Emergence of oseltamivir-resistant influenza A/H3N2 virus with altered hemagglutination pattern in a hematopoietic stem cell transplant recipient.

Background: Persistent influenza virus replication during antiviral therapy in patients undergoing hematopoietic stem cell transplantation (HSCT) could promote the emergence of antiviral drug resistance.

Objectives: To follow the viral genotypic and drug susceptibility changes in a patient who developed progressive influenza A/H3N2 pneumonia despite oseltamivir therapy after haploidentical HSCT.

Study Design: Direct genotypic analysis of the neuraminidase (NA) and hemagglutinin (HA) genes in successive bronchoalveolar lavage specimens was employed in combination with hemagglutination and NA enzymatic activity assays of the corresponding viral isolates.

A summer outbreak of influenza A virus infection among young children.

In the summer of 2003 in Jerusalem, Israel, 23 children were hospitalized with influenza A virus (A/Fujian/411/02-like virus) infection. The majority were neonates and infants. Clinical manifestations included neonatal fever, bronchitis, bronchiolitis, and pneumonia, and outcomes were favorable.