Sep 27, 2010 (CIDRAP News)  Flu activity is showing a late-season flourish in some parts of the Southern Hemisphere, such as Chile, where levels in some areas exceed last year's pandemic peak, and in parts of Australia, the World Health Organization (WHO) said in its most rent influenza update.

The WHO said in a Sep 24 update that flu activity in several of Chile's regions equals or is slightly higher than the country's 2009 winter pandemic wave, with the disease hitting children under age 15 the hardest, followed by those ages 15 to 64.

The 2009 H1N1 virus is cocirculating in Chile alongside seasonal flu viruses. However, limited data from neighboring Argentina suggests low levels of flu, mainly influenza B, between June and late August.

Health officials in Australia have reported steady increases in flu activity since late August, though at levels well below the past three influenza seasons, the WHO reported. Activity is widespread in Victoria in South Australia state and West Australia state, where the 2009 H1N1 and influenza B viruses are cocirculating.

New Zealand also had a late start to its flu season, but activity, most of it 2009 H1N1 flu, has dipped below seasonal baselines.

India and Thailand continue to report significant flu activity, the WHO said. Though activity in India has been geographically widespread, with 17 states and territories reporting new cases, activity is stable or declining in all but a few states, suggesting that national activity may have peaked. The 2009 H1N1 virus has been India's predominant circulating strain.

The country is still reporting many cases and deaths, according to the Indian health ministry's report for the week that ended yesterday. Between Sep 20 and Sep 26, the ministry received 616 reports of lab-confirmed cases, including 93 deaths. States with the highest number of new case for the week were Tamil Nadu (129), Maharashtra (124), and Karnataka (93).

Meanwhile, southern China, Hong Kong, and to a lesser extent northern China have reported increased circulation of the seasonal influenza A (H3N2) virus. Officials in Hong Kong have linked increased H3N2 detections with a steady rise in doctor's visits for flulike illness.

Thailand is reporting active transmission of mainly the 2009 H1N1 virus, along with some H3N2 and influenza B strains, according to the WHO. The rise in flu activity is occurring at a time when increasing flu activity isn't surprising, it added.

The country's health ministry said rising 2009 H1N1 activity was causing officials to consider the possibility of buying more vaccine, the Bangkok Post reported on Sep 24. An official said 20% of people seeking medical care for flulike illnesses were being diagnosed with 2009 H1N1 infections, and he said the country's 2 million monovalent doses might not be enough to meet rising demand.

See also:

Sep 24 WHO influenza update

Sep 26 Indian health ministry weekly flu update

Sep 24 Bangkok Post story