Mysterious Flu Transmitted To Doctor In Hong Kong Case Is First Evidence Of Human-To-Human Transmission
Health workers reported Friday the first evidence of probable human-to-human transmission of a new viral strain of influenza in Hong Kong, but said it was not necessarily a harbinger of a lethal epidemic.
The transmission was detected from recent blood tests in a doctor who cared for the first known human case of the viral strain, a 3-year-old boy who became ill last May. The child later died from complications of the infection. But the physician did not remember developing any symptoms of the respiratory ailment at the time, and remains healthy, suggesting that people can be infected without necessarily becoming sick.
After interviewing the doctor, the health officials suspect that he contracted the viral infection not through the air but by touching the child during treatment. For reasons scientists do not understand, the doctor apparently did not spread the virus to others.
Virologists working at the Centers for Disease Control and Prevention in Atlanta used standard laboratory techniques to develop a blood test to detect evidence of the strain previously known to infect only poultry.
The test showed that of the 54 health care workers who had contact with the child, the doctor was the only one who became infected.
In additional tests on four members of the child’s family, none had been infected. Only one of the 261 staff, students and their parents at the child’s day care center, and one of 63 neighbors, were infected. It is still puzzling how these two were infected.
An official of the CDC, which earlier this month sent a team of scientists to help Hong Kong and the World Health Organization in studying the puzzling outbreak, described the findings in a telephone interview from Hong Kong Friday.
The findings are to be reported at a news conference in Hong Kong where health officials plan to announce that they now know of 11 confirmed and 9 suspected cases of the new strain.
Four of the 20 cases have been fatal. The high death rate is a main reason why experts are tracking the cases so closely. No cases have been detected outside Hong Kong.
Officials constantly keep track of influenza developments because the virus has a nasty habit of changing its basic characteristics.
The changes allow the influenza virus to get past the body’s immune defenses, known as antibodies.
Health officials are particularly eager to follow each case in Hong Kong because the strain has not previously been seen and they are wary of a repeat of the epidemic that in 1918 and 1919 killed 21 million people around the world. Health officials have long predicted that a worldwide epidemic of similar magnitude could occur without warning.