Janet S. Oleszek has won the Democratic primary for the Board of Supervisors seat in the Braddock District, according to a recount by Fairfax County election officials.

Officials called for the recount because of Tuesday’s close vote between Oleszek and Christopher J. Wade, the general registrar said Wednesday.

Oleszek, a former School Board member who once lost a legislative battle to then-state Sen. Ken Cuccinelli II (R) by a whisker, won by 43 votes over Wade, a first-time candidate. She will face John C. Cook (R), the incumbent, in November.

For a time — with just two precincts left to count — the lead was in Wade’s hands. With all 27 precincts reporting late Tuesday, however, Oleszek had a 42-vote lead with 50.54 percent of the vote, compared with Wade’s 49.45 percent. There was one provisional ballot cast, but election officials later found that it was cast in the Republican primary for sheriff.

Edgardo Cortés, general registrar of the Fairfax County Office of Elections, said that although there is no provision in Virginia election law for an automatic recount, the Electoral Board agreed to reexamine the vote Wednesday because of the intense interest in the Braddock District race. Ordinarily, a recount must be requested by a candidate. If the margin is less than 0.5 percent, the commonwealth would pay for the recount. If the margin is between 0.5 percent and 1 percent, the candidate who requests a recount must pay.

By Wednesday afternoon, Cortés said, the vote split had changed slightly but not enough to trigger a full recount. The final tally gave Oleszek 1,959 votes to Wade’s 1,916.

Hours after polls closed Tuesday, Wade called Oleszek to acknowledge that she appeared to have won, but both agreed to postpone making a formal concession or claim of victory until the recount was finished.

In the only other county-level primary, Republican Bill A. Cooper III, 55, of Fairfax Station defeated H. Wes Kammerer, 73, of Centreville to become the GOP nominee against Sheriff Stan G. Barry (D) in November.

With results in from all precincts, Cooper had 11,511 votes, or 76.49 percent, compared with Kammerer’s 3,538, or 23.5 percent.

A sliver of Fairfax’s registered voters showed up at the polls Tuesday for the primaries. And that was before a 5.8-magnitude earthquake, centered in Mineral, Va., rattled the East Coast about 2 p.m. The quake diminished turnout further, officials said, but voting continued with paper ballots at some makeshift polling places set up outside buildings that had closed after the quake.

Oleszek, 64, entered the race with some name recognition. Having lived in Fairfax for nearly four decades, she won election to the School Board in 2003 and lost against Cuccinelli in 2007.

Wade, 38, had the backing of several elected officials, including Board of Supervisors Chairman Sharon Bulova (D). Wade, a father of three, is a businessman and an adjunct instructor at George Mason University.

His campaign was dogged by accusations that he was not really a Democrat, owing to his participation in some GOP primaries. But Wade cast himself as an independent.