Bird flu spreads to humans more easily than thought

NEW YORK (Reuters Health) – Although human bird flu
infection is believed to be a rare, life-threatening disease, a
study in Vietnam suggests that the infection rate may be higher
than was previously thought, often causing relatively mild
respiratory symptoms.

In a report in the Archives of Internal Medicine, Dr. Anna
Thorson and her associates note that high death rates are
derived from avian flu patients admitted to hospitals in major
cities. The researchers believe that the true occurrence and
mortality rates are unknown, since there have been no studies
assessing exposure to the virus and disease in a
population-based setting.

The authors conducted a survey in Bavi, a rural district in
Vietnam in which there had been confirmed outbreaks of severe
bird flu among poultry. Included in the study were 11,942
households with 45,478 inhabitants, interviewed between April 1
and June 30, 2000.

Subjects were asked about the occurrence of cough and fever
during the previous six months as well as contact with poultry.
A total of 8,149 reported having had a flu-like illness.

Having contact with sick or dead poultry was strongly
associated with flu-like-illness. Among young and middle-aged
adults direct contact with such poultry more than doubled the
risk of a flu-like illness.

Thorson, from the Karolinska Institute in Stockholm, and
her team estimate that between 650 and 750 cases could be
attributed to direct contact with sick or dead poultry.

SOURCE: Archives of Internal Medicine, January 9, 2006.