12 February 2007
WHO Reports on 251 Persons with H5N1 Infection (2003-2006) and Confirms First Patient in Nigeria (2007)
The World Health Organization (WHO) 9 February issue of the weekly epidemiological record (WER) contains a detailed update on 251 WHO laboratory-confirmed patients with H5N1 avian influenza A infections from 25 November 2003-24 November 2006. On 3 February the WHO also confirmed the infection of the first patient in Nigeria (Lagos) with H5N1 virus infection.
The patient in Lagos, Nigeria’s largest city, was a 22 year-old woman who died on 16 January 2007. The definitive source of her infection is still under investigation. The 10 Feb 2007 issue of the International Herald Tribune carries an Associated Press article cites Tony Forman, the leader of the U.N. (FAO) team of experts assisting the Nigerian investigators, as attributing the human infection to exposure to a chicken purchased in a live bird market in Lagos just before Christmas. The young woman’s 52 year-old mother died on 4 January of similar flu-like symptoms, but tests for H5N1 have so far been negative for H5N1 infection, as have tests on other close contacts of the 22 year old patient.
Nigeria is the 11th nation to report lab-confirmed H5N1 avian flu infections in humans. The total number of lab-confirmed human infections with this virus is 271 of whom 165 (61 %) have died. The newspaper “Vanguard” published a report online on 5 February, by Chioma Obinna, stating that new outbreaks of H5N1 virus in avian populations have occurred in the states of Edo, Kwara, and Sokoto with at total of 17 states in Nigeria (including Lagos) having reported past H5N1 infections.
The WHO update summarizing clinical and epidemiological data on the initial 251 lab-confirmed patients with H5N1 influenza A virus infection contains 6 tables and 5 figures. Examples of the important findings include:
A: The overall case fatality rate was 60%.
B. Four days was the median time from symptom onset until hospitalization.
C. There was no statistical difference in median duration from symptom onset until hospitalization between persons who lived and those who died.
D. The media time from symptom onset until death was 9 days.
E. The median age was 18 years, with 52% of the 256 patients < 20 years and 89% < 40 years of age.
F. The gender ratio of cases was 1.0 (129 males/127 females).
March 19-21, 2007 the WHO will hold its 2nd consultation on clinical aspects of human infection with H5N1 virus, in Antalya, Turkey.
Daniel R. Lucey, MD, MPH
Director, Center for Biological Counterterrorism and Emerging Diseases, EROne Institute, Department of Emergency Medicine
Washington Hospital Center
Adjunct Professor of Microbiology and Immunology
Georgetown University Medical Center