Health authorities from African island nation São Tomé and Príncipe are grappling with a mysterious dengue fever outbreak - the first ever in the country.
More than 100 cases have been reported to the World Health Organisation (WHO) in just one month - between April 15 and May 17 - but the figure is likely an underestimate.
So far no deaths have been reported but a response plan has been drawn up and epidemiological investigations are underway in several health districts.