Two More Confirmed H5N1 Infected Children in Egypt
Recombinomics Commentary
March 27, 2007
The Ministry of Health and Population of Egypt has reported two new human cases of avian influenza on 26 March 2007 at 11:50 pm. One case is a boy 5 years old from Menia and another is a girl 6 years old from Qena. Both were given oseltaminvir within 24 hours after onset of symptoms. They are in good health condition and will be referred to El Bakry hospital in Cairo.
The above comments from the WHO Eastern Mediterranean Regional Office describe two more H5N1 confirmed children in Egypt. Like the most recent case from Aswan, the patients are described as being “in good health condition”. The Aswan case (3F) was confirmed yesterday and was the third child (10F and 2M) confirmed in Aswan who were hospitalized over a nine day period.
US NAMRU-3 has sequenced the HA and NA from the first two Aswan cases. Like the two surviving cases, the Aswan cases did not have M230I. Earlier this season all cases with M230I were fatal. After seven fatalities, the most recent seven cases, including the two above, have survived. However, the recent isolates from Aswan also had evidence of recombination and reassortment. The NA, which was identical in both Aswan patients, matched two fatal cases from central Egypt, while the HA was unique. Those sequences had a novel HA cleavage site, previously found in whooper swans in Mongolia. Several new polymorphisms in H5N1 isolates from Egypt, including the V223I change in the receptor binding domain have been found in H5N1 Qinghai isolates from Mongolia. These changes were found this season in Egypt, and were appended onto an Egyptian genetic background defined by the H5N1 isolates in Egypt last season.
These acquisitions are most easily explained via recombination. However, the isolates from Aswan are also reassortants, because the HA sequences from Aswan are significantly different than the HA sequences from central Egypt, which have a 3 nucleotide deletion, as well as several additional sub-regional polymorphisms.
Both recombination and reassortment require a dual infection of a host, and Egypt’s location in overlapping flyways, as well as widespread H5N1 infections in poultry, facilitates such exchanges of gene segments in reassortment, and portions of gene segments in recombination.
Media reports indicate the first two Aswan cases have recovered and have been discharged after a brief hospital stay. The WHO description of the three most recent cases suggests that they are also mild cases. Media reports also indicated these patients had high fevers and cold or flu-like symptoms, raising concerns that other patients with H5N1 mild symptoms would not be tested, which would create problems in monitoring or detecting such cases.
These concerns could extend to patients who travel outside of Egypt. Yesterday, passengers on a Hong Kong flight to Montreal were detained because of passengers with flu-like symptoms. The passengers were released, based on the mild symptoms of the ill passengers, and lack of exposure to wet markets or dying poultry. However, the mild symptoms in the H5N1 infected patients in Aswan may have been discounted in current screening protocols.
The above confirmed cases in Egypt raise the total of confirmed cases in the past two weeks to five. All were children between the ages of 2-10 and all appear to have mild infections, raising concerns that the number of recent mild H5N1 infections in Egypt is markedly higher than the five confirmed cases.
Media sources
Phylogenetic Trees