A tsunami after-action report: active disease surveillance in tsunami affected areas, southern Thailand, December 2004-February 2005

Background: On December 26, 2004, the Indian Ocean Tsunami affected 6 provinces of Southern Thailand and caused 5,078 deaths, 8,457 injured and 3,716 missing. The National disease surveillance was interrupted. Post-disaster had many epidemic prone diseases and there was no preparedness plan for this event. The objectives of the surveillance was to 1) identify epidemic prone disease and act as an effective early warning system and 2) initiate immediate investigations and timely interventions. Objective: The purpose is to describe the surveillance system that was implemented and findings from the implementation of the surveillance system. System establishment and implementation: The system covered all affected areas in 20 districts of 6 provinces. For 6 provinces, there were 5 teams of Surveillance and Rapid Response Team (SRRT) that were well trained. Each team composed of medical epidemiologists and health professionals from local, regional and central level. The data collecting sites included public and private medical facilities, shelters for displaced people, forensic identification centers and medical laboratories. The definitions of diseases were based on clinical criteria applied by local physicians. The definition of the outbreaks depended on the diseases and clusters of cases, time and place distribution. Logistics were supported by central and regional level. Laboratory testing was supported by regional laboratory centers and National Institute of Health. The data collecting forms were designed as aggregated data. Data were reported daily via E-mail, facsimile and telephone to local and central level. There was no routine surveillance data at that time because the system was directly and indirectly affected from tsunami. Results: There were 24 diseases of six syndromes under surveillance. During 6 weeks of system establishment, the system reported 4,816 cases. The most common of which was diarrhea (68%), followed by wound infections (8%) and pneumonia (5%), respectively. 11 deaths and 7 outbreaks were reported. Conclusion: The surveillance system achieved all objectives. Individual records should be implemented instead, data quality should be improved and long-term outcomes should be followed up. The public health significance of the study is the surveillance provide the suggestion for the active disease surveillance and the public health preparedness plan

Seroprevalence of Antibodies to Avian Influenza Virus A (H5N1) among Residents of Villages with Human Cases, Thailand, 20051

No evidence of influenza virus A (H5N1) neutralizing antibodies was found in residents of 4 villages where human cases had occurred the previous year

Influenza H5 Hemagglutinin DNA Primes the Antibody Response Elicited by the Live Attenuated Influenza A/Vietnam/1203/2004 Vaccine in Ferrets

Priming immunization plays a key role in protecting individuals or populations to influenza viruses that are novel to humans. To identify the most promising vaccine priming strategy, we have evaluated different prime-boost regimens using inactivated, DNA and live attenuated vaccines in ferrets. Live attenuated influenza A/Vietnam/1203/2004 (H5N1) candidate vaccine (LAIV, VN04 ca) primed ferrets efficiently while inactivated H5N1 vaccine could not prime the immune response in seronegative ferrets unless an adjuvant was used. However, the H5 HA DNA vaccine alone was as successful as an adjuvanted inactivated VN04 vaccine in priming the immune response to VN04 ca virus. The serum antibody titers of ferrets primed with H5 HA DNA followed by intranasal vaccination of VN04 ca virus were comparable to that induced by two doses of VN04 ca virus. Both LAIV-LAIV and DNA-LAIV vaccine regimens could induce antibody responses that cross-neutralized antigenically distinct H5N1 virus isolates including A/HongKong/213/2003 (HK03) and prevented nasal infection of HK03 vaccine virus. Thus, H5 HA DNA vaccination may offer an alternative option for pandemic preparedness

Serological Response to the 2009 Pandemic Influenza A (H1N1) Virus for Disease Diagnosis and Estimating the Infection Rate in Thai Population

BACKGROUND: Individuals infected with the 2009 pandemic virus A(H1N1) developed serological response which can be measured by hemagglutination-inhibition (HI) and microneutralization (microNT) assays. METHODOLOGY/PRINCIPAL FINDINGS: MicroNT and HI assays for specific antibody to the 2009 pandemic virus were conducted in serum samples collected at the end of the first epidemic wave from various groups of Thai people: laboratory confirmed cases, blood donors and health care workers (HCW) in Bangkok and neighboring province, general population in the North and the South, as well as archival sera collected at pre- and post-vaccination from vaccinees who received influenza vaccine of the 2006 season. This study demonstrated that goose erythrocytes yielded comparable HI antibody titer as compared to turkey erythrocytes. In contrast to the standard protocol, our investigation found out the necessity to eliminate nonspecific inhibitor present in the test sera by receptor destroying enzyme (RDE) prior to performing microNT assay. The investigation in pre-pandemic serum samples showed that HI antibody was more specific to the 2009 pandemic virus than NT antibody. Based on data from pre-pandemic sera together with those from the laboratory confirmed cases, HI antibody titers ≥ 40 for adults and ≥ 20 for children could be used as the cut-off level to differentiate between the individuals with or without past infection by the 2009 pandemic virus. CONCLUSIONS/SIGNIFICANCE: Based on the cut-off criteria, the infection rates of 7 and 12.8% were estimated in blood donors and HCW, respectively after the first wave of the 2009 influenza pandemic. Among general population, the infection rate of 58.6% was found in children versus 3.1% in adults