The first case was presented in an adult of 27 years, hospitalized on 25 July in Liberia Hospital. Eleven more cases were confirmed, the last in October. No other cases have been confirmed either in the Guanacaste province or in the rest of the country. Almost all the cases in the first generation in the counties of Liberia and La Cruz had contact with Liberia Hospital as source of infection and were linked to the index case. This suggests that transmission took place within Liberia Hospital.
Viral isolation is required from all chains of transmission.