scholarly journals Chemical Constituents and Larvicidal Properties of n-Hexane Extract of Parinari excelsa Seeds

2021 ◽  
pp. 14-23
Author(s):  
A. Dokubo ◽  
F. G. Obomanu ◽  
N. Ebere ◽  
G. I. Ndukwe
Keyword(s):  
Larvicidal Activity ◽  
Chemical Constituents ◽  
Larval Mortality ◽  
Hexane Extract ◽  
World Health ◽  
Gas Chromatography Mass Spectrometry ◽  
Chemical Compositions ◽  
Vector Borne Diseases ◽  
Standard Procedures ◽  
Health Organization

The study was conducted to investigate the chemical compositions and larvicidal effect of n-hexane extract of Parinari excelsa seeds against fourth instar larvae of Culex mosquito after 24 h and 48 h exposure. The chemical composition of n-hexane extract of P. excelsa seeds were analyzed using Gas Chromatography-Mass Spectrometry (GC-MS). Larvicidal activity was performed following standard procedures of World Health Organization (WHO). GC-MS analysis showed that the seed extract of P. excelsa contained hexadecyl phenyl carbonate with highest percentage (7.502%, RT=26.39), followed by tetradecyl phenyl carbonate (5.77%, RT=25.90), 1-methyl cyclohex-3-enyldodecyl fumarate (5.70%, RT=24.58), decyl phenyl carbonate (4.70%, RT=28.64) and the lowest, octadecyl-2,2,2-trichloroethyl carbonate (0.62%, RT=13.71). The result showed significant (p<0.05) mortality of larvae  in 24 h and 48 h of exposure. However, the highest larval mortality  was recorded at 48 h exposure. Result of regression analysis indicated that mortality rate positively correlated with concentration having a regression coefficient (R) close to one in each exposure case. The estimated lethal concentrations (LC50) for 24 h and 48 h exposure were 2.056±0.176 µg/ml and 0.429±0.150 µg/ml respectively. This indicates that larvicidal activity recorded for 48 h exposure was 4.8 times more than that recorded for 24 h exposure. The study demonstrated that n-hexane extract of P. excelsa seeds exhibited larvicidal potential and can be utilized as biopesticides to minimize the multiplication of mosquitoes that transmit vector borne diseases.

scholarly journals Larvicididal Activity of Natural Repellents Against the Dengue Vector, Aedes aegypti

2020 ◽  
Vol 36 (4) ◽  
pp. 227-232
Author(s):  
Shougang Zhang ◽  
Kai Blore ◽  
Rui-De Xue ◽  
Whitney A. Qualls ◽  
Steve Cermak ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Larvicidal Activity ◽  
Methyl Esters ◽  
Larval Mortality ◽  
Coconut Oil ◽  
Capric Acid ◽  
World Health ◽  
Median Lethal Concentration ◽  
Health Organization ◽  
Larval Bioassay

ABSTRACT The present research aimed to evaluate the larvicidal activity of several recently discovered natural repellents formulated in lotions against larvae of Aedes aegypti. We used a modified larval bioassay method by the World Health Organization standards in evaluating larval mortality at 24-, 48-, and 72-h exposure. Among the test repellents, 2-undecanone showed 100% mortality of Ae. aegypti larvae, followed by catnip oil, capric acid, coconut oil fatty acids, methyl caprate, methyl laurate, and coconut oil methyl esters. The repellent, 2-undecanone showed median lethal concentration (LC50) values of 73.07, 26.45, and 15.68 ppm at 24-, 48-, and 72-h exposure, respectively. Larvicidal activity varied among the other repellents tested.

scholarly journals From the Field to the Laboratory: Quantifying Outdoor Mosquito Landing Rate to Better Evaluate Topical Repellents

2021 ◽  
Author(s):  
Mara Moreno-Gómez ◽  
Rubén Bueno-Marí ◽  
Andrea Drago ◽  
Miguel A Miranda
Keyword(s):  
World Health ◽  
Asian Tiger Mosquito ◽  
Personal Protection ◽  
Evaluation Standards ◽  
Testing Conditions ◽  
Vector Borne Diseases ◽  
Asian Tiger ◽  
The World ◽  
Vector Borne ◽  
Health Organization

Abstract Vector-borne diseases are a worldwide threat to human health. Often, no vaccines or treatments exist. Thus, personal protection products play an essential role in limiting transmission. The World Health Organization (WHO) arm-in-cage (AIC) test is the most common method for evaluating the efficacy of topical repellents, but it remains unclear whether AIC testing conditions recreate the mosquito landing rates in the field. This study aimed to estimate the landing rate outdoors, in an area of Europe highly infested with the Asian tiger mosquito (Aedes albopictus (Skuse, 1894, Diptera: Culididae)), and to determine how to replicate this rate in the laboratory. To assess the landing rate in the field, 16 individuals were exposed to mosquitoes in a highly infested region of Italy. These field results were then compared to results obtained in the laboratory: 1) in a 30 m3 room where nine volunteers were exposed to different mosquito abundances (ranges: 15–20, 25–30, and 45–50) and 2) in a 0.064 m3 AIC test cage where 10 individuals exposed their arms to 200 mosquitoes (as per WHO requirements). The highest mosquito landing rate in the field was 26.8 landings/min. In the room test, a similar landing rate was achieved using 15–20 mosquitoes (density: 0.50–0.66 mosquitoes/m3) and an exposure time of 3 min. In the AIC test using 200 mosquitoes (density: 3,125 mosquitoes/m3), the landing rate was 229 ± 48 landings/min. This study provides useful reference values that can be employed to design new evaluation standards for topical repellents that better simulate field conditions.

scholarly journals Narrative Review on Health-EDRM Primary Prevention Measures for Vector-Borne Diseases

2020 ◽  
Vol 17 (16) ◽  
pp. 5981 ◽  
Author(s):  
Emily Chan ◽  
Tiffany Sham ◽  
Tayyab Shahzada ◽  
Caroline Dubois ◽  
Zhe Huang ◽  
...  
Keyword(s):  
Primary Prevention ◽  
Keyword Search ◽  
Risk Mitigation ◽  
World Health ◽  
Limiting Factors ◽  
Prevention Measures ◽  
Vector Borne Diseases ◽  
Vector Borne ◽  
Health Organization ◽  
The Impact

Climate change is expanding the global at-risk population for vector-borne diseases (VBDs). The World Health Organization (WHO) health emergency and disaster risk management (health-EDRM) framework emphasises the importance of primary prevention of biological hazards and its value in protecting against VBDs. The framework encourages stakeholder coordination and information sharing, though there is still a need to reinforce prevention and recovery within disaster management. This keyword-search based narrative literature review searched databases PubMed, Google Scholar, Embase and Medline between January 2000 and May 2020, and identified 134 publications. In total, 10 health-EDRM primary prevention measures are summarised at three levels (personal, environmental and household). Enabling factor, limiting factors, co-benefits and strength of evidence were identified. Current studies on primary prevention measures for VBDs focus on health risk-reduction, with minimal evaluation of actual disease reduction. Although prevention against mosquito-borne diseases, notably malaria, has been well-studied, research on other vectors and VBDs remains limited. Other gaps included the limited evidence pertaining to prevention in resource-poor settings and the efficacy of alternatives, discrepancies amongst agencies’ recommendations, and limited studies on the impact of technological advancements and habitat change on VBD prevalence. Health-EDRM primary prevention measures for VBDs require high-priority research to facilitate multifaceted, multi-sectoral, coordinated responses that will enable effective risk mitigation.

scholarly journals A Review on the Cosmeceutical and External Applications ofNigella sativa

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Ahmad M. Eid ◽  
Nagib A. Elmarzugi ◽  
Laila M. Abu Ayyash ◽  
Maher N. Sawafta ◽  
Hadeel I. Daana
Keyword(s):  
Health Care ◽  
Wound Healing ◽  
Nigella Sativa ◽  
Chemical Constituents ◽  
Acne Vulgaris ◽  
World Health ◽  
Pharmacological Effects ◽  
The World ◽  
Wound Healing Effect ◽  
Health Organization

It is estimated by the World Health Organization (WHO) that most of the world’s population depends on herbal medicine for their health care.Nigella sativa (N. sativa),also known as black-caraway and as “Kalonji,” is a well-known seed all over the world. It is one of the most common medicinal plants worldwide and contains many useful chemical constituents that we can find in its fixed oil, such as thymoquinone, thymohydroquinone, dithymoquinone, thymol, nigellicine, carvacrol, nigellimine, nigellicine, nigellidine, and alpha-hederin. Due to these numerous important ingredients it was found that it affects different areas of our body and has many pharmacological effects as antibacterial, antiviral, anti-inflammatory, and wound healing effect and also for acne vulgaris, skin cancer, pigmentation, and many cosmeceutical applications. Based on the folklore usage ofN. sativaseeds and oil, they are used in various systems of food and medicines. The aim of this article is to provide a detailed survey of the literature of cosmeceutical and external applications ofN. sativawhich is expected to stimulate further studies on this subject.

scholarly journals The Challenge of Controlling Urban Mosquito-Borne Diseases in a Changing Urban Climate

2021 ◽  
Author(s):  
Antonio Ligsay ◽  
Olivier Telle ◽  
Richard Paul
Keyword(s):  
Rural Areas ◽  
Urban Climate ◽  
Physical Nature ◽  
Mitigation Strategies ◽  
World Health ◽  
Vector Borne Diseases ◽  
The World ◽  
Urban Heat ◽  
Vector Borne ◽  
Health Organization

Cities worldwide are facing ever-increasing pressure to develop mitigation strategies for all sectors to deal with the impacts of climate change. Cities are expected to house 70% of the world&rsquo;s population by 2050 and developing related resilient health systems is a significant challenge. Because of their physical nature, cities&rsquo; surface temperatures are often substantially higher than that of the surrounding rural areas, generating the so-called Urban Heat Island (UHI) effect. Whilst considerable emphasis has been placed on strategies to mitigate against the UHI-associated negative health effects of heat and pollution, the World Health Organization estimates that one of the main consequences of global warming will be an increased burden of such vector-borne diseases. Many of the major mosquito-borne diseases are urban and thus the global population exposed to these pathogens will steadily increase. Mitigation strategies beneficial for one sector may, however, be detrimental for another. Implementation of inter-sectoral strategies that can benefit many sectors (such as water, labour and health) do exist and would enable optimal use of the meagre resources available. Discussion among inter-sectoral stakeholders should be actively encouraged.

scholarly journals Insulin potentiates JAK/STAT signaling to broadly inhibit flavivirus replication in insect vectors

2019 ◽  
Author(s):  
Laura R.H. Ahlers ◽  
Chasity E. Trammell ◽  
Grace F. Carrell ◽  
Sophie Mackinnon ◽  
Brandi K. Torrevillas ◽  
...  
Keyword(s):  
Immune Response ◽  
Insulin Signaling ◽  
World Health ◽  
Rnai Pathway ◽  
Human Pathogens ◽  
Vector Borne Diseases ◽  
Antiviral Responses ◽  
Mosquito Cells ◽  
Health Organization ◽  
Insect Immune Response

SUMMARYThe World Health Organization estimates that over half of the world’s population is at risk for vector-borne diseases, such as those caused by arboviral infection. Because many arboviruses are mosquito-borne, investigation of the insect immune response will help identify targets that could reduce the spread of these viruses by the mosquito. In this study, we used a genetic screening approach to identify insulin-like receptor as a novel component of the immune response to arboviral infection. We determined that vertebrate insulin reduces West Nile virus (WNV) replication in Drosophila melanogaster as well as WNV, Zika, and dengue virus titers in mosquito cells. Mechanistically, we showed that insulin signaling activates the JAK/STAT, but not RNAi, pathway to control infection. Finally, we validated that insulin priming of adult female Culex mosquitoes through a blood meal reduces WNV infection, demonstrating an essential role for insulin signaling in insect antiviral responses to emerging human pathogens.

scholarly journals Groundwater Quality Assessment of Abandoned Dumpsite in Osogbo Suburb, Nigeria: Hydrogeological and Geophysical Condition Six Years after Initial Study

2021 ◽  
Vol 25 (7) ◽  
pp. 1213-1219
Author(s):  
A.O. Ojo ◽  
A.C. Oyelami ◽  
E.M. Babafemi
Keyword(s):  
Ground Penetrating Radar ◽  
Chemical Constituents ◽  
Quality Standard ◽  
Initial Study ◽  
Unconfined Aquifer ◽  
World Health ◽  
Geophysical Investigation ◽  
High Concentrations ◽  
Health Organization ◽  
Ground Penetrating

In this paper, we describe the result of a recent hydrogeological and geophysical investigation carried out within and around Aduramigba - Onibu-Eja Estate dumpsite with the aim of detecting evidence of contamination as well as depths to contamination of the groundwater after a previous study six years ago. Twenty water samples from shallow water wells and boreholes were analyzed for their physico-chemical constituents while five vertical electrical soundings and five electromagnetic ground penetrating radar surveys were conducted. The result shows high concentrations of anions of nitrates (NO3-), bicarbonates (HCO3-), chloride (Cl-) and sulphate (SO42-) with values of 73.97 mg/l, 91.5 mg/l, 331.2 mg/l, 222.4 mg/l respectively, cations values of Mg2+, Fe2+, Na+, and K+ having value of 25.44 mg/l, 6.23 mg/l, 37.31 mg/l and 35.41 mg/l, respectively, which were far above the World Health Organization (WHO) and Nigeria Drinking Water Quality Standard (NDWS). Heavy metal components such as Lead, Zinc, Copper and Nickel were also observed to be on the high side, having been contributed from effluents from rust metallic materials cum chemicals dumped within the dumpsite. Detailed geophysical study reveal the depth to contamination at between 4.1 meters in VES 3 to 5.9 meters in VES 2 with resistivity as low as 5.12 Ωm in VES 2 to 7.12 Ωm in VES 3 while ground penetrating radar (GPR) revealed that the leachate has permeated to a depth of 3.5 – 5.25 meters in traverse 4 and 4.0 – 6.0 meters in traverse 3 which correspond to the depth to unconfined aquifer within the dumpsite. The study conclude that this would pose a greater threat to residents living in this vicinity and as such, this might have contributed to the closure of the dumpsite.

scholarly journals Chemical composition and insecticidal activity of Anacyclus pyrethrum essential oil from the Bensliman area against Culex pipiens

2020 ◽  
Vol 10 (1) ◽  
pp. 13-21
Author(s):  
Kawtar El Mokhtari ◽  
M'hammed EL Kouali ◽  
Mohammed Talbi ◽  
Latifa Hajji ◽  
Abdelhak El Brouzi
Keyword(s):  
Chemical Composition ◽  
Essential Oil ◽  
Insecticidal Activity ◽  
Culex Pipiens ◽  
Larval Mortality ◽  
World Health ◽  
Herbaceous Plant ◽  
Health Organization ◽  
Asteraceae Family ◽  
Lc50 And Lc90

Anacyclus pyrethrum is a herbaceous plant that belongs to the Asteraceae family. The focus of the present study is to extract the essential oil from this plant, to determine its chemical composition and to evaluate its insecticidal activity against the larvae of the mosquito Culex pipiens. The essential oil from A. pyrethrum collected from the region of Bensliman in Morocco was extracted by hydrodistillation and analyzed by gas chromatography coupled to mass spectrometry were studied. Essential oil yield obtained by hydrodistillation was 0.09%. The major aroma constituents were Spathulenol (20.47%), Germacrene D (16.48%), Caryophyllene oxide (13.20%), 4(14)-Salviale-1-one (8.27%) and Caryophyllene 4(14),8(15)-dien-5α-ol (7.30%). The larvicidal test carried out according to a methodology based on the standard protocol of the World Health Organization was studied on 4th instar larvae of C. pipiens and showed that A. pyrethrum essential oil possesses remarkable insecticidal properties.  After 24 hours of exposition, larvicidal assays revealed a 100% mortality of C. pipiens larvae. The dose of 40 μL/mL was toxic enough to cause 100% larval mortality of C. pipiens. The lethal concentrations LC50 and LC90 calculated for the essential oil studied were of the order of 14.79 μL/mL and 19.95 μL/mL, respectively. To control mosquitoes, this essential oil extracted from A. pyrethrum might be used as a natural insecticide and therefore could be an alternative to synthetic insecticides already present on the market.

scholarly journals Bacterial Contamination of Food Handlers in X Hospital Palembang

2018 ◽  
Vol 68 ◽  
pp. 01006
Author(s):  
Sri Utari ◽  
Irsan Saleh ◽  
Hermansyah ◽  
Rindit Pambayun
Keyword(s):  
Escherichia Coli ◽  
World Health ◽  
Personal Hygiene ◽  
Food Handlers ◽  
Cross Sectional ◽  
Pathogenic Organism ◽  
Source Of Infection ◽  
Standard Procedures ◽  
Contaminated Food ◽  
Health Organization

The food handlers in Hospital with the bad personal hygiene could be a potential source of infection of a pathogenic organism. The responsibility of hospital food handlers is greater compared with the common food handlers such as in restaurants, etc. This is because they should provide the healthy food to the patients in Hospital who might have low immunity, and the contaminated food could have very dangerous consequences. This study aimed to investigate the potential contamination of food handlers in X hospital, Palembang. The study was carried out by a cross-sectional method on food handlers’. There were 30 respondents examined in this study. The bacterial examination was conducted by following the standard procedures of World Health Organization (WHO). The results showed that there were 11 (36.7%) from 30respondents positively contaminated by Escherichia coliand there all respondent contaminated in samples were women. There was no worker contaminated by Staphylococcus aureus. The study proved that in X hospital of Palembang, there were some food handlers contaminated by Escherichia coli.

scholarly journals Larvicidal Activity of Essential Oil Constituents against Malaria Vector, Anopheles gambiae (Diptera: Culicidae)

2016 ◽  
Vol 11 (10) ◽  
pp. 1934578X1601101
Author(s):  
Tamires Cardoso Lima ◽  
Eliningaya J. Kweka ◽  
Chrian M. Marciale ◽  
Damião Pergentino de Sousa
Keyword(s):  
Public Health ◽  
Anopheles Gambiae ◽  
Larvicidal Activity ◽  
Chemical Constituents ◽  
Larval Mortality ◽  
Time Dependent ◽  
Important Public Health ◽  
Larvicidal Effect ◽  
Effective Components ◽  
Larval Toxicity

Malaria is one of the most important public health problems worldwide. This illness is controlled, mainly, by combating the vector mosquitoes using chemical insecticides, but this use has caused environmental impact and the emergence of tolerance in adult mosquitoes. Herein, we report the larvicidal activity of nine chemical constituents found in essential oils against third-instar larvae of Anopheles gambiae. All the tested compounds showed larval toxicity. Among the nine effective components, citronellol exhibited a pronounced larvicidal effect against the larvae of An. gambiae, with LC50 values of 96.1 and 55.6 ppm after 12 and 24 hours of treatment, respectively; however, hydroxycitronellal was the most potent compound after 48 and 72 h of exposure (LC50=3.7 and 2.3 ppm, respectively), followed by citronellol (LC50=16.7 and 6.3 ppm, respectively). Moreover, larval mortality was concentration- and time-dependent.

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