15.07.2011

This study (Emerg Inf Dis 17:1056-1059, 2011) on human infection with avian influenza (H5N1) virus in Pakistan raises concern for the possibility of a pandemic. Previous epidemiologic investigation of the outbreak of infl uenza (H5N1) among persons in the Northwest Frontier Province of Pakistan in 2007 found 5 cases: 3 confirmed, 1 asymptomatic, and 1 probable, as defined by the World Health Organization (WHO). The researchers report 20 cases (4 laboratory confirmed, 7 likely, and 9 possible, resulting in a ratio of 4 likely/possible cases for each laboratory-confirmed case), which ranged from asymptomatic to fatal, in Pakistan in 2007. According to this work these cases indicate human-to-human-to-human transmission of this virus.