The sacrificial lifestyle of medical missionaries in the worst known Ebola outbreak -- with two of them coming down with the virus themselves -- cries out for thoughtful, sensitive coverage. So it was a pleasure to see CNN provide it. And in a refreshingly long-form newsfeature.

Kent Brantly and Nancy Writebol, the missionaries, get a searching, respectful look in this 2,087-word piece from a news outfit known better for soundbites and surface treatments. The many-sided article deals with the missionaries' backgrounds and with the number and types of Christian missionaries. It sketches the history of the American missionary initiative and even takes up the question -- as a subhead asks -- of whether Writebol and Brantly were "heroic or foolish" for putting themselves in harm's way.

The heavily researched story cites more than a dozen sources, either directly or via other media. Writers Daniel Burke and Ashley Fantz draw from several reputable groups -- not only missions like Serving in Mission, which Writebol works for, but also think tanks like the Center for the Study of Global Christianity at Gordon-Conwell Theological Seminary in Massachusetts.

Their fact-finding yields some interesting insights. One is that, according to the center at Gordon-Conwell, about 71 percent of the world has heard the gospel as of this summer. Another insight is that although missionaries have worked for centuries, their numbers have "exploded" -- as high as 2.4 million -- since the rise of short-term missions in the 1970s.

The employers of the two American Ebola patients -- Samaritan's Purse for Brantly, Servants in Mission for Writebol -- naturally get a closer look. Burke and Fantz do so by smoothly working in the missionaries' backgrounds and how they felt called to the vocation.

Casual observers may be surprised to find out the language and cultural training that people undergo before they can represent a mission group like SIM. That agency's George Salloum offers this snapshot: