INSIGHTS | PERSPECTIVES
ies (6) indicate that these urban Aaf may
now preferentially choose humans for their
blood meals. The great increase in yellow
fever in sub-Saharan Africa in the past year
may in part be due to this shift: The most
efficient vector of yellow fever virus now resides in densely populated cities in Africa.
Furthermore, Aaa from outside Africa
has found its way back to both West Africa
(Senegal) and East Africa (Kenya), where it
freely interbreeds with Aaf (5, 7). In turn,
Aaf has recently been introduced into Argentina, where it is hybridizing with Aaa
and where populations now breed in tree
holes (8), the classic African larval habitat.
The consequences of increasing hybridization between the two subspecies remain
unclear. Studies of other invasive species
have shown that hybridization leads to an
increase in genetic variation, which may
cause further spread (9).
Clearly, the simple dichotomy of two distinct subtypes of Ae. aegypti has broken
down. Their geographic distributions are
beginning to overlap, and they are hybridizing. Ecologically, they can no longer be
clearly separated, with Aaf increasingly
breeding in urban areas in Africa. Egg-laying behaviors and host preferences are
Ae. aegypti is also increasing its distribution outside Africa and now breeds
year-round in places heretofore free of the
species, such as Madeira (10), the Black Sea
(11), California (12), and Washington, D.C.
(13). These expansions are putting at risk
large human populations that never experienced aegypti-borne viruses and therefore
have no immune defenses against them.
This greatly increases the likelihood of se-
Ae. aegypti’s distribution is in a state of
flux and likely to continue to grow as trade
and human movement increase and climate
change increasingly alters ecosystems.
Monitoring populations and localities will
help to anticipate the spread of the diseases
that this mosquito is so efficient at transmitting. Fortunately, tools are available to
genetically characterize populations (5, 14).
Such genetic characterization is especially
important because populations vary considerably in their ability to transmit viruses
(15). Knowing the genetic makeup of newly
introduced mosquitoes and where they
came from can give indications of their
relative threat and can also guide control
efforts, for example, through knowledge of
which insecticides have proven effective or
ineffective in the source region. j
1. J. A. Kerr, Ed., Building the Health Bridge: Selections from
the Writings of Fred L. Soper (Elsevier, 1970).
2. I. Leparc-Goffart, A. Nougairede, S. Cassadou, C. Prat,
X. de Lamballerie, Lancet 383, 514 (2014).
3. D. Lucey, L. O. Gostin, JAMA 2016, 6606 (2016).
4. B. Kamgang et al ., PLOS Negl. Trop. Dis. 7, e2590 (2013).
5. A. Gloria-Soria et al., Mol. Ecol .25, 5377 (2016).
6. T.M.Sharp et al., Emerg. Infect. Dis.21,1311(2015).
7. M. Sylla et al ., PLOS Negl. Trop. Dis. 3, e408 (2009).
8. C. Mangudo, J. P. Aparicio, R. M. Gleiser, Bull. Entomol. Res.
105, 679 (2015).
9. D. G. Bock et al. , Mol. Ecol. 24, 2277 (2015).
10. A.P.Almeida et al., Euro. Surveill.12,3311(2007).
11. M. Akiner et al., PLOS Negl. Trop. Dis.10, e0004664
12. A.Gloria-Soria et al., PLOS Neg. Trop. Dis. 8,e3029(2014).
13. A.Lima et al., Am. J. Trop. Med. Hyg. 94,231(2016).
14. B. R. Evans et al ., G3 5, 711 (2015).
15. S. Sim et al ., PLOS Negl. Trop. Dis.7, e2295 (2013).
Cold atom manipulation
may enable small quantum
systems to be built to order
By Cindy Regal
In quantum science, the control of indi- vidual particles that was once unimagi- nable is now routine and expanding rapidly to a variety of platforms har- nessing atoms, photons, solid-state circuits, molecules, and more. Yet,
implementation on a large scale that retains individual particle control remains
a frontier challenge. Large-scale quantum
control is predicted to have revolutionary
consequences for studying synthetic quantum matter and for information processing
that harnesses quantum mechanics—that
is, quantum computing. On pages 1021 and
1024 of this issue, Barredo et al. (1) and
Endres et al. (2) report on an experimental
approach in which controlling the spatial
distribution of neutral atoms is taken to a
Neutral atoms have long been considered
to have a special knack for scalability with
regards to many-body quantum states. In
their electronic ground state, they often do
not know of each other’s presence until they
are right on top of each other. Hence, many
can be packed into a small volume; they
are naturally identical, and laser-cooled
reservoirs can consist of billions of atoms.
Thus far, large arrays of neutral atoms have
been demonstrated in approaches where a
quantum-degenerate gas created by special
refrigeration is converted to a Mott insulator. But often these techniques are less amenable to individual manipulation and to
implementing fast interactions required for
Another approach is to build neutral
atom quantum states with a portable “
single atom source” in which single atoms are
isolated in micrometer-scale traps (3). Isolating single atoms can be accomplished
surprisingly simply by forcing atoms to
leave the trap pairwise by inducing highly
Department of Physics, University of Colorado, Boulder, CO
80309, USA. Email: email@example.com
of Aaf into Argentina
with Aaf in Senegal
Black Sea populations of
unknown genetic afnities
Aaa and Aaf
Aedes aegypti formosus and aegypti
Aedes aegypti aegypti (Aaa) Aedes aegypti formosus (Aaf)
Unknown genetic aEnities
Year of introduction is given for locations newly infested with Aedes aegypti since about 2006.