CAIRO, Dec 1 (Reuters) - The United Arab Emirates announced on Wednesday its first known case of the new COVID-19 variant Omicron, state news agency WAM reported. The variant was detected in an African woman who had travelled from an African country and transited through an Arab country, WAM said. The woman had received both doses of the COVID-19 vaccine. Public health authorities have placed her in isolation, as well as those who were in contact with her, WAM reported. The UAE is the second Gulf country to detect a case of the new variant, after Saudi Arabia announced its first case earlier on Wednesday. read more Key questions remain about the variant, which has rattled markets amid signs it may spread quickly and evade some of the defenses provided by vaccines. It has been found in two dozen countries, including the United States, Spain, Canada, Britain, Austria and Portugal. read more Last week, the UAE suspended entry for travellers from South Africa, Namibia, Lesotho, Eswatini, Zimbabwe, Botswana and Mozambique as a precautionary measure against the spread of Omicron.