scholarly journals Adult Anopheles Mosquito Distribution at a Low and High Malaria Transmission Site in Tanzania

2022 ◽  
Vol 2022 ◽  
pp. 1-7
Author(s):  
David Zadock Munisi ◽  
Mary Mathew Mathania
Keyword(s):  
Anopheles Arabiensis ◽  
Mosquito Control ◽  
Indoor Residual Spraying ◽  
Temporal Distribution ◽  
Anopheles Mosquito ◽  
Wet Season ◽  
Anopheles Gambiae S.S ◽  
Cross Sectional ◽  
Mosquito Abundance ◽  
Morphological Criteria

Malaria parasites are only transmitted by female mosquitoes of the genus Anopheles; hence, the disease’s distribution is linked to that of the vector mosquitoes. As such, the goal of this study was to find out the spatial and temporal distribution of Anopheles mosquito adults in the research sites. This was a repeated cross-sectional ecological study that took place in Morogoro and Dodoma, Tanzania. Vacuum aspiration was used to collect mosquitoes both outside and inside human dwellings. All mosquito-related data was collected and entered into appropriate data collection forms. Female mosquitoes were recognized morphologically using Gillies and Coetzee morphological criteria, followed by PCR. In total, about 2742 Anopheles mosquitoes with an average collection of 18.21 ± 1.12 per day were collected outside human houses of which 1717 ( 10.51 ± 1.17 ) and 1025 ( 8.42 ± 1.41 ) were collected from Morogoro and Dodoma, respectively. Of the captured mosquitoes, 89.0%, 10.0%, and 1.0% were recognized as Anopheles arabiensis, Anopheles gambiae s.s., and Anopheles quadrianulatus, respectively. The distribution varied significantly with seasons, whereby 302 ( 4.72 ± 1.04 ) and 2440 ( 12.96 ± 1.52 ) mosquitoes were captured in the cold-dry and warm-wet season, respectively ( p < 0.0001 ). Of the captured mosquitoes, 42.33%, 16.33%, 14.96%, and 4.27 were found on the ceiling, stored junks, verandas, and barks/tree, respectively. In malaria-endemic countries, vector control forms an important component of the malaria control efforts. This study found significant variation of Anopheles mosquito abundance in time and space with Anopheles arabiensis being the most predominant malaria vector. This signifies the need to introduce mosquito control methods that will target the less anthropophilic Anopheles arabiensis or the immature aquatic stages. The study further found that underbeds, store room/piled bags, and undisturbed curtains were the most preferred resting places by mosquitoes signifying to be the most effective strategic sites for spraying insecticides during the implementation of indoor residual spraying (IRS).

scholarly journals Dogs as Sentinels for Flavivirus Exposure in Urban, Peri-Urban and Rural Hanoi, Vietnam

Viruses ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 507
Author(s):  
Long Pham-Thanh ◽  
Thang Nguyen-Tien ◽  
Ulf Magnusson ◽  
Vuong Bui-Nghia ◽  
Anh Bui-Ngoc ◽  
...  
Keyword(s):  
Mosquito Control ◽  
Risk Mitigation ◽  
Significant Risk ◽  
Cross Sectional Study ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Cross Sectional ◽  
Major Health ◽  
Household Level

Diseases caused by flaviviruses, including dengue fever and Japanese encephalitis, are major health problems in Vietnam. This cross-sectional study explored the feasibility of domestic dogs as sentinels to better understand risks of mosquito-borne diseases in Hanoi city. A total of 475 dogs serum samples from 221 households in six districts of Hanoi were analyzed by a competitive enzyme-linked immunosorbent assay (cELISA) for antibodies to the pr-E protein of West Nile virus and other flaviviruses due to cross-reactivity. The overall flavivirus seroprevalence in the dog population was 70.7% (95% CI = 66.4–74.8%). At the animal level, significant associations between seropositive dogs and district location, age, breed and keeping practice were determined. At the household level, the major risk factors were rural and peri-urban locations, presence of pigs, coil burning and households without mosquito-borne disease experience (p < 0.05). Mosquito control by using larvicides or electric traps could lower seropositivity, but other measures did not contribute to significant risk mitigation of flavivirus exposure in dogs. These results will support better control of mosquito-borne diseases in Hanoi, and they indicate that dogs can be used as sentinels for flavivirus exposure.

scholarly journals Insecticide resistance status of Anopheles arabiensis in irrigated and non-irrigated areas in western Kenya

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Pauline Winnie Orondo ◽  
Steven G. Nyanjom ◽  
Harrysone Atieli ◽  
John Githure ◽  
Benyl M. Ondeto ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
Vector Control ◽  
Anopheles Arabiensis ◽  
Crop Protection ◽  
Indoor Residual Spraying ◽  
Malaria Vectors ◽  
Western Kenya ◽  
Animal Protection ◽  
Selection Of ◽  
Selection Of Resistance

Abstract Background Malaria control in Kenya is based on case management and vector control using long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS). However, the development of insecticide resistance compromises the effectiveness of insecticide-based vector control programs. The use of pesticides for agricultural purposes has been implicated as one of the sources driving the selection of resistance. The current study was undertaken to assess the status and mechanism of insecticide resistance in malaria vectors in irrigated and non-irrigated areas with varying agrochemical use in western Kenya. Methods The study was carried out in 2018–2019 in Homa Bay County, western Kenya. The bioassay was performed on adults reared from larvae collected from irrigated and non-irrigated fields in order to assess the susceptibility of malaria vectors to different classes of insecticides following the standard WHO guidelines. Characterization of knockdown resistance (kdr) and acetylcholinesterase-inhibiting enzyme/angiotensin-converting enzyme (Ace-1) mutations within Anopheles gambiae s.l. species was performed using the polymerase chain reaction (PCR) method. To determine the agricultural and public health insecticide usage pattern, a questionnaire was administered to farmers, households, and veterinary officers in the study area. Results Anopheles arabiensis was the predominant species in the irrigated (100%, n = 154) area and the dominant species in the non-irrigated areas (97.5%, n = 162), the rest being An. gambiae sensu stricto. In 2018, Anopheles arabiensis in the irrigated region were susceptible to all insecticides tested, while in the non-irrigated region reduced mortality was observed (84%) against deltamethrin. In 2019, phenotypic mortality was decreased (97.8–84% to 83.3–78.2%). In contrast, high mortality from malathion (100%), DDT (98.98%), and piperonyl butoxide (PBO)-deltamethrin (100%) was observed. Molecular analysis of the vectors from the irrigated and non-irrigated areas revealed low levels of leucine-serine/phenylalanine substitution at position 1014 (L1014S/L1014F), with mutation frequencies of 1–16%, and low-frequency mutation in the Ace-1R gene (0.7%). In addition to very high coverage of LLINs impregnated with pyrethroids and IRS with organophosphate insecticides, pyrethroids were the predominant chemical class of pesticides used for crop and animal protection. Conclusion Anopheles arabiensis from irrigated areas showed increased phenotypic resistance, and the intensive use of pesticides for crop protection in this region may have contributed to the selection of resistance genes observed. The susceptibility of these malaria vectors to organophosphates and PBO synergists in pyrethroids offers a promising future for IRS and insecticide-treated net-based vector control interventions. These findings emphasize the need for integrated vector control strategies, with particular attention to agricultural practices to mitigate mosquito resistance to insecticides. Graphic abstract

scholarly journals SELF-REPORTED MALARIA AND MOSQUITO AVOIDANCE IN RELATION TO HOUSEHOLD RISK FACTORS IN A KENYAN COASTAL CITY

2005 ◽  
Vol 37 (6) ◽  
pp. 761-771 ◽  
Author(s):  
JOSEPH KEATING ◽  
KATE MACINTYRE ◽  
CHARLES M. MBOGO ◽  
JOHN I. GITHURE ◽  
JOHN C. BEIER
Keyword(s):  
Rural Areas ◽  
Mosquito Control ◽  
Control Measure ◽  
Control Measures ◽  
Level Control ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Household Level ◽  
Household Factors ◽  
History Of

A geographically stratified cross-sectional survey was conducted in 2002 to investigate household-level factors associated with use of mosquito control measures and self-reported malaria in Malindi, Kenya. A total of 629 households were surveyed. Logistic regressions were used to analyse the data. Half of all households (51%) reported all occupants using an insecticide-treated bed net and at least one additional mosquito control measure such as insecticides or removal of standing water. Forty-nine per cent reported a history of malaria in the household. Of the thirteen household factors analysed, low (OR=0·23, CI 0·11, 0·48) and medium (OR=0·50, CI 0·29, 0·86) education, mud–wood–coral (OR=0·0·39, CI 0·24, 0·66) and mud block–plaster (OR=0·47, CI 0·25, 0·87) wall types, farming (OR=1·38, CI 1·01, 1·90) and travel to rural areas (OR=0·48, CI 0·26, 0·91) were significantly associated with the use of mosquito control, while controlling for other covariates in the model. History of reported malaria was not associated with the use of mosquito control (OR=1·22, CI 0·79, 1·88). Of the thirteen covariates analysed in the second model, only two household factors were associated with history of malaria: being located in the well-drained stratum (OR=0·49, CI 0·26, 0·96) and being bitten while in the house (OR=1·22, CI 0·19, 0·49). These results suggest that high socioeconomic status is associated with increased household-level mosquito control use, although household-level control may not be enough, as many people are exposed to biting mosquitoes while away from the house and in areas that are more likely to harbour mosquitoes.

Bionomics of Anopheles Arabiensis from Mamfene in KwaZulu-Natal (South Africa): An Area of High Malaria Transmission in the Province

2020 ◽  
Author(s):  
Rajendra Maharaj ◽  
Vishan Lakan ◽  
Kiash Maharaj
Keyword(s):  
South Africa ◽  
Vector Control ◽  
Anopheles Arabiensis ◽  
Mosquito Control ◽  
Sex Ratios ◽  
Adult Mosquito ◽  
Mosquito Vector ◽  
Larval Control ◽  
Kwazulu Natal ◽  
The Impact

Abstract Background: Although great strides have been made in controlling malaria, the disease is of significant public health importance. Historically, efforts to control the vector has concentrated on adult vector control targeting the female Anopheles mosquitoes. As there is now a focus on eliminating residual malaria from KwaZulu-Natal, new strategies are being investigated to increase the impact of malaria elimination strategies. Greater attention is now being given to larval control, as a complementary measure to indoor residual spraying. However, there is a large gap in knowledge of the bionomics of the larval stages of this mosquito vector of malaria in South Africa. In order to focus on both larval and adult mosquito control methods, larval development and the reproductive stages of the vector were investigated since these variables influences our ability to impact mosquito populations through larval control. This study was therefore conducted to determine the peak eruption times and the emergent sex ratios, as well as the peak egg oviposition time in order to attack the mosquito when it is at its most vulnerable and when control interventions will have the most impact.Results: Oviposition studies showed two peaks corresponding with late evening and again just before dawn. Most eggs were also laid in the first half of the night (18h00 – midnight). Most mosquitoes erupted just after sunset and the sex ratios showed that twice as many females as males emerged. Females readily took a bloodmeal after oviposition or just after erupting. Hatch rate to viable first instar larvae was 74.5%.Conclusions: The results of this study have provided information as to when interventions would be most effective in controlling mosquito populations and have provided information that highlights the value of larval control as a complementary measure to adult mosquito control. The most vulnerable stages of the female Anopheles arabiensis are when they have just emerged or when they have just oviposited. Vector control strategies should be designed to target these vulnerable stages at the breeding sites in order to have maximum impact.

scholarly journals Effect of LongRange™ eprinomectin on Anopheles arabiensis by feeding on calves treated with the drug

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Aklilu Belay ◽  
Beyene Petros ◽  
Teshome Gebre-Michael ◽  
Meshesha Balkew
Keyword(s):  
Anopheles Arabiensis ◽  
Control Method ◽  
Indoor Residual Spraying ◽  
Adult Emergence ◽  
Malaria Vector Control ◽  
Egg Hatchability ◽  
Kaplan Meier ◽  
Recorded Data ◽  
Long Lasting Insecticidal Nets ◽  
Nylon Cloth

Abstract Background Misuse of long-lasting insecticidal nets together with resistance of vectors to most of the insecticides for indoor residual spraying and impregnated nets threaten malaria vector control interventions, requiring search for alternative control methods. Reports have shown that Anopheles mosquitoes die when they feed on endectocidal drugs used to treat humans and animals. A study was designed to investigate the efficacy of LongRange™ (eprinomectin 5%) on laboratory reared Anopheles arabiensis fed on treated calves. Methods Anopheles arabiensis from insectary colony was fed on three calves treated with therapeutic dose of LongRange™ eprinomectin (1 ml/50 kg) and on non-treated three other calves as control arm. For the feeding, mosquitoes were placed in paper cups covered with nylon cloth mesh and then allowed to feed on the necks of calves. Subsequently, mosquito survival, fecundity, egg hatchability, larval development and adult emergence were recorded. Data were entered and analysed by using SPSS version 20. The Kaplan–Meier survival analysis and independent sample t-test were used. Results All mosquitoes that fed on LongRange™ Eprinomectin treated calves died within 7 days following blood ingestion. The drug also slightly affected fecundity and hatchability of An. arabiensis. Conclusion Treating livestock with LongRange™ (eprinomectin 5%) may serve as a supplementary control method for zoophagic An. arabiensis.

scholarly journals Rapid high throughput SYBR green assay for identifying the malaria vectors Anopheles arabiensis, Anopheles coluzzii and Anopheles gambiae s.s. Giles

PLoS ONE ◽  
2019 ◽  
Vol 14 (4) ◽  
pp. e0215669 ◽  
Author(s):  
Joseph Chabi ◽  
Arjen Van’t Hof ◽  
Louis K. N’dri ◽  
Alex Datsomor ◽  
Dora Okyere ◽  
...  
Keyword(s):  
Anopheles Gambiae ◽  
High Throughput ◽  
Anopheles Arabiensis ◽  
Sybr Green ◽  
Malaria Vectors ◽  
Anopheles Coluzzii ◽  
Anopheles Gambiae S.S ◽  
Sybr Green Assay

scholarly journals Reference values for N-terminal Pro-brain natriuretic peptide in premature infants during their first weeks of life

2020 ◽  
Author(s):  
Agnes-Sophie Fritz ◽  
Titus Keller ◽  
Angela Kribs ◽  
Christoph Hünseler
Keyword(s):  
Brain Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Preterm Infants ◽  
Premature Infants ◽  
Reference Values ◽  
Gestational Age ◽  
Temporal Distribution ◽  
Cross Sectional ◽  
Extremely Preterm ◽  
Extremely Preterm Infants

Abstract The aim of our study was to observe the temporal distribution of serum N-terminal pro-brain natriuretic peptide (NT-proBNP) in premature infants of ≤ 31 weeks of gestational age (GA) during the first weeks of life. NT-proBNP values of 118 preterm infants born ≤ 31 weeks GA were determined during the first week of life, after 4 ± 1 weeks of life, and at a corrected GA of 36 ± 2 weeks. Infants were divided into two groups: those without relevant complications and those with complications related to prematurity. NT-proBNP values of infants without complications define our exploratory reference values. The Median NT-proBNP level of these infants was 1896 ng/l (n = 27, interquartile range (IQR): 1277–5200) during the first week of life, 463 ng/l (n = 26, IQR: 364–704) at 4 ± 1 weeks of life, and 824 ng/l (n = 33, IQR: 714–1233) at a corrected GA of 36 ± 2 weeks. Infants born < 28 + 0 weeks GA had significantly higher NT-proBNP values (n = 9, median: 5200, IQR: 1750–8972) than infants born ≥ 28 + 0–31 weeks GA (n = 18, median: 1528, IQR: 838–3052; p = 0.017). Growth restriction or PDA status could not account for the difference in NT-proBNP values between GA groups. Conclusions: The results of our observational and cross-sectional study describe exploratory reference values for NT-proBNP levels in preterm infants of ≤ 31 weeks GA according to postnatal age. NT-proBNP levels during the first week of life are high and widely distributed in preterm infants and decrease subsequently to reach a distinctly lower and stable plateau at around 1 month of life. Our results suggest an influence of GA on NT-proBNP values in the first week of life. What is Known:• Several complications related to prematurity, e.g., hemodynamically significant PDA, pulmonary hypertension, bronchopulmonary dysplasia, and retinopathy of prematurity, have been associated with a temporary rise in NT-proBNP values in preterm infants during their first weeks of life.What is New:• This observational study provides reference values for NT-proBNP levels of very and extremely preterm infants during their first weeks of life.• In premature infants without complications, NT-proBNP values during their first week of life depend on gestational age at birth.

scholarly journals Effects of Different Water Seasons on the Residual Characteristics and Ecological Risk of Polycyclic Aromatic Hydrocarbons in Sediments from Changdang Lake, China

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Javid Hussain ◽  
Zhenhua Zhao ◽  
Yong Pang ◽  
Liling Xia ◽  
Ittehad Hussain ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Temporal Distribution ◽  
Impact Factors ◽  
Source Characterization ◽  
Wet Season ◽  
Combustion Source ◽  
Study Results ◽  
Polycyclic Aromatic ◽  
The Impact

The sediments’ samples were collected from Changdang Lake for the concentration of fourteen polycyclic aromatic hydrocarbons in March (dry season), June (wet season), and September (temperate season) 2013. The highest average value of∑PAHswas detected as 295.28 ng/g dw in March, followed by 240.91 ng/g dw in June and 165.81 ng/g dw in September. Source characterization studies based on the analysis of diagnostic ratio (triangular plot method) suggested that the PAHs in sediments from Changdang Lake were mainly from the mixed combustion source of biomass and petroleum, and the origins of PAHs in different sampling sites have a great deal of temporal and spatial variability during different water seasons. Redundancy analysis was applied to identify the impact factors and the possible relationship between PAHs and environmental parameters. The predicted results showed that the main factors impacting PAHs temporal distribution were temperature, dissolved oxygen, pH, and oxidation-reduction potential, while conductivity showed secondary impacts on the PAHs distribution. Risk assessment of PAHs in sediments was carried out based on the US Sediments Quality Guidelines (SQGs). By comparing the present study results with SQGs standard values results showed that the adverse effects are not expected at the present levels of PAHs contamination observed in the sediments from Changdang Lake.

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