scholarly journals Entomological Survey Confirms Changes in Mosquito Composition and Abundance in Senegal and Reveals Discrepancies among Results by Different Host-Seeking Female Traps

Insects ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 692
Author(s):  
El Hadji Malick Ngom ◽  
Chiara Virgillito ◽  
Mattia Manica ◽  
Roberto Rosà ◽  
Verena Pichler ◽  
...  
Keyword(s):  
Temporal Dynamics ◽  
Species Abundance ◽  
Pathogen Transmission ◽  
Malaria Vectors ◽  
Health Issues ◽  
Entomological Survey ◽  
Human Contact ◽  
Host Seeking ◽  
Trapping Performance ◽  
Bg Sentinel

Mosquitoes-borne diseases are major public health issues particularly in Africa. Vector control interventions and human-made environmental/climatic changes significantly affect the distribution and abundance of vector species. We carried out an entomological survey targeting host-seeking mosquitos in two different ecological contexts—coastal and inland—in Senegal, by CDC-light and BG-sentinel traps. Results show high predominance of Culex quinquefasciatus (90%) and of Anopheles arabiensis within malaria vectors (46%), with mean numbers of females/trap/nights =8 and <1, respectively, reinforcing previous evidence of changes in species composition and abundance, highlighting thus increasing risk of transmission of filariasis and emerging arboviruses in the Senegambia region. From the methodological perspective, results show a higher specificity of BG traps for Cx. quinquefasciatus and of CDC traps for An. gambiae s.l. and highlight that, despite both traps target the host-seeking fraction of the population, they provide different patterns of species abundance, temporal dynamics and host-seeking activity, leading to possible misinterpretation of the species bionomics. This draws attention to the need of taking into account trapping performance, in order to provide realistic quantification of the number of mosquitoes per units of space and time, the crucial parameter for evaluating vector–human contact, and estimating risk of pathogen transmission.

Host behaviour, age and sex correlate with ectoparasite prevalence and intensity in a colonial mammal, the little brown bat

Behaviour ◽  
2014 ◽  
Vol 152 (1) ◽  
pp. 83-105 ◽  
Author(s):  
Quinn M.R. Webber ◽  
Liam P. McGuire ◽  
Steven B. Smith ◽  
Craig K.R. Willis
Keyword(s):  
Pathogen Transmission ◽  
Myotis Lucifugus ◽  
Physical Contact ◽  
Wildlife Diseases ◽  
Colonial Species ◽  
Host Seeking ◽  
Host Sex ◽  
Little Brown Bat ◽  
Host Behaviour ◽  
Age And Sex

The influence of behaviour on host-parasite dynamics has theoretical support but few empirical studies have examined this influence for wild-captured hosts, especially in colonial species, which are thought to face generally high risk of exposure. Behavioural tendencies of hosts in novel environments could mediate host exposure. We tested the hypothesis that behavioural tendencies of hosts, and host sex and age, correlate with prevalence and intensity of ectoparasites in a gregarious mammal, the little brown bat (Myotis lucifugus). We also tested whether relationships between host behaviour and parasite prevalence and intensity would vary between taxa of ectoparasites which differ in host-seeking behaviour. We predicted that individual hosts displaying active and explorative behaviours would have higher prevalence and intensity of parasites that depend on physical contact among hosts for transmission (mites) but that host behaviour would not influence prevalence and intensity of mobile ectoparasites with active host-seeking behaviour (fleas). We recorded behavioural responses of wild-captured bats in a novel-environment test and then sampled each individual for ectoparasites. After accounting for age and sex we found mixed support for our hypotheses in some but not all demographics. More active adult and young of the year (YOY) males were more likely to host mites while more active adult and YOY females were less likely to host fleas. Our results highlight possible differences in the influence of host and parasite behaviour on parasite transmission dynamics for colonial compared to non-colonial species and have conservation implications for understanding pathogen transmission in bat white-nose syndrome and other wildlife diseases.

scholarly journals Creating mosquito-free outdoor spaces using transfluthrin-treated chairs and ribbons

2019 ◽  
Author(s):  
John Paliga Masalu ◽  
Marceline Finda ◽  
Gerry F. Killeen ◽  
Halfan S. Ngowo ◽  
Polius G. Pinda ◽  
...  
Keyword(s):  
Anopheles Funestus ◽  
Indoor Residual Spraying ◽  
Malaria Vectors ◽  
Insecticide Treated Nets ◽  
Domestic Spaces ◽  
Host Seeking ◽  
Outdoor Spaces ◽  
Outdoor Biting ◽  
Outdoor Environments ◽  
Almost All

Abstract Background Residents of malaria-endemic communities spend several hours outdoors performing different activities, e.g. cooking, story-telling or eating, thereby exposing themselves to potentially-infectious mosquitoes. This compromises effectiveness of indoor interventions, notably long-lasting insecticide-treated nets (LLINs) and indoor residual spraying (IRS). This study characterized common peri-domestic spaces in rural south-eastern Tanzania, and assessed protective efficacies of hessian fabric mats and ribbons treated with the spatial repellent, transfluthrin and respectively fitted to chairs and outdoor kitchens, against mosquitoes.Methods Two hundred households were surveyed, and their most-used peri-domestic spaces physically characterized. Protective efficacies of locally-made transfluthrin-emanating chairs and hessian ribbons were tested in outdoor environments of eight households using volunteer-occupied exposure-free double net traps. CDC light traps were used to estimate host-seeking mosquito densities within open-structure outdoor kitchens. Field-collected Anopheles arabiensis and Anopheles funestus mosquitoes were exposed underneath the chairs to estimate 24h-mortality. Finally, WHO insecticide susceptibility tests were conducted on wild-caught Anopheles from the villages.Results Approximately half (52%) of houses had verandas. Aside from these verandas, most houses also had peri-domestic spaces where residents stayed most times (67% of houses with verandas and 94% of non-veranda houses). Two-thirds of these spaces were sited under trees, and only one third (34.4%) were built-up. The outdoor structures were usually makeshift kitchens having roofs and partial walls. Transfluthrin-treated chairs reduced outdoor-biting An. arabiensis densities by 70-76% while transfluthrin-treated hessian ribbons fitted to the outdoor kitchens caused 81% reduction in the general peri-domestic area. Almost all the field-collected An. arabiensis (99.4%) and An. funestus (100%) exposed under transfluthrin-treated chairs died. The An. arabiensis were susceptible to non-pyrethroids (pirimiphos methyl & bendiocarb) but resistant to pyrethroids commonly used on LLINs (deltamethrin & permethrin).Conclusion Most houses had actively-used peri-domestic outdoor spaces where exposure to mosquitoes occurred. The transfluthrin-treated chair and ribbons reduced outdoor-biting malaria vectors in these peri-domestic spaces, and also elicited significant mortality among pyrethroid-resistant field-caught malaria vectors. These two new prototype formats for transfluthrin emanators, if developed further, may constitute new options for complementing LLINs and IRS with outdoor protection against malaria and other mosquito-borne pathogens in areas where peri-domestic human activities are common.

Comparison of Trapping Performance Between the Original BG-Sentinel® Trap and BG-Sentinel 2® Trap1

2015 ◽  
Vol 31 (4) ◽  
pp. 384-387 ◽  
Author(s):  
Hanayo Arimoto ◽  
James F. Harwood ◽  
Peter J. Nunn ◽  
Alec G. Richardson ◽  
Scott Gordon ◽  
...  
Keyword(s):  
Trapping Performance ◽  
Bg Sentinel ◽  
Sentinel 2

scholarly journals Seasonal temporal dynamics of marine protists communities in tidally mixed coastal waters

2021 ◽  
Author(s):  
Mariarita Caracciolo ◽  
Fabienne Rigaut-Jalabert ◽  
Sarah Romac ◽  
Frédéric Mahé ◽  
Samuel Forsans ◽  
...  
Keyword(s):  
Community Dynamics ◽  
Temporal Dynamics ◽  
Seasonal Pattern ◽  
Temporal Structure ◽  
Species Abundance ◽  
Temporal Correlation ◽  
Tidal Mixing ◽  
Taxonomic Resolution ◽  
English Channel ◽  
Turnover Rates

AbstractMajor seasonal community reorganizations and associated biomass variations are landmarks of plankton ecology. However, the processes determining marine species and community turnover rates have not been fully elucidated so far. Here, we analyse patterns of planktonic protist community succession in temperate latitudes, based on quantitative taxonomic data from both microscopy counts and ribosomal DNA metabarcoding from plankton samples collected biweekly over 8 years (2009-2016) at the SOMLIT-Astan station (Roscoff, Western English Channel). Considering the temporal structure of community dynamics (creating temporal correlation), we elucidated the recurrent seasonal pattern of the dominant species and OTUs (rDNA-derived taxa) that drive annual plankton successions. The use of morphological and molecular analyses in combination allowed us to assess absolute species abundance while improving taxonomic resolution, and revealed a greater diversity. Overall, our results underpinned a protist community characterised by a seasonal structure, which is supported by the dominant OTUs. We detected that some were partly benthic as a result of the intense tidal mixing typical of the French coasts in the English Channel. While the occurrence of these microorganisms is driven by the physical and biogeochemical conditions of the environment, internal community processes, such as the complex network of biotic interactions, also play a key role in shaping protist communities.

scholarly journals Semi Field Evaluation of Freestanding Transfluthrin Passive Emanators and the BG Sentinel Trap as a “Push-Pull control Strategy” Against Aedes aegypti Mosquitoes

2020 ◽  
Author(s):  
Mgeni Mohamed Tambwe ◽  
Sarah Moore ◽  
Hassan Chilumba ◽  
Johnson Kyeba Swai ◽  
Jason Moore ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Field Experiments ◽  
Protective Efficacy ◽  
Malaria Vectors ◽  
Human Landing Catch ◽  
Regular User ◽  
Pull System ◽  
Significant Difference ◽  
Human Landing ◽  
Bg Sentinel

Abstract Background The use of volatile pyrethroids and odor-baited traps in a push-pull system has been shown to reduce house entry and outdoor bites for malaria vectors. This technology has the potential to control other outdoor biting mosquitoes such as Aedes aegypti that transmit arboviral diseases. In this study, semi-field experiments were conducted to evaluate whether a push-pull system could be used to reduce bites from Aedes.Methods The push and pull under investigation consisted of two freestanding transfluthrin passive emanators (FTPE), and a BG sentinel trap (BGS) respectively. The FTPE contained hessian strips treated with 5.25 g of transfluthrin active ingredient. The efficacies of FTPE and BGS alone and in combination were evaluated by human landing catch in a large semi-field system in Tanzania. We also investigated the protection of FTPE over six months. The data was analyzed using generalized linear mixed models with binomial distribution.Results Two FTPE have a protective efficacy (PE) of 61% (95% Confidence interval (CI): 52.18–69.91) against human landing rate of Aedes aegypti. The BGS did not significantly reduce mosquito landings; the PE was 2.14% (95% CI: -2.87-7.16). The combination of FTPE and BGS (push-pull) provided the PE of 64.46% (95% CI: 59.06–69.85). However, there was no significant difference in the protective efficacy between the push-pull and the two FTPE against Ae. aegypti (p = 0.286). The FTPE offered significant protection against Ae. aegypti at month three, with a PE of 46.44% (95% CI: 41.12–51.76), but not at six months with a PE of 2.20% (95% CI: -9.00-14.02).Conclusions The protective efficacy of the FTPE and the full push-pull system are similar, indicative that bite prevention is primarily due to the activity of the FTPE. While these results are encouraging for the FTPE, further work is needed for a push-pull system to be recommended for Ae. aegypti control. The three-month protection provided by the FTPE against Ae. aegypti bites suggests it would be a useful additional personal protection tool during dengue outbreaks, that does not require regular user compliance.

scholarly journals Host-seeking behavior and hourly biting rhythm of vectors in malaria endemic district of Arba Minch area, Southwest Ethiopia

2020 ◽  
Author(s):  
Melkam Abiye Zeru ◽  
Simon Shibru ◽  
Fekadu Massebo
Keyword(s):  
Malaria Vector ◽  
Negative Binomial ◽  
Malaria Vectors ◽  
Malaria Vector Control ◽  
Southwest Ethiopia ◽  
Anopheles Mosquitoes ◽  
Host Seeking ◽  
Human Landing ◽  
Seeking Behavior ◽  
The Impact

Abstract Background The early and outdoor biting behaviors of malaria vectors are among the key challenges in malaria control. Hence, understanding the host-seeking behavior and the peak biting time of malaria vectors is important in malaria vector control programs. This study assessed the host-seeking behavior and hourly biting activity of malaria mosquitoes in Chano Mille village in Arba Minch district, southwest Ethiopia. Methods The first trial was done by keeping cattle together with human that collects the entered mosquitoes in tent, while the other was done by keeping cattle outside a 1 m distance from human collector inside a tent. In both trials, mosquito collation was done inside tents baited by cattle and human using human landing catches (HLC) techniques. Four human volunteers’ were recruited and trained to collect mosquitoes in the four tents from 18:00-24:00 for three months. Two tents were selected randomly for human alone and two for cattle baited collections in the first night and then rotated to minimize the variation due to location of tents and collectors skill. The tent trial was done close to the shore of the Lake Abaya to minimize the interference of other animals on mosquito movement. The peak biting hour of malaria vectors was assessed within a Chano village from 18:00-6:00. Mosquito collation was done both indoor and outdoor by HLC. Morphological speciation of Anopheles mosquitoes was done. The sporozoite infectivity status of Anopheles pharoensis was examined using enzyme-linked immuno-sorbent assay technique. The data was analyzed using a Generalized Estimating Equations with a negative binomial distribution. Results An. pharoensis, An. gambiae complex and An. tenebrosus were the three species documented during the trial. Keeping cattle together with human collector inside the tent attracted 42% ( P < 0.001) more An. pharoensis compared to human alone tent. Also, keeping cattle outside near to a tent with human at 1 m distance, attracted the entering An. pharoensis into the tent inside with human by 46% ( P = 0.002) than human in a tent with no cattle outside the same tent. The impact was not significant for An. gambiae complex and An. tenebrosus. Anopheles pharoensis and An. gambiae complex showed early night biting activity with peak biting from 19.00-20:00 which was significant for both An. gambiae complex ( P < 0.001) and An. pharoensis ( P = 0.015). Anopheles gambiae complex was mainly biting humans outdoor in the village. Conclusions Finally, keeping cattle within and close to human dwellings could increase malaria vectors bite exposure particularly to the zoophilic malaria vector An. pharoensis and, hence deployment of cattle far from human residence could be recommended to reduce the human exposure. The outdoor and early hours biting behavior of the An. gambiae complex could be a threat for success of current indoor based interventions and hence, tools could be designed to reduce this threat.

The Efficacy of the BG-Sentinel™ CO2Nozzle in Collecting Host-Seeking Mosquitoes in Fairfax County, Virginia

2010 ◽  
Vol 26 (2) ◽  
pp. 226-228 ◽  
Author(s):  
Hina V. Bhalala ◽  
Joshua D. Smith ◽  
Brent A. O'Dea ◽  
Jorge R. Arias
Keyword(s):  
Fairfax County ◽  
Host Seeking ◽  
Bg Sentinel

Chromosome evolution in malaria mosquitoes inferred from physically mapped genome assemblies

2016 ◽  
Vol 14 (02) ◽  
pp. 1630003 ◽  
Author(s):  
Igor V. Sharakhov ◽  
Gleb N. Artemov ◽  
Maria V. Sharakhova
Keyword(s):  
X Chromosome ◽  
Chromosome Evolution ◽  
Mosquito Species ◽  
Genome Rearrangements ◽  
Pathogen Transmission ◽  
High Rate ◽  
Malaria Vectors ◽  
Physiological Adaptations ◽  
Genome Assemblies ◽  
Malaria Mosquitoes

Polymorphic inversions in mosquitoes are distributed nonrandomly among chromosomes and are associated with ecological, behavioral, and physiological adaptations related to pathogen transmission. Despite their significance, the patterns and mechanism of genome rearrangements are not well understood. Recent sequencing and physical mapping of the genomes for 16 Anopheles mosquito species provided an opportunity to study chromosome evolution at the highest resolution. New studies revealed that fixed rearrangement accumulated [Formula: see text]3 times faster on the X chromosome than on autosomes. The highest densities of transposable elements (TEs) and satellites of different sizes have also been found on the X chromosome, suggesting a mechanism for the inversion generation. The high rate of X chromosome rearrangements is in sharp contrast with the paucity of polymorphic inversions on the X in the majority of anopheline species. This paper highlights the advances in understanding chromosome evolution in malaria vectors and discusses possible future directions in studying mechanisms and biological roles of genome rearrangements.

Dynamics of small-mammal communities along an elevational gradient

2019 ◽  
Vol 97 (4) ◽  
pp. 312-318 ◽  
Author(s):  
A.M. Benedek ◽  
I. Sîrbu
Keyword(s):  
Small Mammal ◽  
Temporal Dynamics ◽  
Species Abundance ◽  
Elevational Gradient ◽  
Myodes Glareolus ◽  
Small Areas ◽  
Live Trapping ◽  
Small Mammal Communities ◽  
Mammal Communities ◽  
Bank Vole Myodes Glareolus

Elevation is one of the most important natural gradients that is strongly shaping communities across relatively small areas. However, few studies have followed the temporal dynamics of elevational patterns, even in organisms for which population and community fluctuations have been extensively studied, such as rodents. Here we report the multiannual dynamics of small-mammal communities along an elevational gradient in the Southern Carpathians. During a 5-year survey, we conducted live-trapping in forested and shrubby habitats, at elevations between 820 and 2040 m. We used partial constrained multivariate analysis and mixed-effects models to test the effect of elevation, year, and their interaction. Community metrics differed significantly between even and odd years and temporal changes had stronger effect on small-mammal communities than elevation. The 2-year pattern of dynamics was especially marked in the yellow-necked field mouse (Apodemus flavicollis (Melchior, 1834)). Species abundance was predicted not only by year and elevation, but also by their interaction. The dominant rodent species, the bank vole (Myodes glareolus (Schreber, 1780)) and A. flavicollis, showed opposite annual patterns in relation to elevation, possibly as a strategy to avoid competition. Failure to consider the fluctuations in montane small-mammal communities may lead to wrong assessment of species’ state and distribution.

Sign in / Sign up

Export Citation Format

Share Document