individual agencies.The evaluations in each of the three disasters point to some additional issues:1. Foreign mobile hospitals rarely arrived in time for immediate trauma care. Existing international guidelines for the use of field hospitals often were ignored and must be updated and promoted. Local and neighboring facilities are best at providing immediate, life-saving care;2. Occassionally, the risk of epidemics was grossly overestimated by the agencies and the mass media. Surveillance and improved routine control programs work without resorting to costly, improvised immunization campaigns of doubtless value. Improving or re-establishing water and sanitation must be the first priority;3. Health donations were not always appropriate, nor did they follow the World Health Organization guidelines. The costly destruction of inappropriate donations was a recurrent problem; and4. Medical volunteers from within the affected country were abounding, but did not benefit from the external logistical and material support. The international community should provide logistical and material support before sending expatriate teams that are unfamiliar with the area and its health problems.Investing in the preparedness of the national health services and communities should become a priority for disaster-prone countries and those assisting them in their development.

scholarly journals One-step RT-qPCR assay for ZIKV RNA detection in Aedes aegypti samples: A protocol to study infection & gene expression during ZIKV infection

2020 ◽  
Author(s):  
Ricardo Vieira Araujo ◽  
Fabiana Feitosa-Suntheimer ◽  
Alexander S. Gold ◽  
Berlin Londono-Renteria ◽  
Tonya Michelle Colpitts
Keyword(s):  
Gene Expression ◽  
Aedes Aegypti ◽  
Mammalian Cells ◽  
Detection Methods ◽  
Infected Mosquito ◽  
Zikv Infection ◽  
High Background ◽  
Qrt Pcr ◽  
One Step

Abstract Background : Zika virus (ZIKV) is transmitted to humans during the bite of an infected mosquito. In a scenario of globalization and climate change, the frequency of outbreaks has and will increase in areas with competent vectors, revealing a need for continuous improvement of ZIKV detection tools in vector populations. A simple, rapid and sensitive assay for viral detection is qRT-PCR, yet oligos optimized for ZIKV detection in mammalian cells and samples have repeatedly shown high background when used on mosquito RNA. In this work we present a one-step qRT-PCR protocol that allows for the detection of ZIKV in mosquitoes and for the evaluation of gene expression from the same mosquito sample and RNA. This assay is a less expensive qRT-PCR approach than that most frequently used in the literature and has a much lower background, allowing for confident detection. Methods : Our new oligo design to detect ZIKV RNA included in silico analysis of both viral and mosquito ( Ae. aegypti and Ae. albopictus )genomes, targeting sequences conserved between Asian and African ZIKV lineages, but not matching Aedes genomes. This assay will allow researchers to avoid nonspecific amplification in insect samples due to viral integration into the mosquito genome, a phenomenon known to happen in wild and colonized populations of mosquitoes. Standard curves constructed with in vitro transcribed ZIKV RNA were used to optimize the sensitivity, efficiency and reproducibility of the assay. Results: Finally, the assay was used with success to detect both ZIKV RNA in infected mosquitoes and to detect expression of the Defensin A gene, an antimicrobial peptide (AMP) involved in Aedes aegypti immune response to virus infection. Conclusions : The experimental approach to detect ZIKV RNA in Aedes aegypti presented here has demonstrated to be specific, sensitive and reliable, and additionally it allows for the analysis of mosquito gene expression during ZIKV infection.

scholarly journals One-step RT-qPCR assay for ZIKV RNA detection in Aedes aegypti samples: A protocol to study infection & gene expression during ZIKV infection

2020 ◽  
Author(s):  
Ricardo Vieira Araujo ◽  
Fabiana Feitosa-Suntheimer ◽  
Alexander S. Gold ◽  
Berlin Londono-Renteria ◽  
Tonya Michelle Colpitts
Keyword(s):  
Gene Expression ◽  
Aedes Aegypti ◽  
Mammalian Cells ◽  
Detection Methods ◽  
Infected Mosquito ◽  
Zikv Infection ◽  
High Background ◽  
Qrt Pcr ◽  
One Step

Abstract Background: Zika virus (ZIKV) is transmitted to humans during the bite of an infected mosquito. In a scenario of globalization and climate change, the frequency of outbreaks has and will increase in areas with competent vectors, revealing a need for continuous improvement of ZIKV detection tools in vector populations. A simple, rapid and sensitive assay for viral detection is qRT-PCR, yet oligos optimized for ZIKV detection in mammalian cells and samples have repeatedly shown high background when used on mosquito RNA. In this work we present a one-step qRT-PCR protocol that allows for the detection of ZIKV in mosquitoes and for the evaluation of gene expression from the same mosquito sample and RNA. This assay is a less expensive qRT-PCR approach than that most frequently used in the literature and has a much lower background, allowing for confident detection. Methods: Our new oligo design to detect ZIKV RNA included in silico analysis of both viral and mosquito ( Ae. aegypti and Ae. albopictus )genomes, targeting sequences conserved between Asian and African ZIKV lineages, but not matching Aedes genomes. This assay will allow researchers to avoid nonspecific amplification in insect samples due to viral integration into the mosquito genome, a phenomenon known to happen in wild and colonized populations of mosquitoes. Standard curves constructed with in vitro transcribed ZIKV RNA were used to optimize the sensitivity, efficiency and reproducibility of the assay. Results: Finally, the assay was used with success to detect both ZIKV RNA in infected mosquitoes and to detect expression of the Defensin A gene, an antimicrobial peptide (AMP) involved in Aedes aegypti immune response to virus infection. Conclusions: The experimental approach to detect ZIKV RNA in Aedes aegypti presented here has demonstrated to be specific, sensitive and reliable, and additionally it allows for the analysis of mosquito gene expression during ZIKV infection.

scholarly journals One-step RT-qPCR assay for ZIKV RNA detection in Aedes aegypti samples: A protocol to study infection & gene expression during ZIKV infection

2020 ◽  
Author(s):  
Ricardo Vieira Araujo ◽  
Fabiana Feitosa-Suntheimer ◽  
Alexander S. Gold ◽  
Berlin Londono-Renteria ◽  
Tonya Michelle Colpitts
Keyword(s):  
Gene Expression ◽  
Aedes Aegypti ◽  
Mammalian Cells ◽  
Detection Methods ◽  
Infected Mosquito ◽  
Zikv Infection ◽  
High Background ◽  
Qrt Pcr ◽  
One Step

Abstract Background: Zika virus (ZIKV) is transmitted to humans during the bite of an infected mosquito. In a scenario of globalization and climate change, the frequency of outbreaks has and will increase in areas with competent vectors, revealing a need for continuous improvement of ZIKV detection tools in vector populations. A simple, rapid and sensitive assay for viral detection is qRT-PCR, yet oligos optimized for ZIKV detection in mammalian cells and samples have repeatedly shown high background when used on mosquito RNA. In this work we present a one-step qRT-PCR protocol that allows for the detection of ZIKV in mosquitoes and for the evaluation of gene expression from the same mosquito sample and RNA. This assay is a less expensive qRT-PCR approach than that most frequently used in the literature and has a much lower background, allowing for confident detection. Methods: Our new oligo design to detect ZIKV RNA included in silico analysis of both viral and mosquito ( Ae. aegypti and Ae. albopictus )genomes, targeting sequences conserved between Asian and African ZIKV lineages, but not matching Aedes genomes. This assay will allow researchers to avoid nonspecific amplification in insect samples due to viral integration into the mosquito genome, a phenomenon known to happen in wild and colonized populations of mosquitoes. Standard curves constructed with in vitro transcribed ZIKV RNA were used to optimize the sensitivity, efficiency and reproducibility of the assay. Results: Finally, the assay was used with success to detect both ZIKV RNA in infected mosquitoes and to detect expression of the Defensin A gene, an antimicrobial peptide (AMP) involved in Aedes aegypti immune response to virus infection. Conclusions: The experimental approach to detect ZIKV RNA in Aedes aegypti presented here has demonstrated to be specific, sensitive and reliable, and additionally it allows for the analysis of mosquito gene expression during ZIKV infection.

Larvicidal Activity of Essential Oils Against Aedes aegypti (Diptera: Culicidae)

2020 ◽  
Vol 26 (33) ◽  
pp. 4092-4111
Author(s):  
Mikael A. de Souza ◽  
Larissa da Silva ◽  
Maria A. C. dos Santos ◽  
Márcia J. F. Macêdo ◽  
Luiz J. Lacerda-Neto ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Essential Oils ◽  
Larval Mortality ◽  
Analytical Techniques ◽  
Extraction Methods ◽  
Control Programs ◽  
Plant Parts ◽  
Natural Insecticides ◽  
Methods Analytical ◽  
Meta Analyses

The Aedes aegypti is responsible for the transmission of arboviruses, which compromise public health. In the search for synthetic product alternatives, essential oils (OEs) have been highlighted by many researchers as natural insecticides. This systematic review (SR) was performed according to PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) and its objective was to evaluate studies addressing OEs with larvicidal properties against Ae. aegypti, through electronic database searches (Pubmed, Science Direct and Scielo), covering an overview of the plant sources OEs, which plant parts were used, the extraction methods, analytical techniques, major and/or secondary constituents with greater percentages, as well as the LC50s responsible for larval mortality. Following study analysis, plants distributed across 32 families, 90 genera and 175 species were identified. The Lamiaceae, Myrtaceae, Piperaceae, Asteraceae, Rutaceae, Euphorbiaceae and Lauraceae families obtained the highest number of species with toxic properties against larvae from this vector. Practically all plant parts were found to be used for OE extraction. Hydrodistillation and steam distillation were the main extraction methods identified, with GC-MS/GC-FID representing the main analytical techniques used to reveal their chemical composition, especially of terpene compounds. In this context, OEs are promising alternatives for the investigation of natural, ecologically correct and biodegradable insecticides with the potential to be used in Ae. aegypti control programs.

scholarly journals Analysis and validation of a highly sensitive one-step nested quantitative real-time polymerase chain reaction assay for specific detection of severe acute respiratory syndrome coronavirus 2

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Yang Zhang ◽  
Chunyang Dai ◽  
Huiyan Wang ◽  
Yong Gao ◽  
Tuantuan Li ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Real Time ◽  
Quantitative Polymerase Chain Reaction ◽  
Clinical Samples ◽  
Chain Reaction ◽  
Pcr Assay ◽  
Qrt Pcr ◽  
Highly Sensitive ◽  
One Step ◽  
Polymerase Chain

Abstract Background Coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2, is posing a serious threat to global public health. Reverse transcriptase real-time quantitative polymerase chain reaction (qRT-PCR) is widely used as the gold standard for clinical detection of SARS-CoV-2. Due to technical limitations, the reported positive rates of qRT-PCR assay of throat swab samples vary from 30 to 60%. Therefore, the evaluation of alternative strategies to overcome the limitations of qRT-PCR is required. A previous study reported that one-step nested (OSN)-qRT-PCR revealed better suitability for detecting SARS-CoV-2. However, information on the analytical performance of OSN-qRT-PCR is insufficient. Method In this study, we aimed to analyze OSN-qRT-PCR by comparing it with droplet digital PCR (ddPCR) and qRT-PCR by using a dilution series of SARS-CoV-2 pseudoviral RNA and a quality assessment panel. The clinical performance of OSN-qRT-PCR was also validated and compared with ddPCR and qRT-PCR using specimens from COVID-19 patients. Result The limit of detection (copies/ml) of qRT-PCR, ddPCR, and OSN-qRT-PCR were 520.1 (95% CI: 363.23–1145.69) for ORF1ab and 528.1 (95% CI: 347.7–1248.7) for N, 401.8 (95% CI: 284.8–938.3) for ORF1ab and 336.8 (95% CI: 244.6–792.5) for N, and 194.74 (95% CI: 139.7–430.9) for ORF1ab and 189.1 (95% CI: 130.9–433.9) for N, respectively. Of the 34 clinical samples from COVID-19 patients, the positive rates of OSN-qRT-PCR, ddPCR, and qRT-PCR were 82.35% (28/34), 67.65% (23/34), and 58.82% (20/34), respectively. Conclusion In conclusion, the highly sensitive and specific OSN-qRT-PCR assay is superior to ddPCR and qRT-PCR assays, showing great potential as a technique for detection of SARS-CoV-2 in patients with low viral loads.

scholarly journals Quick and Easy Assembly of a One-Step qRT-PCR Kit for COVID-19 Diagnostics Using In-House Enzymes

ACS Omega ◽  
2021 ◽  
Author(s):  
Masateru Takahashi ◽  
Muhammad Tehseen ◽  
Rahul Salunke ◽  
Etsuko Takahashi ◽  
Sara Mfarrej ◽  
...  
Keyword(s):  
Qrt Pcr ◽  
One Step

scholarly journals Permethrin Resistance in Aedes aegypti Affects Aspects of Vectorial Capacity

Insects ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 71
Author(s):  
Tse-Yu Chen ◽  
Chelsea T. Smartt ◽  
Dongyoung Shin
Keyword(s):  
Aedes Aegypti ◽  
Sodium Channel ◽  
Mosquito Control ◽  
Vector Competence ◽  
Vectorial Capacity ◽  
Parental Population ◽  
Control Programs ◽  
Channel Gene ◽  
Sodium Channel Gene ◽  
Specific Pcr

Aedes aegypti, as one of the vectors transmitting several arboviruses, is the main target in mosquito control programs. Permethrin is used to control mosquitoes and Aedes aegypti get exposed due to its overuse and are now resistant. The increasing percentage of permethrin resistant Aedes aegypti has become an important issue around the world and the potential influence on vectorial capacity needs to be studied. Here we selected a permethrin resistant (p-s) Aedes aegypti population from a wild Florida population and confirmed the resistance ratio to its parental population. We used allele-specific PCR genotyping of the V1016I and F1534C sites in the sodium channel gene to map mutations responsible for the resistance. Two important factors, survival rate and vector competence, that impact vectorial capacity were checked. Results indicated the p-s population had 20 times more resistance to permethrin based on LD50 compared to the parental population. In the genotyping study, the p-s population had more homozygous mutations in both mutant sites of the sodium channel gene. The p-s adults survived longer and had a higher dissemination rate for dengue virus than the parental population. These results suggest that highly permethrin resistant Aedes aegypti populations might affect the vectorial capacity, moreover, resistance increased the survival time and vector competence, which should be of concern in areas where permethrin is applied.

Investigating Male Aedes aegypti (Diptera: Culicidae) Attraction to Different Oviposition Containers Using Various Configurations of the Sound Gravid Aedes Trap

2019 ◽  
Vol 57 (3) ◽  
pp. 957-961
Author(s):  
Kyran M Staunton ◽  
Barukh B Rohde ◽  
Michael Townsend ◽  
Jianyi Liu ◽  
Mark Desnoyer ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Zika Virus ◽  
Disease Transmission ◽  
Urban Landscape ◽  
Mosquito Control ◽  
Transmission Risk ◽  
Northern Australia ◽  
Control Programs ◽  
Male Dispersal ◽  
Olfactory Attractant

Abstract Aedes aegypti (Linnaeus), the primary vectors of the arboviruses dengue virus and Zika virus, continue to expand their global distributions. In efforts to better control such species, several mosquito control programs are investigating the efficacy of rearing and releasing millions of altered male Aedes throughout landscapes to reduce populations and disease transmission risk. Unfortunately, little is known about Ae. aegypti, especially male, dispersal behaviors within urban habitats. We deployed Sound-producing Gravid Aedes Traps (SGATs) in Cairns, northern Australia, to investigate male Ae. aegypti attraction to various oviposition container configurations. The traps were arranged to include: 1) water only, 2) organically infused water, 3) infused water and L3 larvae, 4) infused water and a human-scented lure, and lastly 5) no water or olfactory attractant (dry). Our data suggest that males were more attracted to SGATs representing active larval sites than potential larval sites, but were equally attracted to dry SGATs relative to those containing water and/or infusion. Additionally, we found that female Ae. aegypti were equally attracted to wet SGATs, with or without infusion, but not dry ones. These results suggest that male Ae. aegypti within northern Australia are more attracted to active larval sites and equally attracted to dry containers as wet or infused ones. Additionally, female Ae. aegypti are unlikely to enter dry containers. Such findings contribute to our understanding of potentially attractive features for local and released Ae. aegypti throughout the northern Australian urban landscape.

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