Dengue is an emerging vectorborne infectious disease that is a major public health concern in the Asia Pacific region. Official dengue surveillance data for 2010 provided by the ministries of health were summarized as part of routine activities of the World Health Organization Regional Office for the Western Pacific. Based on reported data, dengue has continued to show an increasing trend in the Western Pacific Region. In 2010, countries and areas reported a total of 353 907 dengue cases, of which 1073 died, for a case fatality ratio of 0.30%. More than 1000 cases were reported each from Australia (North Queensland), Cambodia, the Lao People's Democratic Republic, Malaysia, the Philippines, Singapore and Viet Nam. All of these countries, except for Australia where the dengue virus is not endemic, reported an increase in the number of reported cases in 2010 compared to 2009. The elevated number of cases reported in 2010 in some countries, such as the Philippines, is likely due to several factors, such as enhanced reporting and continued epidemic activity. However, increases in reported number of cases in other areas, such as Singapore and Malaysia, appear to indicate sustained epidemic activity in those countries. The continued epidemic dengue activity in the Region highlights the need for timely and routine regional sharing of information.

Dengue has caused a substantial public health burden in the Western Pacific Region. To assess this burden and regional trends, data were collated and summarized from indicator-based surveillance systems on dengue cases and deaths from countries and areas in the Western Pacific Region. In 2012, dengue notifications continued to increase with 356 838 dengue cases reported in the Region (relative to 244 855 cases reported in 2011) of which 1248 died. In the Asia subregion, the notification rate was highest in Cambodia, the Philippines and the Lao People's Democratic Republic (316.2, 198.9 and 162.4 per 100 000 population, respectively), and in the Pacific island countries and areas, the notification rate was highest in Niue, the Marshall Islands and the Federated States of Micronesia (8556.0, 337.0 and 265.1 per 100 000 population, respectively). All four serotypes were circulating in the Region in 2012 with considerable variabilitiy in distribution. Regional surveillance provides important information to enhance situational awareness, conduct risk assessments and improve preparedness activities.

After a devastating earthquake and tsunami struck north-eastern Japan in March 2011, the public health system, including the infectious disease surveillance system, was severely compromised. While models for post-disaster surveillance exist, they focus predominantly on developing countries during the early recovery phase. Such models do not necessarily apply to developed countries, which differ considerably in their baseline surveillance systems. Furthermore, there is a need to consider the process by which a surveillance system recovers post-disaster. The event in Japan has highlighted a need to address these concerns surrounding post-disaster surveillance in developed countries.

In May 2011, the World Health Organization convened a meeting where post-disaster surveillance was discussed by experts and public health practitioners. In this paper, we describe a post-disaster surveillance approach that was discussed at the meeting, based on what had actually occurred and what may have been, or would be, ideal. Briefly, we describe the evolution of a surveillance system as it returns to the pre-existing system, starting from an event-based approach during the emergency relief phase, a syndromic approach during the early recovery phase, an enhanced sentinel approach during the late recovery phase and a return to baseline during the development phase. Our aim is not to recommend a specific model but to encourage other developed countries to initiate their own discussions on post-disaster surveillance and develop plans according to their needs and capacities. As natural disasters will continue to occur, we hope that developing such plans during the “interdisaster” period will help mitigate the surveillance challenges that will arise post-disaster.

Dengue is an emerging vectorborne infectious disease that is a major public health concern in Asia and the Pacific. Official dengue surveillance data for 2011 provided by ministries of health were summarized as part of routine activities of the World Health Organization Regional Office for the Western Pacific. Based on officially reported surveillance data, dengue continued to show sustained activity in the Western Pacific Region. In 2011, Member States reported a total of 244 855 cases of which 839 died. More than 1000 cases were reported each from Cambodia, the Federated States of Micronesia, the Lao People’s Democratic Republic, Malaysia, the Philippines, the Marshall Islands, Singapore and Viet Nam. Cambodia, the Federated States of Micronesia and the Marshall Islands reported more cases relative to 2010. There continues to be great variability among the dengue-endemic countries and areas in the Region in the number of cases and serotype distribution. The continued high notification rate and complex dengue epidemiology in the Region highlight the need for information-sharing on a routine and timely basis.

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Objective：In August 2012, an outbreak of enterohaemorrhagic Escherichia coli (EHEC) O157 infection was investigated by the City of Sapporo and Hokkaido Prefectural Government. The initial notification reported an illness affecting 94 residents of 10 private nursing homes distributed across multiple areas of Hokkaido, the northernmost island of Japan; at this time three cases were confirmed as EHEC O157 infection. The objectives of the investigation were to identify the source of infection and recommend control measures to prevent further illness.Methods：A suspected case was defined as a resident of one of the private nursing homes in Hokkaido who had at least one of the following gastrointestinal symptoms: diarrhoea, bloody stool, abdominal pain or vomiting between 10 July and 10 September 2012. Cases were confirmed by the presence of Shiga toxin 1- and 2-producing EHEC O157 in stool samples of suspected cases. We conducted an epidemiological analysis and an environmental investigation.Results：We identified 54 confirmed and 53 suspected cases in 12 private nursing homes including five fatalities. Of the 107 cases, 102 (95%) had consumed pickles, all of which had been manufactured at the same facility. EHEC O157 isolates from two pickle samples, 11 cases and two staff members of the processing company were indistinguishable. The company that produced the pickles used inadequate techniques to wash and sanitize the vegetables.Discussion：Contaminated pickles were the likely source of this outbreak. We recommended that the processing company improve their methods of washing and sanitizing raw vegetables. As a result of this outbreak, the sanitation requirements for processing pickles were revised.

Problem: Six invasive meningococcal disease cases occurred among Scottish and Swedish nationals associated with the World Scout Jamboree (WSJ), an international mass gathering, held in Japan. The index case developed symptoms while returning home. The strains from all six cases were identical and seldom seen in Japan. Context: Over 33 000 participants from 155 countries attended WSJ. At the Jamboree site, participants of the North of Scotland’s and Sweden’s units camped within the same subcamp and kept the same schedule of events. No information was available about the Swedish and Scottish cases’ close personal contact history. Action: Health Protection Scotland investigated Scottish cases, conducted active case finding, provided chemoprophylaxis, vaccinated close contacts and advised Scottish WSJ participants and contacts to seek medical care if they developed symptoms. The Public Health Agency of Sweden recommended chemoprophylaxis to all participants in Sweden. In Japan, the Ministry of Health, Labour and Welfare (MHLW) requested the Scout Association of Japan advise all participants to seek medical attention if they developed symptoms. MHLW shared information about the event with local authorities, medical associations, and the Ministry of Education, Culture, Sports, Science and Technology. Outcome: No additional case related to WSJ has been reported. This outbreak highlighted the risk for international spread of invasive meningococcal disease at international mass gatherings. Discussion: Assessing risk, educating participants, enhancing surveillance and sharing timely information among related countries are significant for prevention and response against invasive meningococcal disease outbreaks at mass gatherings.

Objective: Adolescent and young adult males account for a large proportion of dengue cases reported through national surveillance systems in the Western Pacific Region. To preliminarily assess the validity of these observed distributions, a field investigation was conducted in the Lao People’s Democratic Republic’s Savannakhet Province in November 2011. Methods: Mixed quantitative and qualitative methods were used. Dengue surveillance data from Savannakhet Province, and aggregate hospital admission data from the Savannakhet Provincial Hospital for outpatients and inpatients were analysed by age and sex. Unstructured informal interviews were conducted with local health care workers, primary and secondary school officials and villagers. Results: An excess of males was found among reported dengue cases in Savannakhet Province in the 15–49 year age group. Females in the same age group, however, were found to access health care more than their male counterparts. Qualitative assessments attributed this distribution to young females being more health-conscious and having greater health care-seeking behaviour. Discussion: The excess of male dengue cases in the surveillance data appeared to be associated with a truly higher risk of dengue rather than greater health care access or health care-seeking behaviour by young men. This investigation indicated the importance of assessing the reported surveillance data within the context of health care utilization behaviour of the population under surveillance.