The new outbreak is centered along the border of North Kivu and Ituri provinces, the epicenters of Congo’s decades-long armed conflict.
Emmerson Mnangagwa narrowly avoided a runoff with 50.8% of the vote.
At least six people were killed Wednesday when the military opened fire on rioting opposition supporters.
A delay in the results of the presidential election triggered opposition protests.
After Zimbabwean opposition protests against the delay in reporting election results turned violent in the capital on Aug. 1, the army opened fire on the crowd.
On July 31, jubilant Zimbabweans gathered outside opposition headquarters in Harare, prematurely claiming the MDC Alliance's candidate, Nelson Chamisa, had beaten the ruling party's candidate, Emmerson Mnangagwa, in the polls.
There have been few reports of irregularities, though opposition and civil rights groups have documented widespread state-sponsored intimidation and vote-buying.
In doing so, Mugabe all but announced his support for the opposition he long suppressed.
Both candidates have promised to abide by democratic principles, keeping hopes high that this time it will be different.
Out of an abundance of caution, health officials will wait three more weeks before a final declaration.