title: Long-term persistence of Chikungunya virus neutralizing antibodies in human populations of North Eastern Thailand.
abstract: BACKGROUND
  Chikungunya virus (CHIKV) outbreak recurrences in Thailand are unpredictable and separated by unexplained and often long silent epidemiological periods that can last for several years. These silent periods could be explained in part by the fact that infection with one CHIKV strain confers lasting natural immunity, even against other CHIKV strains. In this study we evaluated the persistence of CHIKV-specific neutralizing antibodies in the population of Chumpae District, Khon Kaen Province, nineteen years after a CHIKV outbreak occurred in the same area in 1991.
  
  
  RESULTS
  Overall 39% (44/111) of 111 former patients had neutralizing antibodies reacting against CHIKV ECSA strain. Consistently high titers of neutralizing antibodies were found in 75% (33/44) of all positively-reacting sera, 70% of which (23/33) were collected from individuals amongst the >60 years old age group. Although the prevalence found in Pong Haeng village (70%) was significantly higher than the prevalence detected in the Nong Thum village (14%), control study villages without known previous Chikungunya epidemics had a high Chikungunya neutralizing antibody prevalence (65%).
  
  
  CONCLUSIONS
  More than one-third of the pre-exposed population had persisting natural immunity that was more likely boosted by recent and repetitive exposure to the emerging ECSA CHIKV in Thailand. Also, Chikungunya virus appears to largely circulate in the country with a great variability appears between villages or area probably associated with the vector abundance and efficiency. Altogether these results show a potential for a lifelong immunity against CHIKV. Given the rapid spread of the highly pathogenic ECSA strain in Southern Thailand, the development of CHIK vaccine is strongly recommended.
authors.forename: Narong
authors.initials: N
authors.lastname: Nitatpattana
authors.forename: Kobkan
authors.initials: K
authors.lastname: Kanjanopas
authors.forename: Sutee
authors.initials: S
authors.lastname: Yoksan
authors.forename: Wichai
authors.initials: W
authors.lastname: Satimai
authors.forename: Narong
authors.initials: N
authors.lastname: Vongba
authors.forename: Sasiporn
authors.initials: S
authors.lastname: Langdatsuwan
authors.forename: Khajornpong
authors.initials: K
authors.lastname: Nakgoi
authors.forename: Supot
authors.initials: S
authors.lastname: Ratchakum
authors.forename: Nadia
authors.initials: N
authors.lastname: Wauquier
authors.forename: Marc
authors.initials: M
authors.lastname: Souris
authors.forename: Prasert
authors.initials: P
authors.lastname: Auewarakul
authors.affiliation: Institute of Molecular Bioscience, Mahidol University, Nakhon Pathom, Thailand. jpgonzalez@metabiota.com.
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Gonzalez
mesh_terms: D000328:Adult; D000368:Aged; D057134:Antibodies, Neutralizing / Q000097:blood* / Q000276:immunology; D000914:Antibodies, Viral / Q000097:blood* / Q000276:immunology; D065632:Chikungunya Fever / Q000097:blood* / Q000276:immunology / Q000821:virology; D002646:Chikungunya virus / Q000276:immunology* / Q000302:isolation & purification; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013785:Thailand; D055815:Young Adult
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral