Zoonotic transmission of avian influenza virus (H5N1), Egypt, 2006-2009.

During March 2006-March 2009, a total of 6,355 suspected cases of avian influenza (H5N1) were reported to the Ministry of Health in Egypt. Sixty-three (1%) patients had confirmed infections; 24 (38%) died. Risk factors for death included female sex, age > or = 15 years, and receiving the first dose of oseltamivir >2 days after illness onset. All but 2 case-patients reported exposure to domestic poultry probably infected with avian influenza virus (H5N1). No cases of human-to-human transmission were found. Greatest risks for infection and death were reported among women > or = 15 years of age, who accounted for 38% of infections and 83% of deaths. The lower case-fatality rate in Egypt could be caused by a less virulent virus clade. However, the lower mortality rate seems to be caused by the large number of infected children who were identified early, received prompt treatment, and had less severe clinical disease.

Oseltamivir resistance mutation N294S in human influenza A(H5N1) virus in Egypt.

In December 2006, three human specimens were received that were suspected positive for influenza A(H5N1). The specimens were tested using real time PCR. And the presence of A(H5N1) virus was confirmed in 2 patients (16F and 26M), The NA sequence from A(H5N1) positive specimens collected before and after antiviral therapy revealed a mutation (N294S) (N295S according to N1 numbering), previously associated with resistance to oseltamivir. When tested with NA inhibition assays, the two N294S viruses from Egypt exhibited from 57 to 138-fold reduction in susceptibility to oseltamivir, depending on the assay. To our knowledge, this is the first time oseltamivir resistance has been detected in A(H5N1) infecting a human prior to treatment.