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The construction industry employs millions of workers in the USA. However, little is known about how environmental disturbances caused by the construction industry impacts vector mosquito ecology and behavior, and whether it is responsible for increasing the abundance of mosquitoes. There is a major scientific gap on how to assess the occupational exposure risk of mosquito biting and arbovirus transmission among outdoor worker populations who spend a disproportionate amount of time working outdoors. In our opinion, it is critical to address how construction workers and the surrounding communities may be geographically and seasonally exposed to vector mosquitoes. Research should identify modifiable worker- and organizational-level factors that improve worksite mosquitocontrol practices to give insights into future vector-control strategies in urban environments.
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Opinion
Mosquito Adaptation to the Extreme Habitats of
Urban Construction Sites
André B.B. Wilke ,
1,
*Alberto J. Caban-Martinez,
1
Marco Ajelli,
2,3
Chalmers Vasquez,
4
William Petrie,
4
and John C. Beier
1
The construction industry employs millions of workers in the USA. However, little
is known about how environmental disturbances caused by the construction in-
dustry impacts vector mosquito ecology and behavior, and whether it is respon-
sible for increasing the abundance of mosquitoes. There is a major scientic gap
on how to assess the occupational exposure risk of mosquito biting and arbovi-
rus transmission among outdoor worker populations who spend a disproportion-
ate amount of time working outdoors. In our opinion, it is critical to address how
construction workers and the surrounding communities may be geographically
and seasonally exposed to vector mosquitoes. Research should identify modi-
able worker- and organizational-level factors that improve worksite mosquito-
control practices to give insights into future vector-control strategies in urban
environments.
Urbanization and the Construction Industry
In the late 19th century humanity entered a new geological era known as the Anthropocene (see
Glossary), dened by mansinuence in modulating the environment on a level compared to that
of the natural forces of planet Earth [1]. Human migration from rural areas to urban areas, and the
construction of new dwellings, has been increasing since then and, as a consequence, urbani-
zation processes have been intensied to accommodate new residents, urbanizing adjacent
peri-urban areas, increasing urban verticalization, and population density [24].
Construction sites are an integral part of the urbanization process. They often lead to a
signicant disturbance in the environment, modifying land usage, increasing human presence,
and generating signicant amounts of waste, signicantly affecting local fauna and ora [5]. The
construction industry in the USA alone spent approximately US$1.3 trillion in 2018, with
more than 13 million new residential permits issued in the same period employing approximately
9.4 million workers on average
i
[6]. However, very little is known to what extent the environmental
disturbances caused by the construction industry impact the biodiversity and abundance of mos-
quito vector species.
Construction Sites Are Complex Environments
Construction sites, especially geographically large ones, are complex and dynamic. Several em-
ployers work on one site simultaneously, with a mix of contractors changing with the phases of
the project [7,8]. Moreover, as the project develops, different building materials are brought to
the worksite or, as the weather changes, the ambient conditions such as ventilation and temper-
ature change too.
In 2016, the United States Occupational Safety and Health Administration (OSHA) issued
empirical mosquito control guidelines considering the threat Zika virus poses for construction
Highlights
Recent studies have shown that the pro-
liferation of vector mosquitoes is partially
attributable to construction sites.
Very little is known about how environ-
mental disturbances caused by con-
struction sites impact vector mosquito
ecology and behavior.
There is a signicant scientic gap on
how to assess the risk of mosquito biting
and arbovirus transmission in construc-
tion sites.
In our opinion, it is critical to address how
construction sites may be geographically
and seasonally exposed to vector mos-
quitoes and their effect on the transmis-
sion of arboviruses in the surrounding
communities and in the population as a
whole.
Research should also identify modiable
worker- and organizational-level factors
that improve mosquito-control practices
to guide future vector-control strategies
in urban environments.
1
Department of Public Health Sciences,
Miller School of Medicine, University of
Miami, Miami, FL, USA
2
Laboratory for the Modeling of Biological
and Socio-technical Systems,
Northeastern University, Boston, MA, USA
3
Bruno Kessler Foundation, Trento, Italy
4
Miami-Dade County Mosquito Control
Division,Miami,FL,USA
*Correspondence:
axb1737@med.miami.edu (A.B.B. Wilke).
Trends in Parasitology, Month 2019, Vol. xx, No. xx https://doi.org/10.1016/j.pt.2019.05.009 1
© 2019 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Trends in Parasitology
TREPAR 1878 No. of Pages 8
workers
ii
. However, several features of construction sites (e.g., size, duration and phase, number
and type of workers, presence and abundance of vector mosquito species) account for the
effectiveness of vector-control guidelines in construction sites to effectively reduce the risk of
arbovirus transmission.
Therefore, effective safety measures and guidelines must account for the complex worker
mosquito interaction in the highly heterogeneous job site environment, in which several variables
account for the assessment of the multifactorial risk of workers being exposed to vector
mosquitoes.
Indeed, the spread of mosquito-borne disease in the job-site environment represents a prototyp-
ical complex system, where the behaviors of human hosts and mosquito vectors mutually inter-
play and affect each other. This feedback cycle encompasses nonlinear dynamic aspects,
emergent phenomena, and critical points that describe how each process affects the other
both microscopically and macroscopically, in which a small change in a variable (e.g., mosquito
abundance) can have a disproportionate effect on the risk of infection for workers.
Here, we hypothesize that features associated with the proliferation of vector mosquitoes in con-
struction sites are likely to vary across space, such that high and low levels of vector mosquitoes
are concentrated in specic geographic areas according to the size of the construction site, the
number of workers present at the job site, the project duration and phase, each with unique bio-
logical, environmental, and physical features and respectively associated risks for the production
of mosquitoes and the transmission of vector-borne diseases.
In perspective, a signicant gap in the scientic literature includes worker- and organizational-level
factors across the construction project life. The better understanding of these factors is needed for
the development of more effective targeted evidence-based guidelines, tailor-made for construc-
tion workers, based on scientic evidence to support and potentially improve these guidelines
aiming for the reduction of construction worker exposure to mosquito vectors of arboviruses.
Construction Sites and the Proliferation of Vector Mosquitoes
Urbanization processes are often responsible for reducing the overall biodiversity of species [9],
leading to a decrease in the richness of species and subsequent increase in the abundance of se-
lected species capable of prospering in urban environments in a nonrandom process of biodiver-
sity loss [10]. The mosquito vectors Aedes aegypti and Culex quinquefasciatus are among the
species that are able to thrive in such urban habitats amongst the human population [11,12].
Ae. aegypti and Cx. quinquefasciatus are adapted to oviposit their eggs in articial breeding hab-
itats that are often widely available in construction sites, in which immature mosquitoes can de-
velop without predators and blood feed on the exposed construction workers [13,14].Ae.
aegypti and Cx. quinquefasciatus are responsible for transmitting many arboviruses, such as
dengue, chikungunya, yellow fever, and Zika viruses [1519], and West Nile and Eastern Equine
Encephalitis viruses [20,21] respectively.
Research done in Miami-Dade County, Florida, by Wilke et al.[14] found that immature and adult
Ae. aegypti and Cx. quinquefasciatus were breeding in high numbers at construction sites in the
accumulated stagnant water in elevator and stair shafts, Jersey plastic barriers, and on puddles
on the oor (Figure 1AC). Findings of this study provided information on how early-phase con-
struction sites are often vulnerable to ambient elements and may collect rain and groundwater
on the widely available articial containers spread out throughout the area. These mosquito-
Glossary
Anthropoce ne: hypotheticalgeological
age in which human activities have an
inuence equivalent to that of the forces
of nature on the environment.
Arbovirus (arthropod-borne virus):
an acronym used to refer to any viruses
that are transmitted by arthropod
vectors.
Construction site: a delimited area in
which construction workers are working
on the addition of a structure to real
property in the form of residential or
nonresidential buildings, infrastructure or
industrial.
Mosquito control: public-health
practice targeted to the management of
mosquito populations aiming to reduce
disease transmission and nuisance
caused by their bites.
Occupational Safety and Health
Administration (OSHA): an agency of
the United States Department of Labor
that aims to regulate work condition
safety based on enforcement of laws,
training outreach, education, and
assistance.
Safety guidelines and best
practices: a group of recommended
practices to increase workerssafety
and to prevent injuries, illnesses, and
deaths in the construction work site.
Urbanization: a set of processes by
which towns and cities are formed,
consisting of the conversion of rural
areas into urban areas to accommodate
the growth of the human populationand
human migration from rural areas to
cities.
Vector mosquitoes: mosquito species
capable of carrying and transmitting
infectious pathogens such as viruses,
parasites, or bacteria into another living
organism.
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2Trends in Parasitology, Month 2019, Vol. xx, No. xx
breeding sites provide Ae. aegypti and Cx. quinquefasciatus with suitable conditions to freely
reproduce and populate construction sites. The construction sites surveyed by Wilke et al. had
a reduced species biodiversity, and even though 13 different mosquito species were collected
in this study, Ae. aegypti and Cx. quinquefasciatus comprised 95% of all the 3351 mosquitoes
collected and were the only species found in their immature form breeding inside construction
sites. Such ndings suggest that construction sites have highly favorable habitats for vector
mosquitoes adapted to urban environments.
However, despite the size and world-wide importance of the construction industry, there is a
lack of information globally on the relationship between construction sites and mosquito
vectors. The role of construction sites in the proliferation of vector mosquitoes has been largely
neglected and ignored and is for the most part unknown. There are only a few studies available
on the subject, and many questions remain unanswered [2226]. We still do not know the
effect of construction sites on the epidemiology of vector-borne diseases. Moreover, longitudi-
nal studies focusing on seasonal variation in the species composition of mosquito vectors, and
their abundance according to uctuations in weather conditions, the phase of construction,
and specic physical features, are also lacking, substantiating the paucity of studies on this
subject.
Construction Workers Are Exposed to Mosquito Vectors of Arboviruses
During the Zika virus outbreak in Miami-Dade County in 2016, construction workers from the
Caribbean with asymptomatic infection inadvertently brought the Zika virus to Miami, and
were subsequently bitten by Ae. aegypti mosquitoes breeding in high numbers at a construc-
tion site located in the city of Miami Beach, Florida, triggering a Zika virus outbreak [27,28].
Proactively, the Miami-Dade Mosquito Control Division issued a brochure alerting for the risk
(A) (C)
(B) (D)
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Figure 1. The Risk of Mosquito Proliferation at Construction Sites. (A) Elevator shaft ooded with stagnated water in a construction site. From left to right: elevator
shaft; stagnated water and accumulated trash inside elevator shaft; survey of immature mosquitoes breeding in the elevator shaft. (B) Jersey plastic barrier, lledwith water,
breeding vector mosquitoes. From left to right: Jersey plastic barrier; stagnated water inside Jersey plastic barrier; adult Aedes aegypti inside a Jersey plastic barrier.
(C) Stagnant water on the construction site oor serving as breeding sites for Ae. aegypti mosquitoes. From left to right: shallow pool of stagnant water; Ae. aegypti
larvae and pupae breeding in this habitat. (D) Accumulated trash in a construction site environment potentially creating breeding sites for vector mosquitoes.
Trends in Parasitology
Trends in Parasitology, Month 2019, Vol. xx, No. xx 3
of the proliferation of mosquitoes in construction sites (see Figure S1 in the supplemental
information online).
Vector-borne diseases have considerable implications for construction worker safety due to the
impairment these diseases may cause, comprising: severe joint pain, risks for conception and se-
vere neurological diseases, such as GuillainBarré syndrome, leading to worker absenteeism,
long-term health consequences, and even death [16,29,30]. The arboviruses can be introduced
into the construction job sites by workers who become infected during travel to other countries in
regions where there is active transmission and then return to their job with asymptomatic infec-
tions (e.g., 80% of active Zika infections are inapparent) [31] and serve as reservoirs for the
arboviruses.
Construction workers are available in large numbers and spend a disproportional amount of the
workday outdoors being exposed to vector mosquitoes present in high numbers at the job site.
Moreover, by neglecting existing safety guidelines and best practices, such as the removal of
accumulated trash and stagnated water, construction companies are making available many po-
tential breeding habitats for mosquito vector species (Figure 1D).
The development of effective safety guidelines to reduce the risk of subjecting construction
workers to the presence of arbovirus mosquito vectors depends directly on reliable data on
how construction site environments are driving the population dynamics of vector mosquitoes,
and the interaction between mosquito and construction workers. It is of paramount importance
to developing and put into action effective safety guidelines and best practices for the construc-
tion workers and construction rms taking into account how vector mosquitoes are currently ex-
ploring and thriving in habitats created by construction sites [32,33].
Current Conceptual Framework for Construction WorkersSafety and Health
Several theoretical frameworks indicate that worker safety and health is the result of a complex
interplay of factors involving the individual worker and the immediate work environment, as well
as characteristics of the broader contexts in which both the worker and the construction work
site are embedded [34,35]. Future studies should specify the causal pathways through which
the worker- and organizational-level factors are intended to inuence mosquito-control practices,
acknowledging these multifaceted inuences.
By illuminating these pathways, it becomes possible to design mosquito-control interventions
that are meaningful and relevant for this construction worker audience because they attend to rel-
evant work conditions, thereby potentially enhancing intervention efcacy.
We hypothesize that these workplace policies, programs, and practices will impact mosquito-
control practices for several reasons. In addition, psychosocial factors, including supervisor
and coworker support, have been shown to be associated with mosquito-control practices
[36,37]. The physical work environment of the construction site may also provide opportunities
for engaging in positive mosquito-control practices, for example, by the increased availability of
mosquito repellant, surveillance/removal of standing-water sites, and application of larvicides to
water sources [38].
Thus, in this model, workplace policies and practices are the primary engines which drive how
work is organized. They are the upstream conditions that shape multiple downstream conditions
[39]. In addition, for the individual worker,it would be desirable to build self-efcacy and skills for
engaging in mosquito-control behavioral changes.
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4Trends in Parasitology, Month 2019, Vol. xx, No. xx
The arboviruses, such as Zika and chikungunya viruses, are of high concern because Ae. aegypti
is highly anthropophilic and exhibits increased biting activity during the day when outdoor con-
struction workers are most vulnerable [16,40,41]. It is currently unknown how worker health
and safety at outdoor construction sites may be geographically and seasonally compromised
by their exposure to the bites of mosquito vectors of arboviruses.
Unknown Epidemiological Importance of Construction Sites
Currently, risks to construction site workers are unknown because: (i) there is a lack of scientic
information on how construction sites create favorable conditions for mosquitoes species; (ii) it
is unknown to what extent mosquitoes are blood feeding on construction workers and oviposing
in breeding sites produced by construction sites; (iii) it is unknown how much construction
workers are seasonally exposed to the bites of blood-feeding mosquitoes or how this risk varies
across sites; (iv) the actual on-site health risks of workers exposed to mosquitoes remain
uncharacterized; and (v) the possible effect of construction sites in shaping the epidemiology of
arbovirus diseases at the population level is even more uncertain. However, as shown by the
2016 Zika outbreak in Miami-Dade County, we cannot exclude the possibility that construction
sites may serve both as an amplier of the transmission and as a trigger for population-wide
epidemics [27,28].
The production of vector mosquitoes in construction sites is likely to vary across space, such that
high and low levels of vector mosquitoes are concentrated in specic worksite areas according to
the size of the construction site, duration and phase, number and type of workers, each with
unique biological, environmental and physical features. Consequently, health and safety mes-
sages to construction workers provided by mosquito-control agencies, county ofcials, and fed-
eral agencies guiding worker protection are not solidly grounded on scientic evidence
iii,iv
.
A Better Understanding of the Risk That Vector Mosquitoes Represent to
Construction Workers Is Needed
Despite the risk that vector mosquitoes pose in the workplace to the construction workforce, little
is known about what species of mosquito are present in construction sites, what features are
driving their incidence and abundance, and the inherent risk thatmosquito vectors of arboviruses
represent to construction workers and the surrounding area. Additionally, there is a need to ac-
count for human behavior and best practices at the job site (worker- and organizational-levels)
in order to evaluate the effectiveness and possible improvements of the current safety standards
and guidelines employed in the construction workplace for the suppression of vector mosquito
populations.
Furthermore, by developing data-driven predictive models for the complex workermosquito in-
teraction in the construction site environment, it will be possible to understand transmission pat-
terns of arboviruses in the construction site and surrounding communities, provide guidance to
construction-site-specic mosquito-control strategies, which would otherwise be difcult to
test without modeling, and to assess to what extent construction sites shape the epidemiology
of arboviruses at the population level.
Concluding Remarks
More studies should be directed to address how individual construction workers and communi-
ties may be geographically and seasonally exposed to bites of vector mosquitoes (see Outstand-
ing Questions). It is also essential to identify modiable worker- and organizational-level factors
that improve worksite mosquito-control practices to guide future mosquito-control strategies in
urban environments (Box 1).
Outstanding Questions
What are the physical features in con-
struction sites responsible for driving
mosquito presence and abundance?
What are the essential resources present
in constructions sites being used by
mosquitoes for blood and sugar feed-
ing? Are vector mosquitoes adapting to
thrive in the extreme conditions of con-
struction sites?
What is the impact of construction sites
on the biodiversity of mosquito vector
species? To what extent do const ruction
sites promote biotic homogenization
processes?
What human behaviors are associated
with the proliferation of vector mosqui-
toes in construction sites? How much
are construction workers seasonally ex-
posed to vector mosquitoes in construc-
tion sites? What is the risk of arbovirus
transmission on construction sites and
surrounding communities?
What are the modiable physical features
in construction sites and human behavior
that could reduce the proliferation of vec-
tor mosquitoes? How can we effectively
control vector mosquitoes under differ-
ent conditions and phases in construc-
tion sites? How is the interaction
between mosquito and construction
workers driving the population dynamics
of vector mosquitoes and the transmis-
sion patterns of arboviruses?
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Trends in Parasitology, Month 2019, Vol. xx, No. xx 5
Recent arbovirus outbreaks exposed the vulnerability of many countries to mosquito-borne
pathogens transmitted by vector mosquitoes, including the USA. and many countries in
Europe [18,27,4143]. Future studies should focus on construction workers at high risk for expo-
sure to mosquito biting and vector-borne disease, and modiable work organization factors likely
to be associated with these mosquito-transmission risks.
Studies should be conducted in collaboration with major construction rms and construction
equipment vendors (i.e., safety barrier materials), which will support this research through in-
kind contributions of project leadership time and by facilitating these organizational changes
(i.e., mosquito-control practices). This process may be facilitated due their visibility and role in pro-
viding construction services. The major construction rms are key to set the pace of policy
change for mosquito control among other employers, thereby maximizing the potential impact
of research.
There is also a need to identify characteristics of the work organization, mosquito ecology, worker
behavior, and aspects of the job-site environment that can be feasibly modied through changes
in management and worker practices. Mosquito-control strategies should be based on both
mosquito and human surveillance surveys across various construction phases and types of
construction job sites with a random sample of construction workers and focus groups with
construction rm leadership, management and entry-level construction workers.
Box 1. Research Framework for the Development and Improvement of Mosquito-Control Strategies in
Construction Sites
1. Investigate the complex dynamics of mosquitoworker interaction in the highly heterogeneous environment of the con-
struction site to assess how worker health and safety at construction jobsites may be driven by their exposure to bites
of mosquito vectors.
There is a dearth in knowledge about the interaction between mosquitoes and construction workers at construction
sites.
It is unknown how construction sites are increasing the production of vector mosquitoes, and how much risk this
scenario represents for the construction workforce and the community.
A key aspect of developing effective tailor-made guidelines for controlling arbovirus mosquito vectors on construc-
tion sites is the identication of specic species of mosquito present in the construction site workplace.
It also requires the identication of the mechanisms that vector mosquitoes are employing to thrive in construction
sites. What is the potential risk of arbovirus transmission, given the complex scenario of construction environments?
2. Elucidate what species of vector mosquitoes are in contact with construction workers and what features commonly
found in construction sites are driving their population dynamics and geographic distribution, rendering it possible to
employ species-specic vector-control strategies for maximum efcacy for mosquito population suppression and con-
trol to lower the risks to construction workers and the surrounding community.
Determine the impact of worksite physical features (i.e., building materials, phases of the building project, workforce
composition, job site sanitation) on mosquito ecology and human biting.
Determine the inuence that worker behavior and practices (use of repellant, long sleeves, applicationof chlorine tab-
lets to standing water) has on mosquito biting and mosquito population abundance.
3. Develop, calibrate, and validate predictive data-driven models of the complex construction workermosquito interac-
tion in the job-site environment to evaluate the risk that vector mosquitoes pose to construction workers and the
community.
Guide best practices in on-site mosquito-control operations to ensure a negligible risk of arbovirus transmission and,
potentially, a mosquito-free work environment.
Develop more effective targeted safety measures and guidelines for reducing vector mosquitoes in the workplace
and the risk of arbovirus transmission.
4. Guide and improve safety and mosquito-control guidelines for outdoor workers based on scientic evidence for ef-
fective reduction of risk of vector-borne disease transmission and exposure to nuisance-biting mosquitoes.
Provide effective protection from vector-borne disease transmission in an effort that will reach millions of workers that
are exposed to vector-mosquitoes on a daily basis during their working day.
Protect the general population from mosquito vectors of arboviruses, given that, during the Zika crisis that struck
Miami-Dade County in 2016, many Zika cases were associated with transmission at the workplace.
Trends in Parasitology
6Trends in Parasitology, Month 2019, Vol. xx, No. xx
Disclaimer Statement
The authors declare no competing interests.
Acknowledgment
This research was supported by the CDC (https://www.cdc.gov/) Grant 1U01CK000510-03: Southeastern Regional Center
of Excellence in Vector-Borne Diseases: The Gateway Program. CDC had no role in the design of the study, the collection,
analysis, and interpretation of data, or in writing the manuscript.
Supplemental Information
Supplemental information associated with this article can be found online at https://doi.org/10.1016/j.pt.2019.05.009.
Resources
i
www.census.gov/topics/income-poverty/income.
ii
www.osha.gov/laws-regs/regulations/standardnumber/1926
iii
www.osha.gov/Publi- cations/OSHA3855.pdf
iv
www.cdc.gov/niosh/
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... For instance, Ae. (Stg.) aegypti breeding sites are usually located inside households (Valle 2016), yet also being described for other urban habitats, such as construction sites (Wilke et al. 2019b). The entire territory of RS has favorable climatic conditions for the Ae. ...
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Mosquitoes (Diptera: Culicidae) from Porto Alegre region (Rio Grande do Sul state, Brazil) remain understudied. We therefore investigated mosquitoes occurring in 11 sites of this region, and evaluated which landscape features may explain the variation of species richness and composition of mosquito populations in different urban-natural areas of the study region. Using BG-Pro traps, we collected 4311 mosquitoes, from at least 50 species, 14 genera, and two subfamilies. Mansonia titillans (n = 598, 13.87%), Culex spp. (n = 513, 11.9%), and Mansonia wilsonii (n = 502, 11.65%) were the most abundant taxa. Aedes aegypti (n = 36, 0.84%) is potentially exploring new landscapes in the region, beyond human habitations. We identified two new descriptions for the Rio Grande do Sul state, Mansonia pessoai (n = 70, 1.62%) and Toxorhynchites theobaldi (n = 6, 0.14%). The model selection procedure identified that the percentage coverage of temporary crops and the Simpson’s diversity index at landscape level as possible variables explaining the species richness, while percentage coverage of urban and temporary crops were the best predictors of species composition. BG-Pro traps were efficient for catching several adult mosquito species including Toxorhynchites mosquitoes. Therefore, this could be an interesting sampling methodology for mosquito surveillance. Implications for insect conservation: This study expanded the knowledge about Culicidae diversity in Brazil, highlighted the importance of green urban areas for biodiversity conservation, and provided data for entomological surveillance programs. This study also contributes to the conservation of mosquito species that pose no risk to human health (e.g., Toxorhynchites), highlighting that such species have relevant ecological roles, unrelated to disease transmission.
... People coming and going from endemic areas may inadvertently become infected and introduce arboviruses to Miami-Dade to areas where workers spent a disproportionate amount of time outdoors and are exposed to large numbers of vector mosquito species. A similar scenario was documented during the Zika virus outbreak, in which construction workers were exposed to Zika-infected Ae. aegypti mosquitoes breeding in large numbers in a construction site [39,40]. Furthermore, added to the risk of arbovirus introductions to Miami-Dade and the United States, there is also the risk of introduction of ...
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Invasive mosquito vector species have been inadvertently transported to new areas by humans for decades. Strong evidence supports that monitoring maritime, terrestrial, and aerial points of entry is an essential part of the effort to curb the invasion and establishment of invasive vector mosquito species. Miami-Dade County, Florida is an important operational hub for the cruise ship industry and leisure boats that routinely visit nearby areas in the Caribbean, and freight cargo ships transporting goods from Miami-Dade to Caribbean countries and vice versa. To deal with the increasing public health concern, we hypothesized that mosquito surveillance in small-and medium-sized maritime ports of entry in Miami-Dade is crucial to allow the early detection of invasive mosquito species. Therefore, we have selected 12 small-and medium-sized maritime ports of entry in Miami-Dade County with an increased flow of people and commodities that were not covered by the current mosquito surveillance system. Collection sites were comprised of two distinct environments , four marinas with international traffic of leisure boats, and eight maintenance and commercial freight cargo ship ports. Mosquitoes were collected weekly at each of the 12 collection sites for 24 hours for 6 weeks in the Spring and then for 6 additional weeks in the Summer using BG-Sentinel traps. A total of 32,590 mosquitoes were collected, with Culex quinquefasciatus and Aedes aegypti being the most abundant species totaling 19,987 and 11,247 specimens collected, respectively. Our results show that important mosquito vector species were present in great numbers in all of the 12 maritime ports of entry surveyed during this study. The relative abundance of Cx. quinquefasciatus and Ae. aegypti was substantially higher in the commercial freight cargo ship ports than in the marinas. These results indicate that even though both areas are conducive for the proliferation of vector mosquitoes, the port area in the Miami River is especially suitable for the proliferation of vector mosquitoes. Therefore, this potentially allows the establishment of invasive mosquito species inadvertently brought in by cargo freights.
... Urban features such as tire shops or underground subway stations may allow populations of vector mosquito species to survive scorching and freezing temperatures that normally would kill them 72,73 . Furthermore, these highly productive urban environments that are responsible for the proliferation of vector mosquitoes are often located in populous areas, increasing, even more, the contact between humans and mosquito vectors 28,70 . ...
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Urbanization processes are increasing globally. Anthropogenic alterations in the environment have profound effects on biodiversity. Decreased biodiversity due to biotic homogenization processes as a consequence of urbanization often result in increased levels of mosquito vector species and vector-borne pathogen transmission. Understanding how anthropogenic alterations in the environment will affect the abundance, richness, and composition of vector mosquito species is crucial for the implementation of effective and targeted mosquito control strategies. We hypothesized that anthropogenic alterations in the environment are responsible for increasing the abundance of mosquito species that are adapted to urban environments such as Aedes aegypti and Culex quinquefasciatus . Therefore, our objective was to survey mosquito relative abundance, richness, and community composition in Miami-Dade County, Florida, in areas with different levels of urbanization. We selected 24 areas, 16 remote areas comprised of natural and rural areas, and 8 urban areas comprised of residential and touristic areas in Miami-Dade County, Florida. Mosquitoes were collected weekly in each area for 24 h for 5 consecutive weeks from August to October 2020 using BG-Sentinel traps baited with dry ice. A total of 36,645 mosquitoes were collected, from which 34,048 were collected in the remote areas and 2,597 in the urban areas. Our results show a clear and well-defined pattern of abundance, richness, and community composition according to anthropogenic modifications in land use and land cover. The more urbanized a given area the fewer species were found and those were primary vectors of arboviruses, Ae. aegypti and Cx. quinquefasciatus .
... Similar observations were made in Nigeria and Tanzania, where clogged gutters and sewage channels are playing similar roles [59]. Thus, the ecologyand behaviour-related adaptations of the mosquitoes delay control and make such efforts less effective, thereby contributing to the persistence of malaria in cities [60]. ...
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Background Several studies that aim to enhance the understanding of malaria transmission and persistence in urban settings failed to address its underlining complexity. This study aims at doing that by applying qualitative and participatory-based system analysis and mapping to elicit the system’s emergent properties. Methods In two experts’ workshops, the system was sketched and refined. This system was represented through a causal loop diagram, where the identification of leverage points was done using network analysis. Results 45 determinants interplaying through 56 linkages, and three subsystems: urbanization-related transmission, infection-prone behaviour and healthcare efficiency, and Plasmodium resistance were identified. Apart from the number of breeding sites and malaria-positive cases, other determinants such as drug prescription and the awareness of householders were identified by the network analysis as leverage points and emergent properties of the system of transmission and persistence of malaria. Conclusion Based on the findings, the ongoing efforts to control malaria, such as the use of insecticide-treated bed nets and larvicide applications should continue, and new ones focusing on the public awareness and malaria literacy of city dwellers should be included. The participatory approach strengthened the legitimacy of the recommendations and the co-learning of participants.
... While the disturbance of natural habitats through deforestation or drainage of wetlands negatively affects the life cycle of rather specialized species, adaptive generalists are promoted by urbanization. Indeed, some of the most competent vectors of the Aedes, Culex, and Anopheles genera show tendencies to exploit edges of disturbance such as forest-arable land transitions, abandoned stables, or construction sites at urban expansion borders [21,83]. The tendency of submitted Aedes specimens to be collected predominantly in peri-urban areas could therefore also be due to high submission numbers of Ae. japonicus, a species that also prefers these transition zones, to the 'Mückenatlas' scheme [84]. ...
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Urbanization has been associated with a loss of overall biodiversity and a simultaneous increase in the abundance of a few species that thrive in urban habitats, such as highly adaptable mosquito vectors. To better understand how mosquito communities differ between levels of urbanization, we analyzed mosquito samples from inside private homes submitted to the citizen science project ‘Mückenatlas’. Applying two urbanization indicators based on soil sealing and human population density, we compared species composition and diversity at, and preferences towards, different urbanization levels. Species composition between groups of lowest and highest levels of urbanization differed significantly, which was presumably caused by reduced species richness and the dominance of synanthropic mosquito species in urban areas. The genus Anopheles was frequently submitted from areas with a low degree of urbanization, Aedes with a moderate degree, and Culex and Culiseta with a high degree of urbanization. Making use of citizen science data, this first study of indoor mosquito diversity in Germany demonstrated a simplification of communities with increasing urbanization. The dominance of vector-competent species in urban areas poses a potential risk of epidemics of mosquito-borne diseases that can only be contained by a permanent monitoring of mosquitoes and by acquiring a deeper knowledge about how anthropogenic activities affect vector ecology.
... The particular relationship between Aedes aegypti and urban humans creates opportunistic environments for both co-viral exposition and coinfection from similar or distinct infection routes ( Figure 3) [109][110][111]. The city life promotes opportunities related to human behaviors for ZIKV infection and coinfections via other modes of transmission [59,60,112,113]. ...
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The emergence of the Zika virus (ZIKV) mirrors its evolutionary nature and, thus, its ability to grow in diversity or complexity (i.e., related to genome, host response, environment changes, tropism, and pathogenicity), leading to it recently joining the circle of closed congenital pathogens. The causal relation of ZIKV to microcephaly is still a much-debated issue. The identification of outbreak foci being in certain endemic urban areas characterized by a high-density population emphasizes that mixed infections might spearhead the recent appearance of a wide range of diseases that were initially attributed to ZIKV. Globally, such coinfections may have both positive and negative effects on viral replication, tropism, host response, and the viral genome. In other words, the possibility of coinfection may necessitate revisiting what is considered to be known regarding the pathogenesis and epidemiology of ZIKV diseases. ZIKV viral coinfections are already being reported with other arboviruses (e.g., chikungunya virus (CHIKV) and dengue virus (DENV)) as well as congenital pathogens (e.g., human immunodeficiency virus (HIV) and cytomegalovirus (HCMV)). However, descriptions of human latent viruses and their impacts on ZIKV disease outcomes in hosts are currently lacking. This review proposes to select some interesting human latent viruses (i.e., herpes simplex virus 2 (HSV-2), Epstein–Barr virus (EBV), human herpesvirus 6 (HHV-6), human parvovirus B19 (B19V), and human papillomavirus (HPV)), whose virological features and co-exposition with ZIKV may provide evidence of the syndemism process, shedding some light on the emergence of the ZIKV-induced global congenital syndrome in South America.
... Similar observations were made in Nigeria and Tanzania, where clogged gutters and sewage channels are playing similar roles [55]. Thus, the ecology-and behavior-related adaptations of the mosquitoes delay control and make such efforts less effective, thereby contributing to the persistence of malaria in cities [56]. ...
Preprint
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Several studies that aim to enhance the understanding of malaria transmission and persistence in urban settings failed to address its underlining complexity. We aim at doing that by applying a qualitative and participatory-based system analysis and mapping to elicit the system’s emergent properties. In two experts’ workshops, we sketched and refined the system, which was represented through a causal loop diagram, where the identification of leverage points was done using network analysis. We found 45 determinants interplaying through 56 linkages, and identified three subsystems: urbanization-related transmission, infection-prone behavior and healthcare efficiency, and Plasmodium resistance. Apart from the number of breeding sites and malaria positive cases, other determinants such as drug prescription and the awareness of householders were identified by the network analysis as leverage points and emergent properties of the system of transmission and persistence of malaria. Based on our findings, we suggest that ongoing efforts to control malaria, such as the use of insecticide-treated bed nets and larvicide applications should continue, and include new ones focusing on the public awareness and malaria literacy of city dwellers. We found that our participatory approach strengthened the legitimacy of the recommendations and the co-learning of participants.
... Typically, urban settings have high landscape heterogeneity, providing optimal conditions for A. aegypti mosquitoes to thrive and foster arbovirus transmission to humans. 49,50 Urbanisation has high predictive power for estimating ZIKV risk, 18,37 along with population density, which is a significant risk factor. 17,35 Variables relating to healthcare infrastructure have rarely been included as explanatory variables in existing ZIKV modelling studies. ...
Article
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In recent years, Zika virus (ZIKV) has expanded its geographic range and in 2015-2016 caused a substantial epidemic linked to a surge in developmental and neurological complications in newborns. Mathematical models are powerful tools for assessing ZIKV spread and can reveal important information for preventing future outbreaks. We reviewed the literature and retrieved modelling studies that were developed to understand the spatial epidemiology of ZIKV spread and risk. We classified studies by type, scale, aim and applications and discussed their characteristics, strengths and limitations. We examined the main objectives of these models and evaluated the effectiveness of integrating epidemiological and phylogeographic data, along with socioenvironmental risk factors that are known to contribute to vector-human transmission. We also assessed the promising application of human mobility data as a real-time indicator of ZIKV spread. Lastly, we summarised model validation methods used in studies to ensure accuracy in models and modelled outcomes. Models are helpful for understanding ZIKV spread and their characteristics should be carefully considered when developing future modelling studies to improve arbovirus surveillance.
... Further, mosquitoes can quickly breed in urban infrastructure where water stagnates (Wilke et al., 2019b). Reduction in biodiversity, deforestation (Burkett-Cadena and Vittor, 2018;Sylvie Manguin and Christophe Boete, 2011), increased construction (Wilke et al., 2019a), proximity to agricultural areas (Nguyen-Tien et al., 2019), higher humidity, and many other factors may have a role to play in the spread of mosquitoes and MBDs. ...
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Machine learning (ML) techniques excel at forecasting, clustering, and classification tasks, making them valuable for various aspects of mosquito control. In this literature review, we selected 120 papers relevant to the current state of ML for mosquito control in urban settings. The reviewed work covers several different methodologies, objectives, and evaluation criteria from various environmental contexts. We first divided the existing papers into geospatial, visual, or audio categories. For each category, we analyzed the machine learning pipeline, from dataset creation to model performance. We conclude with a discussion of the challenges and opportunities for further research. While the reviewed ML methods in mosquito control are promising, we recommend a) increased use of crowdsourced and citizen science data, b) a standardized and open ML pipeline for reproducible results, and c) research that incorporates advances in ML. With these suggestions, ML techniques could lead to effective mosquito control in urban environments.
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There are limited data on why the 2016 Zika outbreak in Miami-Dade County, Florida was confined to certain neighborhoods. In this research, Aedes aegypti , the primary vector of Zika virus, are studied to examine neighborhood-level differences in their population dynamics and underlying processes. Weekly mosquito data were acquired from the Miami-Dade County Mosquito Control Division from 2016 to 2020 from 172 traps deployed around Miami-Dade County. Using Random Forest, a machine learning method, predictive models of spatiotemporal dynamics of Ae. aegypti in response to meteorological conditions and neighborhood-specific socio-demographic and physical characteristics, such as land-use and land-cover type and income level, were created. The study area was divided into two groups: areas affected by local transmission of Zika during the 2016 outbreak and unaffected areas. Aedes aegypti populations in areas affected by Zika were more strongly influenced by 14- and 21-day lagged weather conditions. In the unaffected areas, mosquito populations were more strongly influenced by land-use and day-of-collection weather conditions. There are neighborhood-scale differences in Ae. aegypti population dynamics. These differences in turn influence vector-borne disease diffusion in a region. These results have implications for vector control experts to lead neighborhood-specific vector control strategies and for epidemiologists to guide vector-borne disease risk preparations, especially for containing the spread of vector-borne disease in response to ongoing climate change.
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Mosquitoes are well known for their epidemiological importance as vectors of a wide range of human pathogens. Despite the many studies on medically important species, little is known about the diversity patterns of these insects in urban green spaces, which serve as shelter and refuge for many native and invasive species. Here, we investigate drivers of mosquito richness and composition in nine urban parks in the city of São Paulo, Brazil. Using the equilibrium theory of island biogeography, we tested predictive models for species richness and composition and performed nestedness analysis. We also investigated whether species loss tends to benefit vector mosquitoes. In the period 2011 to 2013, a total of 37,972 mosquitoes belonging to 73 species and 14 genera were collected. Our results suggest there is a species-area relationship, an increase in species similarity as richness is lost and a nested species composition pattern. Seven of the eight most commonly found species are considered vectors of human pathogens, suggesting a possible link between species loss and increased risk of pathogen transmission. Our data highlight the need for studies that seek to understand how species loss may affect the risk of infectious diseases in urban areas.
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Background Zika virus transmission dynamics in urban environments follow a complex spatiotemporal pattern that appears unpredictable and barely related to high mosquito density areas. In this context, human activity patterns likely have a major role in Zika transmission dynamics. This paper examines the effect of host variability in the amount of time spent outdoors on Zika epidemiology in an urban environment. Methodology/Principal findings First, we performed a survey on time spent outdoors by residents of Miami-Dade County, Florida. Second, we analyzed both the survey and previously published national data on outdoors time in the U.S. to provide estimates of the distribution of the time spent outdoors. Third, we performed a computational modeling evaluation of Zika transmission dynamics, based on the time spent outdoors by each person. Our analysis reveals a strong heterogeneity of the host population in terms of time spent outdoors–data are well captured by skewed gamma distributions. Our model-based evaluation shows that in a heterogeneous population, Zika would cause a lower number of infections than in a more homogenous host population (up to 4-fold differences), but, at the same time, the epidemic would spread much faster. We estimated that in highly heterogeneous host populations the timing of the implementation of vector control measures is the major factor for limiting the number of Zika infections. Conclusions/Significance Our findings highlight the need of considering host variability in exposure time for managing mosquito-borne infections and call for the revision of the triggers for vector control strategies, which should integrate mosquito density data and human outdoor activity patterns in specific areas.
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Yellow fever virus (YFV) causing a deadly viral disease is transmitted by the bite of infected mosquitoes. In Brazil, YFV is restricted to a forest cycle maintained between non-human primates and forest-canopy mosquitoes, where humans can be tangentially infected. Since late 2016, a growing number of human cases have been reported in Southeastern Brazil at the gates of the most populated areas of South America, the Atlantic coast, with Rio de Janeiro state hosting nearly 16 million people. We showed that the anthropophilic mosquitoes Aedes aegypti and Aedes albopictus as well as the YFV-enzootic mosquitoes Haemagogus leucocelaenus and Sabethes albiprivus from the YFV-free region of the Atlantic coast were highly susceptible to American and African YFV strains. Therefore, the risk of reemergence of urban YFV epidemics in South America is major with a virus introduced either from a forest cycle or by a traveler returning from the YFV-endemic region of Africa.
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Zika virus (ZIKV) is causing an unprecedented epidemic linked to severe congenital abnormalities. In July 2016, mosquito-borne ZIKV transmission was reported in the continental United States; since then, hundreds of locally acquired infections have been reported in Florida. To gain insights into the timing, source, and likely route(s) of ZIKV introduction, we tracked the virus from its first detection in Florida by sequencing ZIKV genomes from infected patients and Aedes aegypti mosquitoes. We show that at least 4 introductions, but potentially as many as 40, contributed to the outbreak in Florida and that local transmission is likely to have started in the spring of 2016-several months before its initial detection. By analysing surveillance and genetic data, we show that ZIKV moved among transmission zones in Miami. Our analyses show that most introductions were linked to the Caribbean, a finding corroborated by the high incidence rates and traffic volumes from the region into the Miami area. Our study provides an understanding of how ZIKV initiates transmission in new regions.
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Transmission of Zika virus (ZIKV) in the Americas was first confirmed in May 2015 in northeast Brazil. Brazil has had the highest number of reported ZIKV cases worldwide (more than 200,000 by 24 December 2016) and the most cases associated with microcephaly and other birth defects (2,366 confirmed by 31 December 2016). Since the initial detection of ZIKV in Brazil, more than 45 countries in the Americas have reported local ZIKV transmission, with 24 of these reporting severe ZIKV-associated disease. However, the origin and epidemic history of ZIKV in Brazil and the Americas remain poorly understood, despite the value of this information for interpreting observed trends in reported microcephaly. Here we address this issue by generating 54 complete or partial ZIKV genomes, mostly from Brazil, and reporting data generated by a mobile genomics laboratory that travelled across northeast Brazil in 2016. One sequence represents the earliest confirmed ZIKV infection in Brazil. Analyses of viral genomes with ecological and epidemiological data yield an estimate that ZIKV was present in northeast Brazil by February 2014 and is likely to have disseminated from there, nationally and internationally, before the first detection of ZIKV in the Americas. Estimated dates for the international spread of ZIKV from Brazil indicate the duration of pre-detection cryptic transmission in recipient regions. The role of northeast Brazil in the establishment of ZIKV in the Americas is further supported by geographic analysis of ZIKV transmission potential and by estimates of the basic reproduction number of the virus.
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Since Zika virus (ZIKV) was detected in Brazil in 2015, it has spread explosively across the Americas and has been linked to increased incidence of microcephaly and Guillain-Barré syndrome (GBS). In one year, it has infected over 500,000 people (suspected and confirmed cases) in 40 countries and territories in the Americas. Along with recent epidemics of dengue (DENV) and chikungunya virus (CHIKV), which are also transmitted by Aedes aegypti and Ae. albopictus mosquitoes, the emergence of ZIKV suggests an ongoing intensification of environmental and social factors that have given rise to a new regime of arbovirus transmission. Here, we review hypotheses and preliminary evidence for the environmental and social changes that have fueled the ZIKV epidemic. Potential drivers include climate variation, land use change, poverty, and human movement. Beyond the direct impact of microcephaly and GBS, the ZIKV epidemic will likely have social ramifications for women’s health and economic consequences for tourism and beyond.
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Pandemic arboviruses have emerged as a major global health problem in the past four decades. Predicting where and when the next arbovirus epidemic will occur is a challenge, but history suggests that arboviral black swan events (epidemics that are difficult to predict and that have an extreme effect) will continue to occur as urban growth and globalisation expand. We briefly review unexpected arbovirus epidemics that have occurred in the past 50 years, with emphasis on the American and Pacific regions, to illustrate their unpredictability, and to highlight the need for improved global preparedness, including laboratory-based surveillance, prevention, and control programmes.
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Our planet is an increasingly urbanized landscape, with over half of the human population residing in cities. Despite advances in urban ecology, we do not adequately understand how urbanization affects the evolution of organisms, nor how this evolution may affect ecosystems and human health. Here, we review evidence for the effects of urbanization on the evolution of microbes, plants, and animals that inhabit cities. Urbanization affects adaptive and nonadaptive evolutionary processes that shape the genetic diversity within and between populations. Rapid adaptation has facilitated the success of some native species in urban areas, but it has also allowed human pests and disease to spread more rapidly. The nascent field of urban evolution brings together efforts to understand evolution in response to environmental change while developing new hypotheses concerning adaptation to urban infrastructure and human socioeconomic activity. The next generation of research on urban evolution will provide critical insight into the importance of evolution for sustainable interactions between humans and our city environments.