Human infection with avian influenza virus, Pakistan, 2007

Abstract

Human infection with avian influenza (H5N1) virus raises concern for the possibility of a pandemic. We report 20 cases, which ranged from asymptomatic to fatal, in Pakistan in 2007. These cases indicate human-to-human-to-human transmission of this virus, and the number of cases may be higher than realized.

Figure 1

Areas of influenza (H5N1) cases in humans, Pakistan, 2007. Red shading indicates districts that reported suspected human cases of influenza (H5N1). Light brown shading indicates Northwest Frontier Province. Source: World Health Organization (WHO). Districts of avian influenza suspected cases in Northwest Frontier Province, Pakistan. WHO map no. WHO-PAK-002 (www.whopak.org/disaster).

Figure 2

Path of infection of influenza (H5N1), Pakistan, 2007. During October 22–30, patient 1 worked culling infected chickens; on November 2, he moved home and had contact with 4 brothers (patients 2–5) and possibly a cousin (patient 6). He was hospitalized on November 5 and transferred to an intensive care unit the next day. His cousin cared for him and became patient 6; his attending doctor became patient 7. On November 23, patient 3 was hospitalized and on November 28 was transferred to an intensive care unit; during this time, patient 8 frequently visited his wife in the same intensive care unit.