Hong Kong health authorities have identified 21 people showing mild symptoms of chikungunya fever who required blood tests, as the city’s leader pledged that his administration would go all out to prevent the viral disease from taking root locally. The Centre for Health Protection on Tuesday also said the source of infection in a 55-year-old woman confirmed with the mosquito-borne illness a day earlier was still under investigation, but a genome analysis was being conducted. The centre said it...