Helen Branswell's “Ebola War” provides excellent coverage of the many unknowns regarding the Ebola virus, as well as the unprecedented speed with which the two most promising vaccines are being tested. Yet although vaccines, and greatly improved health care infrastructure, are essential to Ebola prevention and containment, little mention was made of another critical dimension: the early, active and sustained engagement of affected communities and their leaders and networks. Attacks on health care facilities and personnel, borne of rumors that the outsiders were intentionally spreading Ebola, are reminders that the best-intentioned efforts can fail when affected communities are not involved as part of the solution.

Enhanced community engagement will be critical to vaccine testing and rollout in affected regions. But it will also help build local capacity and readiness before the next Ebola crisis has a chance to take hold.

University of California, Berkeley, School of Public Health

Western Cape Department of Health, South Africa

I was shocked to read there was a placebo-based trial of Ebola vaccines in infected areas. This seems beyond unethical. No one would be okay with this Russian roulette game if it were their own family and friends involved in the study.

Boardman, Ore.

I was disappointed that the author mainly cites the competing vaccines by their manufacturers' names (“GlaxoSmithKline vaccine” and “New Link vaccine”). Doing so is a bit off, don't you think?

Cairo, Egypt


Readers of “Oceans from the Skies,” by David Jewitt and Edward D. Young, on whether Earth's water originated from asteroids, comets or another source might be interested to know that the observations of two comets with Earth-like deuterium/hydrogen (D/H) ratios, as well as the detection of evidence of water on Ceres referred to by the authors, were carried out using the HIFI instrument on the Herschel Space Observatory. (We have both worked extensively with Herschel.)

High-resolution spectroscopy with a submillimeter telescope is a valuable tool for observing numerous comets and asteroids and thus addressing the issue of the origin of the Earth's oceans on a statistical rather than an object-by-object basis.

NASA Jet Propulsion Laboratory

Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Paris


Shock Medicine,” Kevin J. Tracey's article on the inflammatory reflex—the body's circuit for keeping the immune system from becoming overactive or underactive—contains an apparent paradox. Cutting the vagus nerve blocked fever caused by the signaling molecule interleukin-1, presumably the result of systemic release of the inflammatory molecule tumor necrosis factor (TNF). Cutting the nerve also blocked the systemic release of TNF after its injection in the brain. But stimulating the vagus nerve also reduced systemic TNF release.

To achieve the same effect as cutting the nerve would seem to require a blocking current, not a stimulating current. Could it be that the stimulating current somehow selectively stimulated only the sensory input, which then reflexively reduced the motor output by the vagus?

Department of Neurosurgery, Massachusetts General Hospital

I wonder whether Tracey has considered that acupuncture may somehow mimic the responses he found. I haven't tried it, but friends have reported positive experiences, including for migraines.

Fernandina Beach, Fla.

TRACEY REPLIES: Wilkinson correctly proposes that signals in the vagus nerve can either enhance or inhibit inflammation. The vagus nerve has almost 100,000 fibers, which mediate millions of discrete biochemical effects. The challenge and opportunity to developing bioelectronic medicine is to be able to deliver specific signals that target individually defined circuits. Our results indicate that inflammation can be inhibited by targeting only about 5 percent of these vagus nerve fibers in rodents.

In answer to McDonald: there has been extensive interest in the scientific and medical community about the relation between acupuncture and controlling inflammation, and many labs are studying it. For example, Luis Ulloa of Rutgers New Jersey Medical School has published a study suggesting that electrically stimulating an acupuncture point in the leg inhibits inflammation by activating vagus nerve signals to the adrenal gland.


Dust Up,” by Mark Fischetti [Graphic Science], discusses a “gigantic reservoir of magma” below Yellowstone National Park.

So why are we not tapping that reservoir for geothermal energy? Power plants could be located outside of the park and use horizontal drilling to access it.

Carriere, Miss.


In “Forging Doubt” [Skeptic], Michael Shermer discusses how industries for products that have ill effects plant doubt of those effects in the mind of the public.

Why did Shermer omit alcohol from such industries? It is more dangerous than food additives and flame retardants.

Longwood, Fla.

SHERMER REPLIES: Poole makes a good point that also applies to the legalization of marijuana. Although it may be debatable whether booze or pot is worse, there is no question that a double standard exists that has far more to do with politics and the law than with science and evidence. If we were consistent, we would apply the same standards of health and safety to alcohol as we do to other products, but humans and societies are nothing if not inconsistent.


Quick Hits” [Advances] includes a short reference to the California High-Speed Rail project that repeats its proponents' claim of a travel time of 2.5 hours between San Francisco and Los Angeles. This claim is both the truth and a fabrication: it is only the time “city to city.”

Including travel to the station, security, wait time, renting a car in Los Angeles and driving to one's final destination would make the “door to door” time much longer. In addition, drivers can carry more and have their own car when they arrive.

Sacramento, Calif.


Shock Medicine,” by Kevin J. Tracey, incorrectly cites the Scientific American article “Treating Depression at the Source,” by Andres M. Lozano and Helen S. Mayberg, as published on February 2014. The correct date is February 2015.