Since 2009, Kaohsiung Medical University Hospital organized a medical team to provide the medical service for people in Solomon Islands thru Taiwan Health Center at the local. In addition to Malaria and pulmonary tuberculosis, the investigators also found dengue virus, Japanese Encephalitis virus, Chikungunya virus infections and intestinal parasitic infections might be the existing but overlooked and neglected medical issues in Solomon Islands. These infections show similarity in clinical manifestations and usually difficulty in clinical diagnosis, instead these infections rely on the laboratory identification with good laboratory quality and facility.

In this study, the investigators plan to investigate the local people, either from the community or the hospitals, to identify the prevalence and incidence of dengue fever, including laboratory identification of related infections for differential diagnosis, including Japanese Encephalitis virus, Chikungunya virus and intestinal parasitic infections. Intestinal parasite survey has been the routine long-term service offered by the Kaohsiung Medical University Hospital in Solomon Islands. At the same time, the subjects enrolled in this study will also be asked the common medical illness in Solomon Islands (i.e. malaria, pulmonary tuberculosis and metabolic syndrome etc.) in order to delineate the association of dengue fever and these acute and chronic illness.

Inclusion Criteria:

• healthy volunteer
• reported dengue virus infection volunteer
• people who understand the purpose of the study and agree the to sign the informed consent

Exclusion Criteria:

• people who refuse to join the study

• Residents of Solomon Islands
• people who understand the purpose of the study
• people who agree to sign the informed consent