* Nikkei reverses morning gains * Ebola-related shares boosted on suspected Ebola case * Test results expected by Tuesday morning By Thomas Wilson TOKYO, Dec 29 (Reuters) - Japan's Nikkei gave up early gains on Monday after the health ministry announced a suspected case of the deadly Ebola virus, dampening investor risk appetite but boosting health-related shares. The benchmark index was down 0.8 percent at 17,672.97 points by 0431 GMT, after advancing 0.4 percent in morning trade. It briefly fell as far as much as 1.6 percent. A man in his thirties who returned from Sierra Leone on Dec. 23 was suspected on contracting the disease, the Ministry of Health, Labour and Welfare said. Test results are expected by Tuesday morning. If confirmed, it would be the first case of the Ebola virus in Japan. "The Nikkei was heading towards 18,000, but the Ebola news has pushed investors to a risk-off position," said Masayuki Doshida, senior market analysts at Rakuten Securities. "For now, everyone is waiting for the results to come in." Ebola-related shares jumped, with air filter manufacturer Airtech Japan Ltd soaring 14.5 percent and protective clothing maker Azearth Corp climbing 16.0 percent. Fujifilm Holdings Corp, which said in November it expected its influenza drug Avigan to be approved to treat Ebola as soon as the end of 2014, gained as much as 2.3 percent. The Nikkei had gained in early trade after a strong Wall Street performance last week boosted appetite for riskier assets and buoyed investors' confidence in the outlook for equities in 2015. In a holiday-shortened Christmas week, both the Dow and the S&P 500 closed at record highs in a broad rally. Recent gains have come on the back of promising economic data that has lifted expectations of sustainable growth in the world's largest economy. The broader Topix and JPX-Nikkei Index 400 also surrendered earlier gains. The Topix shed 0.5 percent to 1,420.56, while the JPX-400 lost 0.6 percent to 12,880.60. ($1 = 120.4900 yen) (Reporting by Thomas Wilson; Editing by Kim Coghill)