title: Evidence for endemic chikungunya virus infections in Bandung, Indonesia.
abstract: Chikungunya virus (CHIKV) is known to cause sporadic or explosive outbreaks. However, little is known about the endemic transmission of CHIKV. To ascertain the endemic occurrence of CHIKV transmission, we tested blood samples from patients with a non-dengue febrile illness who participated in a prospective cohort study of factory workers in Bandung, Indonesia. From August 2000 to June 2004, and September 2006 to April 2008, 1901 febrile episodes occurred and 231 (12.2%) dengue cases were identified. The remaining febrile cases were evaluated for possible CHIKV infection by measuring anti-CHIKV IgM and IgG antibodies in acute and convalescent samples. Acute samples of serologically positive cases were subsequently tested for the presence of CHIKV RNA by RT-PCR and/or virus isolation. A total of 135 (7.1%) CHIKV infections were identified, providing an incidence rate of 10.1/1,000 person years. CHIKV infections were identified all year round and tended to increase during the rainy season (January to March). Severe illness was not found and severe arthralgia was not a prominently reported symptom. Serial post-illness samples from nine cases were tested to obtain a kinetic picture of IgM and IgG anti-CHIKV antibodies. Anti-CHIKV IgM antibodies were persistently detected in high titers for approximately one year. Three patients demonstrated evidence of possible sequential CHIKV infections. The high incidence rate and continuous chikungunya cases in this adult cohort suggests that CHIKV is endemically transmitted in Bandung. Further characterization of the circulating strains and surveillance in larger areas are needed to better understand CHIKV epidemiology in Indonesia.
authors.affiliation: United States Naval Medical Research Unit Two, Jakarta, Indonesia ; Health Research Unit, Faculty of Medicine, Universitas Padjadjaran, Bandung, Indonesia.
authors.forename: Herman
authors.initials: H
authors.lastname: Kosasih
authors.forename: Quirijn
authors.initials: Q
authors.lastname: de Mast
authors.forename: Susana
authors.initials: S
authors.lastname: Widjaja
authors.forename: Primal
authors.initials: P
authors.lastname: Sudjana
authors.forename: Ungke
authors.initials: U
authors.lastname: Antonjaya
authors.forename: Chairin
authors.initials: C
authors.lastname: Ma'roef
authors.forename: Silvita Fitri
authors.initials: SF
authors.lastname: Riswari
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Porter
authors.forename: Timothy H
authors.initials: TH
authors.lastname: Burgess
authors.forename: Bachti
authors.initials: B
authors.lastname: Alisjahbana
authors.forename: Andre
authors.initials: A
authors.lastname: van der Ven
authors.forename: Maya
authors.initials: M
authors.lastname: Williams
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D018354:Alphavirus Infections / Q000453:epidemiology* / Q000821:virology; D000914:Antibodies, Viral / Q000097:blood; D002646:Chikungunya virus / Q000235:genetics / Q000302:isolation & purification*; D015331:Cohort Studies; D019353:Endemic Diseases; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D015994:Incidence; D007214:Indonesia / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D011446:Prospective Studies; D012367:RNA, Viral / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D012367:RNA, Viral