Recombinomics: Mild H5N1 Cases in Egypt Raise Concerns

Commentary

Mild H5N1 Cases in Egypt Raise Concerns
Recombinomics Commentary 14:30
March 19, 2009

Woman, age 38, began experiencing fever and headache March 14. She was admitted to Assiut Fever Hospital and given Tamiflu on March 14. Infection with avian influenza was confirmed March 18. The woman reported contact with dead and sick poultry. She was reported clinically free and in a good general condition on March 18.

Girl, age 1½, began experiencing symptoms March 6. She was admitted to Menouf Fever Hospital upon showing symptoms of high fever and cough, and was given Tamiflu. Infection with avian influenza was confirmed March 10. The child was reported in a good general condition on March 10.

The above comments describe the two most recent confirmed cases in Egypt (see updated map). As seen in the description of the most recent case, the disease course is short and the patient was only symptomatic for four days, which is less than most season flu courses. Moreover, all eight confirmed cases this year have recovered. There is no indication that the two patients above developed pneumonia and only one of the eight cases this year was described as being in critical condition. The last fatal confirmed case in Egypt died in December.

The mild H5N1 cases this year are similar to the Egyptian cases in the spring of 2007, when 16/17 cases survived. Most of those cases were in children from upper Egypt. However, this year the cases are spread over a wide area and are likely infected with the vaccine resistant strain first described in late 2007.

Although NAMRU-3 has not released any sequences from this season, two of the human isolates from this year, A/Egypt/0001-NARMRU3/2009 and A/Egypt/0585-NARMRU3/2009, appear to be somewhat related to the vaccine-resistant strain, but may be recombinants, with additional genetic information from earlier Egyptian isolates. Release of sequences from these cases would be useful.

However, the recent mild cases raise concerns that the level of H5N1 cases in Egypt is markedly higher than reported. Many cases who do not develop pneumonia and have mild cases similar to the most recent case likely do not seek medical attention, while others may be treated for seasonal flu and recover untested for H5N1. Moreover, all seven confirmed cases in Egypt this year, prior to the most recent case were 1 ½ to 2 ½ years old. The confirmation of this number of toddlers, also suggests that there are more cases in older children and adults.

These mild cases in Egypt also raise concerns that the level of H5N1 in countries which report high case fatality rates, like Indonesia, Vietnam, and China also have a high number of mild cases that are untested or test negative, especially on samples collected after the start of Tamiflu treatment.

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