By Swati Pandey SYDNEY (Reuters) - Asian shares got the week off to a cautious start on Monday as a spike in coronavirus cases across Asia over the weekend hurt investor sentiment while oil hovered around 2-1/2 year highs. MSCI's broadest index of Asia-Pacific shares outside Japan was last a shade weaker at 703.17, still near a two-week high of 705.35 made on June 16. Australian shares slipped 0.3% while South Korea's KOSPI index was slightly higher. Japan's Nikkei was 0.1% weaker. Investors were concerned about a spike in coronavirus infections in Asia with Australia's most populous city of S...