In its most recent communication on 25 April, the United States CDC in Atlanta confirmed eight cases of an infection with a novel swine influenza A(H1N1) virus in two US states (California and Texas). These cases have presented with mild flu-like symptoms between the end of March and mid-April and all have fully recovered. Parallel to this there is an ongoing outbreak in Mexico with a considerable number of cases and deaths and preliminary laboratory investigations have shown that viruses from patients with respiratory symptoms were similar to the US viruses. So far it remains unclear why cases in Mexico appear to be more severe than those in the US. No cases were reported in Europe or in other regions.

Public health authorities in Mexico and the US have initiated comprehensive prevention and control measures including intensified surveillance. For Mexico the measures also comprise limited school closure and suspension of mass gathering events. Furthermore, the Mexican authorities have issued public recommendations on personal hygiene measures to reduce the spread of flu.

The ongoing situation is of great concern and requires particular attention. The World Health Organization (WHO) is coordinating the worldwide response to the event and monitoring the corresponding threat of an influenza pandemic. On 25 April the viral gene sequences of the current swine influenza A(H1N1) were published on the organisation’s website together with a guidance document for influenza laboratories.

ECDC is continuing to assess the situation and the potential public health implications. ECDC is exchanging information with its partners in the European Commission, the Member States as well as with the WHO and US CDC in Atlanta. The European Commission is working closely together with the Member States addressing all risk management issues within the Early Warning and Response System (EWRS). The Health Security Committee is also meeting to discuss the situation. The Global Health Security Initiative is exchanging information on the current status of the situation and counter-measures.

A document with questions and answers on human swine influenza is available on ECDC’s website and the Centre will continue to update information on a daily basis.

Find additional information:

CDC (Centers for Disease Control and Prevention): Human Swine influenza investigation

European Commission: Health threat information

WHO: Viral gene sequences to assist update diagnostics for swine influenza A(H1N1)

WHO: Guidance to Influenza Laboratories

WHO: 24 April 2009 : Statement on Swine influenza outbreak  

See also Eurosurveillance articels in Issue 7 of 2009.