Harare – Zimbabwe's opposition leader Morgan Tsvangirai is reportedly back in South Africa for medical attention, just a few weeks after his last trip.Tsvangirai announced last year that he had been diagnosed with colon cancer and that he had begun chemotherapy.The Movement for Democratic Change (MDC) leader returned to Harare a few weeks ago after being rushed to South Africa where he spent a month receiving medical treatment.According to reports, he was now back again.A senior MDC official confirmed Tsvangirai's latest trip, saying that he caught a scheduled flight to Johannesburg on Friday morning. The official, however, maintained that that "it wasn't an emergency, just a check-up", said EWN A report by eNCA said that Tsvangirai had not been seen in public since he returned to Zimbabwe on October 13.The report quoted his spokesperson Luke Tamborinyoka as saying: "He (Tsvangirai) came back knowing full well he would return for a review and he went for the review as scheduled."Tamborinyoka also wrote on his Facebook page on Friday dismissing private press reports that Tsvangirai was critically ill. Tsvangirai's illness has raised concerns among the opposition, with some senior officials saying that he should consider stepping down to make way for a younger and fit leader. But according to NewsDay, the leader of the breakaway MDC formation, Welsman Ncube, who recently formed an alliance with Tsvangirai, maintained that the former trade unionist was the MDC Alliance presidential candidate despite battling ill heath.Ncube said that discussion surrounding the latter’s health status is unwarranted."…president Tsvangirai remains our best foot forward. There is no doubt that we will campaign for him without hesitation, without qualification and unconditionally and will not engage in such a debate," Ncube was quoted as saying.