WHO : Pandemic (H1N1) 2009 - update 111

The latest H1N1 update from WHO :

" Weekly update

30 July 2010 -- As of 25 July 2010, worldwide more than 214 countries and overseas territories or communities have reported laboratory confirmed cases of pandemic influenza H1N1 2009, including over 18398 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:

Summary: Worldwide, overall pandemic and seasonal influenza activity remains low. In the southern hemisphere (where the winter season is in progress), current influenza activity remains variable: ranging from low and stable activity in Chile and Argentina, to low but increasing activity in Australia and New Zealand, to elevated and recently peaked activity in South Africa. Significant seasonal and pandemic influenza virus transmission continues to be detected at variable levels across parts of the tropics, particularly in several countries of the Americas and South and Southeast Asia.

In the southern hemisphere, overall influenza virus transmission remains low to sporadic, except in South Africa, where recent wintertime influenza activity appears to have peaked, and in Australia and New Zealand, where influenza activity remains low but continues to increase steadily, particularly in recent weeks. In South Africa, virologic data from outpatient sentinel surveillance suggest that the current period of influenza activity (primarily attributable to circulating seasonal influenza H3N2 and B viruses) began and rose sharply during early June 2010, with a likely peak and decline in activity occurring since the first week of July 2010. Data on the full extent of severe illness associated with recent influenza activity are not yet available, however, early reports suggest the current influenza season has been generally mild in terms of levels of clinical disease in the population. In Australia, overall rates of ILI remain low and have increased only slightly over the past four weeks (through the second week of July 2010); however, of note, the number of viral respiratory disease presentations to the emergency departments in Western Australia increased more dramatically during the same period. Overall, the proportion of respiratory specimens testing positive for influenza virus was 5% at sentinel laboratories across Australia, of which approximately two-thirds were pandemic influenza viruses and one-third were seasonal influenza H3N2 viruses; respiratory viruses other than influenza continue to predominant in several regions of Australia. In New Zealand, rates of ILI are below the seasonal baseline but have increased steadily over the past month; recent reports suggest that more significant, but geographically uneven increases may have occurred during the third week of July 2010. Although the number of influenza virus detections remains low, the majority of virus isolates in New Zealand have been pandemic influenza virus. The most recent available virologic surveillance data (mid-July 2010) from Chile and Argentina indicate that very low levels of influenza viruses are currently circulating in the southern temperate regions of the Americas; the predominant circulating influenza viruses in Chile and Argentina are pandemic and seasonal influenza type B viruses, respectively. Recently data from Chile also indicate that overall levels of ILI in the population remain very low, except in the Los Lagos region, which has seen recent late season increases in levels of ILI slightly above the epidemic threshold.

In Asia, the most active areas of pandemic influenza virus transmission currently are in parts of India, particularly in several western and southern states. The majority of new cases continue to be reported in the southern state of Kerala and in the western state of Maharashtra, the later of which reported a sharp increase in the number of cases, including small numbers of fatal cases, between the second and third week of July 2010. Smaller numbers of new cases have also been recently reported in other southern states and in the eastern state of West Bengal. In neighboring Bangladesh, low level co-circulation of pandemic and seasonal influenza type B viruses continued to be detected over the month of July 2010. In Southeast Asia, low levels of pandemic influenza virus circulation were detected in several countries during July 2010, including Cambodia, Singapore and Malaysia. Significant levels of seasonal influenza H3N2 viruses continued to circulate in Singapore."