scholarly journals The risk of urban yellow fever resurgence in Aedes-infested American cities

2018 ◽  
Vol 146 (10) ◽  
pp. 1219-1225 ◽  
Author(s):  
Eduardo Massad ◽  
Marcos Amaku ◽  
Francisco Antonio Bezerra Coutinho ◽  
Claudio José Struchiner ◽  
Luis Fernandez Lopez ◽  
...  
Keyword(s):  
Yellow Fever ◽  
Urban Areas ◽  
Endemic Area ◽  
Unit Area ◽  
Vector Competence ◽  
Eradication Programme ◽  
Sylvatic Cycle ◽  
Force Of Infection ◽  
American Cities ◽  
Urban Cycle

AbstractAedes aegypti, historically known as yellow fever (YF) mosquito, transmits a great number of other viruses such as Dengue, West Nile, Chikungunya, Zika, Mayaro and perhaps Oropouche, among others. Well established in Africa and Asia, Aedes mosquitoes are now increasingly invading large parts of the American continent, and hence the risk of urban YF resurgence in the American cities should because of great concern to public health authorities. Although no new urban cycle of YF was reported in the Americas since the end of an Aedes eradication programme in the late 1950s, the high number of non-vaccinated individuals that visit endemic areas, that is, South American jungles where the sylvatic cycle of YF is transmitted by canopy mosquitoes, and return to Aedes-infested urban areas, increases the risk of resurgence of the urban cycle of YF. We present a method to estimate the risk of urban YF resurgence in dengue-endemic cities. This method consists in (1) to estimate the number of Aedes mosquitoes that explains a given dengue outbreak in a given region; (2) calculate the force of infection caused by the introduction of one infective individual per unit area in the endemic area under study; (3) using the above estimates, calculate the probability of at least one autochthonous YF case per unit area produced by one single viraemic traveller per unit area arriving from a YF endemic or epidemic sylvatic region at the city studied. We demonstrate that, provided the relative vector competence, here defined as the capacity to being infected and disseminate the virus, of Ae. aegypti is greater than 0.7 (with respect to dengue), one infected traveller can introduce urban YF in a dengue endemic area.

scholarly journals Colonized Sabethes cyaneus, a Sylvatic New World Mosquito Species, Shows a Low Vector Competence for Zika Virus Relative to Aedes aegypti

Viruses ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 434 ◽  
Author(s):  
Ajit K. Karna ◽  
Sasha R. Azar ◽  
Jessica A. Plante ◽  
Rumei Yun ◽  
Nikos Vasilakis ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Yellow Fever ◽  
Zika Virus ◽  
New World ◽  
Yellow Fever Virus ◽  
Vector Competence ◽  
Mosquito Species ◽  
Sylvatic Cycle ◽  
Post Feeding ◽  
Body Compartments

The introduction of Zika virus (ZIKV) to the Americas raised concern that the virus would spill back from human transmission, perpetuated by Aedes aegypti, into a sylvatic cycle maintained in wildlife and forest-living mosquitoes. In the Americas, Sabethes species are vectors of sylvatic yellow fever virus (YFV) and are therefore candidate vectors of a sylvatic ZIKV cycle. To test the potential of Sabethes cyaneus to transmit ZIKV, Sa. cyaneus and Ae. aegypti were fed on A129 mice one or two days post-infection (dpi) with a ZIKV isolate from Mexico. Sa. cyaneus were sampled at 3, 4, 5, 7, 14, and 21 days post-feeding (dpf) and Ae. aegypti were sampled at 14 and 21 dpf. ZIKV was quantified in mosquito bodies, legs, and saliva to measure infection, dissemination, and potential transmission, respectively. Of 69 Sa. cyaneus that fed, ZIKV was detected in only one, in all body compartments, at 21 dpf. In contrast, at 14 dpf 100% of 20 Ae. aegypti that fed on mice at 2 dpi were infected and 70% had virus in saliva. These data demonstrate that Sa. cyaneus is a competent vector for ZIKV, albeit much less competent than Ae. aegypti.

scholarly journals Potential for Zika virus to establish a sylvatic transmission cycle in the Americas

2016 ◽  
Author(s):  
Benjamin M. Althouse ◽  
Nikos Vasilakis ◽  
Amadou A. Sall ◽  
Mawlouth Diallo ◽  
Scott C. Weaver ◽  
...  
Keyword(s):  
Zika Virus ◽  
New World ◽  
Vector Competence ◽  
Host Population ◽  
Transmission Model ◽  
New World Monkeys ◽  
Sylvatic Cycle ◽  
Transmission Cycle ◽  
Force Of Infection ◽  
Congenital Zika Syndrome

AbstractZika virus (ZIKV) originated and continues to circulate in a sylvatic transmission cycle between non-human primate hosts and arboreal mosquitoes in tropical Africa. Recently ZIKV invaded the Americas, where it poses a threat to human health, especially to pregnant women and their infants. Here we examine the risk that ZIKV will establish a sylvatic cycle in the Americas, focusing on Brazil. We review the natural history of sylvatic ZIKV and present a mathematical dynamic transmission model to assess the probability of establishment of a sylvatic ZIKV transmission cycle in non-human primates and/or other mammals and arboreal mosquito vectors in Brazil. Brazil is home to multiple species of primates and mosquitoes potentially capable of ZIKV transmission, though direct assessment of host competence (ability to mount viremia sufficient to infect a feeding mosquito) and vector competence (ability to become infected with ZIKV and disseminate and transmit upon subsequent feedings) of New World species is lacking. Modeling reveals a high probability of establishment of sylvatic ZIKV across a large range of biologically plausible parameters. Probability of establishment is dependent on host population sizes and birthrates and ZIKV force of infection, but a network of as few as 6,000 primates with 10,000 mosquitoes is capable of supporting establishment of a ZIKV sylvatic cycle. Research on the susceptibility of New World monkeys or other small mammals to ZIKV, on the vector competence of New World Aedes, Sabethes, and Haemagogus mosquitoes for ZIKV, and on the geographic range of these species is urgently needed. A sylvatic cycle of ZIKV would make future elimination efforts in the Americas practically impossible, and paints a dire situation for the epidemiology of ZIKV and ending the ongoing outbreak of congenital Zika syndrome.

scholarly journals The interplay between environmental factors, Vector Competence and vaccine immunodynamics as possible explanation of the 2019 Yellow fever Re-emergence in Nigeria

2021 ◽  
pp. 100858
Author(s):  
Idris Nasir Abdullahi ◽  
Abubakar Umar Anka ◽  
Anthony Uchenna Emeribe ◽  
Kabir Umar ◽  
Hafeez Aderinsayo Adekol ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Yellow Fever ◽  
Vector Competence

Pollinator gardens more than triple in visitation rate and diversity of flower-visiting insects than other ornamental plantings in Kingston, Ontario

2018 ◽  
Author(s):  
Marika Vogelzang
Keyword(s):  
Urban Areas ◽  
Unit Area ◽  
The Other ◽  
Individual Plant ◽  
University Campus ◽  
Pollinator Visitation ◽  
Visitation Rate ◽  
Queen's University ◽  
Flower Visiting ◽  
Pollinator Populations

In this study I determined the effectiveness of pollinator gardens by testing if visitation rate and diversity of flower-visiting insects is higher in pollinator gardens compared to other ornamental plantings. I observed pollinator visitation for individual plant taxa, per unit area, in three different pollinator gardens, eight ornamental gardens and eight ornamental planters on the Queen’s University campus in Kingston, Ontario, Canada. Visitation was about 4- times higher in pollinator gardens compared to the other two ornamental garden types and visitor richness (the number of types of pollinators) in pollinator gardens was about 6- times higher compared to ornamental gardens, and about 3- times higher compared toornamental planters. The results of this study conclude that the planting of pollinator gardens is an effective way of supporting pollinator populations in urban areas.

scholarly journals The history and characteristics of the 1980–2005 Portuguese rural fire database

2011 ◽  
Vol 11 (12) ◽  
pp. 3343-3358 ◽  
Author(s):  
M. G. Pereira ◽  
B. D. Malamud ◽  
R. M. Trigo ◽  
P. I. Alves
Keyword(s):  
Urban Areas ◽  
Unit Area ◽  
Fire Regime ◽  
Minimum Area ◽  
Burnt Area ◽  
Forested Areas ◽  
Large Fires ◽  
Burnt Areas

Abstract. We focus here on a mainland Continental Portuguese Rural Fire Database (PRFD) that includes 450 000 fires, the largest such database in Europe in terms of total number of recorded fires in the 1980–2005 period. In this work, we (a) list the most important factors for triggering and controlling the fire regime in mainland Continental Portugal, (b) describe the dataset's production, (c) discuss procedures adopted to identify and correct different fire data inconsistencies, creating a modified PRFD which we use here and make available as Supplement, (d) explore some basic temporal and completeness properties of the data. We find that the dataset's minimum measured burnt areas have changed with time between AF = 0.1 ha (1980–1990), AF = 0.01 ha (1991–1992), and AF = 0.001 ha (1992–2005), with varying degrees of completeness down to these values. These changes in minimum area measured are responsible for greater numbers of fires being recorded. A relatively small number of large fires in the PRFD are responsible for the majority of the burnt area. For example, fires with AF > 100 ha represent about 1% of all fire records but 75% of total burnt area. Finally, we consider for each Continental Portugal district and for the 26-yr period, the total number of rural fires and area burnt in forests and shrublands, each normalized by district areas. We find that the highest numbers of fires per unit area are in highly populated districts, and that the largest fraction of burnt area is in forested areas, coinciding with large parcels of continuous forests (predominantly rural and moderately urban areas).

scholarly journals Identification of Primary Container of Aedes Mosquitoes Breeding Site in Urban Region of Dengue Endemic Area, Purwokerto Indonesia

2020 ◽  
pp. 181-188
Author(s):  
Siwi Pramatama Mars Wijayanti ◽  
Devi Octaviana ◽  
Sri Nurlaela
Keyword(s):  
Urban Areas ◽  
Endemic Area ◽  
Breeding Site ◽  
Cross Sectional Study ◽  
Urban Region ◽  
Adult Mosquito ◽  
Mosquito Larvae ◽  
Cross Sectional ◽  
Mosquito Breeding ◽  
Dengue Prevention

Dengue prevention and control more reliant on reducing its vector,  Aedes sp. mosquitoes by mosquito breeding nest eradication method. Therefore, identification of the primary container of the Aedes sp. breeding site particularly in the urban region of dengue-endemic area is a crucial effort to conduct an effective dengue prevention program. This research aimed to identify the primary container of the Aedes sp. breeding site in the urban region of the dengue-endemic area. This is a descriptive cross-sectional study, located in an urban region of dengue-endemic area within Banyumas Regency of Central Java Indonesia. A total of 300 houses in three urban areas were observed in urban areas of Purwokerto namely Arcawinangun, Purwanegara, and Karangpucung (100 houses each area). A total of 1504 water-holding containers were observed. All container was observed and recorded the type, color, lid condition, position, and the presence of mosquito larvae. The analysis was conducted by calculating the percentage of types, color, lid condition, and position of the container also the presence of mosquito larvae. The result of this study highlighted that flower pots and bathtubs were the primary types of containers with Aedes sp. larvae in the urban area. The characteristics of larvae-positive containers mostly open, bright, and located indoor position. Dengue prevention efforts by targeting the primary types of containers for mosquito breeding are expected to reduce the adult mosquito population.

scholarly journals Zika mosquito vectors: the jury is still out

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 2546 ◽  
Author(s):  
Walter S. Leal
Keyword(s):  
Aedes Aegypti ◽  
Yellow Fever ◽  
Culex Quinquefasciatus ◽  
Zika Virus ◽  
Field Data ◽  
Vector Competence ◽  
Sexual Transmission ◽  
Mosquito Vectors ◽  
Yellow Fever Mosquito ◽  
The Common

After a 40-year hiatus, the International Congress of Entomology (ICE 2016) convened in Orlando, Florida (September 25-30, 2016). One of the symposia at ICE 2016, the Zika Symposium, covered multiple aspects of the Zika epidemic, including epidemiology, sexual transmission, genetic tools for reducing transmission, and particularly vector competence. While there was a consensus among participants that the yellow fever mosquito, Aedes aegypti, is a vector of the Zika virus, there is growing evidence indicating that the range of mosquito vectors might be wider than anticipated. In particular, three independent groups from Canada, China, and Brazil presented and discussed laboratory and field data strongly suggesting that the southern house mosquito, Culex quinquefasciatus, also known as the common mosquito, is highly likely to be a vector in certain environments.

scholarly journals Proporsi Larva Aedes aegypti dan Aedes albopictus, Hubungannya dengan Kejadian Demam Berdarah Dengue di Daerah Endemik Suburban Kabupaten Sleman, Yogyakarta

2019 ◽  
pp. 163-170
Author(s):  
Bobby Fahmi Muldan Pahlevi ◽  
Tri Wulandari Kesetyaningsih
Keyword(s):  
Aedes Aegypti ◽  
Aedes Albopictus ◽  
Dengue Hemorrhagic Fever ◽  
Urban Areas ◽  
Endemic Area ◽  
Hemorrhagic Fever ◽  
Suburban Area ◽  
Dengue Transmission ◽  
The Relationship

Dengue Hemorrhagic Fever (DHF) is transmitted by Aedes aegypti and Ae. albopictus. Aedes aegypti chooses to live indoors and Ae. albopictus in outdoors. Aedes aegypti has been proven to play a role in dengue transmission in urban areas. It is assumed that suburbs dominated by gardens, so it is possible that Ae. albopictus acts as a vector. The study aimed to analyze the relationship between Ae. albopictus and DHF incidence in suburban area. The study was conducted in Godean, Sleman Regency. 280 ovitrap were placed indoors and outdoors at across seven villages. Each village was represented by one hamlet, so there were 40 ovitrap of each hamlet. The proportion of ovitrap containing Ae. aegypti and Ae. albopictus larvae was calculated. The results showed that Ae. aegypti larvae was more indoors (78.50%) than outdoors (21.45%) in all villages and negatively correlates with DHF (p=0.036; r=-0.776). Aedes albopictus larvae is more commonly found in gardens (80.64%) than in homes (19.36%) and does not correlate with DHF (p = 0.702). It was concluded that in suburban endemic area of ​​Sleman Regency, Ae. aegypti larvae was more indoors and negatively correlated with DHF. Aedes albopictus larva was more in the garden and did not correlate with DHF incidence.

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