Commentary
H5N1
Toddler Cluster in Beheira Egypt Raises Concerns
Recombinomics Commentary
19:14
April 5, 2009
Magdy Attallah Al-Chief of the Unit for the local center town of Badr in Beheira, the 61 cases and 62 of the bird-flu-affected children, Mohamed El-Shahat Mohamed Hassan Amer, two years, and Jamil Hassan Mohamed Hassan Amer, years and 9 months, with two children and live in adjacent houses
The above translations describe the two most recent confirmed toddlers in Beheira. The index case (confirmed case #61) developed symptoms while visiting relatives in Menoufiya, suggesting the infection was linked to that visit. However, the second translation describes the second case (confirmed case #62), who is the next door neighbor of the index case (see updated map), suggesting the second case was infected in Beheira and the infection was from the neighbor, supporting human to human (H2H) transmission, and predicting that the H5N1 from the neighbors will be virtually identical.
However, these cases have much in common with an earlier mild outbreak in the summer of 2007. The spike in cases involved young children aged 3-10, which was a distinct departure for prior cases which were frequently fatal and were female teenagers and young adults. The mild outbreak of the spring of 2007 was largely confined to central and southern Egypt and the sequences fell into two major sub-clades, one with a Mongolian cleavage site and another with a 3 BP deletion. More striking however, was the virtual identity between isolates from unrelated patients. This identity, coupled with the mild nature of the infections, raised concerns that H5N1 was silently spreading among this patient population.
Because the cases were mild and did not develop pneumonia, misdiagnosis as seasonal flu or some other respiratory disease was a concern. Moreover, almost all H5N1 testing was limited to patients with a known poultry contact, so human to human transmission would be largely missed because those without a poultry contact would not be tested.
Moreover, widespread mild H5N1 infections would create protective immunity, which would limit confirmed cases in this age group. In the current outbreak, none of the confirmed cases are in this age group. 10/11 cases in 2009 are toddlers, and the remaining confirmed case is an adult (38F). Like the low case fatality rate in the spring of 2007 (16/17 patients survived), the case fatality rate in the 2009 cases is zero. The latest confirmed fatality in Egypt was in 2008.
The two confirmed cases in Beheira raise significant H2H concerns. WHO has not issued an update on these cases to clarify where the index case was infected. Similarly, a poultry contact with the Beheira neighbor has not been cited. More detail on these cases, and both poultry and human H5N1 sequences from 2009 would be useful. To date, only two isolates, represented in a phylogenetic tree in the WHO update on vaccine targets has been released. The delay in the release of sequences by NAMRU-3, a WHO regional center, continues to be cause for concern.
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