Commentary
Mild
H5N1 Toddlers in Egypt Raise Concerns
Recombinomics Commentary
15:40
March 29, 2009
The above comments on H5N1 in Egypt were made prior to the long string of mild cases in Egypt this year. Eight of the nine cases were children, but all eight were toddlers between the ages of 1 ½ to 2 ½. Moreover only one was described as being in serious condition on March 1, and since there have been no reported H5N1 fatalities in Egypt in 2009, it is likely that all cases this year will be discharged. Moreover, detailed reports on these cases fail to mention pneumonia or ventilators for any of the cases except the one case that was in critical condition four weeks ago.
Like the one adult, the toddlers presented with a headache and fever as well as exposure of poultry. The poultry exposure led to testing and treatment, but it remains unclear why all of the confirmed children are toddlers. Mild cases were also reported in the spring of 2007, and although many were children, most were not toddlers. Only 3 of the 25 cases in 2007 were toddler. Similar low frequencies were also reported for 2006 (2/18 were toddlers) and 2008 (1/8 was a toddler).
In the spring of 2007, most of the mild H5N1 were in central or southern Egypt. In late 2006 / early 2007 all of the cases were fatal and most were from northern Egypt. In the north, many had M230I and all cases with M230I died. In the south most cases either had H5N1 with a Mongolian cleavage site or a 3 BP deletion. This year, none of the sequences have been released, but the cases have been spread throughout the country (see updated map).
The concentration of cases in such a narrow age group raises concerns that there are additional unreported cases which are not being tested. The confirmed cases were mild and testing was precipitated by a poultry link. Mild cases without such a reported link would probably not be tested early. Some may be treated, based on a misdiagnosis of seasonal flu, and testing of patients that recovered would be minimal.
The risk factors for the toddlers are unclear. Increased mobility may lead to more exposure to backyard flocks, but infections in older children has been frequently reported previously suggesting the sudden rising in toddler cases may be linked to immunological protection in older patients due to cross reactivity with H1N1 seasonal flu, or an unreported exposure to prior H5N1 infections.
More testing of toddlers with symptoms, but lacking a poultry connection would be useful.
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