The 26-year-old male nurse reportedly took care of a 14-year-old girl from Viet Nam's Thai Binh Province, one of four new cases of H5N1 avian influenza, or bird flu, earlier reported by the Ministry of Health, who died. She developed symptoms on February 21 and was hospitalized the following day.

Latest Confirmed Cases

The afflicted nurse also attended the girl's 21-year-old brother, another resident of Thai Binh Province, who developed symptoms on February 14 and was admitted to hospital on February 20.

The other two cases confirmed as of March 7, according to the World Health Organization, are a 69-year-old man from Thai Binh Province who developed symptoms on February 19, was admitted to hospital the same day, and died on February 23, and a 35-year-old woman from Hanoi. She developed symptoms on February 18 and was hospitalized on February 24.

Retesting Identifies More Cases

WHO reports it is working closely with the Vietnamese Ministry of Health to further investigate additional cases that may have occurred since February 2 and will update its cumulative list of confirmed cases accordingly.

Earlier this year, staff from WHO, Japan’s National Institute of Infectious Diseases in Tokyo, and Centers for Disease Control and Prevention, Atlanta, Georgia, USA, began working with health authorities in Viet Nam to improve the sensitivity and reliability of laboratory diagnostic tests, WHO notes.

This activity, which aimed to upgrade laboratory capacity and included a training component, involved the retesting in Tokyo of specimens from several persons initially classified in Viet Nam in January as negative for H5N1 infection.

Retesting detected H5N1 in specimens from seven persons. WHO is awaiting further details about these cases, including outcomes. Upon receipt of this information, WHO will also include these cases in the cumulative total for Viet Nam.

Pandemic Preparedness Activities

One additional case in Viet Nam, dating back to February 2004, has been identified retrospectively from specimens stored as part of a study of encephalitis (see the New England Journal of Medicine, 2005, 352:686-691).

H5N1 infection, which was not considered in the diagnosis of this fatal case, was identified in November 2004 when specimens were submitted to a battery of tests. Specimens collected from other patients in this study are now being systematically tested for possible H5N1 infection.

Information on new cases is of greatest concern, says WHO, as it continues to gather as much data as possible on each new case. Such data are urgently needed at a time when many countries are intensifying their pandemic preparedness activities.