WHO : Pandemic (H1N1) 2009 - update 108

From WHO, H1N1 update 108, excerpt :

" Weekly update

9 July 2010 : As of 4 July, worldwide more than 214 countries and overseas territories or communities have reported laboratory confirmed cases of pandemic influenza H1N1 2009, including over 18311 deaths.

WHO is actively monitoring the progress of the pandemic through frequent consultations with the WHO Regional Offices and Member States and through monitoring of multiple sources of information.

Situation update:

Worldwide, overall pandemic influenza activity remains low. Active circulation of pandemic influenza virus persists in areas of the tropics, particularly in South and Southeast Asia, the Caribbean and West Africa. Overall pandemic and seasonal influenza activity has remained low during the early part of the current winter season in the temperate zone of the southern hemisphere. Low levels of seasonal influenza (H3N2 and type B) viruses were detected during June 2010 in South Africa, while Chile, Australia, and New Zealand, have all recently detected low levels of predominantly pandemic influenza virus. Increasing seasonal influenza activity has also recently been observed in several countries of Central America.

Although rates of respiratory disease have begun to increase in several countries of the temperate zone of the southern hemisphere, little pandemic or seasonal influenza activity has been seen so far during early part of the winter season. In South Africa, a sharp increase in the detection rate of influenza virus, primarily seasonal influenza H3N2 and type B, was observed during the later part of June and early July (> 40% of sentinel respiratory samples from patients with ILI tested positive for influenza during the first week of July); however, levels of respiratory illness-related outpatient consultations and hospitalizations do not appear to be significantly elevated. In Australia, slight increases in the rates of ILI have been reported in recent weeks, however, the overall number of influenza virus detections (primarily pandemic H1N1 and seasonal H3N2) remain low. In New Zealand, rates of ILI have steadily increased over the month of June; however, only small numbers of predominantly pandemic influenza virus have been detected so far. In both Australia and New Zealand, current levels of ILI are similar to those observed during the same period in 2008, when the influenza season was noted to have arrived and peaked late in winter. In Chile, overall levels of ILI remain very low; less than 5% of respiratory samples tested positive for influenza in late June 2010 (the majority were pandemic H1N1 virus with small numbers of seasonal influenza H3N2 and type B detected as well). In Argentina, overall levels of ILI remained low and below levels observed during the past three winter influenza seasons; only small numbers of seasonal influenza type B viruses have been detected during recent weeks. In both Chile and Argentina, RSV has been the predominant circulating respiratory virus since mid-April 2010.

In Asia, overall pandemic influenza activity remains low to sporadic, except in parts of India, Malaysia, and Singapore. In India, transmission of pandemic influenza virus remains active but stable in the southern state of Kerala; similar numbers of new, severe and fatal cases have been reported on a weekly basis since transmission first increased during mid-June 2010. Smaller increases in pandemic influenza virus circulation have also been observed since mid-June 2010 in other southern and western states of India. In Singapore, levels of ARI and pandemic influenza virus transmission declined during June 2010 after peaking in May 2010; the proportion of patients with ILI testing positive for pandemic influenza virus remained stable at 16% during the first week of July 2010. Of note, substantial co-circulation of pandemic and seasonal influenza H3N2 viruses was detected in Singapore throughout May and June 2010. In Malaysia, declining numbers of new cases of pandemic influenza continued to be reported suggesting that overall pandemic influenza activity continued to decline substantially in June 2010 after peaking during mid-April to mid-May 2010. Very low level of seasonal influenza type B viruses continue to circulate across China, Hong Kong SAR (China), Chinese Taipei and the Republic of Korea."