Co-transmission of H5N1 with Pandemic H1N1 in Egypt? Recombinomics Commentary 18:16
September 2, 2009

A 35 year-old Italian tourist is one of three people believed to have been infected with A(H1N1) virus, or swine flu, as well as the H5N1 virus, known as avian flu. The patients are recovering in the Egyptian Red Sea resort of Hurghada, said Mohammed Rifai, director general of preventive medicine.

Rifai also spoke of a 28-year-old man who tested positive for both viruses, after arriving at the port of Safaga after a pilgrimage to Saudi Arabia.

"We are waiting the results of the tests that have already been carried out in some patients suspected of having been infected by the H5N1 and the A(H1N1)," said World Health Organisation spokesman Gregory Hartl in an interview with Adnkronos Salute.

The above comments raise concerns of co-infections of pandemic H1N1 and H5N1, as well as human to human co-transmission. This development would create serious pandemic concerns. 

The ability of the pandemic H1N1 to infected multiple species has been demonstrated by the widespread outbreaks in swine.  Outbreaks in Canada have been reported in three provinces (Alberta, Quebec, and Manitoba) as well as two locations in Argentina near Buenos Aires, as well as three locations in Australia,  These swine infections demonstrate the ease of transmission from humans to swine, as well as swine to swine.  Recent results in Chile also demonstrated transmission to turkeys, raising concerns that H1N1 could be silently transmitting to multiple mammalian and avian species.

The jump to avian raised concerns that the H1N1 could interact with H5N1, which is predominantly found in birds, including long range migratory birds.  Recent data also demonstrated H5N1 in pikas at Qinghai Lake, which is a mammalian reservoir.

Results from Egypt also raised concerns of co-infections because of the large number of mild H5N1 cases and the concentration in children.  The heavy concentration in children raised concerns of silent spread of H5N1 in adults, providing opportunities for co-infection, which could lead to the H1N1 "rescuing" H5N1 leading to co-transmissions.

The presence of both viruses in multiple individuals identified over a brief time period suggests the viruses are efficiently co-transmitting, which creates serious concerns due to co-infections, or exchanges of genetic information via reassortment or recombination. Mammalian polymorphisms have been noted in prior H5N1 isolates, and pandemic  H1N1 has H5N1 polymorphisms, indicating exchanges via recombination have happened previously. 

However- co-infection and co-transmission would significantly increase the frequency and efficiency of recombination, which would be serious cause for concerns.

Confirmation that these three patients have co-infections of H5N1 and H1N1 (or swine and seasonal H1N1) would be useful.

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