Emerging disease surveillance and response

Dengue Situation Updates

as of 8 April 2014

Regional dengue activity is variable. Malaysia continues to report a greater number of reported cases in 2014 compared to 2013, for the same time period, however, the recent trend has decreased. Australia and Singapore, have reported a similar number of cases in 2014 compared to 2013, for the same time period. Lao PDR and the Philippines continued to report a decrease in trend whilst Cambodia reported a recent increase in trend, however the number of cases was much lower than 2013, for the same time period.

Dengue virus infection in the Pacific Region High level of dengue activity is being observed in Fiji, New Caledonia and French Polynesia.

In Fiji, there are over 20,000 suspected dengue cases and a total of 12 confirmed dengue deaths. Majority (70%) of the cases were from the Central division, followed by the West (20%), the North (9.5%) and few from the East (0.5%). DENV-3 has been isolated. WHO, Australian Aid program (Fiji Health Sector Support Program), Fiji Red Cross, IFRC, US CDC, QUT (WHO CC Brisbane), UNICEF and SPC have provided technical and financial support to assist in the confirmation and response to the outbreak. This includes, the provision by WHO of dengue test kits. MOH are responding to the situation and has issued a National Dengue Action Plan with focus on strengthening dengue surveillance, dengue clinical management, dengue laboratory reporting and management, strengthen public health response, coordination and logistics for outbreak and improve communication.

In New Caledonia, as of 8 April 2014, there have been 154 cases of dengue since September 2013: 24 cases in 2013, 16 cases in January 2014, 58 cases in February, 56 cases in March and 24 cases in April 2014. Given the high level of activity in the region and the increasing number of cases with zika virus infection, arboviral surveillance and public health response measures have been reviewed and strengthened. DENV-3 has been isolated in addition to DENV-1 (isolated in an imported case) from cases occurring in New Caledonia.

In French Polynesia, the dengue cases reported continue to decline each week. As of 28 Mar 2014, the total number of cases is 1,865 and there has been one death. Since the first quarter of 2014, the number is decreasing: 146 in January, 127 in February and 102 cases in March. Both dengue serotype-1 and serotype-3 were isolated.

Dengue virus serotype 3 (DENV-3), to which a large proportion of the population of the Pacific Islands is likely to be susceptible has been recently isolated in the Region and is now co-circulating with serotype 1 (DENV-1). Dengue virus serotype 3 has recently re-emerged in several countries and territories in the South Pacific after nearly 20 years. WHO is closely monitoring the situation in the Region, especially with regard to serotype circulation.

Zika virus infection in the Pacific region Recently, a number of islands and territories have detected zika virus including French Polynesia, New Caledonia and Cook Islands.

In French Polynesia, there were 8,700 suspected cases of zika virus infection reported by the health professionals sentinel network since early October 2013. All islands of French Polynesia have been affected, and in all islands, the epidemic seems to have entered a phase of decline.

In New Caledonia, the Department of Health and Social Affairs had detected the first indigenous case of zika virus infection on 19 Jan 2014. Since then, indigenous transmission has been on the rise in New Caledonia. As of 27 Mar, there have been 352 confirmed cases of zika virus since 25 November 2013. Of these, 320/352 (91%) were locally transmitted cases and 32/352 (9%) imported from French Polynesia. Current public health surveillance and response measures aimed at arboviruses in New Caledonia were reviewed and strengthened. Surveillance and response capacities are strong and at this stage, WHO assistance has not been requested. WHO continues to monitor the situation closely.

In Cook Islands, an outbreak of zika virus has been declared by health authorities. As of March 23, 2014, 49 laboratory-confirmed cases and 648 suspected cases have been reported. Health authorities are currently responding to and implementing measures to control the outbreak.

Zika virus infection is usually a mild disease; no hospitalizations directly related to acute infection have been reported. However, recently, a more severe single case of zika infection complicated by dengue co-infection has been reported in French Polynesia (http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=20720). Hence, disease severity and clinical presentation in zika infections need to be monitored closely; further, the results of studies examining the impact of underlying dengue infection for zika clinical disease severity need to be considered for assessing the overall public health risk of zika infection.

Table. Reported number of dengue cases in 2014 and 2013 (for the same time period), by country.* NA: Not applicable.

*Dengue reporting systems vary by country and any change in the surveillance system over time is not reflected in the above figures. Number of reported cases listed for 2014 and 2013 (or, if stated for 2013 and 2012) are for the same time period for each year.
**Recent trend is based on the 3 week moving average for countries reporting by week and monthly comparisons for the last complete month for countries reporting by month.
***Australia: Aedes aegypti and Aedes albopictus are present only in Northern Queensland and Torres Strait Islands
^ No available data in 4 regions

Chikungunya Update (As of 2 October 2013)

In recent times, the Western Pacific Region has been experiencing increased reports of chikungunya. In Singapore, 704 cases have been reported up to 21 September in 2013 relative to 9 cases for the same time period in 2012; weekly trend has been increasing for the last several weeks, with 49 cases reported during 15-21 September 2013. In Cambodia, chikungunya reemerged and was detected February-March 2012, soon to be followed by the detection and report of chikungunya for the first time in neighboring Lao PDR, May- September 2012 (see WPSAR: http://ojs.wpro.who.int/ojs/index.php/wpsar/article/view/192/252).

In the Oceania region, since chikungunya was reported February-June 2011 in New Caledonia, Papua New Guinea has reported a large outbreak in June 2012 (see WPSAR: http://ojs.wpro.who.int/ojs/index.php/wpsar/article/view/96/287). In Australia, 107 cases were reported up to 30 September in 2013 relative to 9 in 2012 and 27 in 2011 for the same time period; currently, however, the trend in number of reported cases have been decreasing (18 cases in July, 8 cases in August and no cases reported in September 2013).

For further information on the dengue situation or its surveillance, please visit the following links: