title: Chikungunya virus outbreak in Kerala, India, 2007: a seroprevalence study.
abstract: India was affected by a major outbreak of chikungunya fever caused by Chikungunya virus (CHIKV) during 2006-2007. Kerala was the worst affected state during 2007 with a contribution of 55.8% suspected cases in the country. However, except for clinically reported case records, no systematic information is available on infection status of CHIKV in the region. Hence, we carried out a post-epidemic survey to estimate seroprevalence status [immunoglobulin G (IgG)] in the community using commercially available indirect immunofluorescence test. This methodology had been reported to be highly specific and sensitive for CHIKV infection. The study area selected was the worst affected mid-highlands region of Kerala which harbour vast area of rubber plantations. The study evidenced 68% of the population to be seropositive for CHIKV IgG. Males were found more affected than females (χ2 = 9.86; p = 0.002). Among males, prevalence was significantly higher in the age classes 21-30 (χ2 = 5.46; p = 0.019) and 31-40 (χ2 = 5.84; p = 0.016) years. This may be due to high occupational risk of the male population engaged in plantation activities exposed to infective bites of Aedes albopictus. The current study provides an insight into the magnitude of CHIKV outbreak in Kerala.
authors.affiliation: Vector Control Research Centre Field Station, Kerala, India. kumarnp@hotmail.com
authors.forename: Narendran Pradeep
authors.initials: NP
authors.lastname: Kumar
authors.forename: Abidha
authors.initials: A
authors.lastname: Suresh
authors.forename: Perumal
authors.initials: P
authors.lastname: Vanamail
authors.forename: Shanmugavelu
authors.initials: S
authors.lastname: Sabesan
authors.forename: Kalianna Gounder
authors.initials: KG
authors.lastname: Krishnamoorthy
authors.forename: Jacob
authors.initials: J
authors.lastname: Mathew
authors.forename: Varakilparambil Thomas
authors.initials: VT
authors.lastname: Jose
authors.forename: Purushothaman
authors.initials: P
authors.lastname: Jambulingam
mesh_terms: D000328:Adult; D018354:Alphavirus Infections / Q000175:diagnosis / Q000453:epidemiology*; D000914:Antibodies, Viral / Q000097:blood*; D065632:Chikungunya Fever; D002646:Chikungunya virus / Q000276:immunology*; D003430:Cross-Sectional Studies; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D007194:India / Q000453:epidemiology; D008297:Male; D015995:Prevalence; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity; D016036:Seroepidemiologic Studies; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D007074:Immunoglobulin G; D011933:Reagent Kits, Diagnostic