Adaptation of Freshwater Mosquito Vectors to Salinity Increases Arboviral Disease Transmission Risk in the Context of Anthropogenic Environmental Changes

2015 ◽  
pp. 45-54 ◽  
Author(s):  
Ranjan Ramasamy
Keyword(s):  
Disease Transmission ◽  
Environmental Changes ◽  
Transmission Risk ◽  
Mosquito Vectors ◽  
Arboviral Disease

scholarly journals Livestock movement informs the risk of disease spread in traditional production systems in East Africa

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Divine Ekwem ◽  
Thomas A. Morrison ◽  
Richard Reeve ◽  
Jessica Enright ◽  
Joram Buza ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Production Systems ◽  
Control Strategies ◽  
Herd Size ◽  
Transmission Risk ◽  
Disease Spread ◽  
Transmission Potential ◽  
Spatial And Temporal Scales ◽  
Transmission Distance ◽  
Risk Of Disease

AbstractIn Africa, livestock are important to local and national economies, but their productivity is constrained by infectious diseases. Comprehensive information on livestock movements and contacts is required to devise appropriate disease control strategies; yet, understanding contact risk in systems where herds mix extensively, and where different pathogens can be transmitted at different spatial and temporal scales, remains a major challenge. We deployed Global Positioning System collars on cattle in 52 herds in a traditional agropastoral system in western Serengeti, Tanzania, to understand fine-scale movements and between-herd contacts, and to identify locations of greatest interaction between herds. We examined contact across spatiotemporal scales relevant to different disease transmission scenarios. Daily cattle movements increased with herd size and rainfall. Generally, contact between herds was greatest away from households, during periods with low rainfall and in locations close to dipping points. We demonstrate how movements and contacts affect the risk of disease spread. For example, transmission risk is relatively sensitive to the survival time of different pathogens in the environment, and less sensitive to transmission distance, at least over the range of the spatiotemporal definitions of contacts that we explored. We identify times and locations of greatest disease transmission potential and that could be targeted through tailored control strategies.

scholarly journals Ligusticum sinense Nanoemulsion Gel as Potential Repellent against Aedes aegypti, Anopheles minimus, and Culex quinquefasciatus (Diptera: Culicidae)

Insects ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 596
Author(s):  
Anuluck Junkum ◽  
Wanchai Maleewong ◽  
Atiporn Saeung ◽  
Danita Champakaew ◽  
Arpaporn Chansang ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Culex Quinquefasciatus ◽  
Disease Transmission ◽  
Skin Irritation ◽  
Mosquito Vectors ◽  
Plant Family ◽  
Anopheles Minimus ◽  
Human Volunteers ◽  
Nanoemulsion Gel ◽  
Fresh Preparation

Ligusticum sinense Oliv. cv. is a species of Umbelliferae (Apiaceae), a large plant family in the order Apiales. In this study, L. sinense hexane extract nanoemulsion gel (LHE-NEG) was investigated for mosquito repellency and compared to the standard chemical, N,N-diethyl-3-methylbenzamide (DEET), with the goal of developing a natural alternative to synthetic repellents in protecting against mosquito vectors. The results demonstrated that LHE-NEG afforded remarkable repellency against Aedes aegypti, Anopheles minimus, and Culex quinquefasciatus, with median protection times (MPTs) of 5.5 (4.5–6.0), 11.5 (8.5–12.5), and 11.25 (8.5–12.5) h, respectively, which was comparable to those of DEET-nanoemulsion gel (DEET-NEG: 8.5 (7.0–9.0), 12.0 (10.0–12.5), and 12.5 (10.0–13.5) h, respectively). Evaluation of skin irritation in 30 human volunteers revealed no potential irritant from LHE-NEG. The physical and biological stability of LHE-NEG were determined after being kept under heating/cooling cycle conditions. The stored samples of LHE-NEG exhibited some changes in appearance and differing degrees of repellency between those kept for 3 and 6 heating/cooling cycles, thus providing slightly shorter MPTs of 4.25 (4.0–4.5) and 3.25 (2.5–3.5) h, respectively, when compared to those of 5.0 (4.5–6.0) h in fresh preparation. These findings encourage commercially developed LHE-based products as an alternative to conventional synthetic repellents in preventing mosquito bites and helping to interrupt mosquito-borne disease transmission.

scholarly journals Feeding sites promoting wildlife-related tourism might highly expose the endangered Yunnan snub-nosed monkey (Rhinopithecus bieti) to parasite transmission

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Eve Afonso ◽  
Rong Fu ◽  
Amaël Dupaix ◽  
Anne-Claude Goydadin ◽  
ZhongHua Yu ◽  
...  
Keyword(s):  
Disease Transmission ◽  
High Throughput Sequencing ◽  
Animal Health ◽  
Buffer Zone ◽  
Transmission Risk ◽  
Parasite Transmission ◽  
Rhinopithecus Bieti ◽  
Domesticated Animals ◽  
Feeding Sites ◽  
In The Wild

AbstractAn increasing number of studies have found that the implementation of feeding sites for wildlife-related tourism can affect animal health, behaviour and reproduction. Feeding sites can favour high densities, home range overlap, greater sedentary behaviour and increased interspecific contacts, all of which might promote parasite transmission. In the Yunnan snub-nosed monkey (Rhinopithecus bieti), human interventions via provisioning monkeys at specific feeding sites have led to the sub-structuring of a group into genetically differentiated sub-groups. The fed subgroup is located near human hamlets and interacts with domesticated animals. Using high-throughput sequencing, we investigated Entamoeba species diversity in a local host assemblage strongly influenced by provisioning for wildlife-related tourism. We identified 13 Entamoeba species or lineages in faeces of Yunnan snub-nosed monkeys, humans and domesticated animals (including pigs, cattle, and domestic chicken). In Yunnan snub-nosed monkeys, Entamoeba prevalence and OTU richness were higher in the fed than in the wild subgroup. Entamoeba polecki was found in monkeys, pigs and humans, suggesting that this parasite might circulates between the wild and domestic components of this local social–ecological system. The highest proportion of faeces positive for Entamoeba in monkeys geographically coincided with the presence of livestock and humans. These elements suggest that feeding sites might indirectly play a role on parasite transmission in the Yunnan snub-nosed monkey. The implementation of such sites should carefully consider the risk of creating hotspots of disease transmission, which should be prevented by maintaining a buffer zone between monkeys and livestock/humans. Regular screenings for pathogens in fed subgroup are necessary to monitor transmission risk in order to balance the economic development of human communities dependent on wildlife-related tourism, and the conservation of the endangered Yunnan snub-nosed monkey.

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.

scholarly journals Mapping Malaria Transmission Risk in Northern Morocco Using Entomological and Environmental Data

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
E. Adlaoui ◽  
C. Faraj ◽  
M. El Bouhmi ◽  
A. El Aboudi ◽  
S. Ouahabi ◽  
...  
Keyword(s):  
Plasmodium Vivax ◽  
Malaria Transmission ◽  
Satellite Imagery ◽  
Malaria Vector ◽  
Environmental Changes ◽  
Temporal Variations ◽  
Environmental Data ◽  
Transmission Risk ◽  
Cultivation Period ◽  
Very High

Malaria resurgence risk in Morocco depends, among other factors, on environmental changes as well as the introduction of parasite carriers. The aim of this paper is to analyze the receptivity of the Loukkos area, large wetlands in Northern Morocco, to quantify and to map malaria transmission risk in this region using biological and environmental data. This risk was assessed on entomological risk basis and was mapped using environmental markers derived from satellite imagery. Maps showing spatial and temporal variations of entomological risk for Plasmodium vivax and P. falciparum were produced. Results showed this risk to be highly seasonal and much higher in rice fields than in swamps. This risk is lower for Afrotropical P. falciparum strains because of the low infectivity of Anopheles labranchiae, principal malaria vector in Morocco. However, it is very high for P. vivax mainly during summer corresponding to the rice cultivation period. Although the entomological risk is high in Loukkos region, malaria resurgence risk remains very low, because of the low vulnerability of the area.

scholarly journals Effect of Hurricane Katrina on Arboviral Disease Transmission

2007 ◽  
Vol 13 (8) ◽  
pp. 1273-1274 ◽  
Author(s):  
Jennifer A. Lehman ◽  
Alison F. Hinckley ◽  
Krista L. Kniss ◽  
Roger S. Nasci ◽  
Theresa L. Smith ◽  
...  
Keyword(s):  
Hurricane Katrina ◽  
Disease Transmission ◽  
Arboviral Disease

scholarly journals Assessing entomological risk factors for arboviral disease transmission in the French Territory of the Wallis and Futuna Islands

2020 ◽  
Vol 14 (5) ◽  
pp. e0008250
Author(s):  
Elodie Calvez ◽  
Nicolas Pocquet ◽  
Atoloto Malau ◽  
Sosiasi Kilama ◽  
Alefosio Taugamoa ◽  
...  
Keyword(s):  
Risk Factors ◽  
Disease Transmission ◽  
Arboviral Disease

scholarly journals Microgeographic Epidemiology of Malaria Parasites in an Irrigated Area of Western Kenya by Deep Amplicon Sequencing

2020 ◽  
Author(s):  
Elizabeth Hemming-Schroeder ◽  
Daibin Zhong ◽  
Solomon Kibret ◽  
Amanda Chie ◽  
Ming-Chieh Lee ◽  
...  
Keyword(s):  
Malaria Transmission ◽  
Environmental Changes ◽  
Amplicon Sequencing ◽  
Transmission Intensity ◽  
Transmission Risk ◽  
Irrigated Agriculture ◽  
Irrigation Scheme ◽  
Malaria Parasites ◽  
Irrigated Area ◽  
The Impact

Abstract To improve food security, investments in irrigated agriculture are anticipated to increase throughout Africa. However, the extent to which environmental changes from water resource development will impact malaria epidemiology remains unclear. This study was designed to compare the sensitivity of molecular markers used in deep amplicon sequencing for evaluating malaria transmission intensities and to assess malaria transmission intensity at various proximities to an irrigation scheme. Compared to ama1, csp, and msp1 amplicons, cpmp required the smallest sample size to detect differences in infection complexity between transmission risk zones. Transmission intensity was highest within 5 km of the irrigation scheme by polymerase chain reaction positivity rate, infection complexity, and linkage disequilibrium. The irrigated area provided a source of parasite infections for the surrounding 2- to 10-km area. This study highlights the suitability of the cpmp amplicon as a measure for transmission intensities and the impact of irrigation on microgeographic epidemiology of malaria parasites.

scholarly journals Place-based social contact and mixing: a typology of generic meeting places of relevance for infectious disease transmission

2017 ◽  
Vol 145 (12) ◽  
pp. 2582-2593 ◽  
Author(s):  
M. STRÖMGREN ◽  
E. HOLM ◽  
Ö. DAHLSTRÖM ◽  
J. EKBERG ◽  
H. ERIKSSON ◽  
...  
Keyword(s):  
Infectious Disease ◽  
Disease Transmission ◽  
Social Contact ◽  
Physical Contact ◽  
Transmission Risk ◽  
Geographical Differences ◽  
Infectious Disease Transmission ◽  
Swedish Population ◽  
The Social ◽  
The Family

SUMMARYThis study aims to develop a typology of generic meeting places based on social contact and mixing of relevance for infectious disease transmission. Data were collected by means of a contact diary survey conducted on a representative sample of the Swedish population. The typology is derived from a cluster analysis accounting for four dimensions associated with transmission risk: visit propensity and its characteristics in terms of duration, number of other persons present and likelihood of physical contact. In the analysis, we also study demographic, socio-economic and geographical differences in the propensity of visiting meeting places. The typology identifies the family venue, the fixed activity site, the family vehicle, the trading plaza and the social network hub as generic meeting places. The meeting place typology represents a spatially explicit account of social contact and mixing relevant to infectious disease modelling, where the social context of the outbreak can be highlighted in light of the actual infectious disease.

Mapping the Potential for Infectious Disease Transmission in a Wide-Body Aircraft Cabin

2019 ◽  
Author(s):  
Seif Mahmoud ◽  
James S. Bennett ◽  
Mohammad H. Hosni ◽  
Byron Jones
Keyword(s):  
Infectious Diseases ◽  
Disease Transmission ◽  
Radial Distance ◽  
Transmission Risk ◽  
Disease Spread ◽  
Health Concern ◽  
Tracer Gas ◽  
Infectious Disease Transmission ◽  
Gas Concentration ◽  
Aircraft Cabin

Abstract With more than two billion passengers annually, in-flight transmission of infectious diseases is a major global health concern. It is widely believed that principal transmission risk associated with air travel for most respiratory infectious diseases is limited to within two rows of an infectious passenger. However, several passengers became infected despite sitting several rows away from the contagious passenger. This work thoroughly investigated the potential for disease spread inside airplane cabins using tracer gas to quantify airborne dispersion. Measurements were conducted in a full-scale, 11-row mock-up of a wide-body aircraft cabin. Heated mannequins to simulate passengers’ thermal load were placed on the cabin seats. Tracer gas was injected at the breathing level at four different hypothetical contagious passenger locations. The tracer gas concentration was measured radially up to 3.35 m away from the injection location representing four rows of a standard aircraft. A four-port sampling tree was used to collect samples at the breathing level at four different radial locations simultaneously. Each port was sampled for 30 minutes. A total of 42 tests were conducted in matching pairs to alleviate potential statistical or measurements bias. The results showed that the airflow pattern inside the mock-up airplane cabin plays a major role in determining tracer gas concentration meaning that the concentration at the same radial distance in different directions are not necessarily the same. Also, due to the air distribution pattern and cabin walls, concentrations at some seats may be higher than the source seat.

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