Tuesday, August 28, 2018

PRO/AH/EDR> Yellow fever - Americas (35): Brazil

YELLOW FEVER - AMERICAS (35): BRAZIL
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Date: Thu 23 Aug 2018
Source: Science journal [edited]
<http://science.sciencemag.org/content/early/2018/08/22/science.aat7115>


ref: Faria NR, Kraemer MUG, Hill SC, et al. Genomic and
epidemiological monitoring of yellow fever virus transmission
potential. Science. 2018. pii: eaat7115. doi: 10.1126/science.aat7115
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Abstract
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The yellow fever virus (YFV) epidemic in Brazil is the largest in
decades. The recent discovery of YFV in Brazilian _Aedes_ species
mosquitos highlights a need to monitor the risk of reestablishment of
urban YFV transmission in the Americas. We use a suite of
epidemiological, spatial, and genomic approaches to characterize YFV
transmission. We show that the age and sex distribution of human cases
is characteristic of sylvatic transmission. Analysis of YFV cases
combined with genomes generated locally reveals an early phase of
sylvatic YFV transmission and spatial expansion toward previously
YFV-free areas, followed by a rise in viral spillover to humans in
late 2016. Our results establish a framework for monitoring YFV
transmission in real time that will contribute to a global strategy to
eliminate future YFV epidemics.

[Background]
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Brazil has recently experienced its largest-recorded YF outbreak in
decades, with 2043 confirmed cases and 676 deaths since December 2016.
Between December 2016 and the end of June 2017, there were 777
polymerase chain reaction (PCR)-confirmed human cases of YF across 10
Brazilian states--mostly in Minas Gerais (MG) (60 percent of cases),
followed by Espírito Santo (32 percent), Rio de Janeiro (3 percent),
and São Paulo (3 percent) (18). The fatality ratio of severe YF cases
was estimated at 33.6 percent, comparable to previous outbreaks.

Conclusion
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Epidemiological and genomic surveillance of human and animal
populations at risk is crucial for early detection and rapid
containment of YFV transmission. The YFV epidemic in Brazil continues
to unfold with an increase in cases since December 2017. Longitudinal
studies of non-human primates are needed to understand how YFV
lineages disseminate across South America between outbreaks and how
epizootics are determined by the dynamics of susceptible animals in
the reservoir. To achieve the WHO's goal to eliminate YF epidemics by
2026, YF surveillance necessitates a global, coordinated strategy. Our
results and analyses show that rapid genomic surveillance of YFV, when
integrated with epidemiological and spatial data, could help
anticipate the risk of human YFV exposure through space and time and
monitor the likelihood of sylvatic versus urban transmission. We hope
that the toolkit introduced here will prove useful in guiding YF
control in a resource-efficient manner.

--
Communicated by:
ProMED-mail Rapporteur Mary Marshall

[The toolkit that the authors developed may be very useful when
another yellow fever (YF) outbreak occurs. Readers interested in the
details of the development of the toolkit can access them at the
source URL above.

Interestingly, as this YF outbreak developed in Brazil, there was no
mention of the virus being found in _Aedes aegypti_, which was
abundant in the affected states with a risk of an outbreak in
populated areas. That urban outbreak did not occur. The conclusion was
that all cases resulted from spillover from the sylvan (forest) cycle
of transmission and not the urban cycle. - Mod.TY

Maps of Brazil:
<https://www.mapsland.com/maps/south-america/brazil/large-brazil-regions-map.jpg>
and <http://healthmap.org/promed/p/6>]

[See Also:
Yellow fever - Americas (33): Brazil, monkeys
http://promedmail.org/post/20180705.5890194
Yellow fever - Americas (32): Brazil (MT)
http://promedmail.org/post/20180627.5880041
Yellow fever - Americas (31): Brazil
http://promedmail.org/post/20180511.5792117
Yellow fever - Americas (30): Brazil
http://promedmail.org/post/20180506.5786329
Yellow fever - Americas (29): Brazil
http://promedmail.org/post/20180430.5774384
Yellow fever - Americas (28): Brazil
http://promedmail.org/post/20180422.5761942
Yellow fever - Americas (27): Brazil
http://promedmail.org/post/20180415.5747516
Yellow fever - Americas (26): Brazil (SP)
http://promedmail.org/post/20180405.5727827
Yellow fever - Americas (25): Brazil
http://promedmail.org/post/20180329.5716763
Yellow fever - Americas (24): Germany ex Brazil (RJ)
http://promedmail.org/post/20180327.5714395
Yellow fever - Americas (23): Brazil
http://promedmail.org/post/20180325.5708856
Yellow fever - Americas (22): South America
http://promedmail.org/post/20180321.5699760
Yellow fever - Americas (20): Brazil
http://promedmail.org/post/20180308.5674952
Yellow fever - Americas (19): Brazil
http://promedmail.org/post/20180304.5662410
Yellow fever - Americas (18): WHO Brazil, Europe ex Brazil
http://promedmail.org/post/20180301.5657769
Yellow fever - Americas (17): Europe, Argentina ex Brazil
http://promedmail.org/post/20180228.5655137
Yellow fever - Americas (16): Brazil
http://promedmail.org/post/20180224.5645739
Yellow fever - Americas (15): Brazil (RJ)
http://promedmail.org/post/20180222.5643503
Yellow fever - Americas (14): PAHO/WHO
http://promedmail.org/post/20180217.5634899
Yellow fever - Americas (13): Brazil
http://promedmail.org/post/20180217.5634865
Yellow fever - Americas (12): Brazil monkeys
http://promedmail.org/post/20180211.5622003
Yellow fever - Americas (11): Brazil monkeys
http://promedmail.org/post/20180208.5613594
Yellow fever - Americas (10): Brazil
http://promedmail.org/post/20180131.5597486
Yellow fever - Americas (09): Brazil, monkeys
http://promedmail.org/post/20180129.5593289
Yellow fever - Americas (08): Brazil
http://promedmail.org/post/20180127.5589055
Yellow fever - Americas (07): Brazil vaccination PAHO/WHO
http://promedmail.org/post/20180126.5585612
Yellow fever - Americas (06): Brazil (SP)
http://promedmail.org/post/20180124.5582416
Yellow fever - Americas (05): Brazil, WHO
http://promedmail.org/post/20180124.5579973
Yellow fever - Americas (04): PAHO/WHO Brazil
http://promedmail.org/post/20180117.5566554
Yellow fever - Americas (03): Brazil (SP)
http://promedmail.org/post/20180117.5564150
Yellow fever - Netherlands: ex Brazil (SP)
http://promedmail.org/post/20180115.5561671
Yellow fever - Americas (02): Brazil vaccination
http://promedmail.org/post/20180112.5553721
Yellow fever - Americas: Brazil (SP)
http://promedmail.org/post/20180109.5546267]
.................................................lxl/ty/mj/dk
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