Northern Hemisphere countries show steady rise in flu

Jan 18, 2011 (CIDRAP News) – Flu activity is increasing in many of the Northern Hemisphere's temperate-zone countries, with influenza B cocirculating with the 2009 pandemic H1N1 virus across Europe and teaming up with influenza A (H3N2) in the United States and Canada, the World Health Organization (WHO) said in its latest update.

North African and Middle East countries are among the regions reporting increases in flu activity, with Morocco, Algeria, and Tunisia reporting mostly influenza B and Iran and Pakistan reporting that most viruses are the 2009 H1N1 strain, according to the WHO in its Jan 14 update.

In recent weeks some countries in northern Asia have reported rises in respiratory disease levels, the WHO said. Flu activity, most of it H3N2, appears to have peaked in Mongolia and northern China in the third week of December, but South Korea and Japan are reporting that the 2009 H1N1 virus has become the dominant strain.

Over the past several weeks UK countries have seen a steady rise in the number of hospitalizations and deaths from the 2009 H1N1 virus, but other European countries such as France, Portugal, the Netherlands, and Denmark are also reporting hospitalizations and deaths from it and influenza B.

The European Centre for Disease Prevention and Control (ECDC) also issued a flu surveillance report on Jan 14, which provided more details on influenza in that region. It said most countries are reporting regional or widespread activity, especially in western European countries. In Denmark doctors visits for flu-like illness were highest in children younger than 15, but Ireland, England, and Norway all reported that visits were highest in those ages 15 to 64.

In Ireland, the level of doctor's visits for flu-like illnesses is now the same as for last year at this time, which was during the pandemic. England's level is three times higher than at this time last year.

Countries in tropical zones and the Southern Hemisphere's temperate zones are reporting very little flu activity. H3N2 circulation in Paraguay and severe 2009 H1N1 infections in Sri Lanka that were reported earlier are declining. The WHO noted that one exception is Australia, where small numbers of H3N2 and influenza B viruses continue to circulate.

In a separate update on oseltamivir (Tamiflu) resistance among 2009 H1N1 viruses, the WHO said it received three more reports of viruses carrying the H275Y substitution known to confer resistance to the drug, raising the total to 319 so far.

The ECDC said two 2009 H1N1 viruses from patients in the United Kingdom had the H275Y substitution, neither of whom had been treated with oseltamivir.

In other global flu developments, Hong Kong's Center for Health Protection (CHP) released a statement on Jan 15 detailing a novel flu infection in a 3-year-old boy from China's Jiangsu province. The boy, who has a chronic kidney condition and is on long-term corticosteroid treatment, got sick on Dec 31.

Tests on the boy's respiratory specimens by China's Centre for Disease Control and Prevention revealed a "European avian-like H1N1" swine influenza reassortant. The CHP said the boy's close contacts were asymptomatic, but did not say if he had any contact with pigs or other animals.

See also:

Jan 14 WHO global flu update

Jan 14 ECDC flu surveillance report

Jan 15 CHP statement

This week's top reads