Bird-flu virus can pass from mother to fetus

2 October, 2007

The H5N1 bird-flu virus can pass through a pregnant woman’s placenta and infect the fetus.

Researchers have also found evidence of what doctors had long suspected – that the virus not only affects the lungs but also passes throughout the body into the gastrointestinal tract, the brain, liver, and blood cells.

Dr Ian Lipkin of Columbia University in New York, the United States, who directed the study, said “the work helps us to understand H5N1’s high fatality ate as well as serving as a model for global collaboration in the field of emerging infectious diseases.”

Dr Lipkin and a team at Peking University in Beijing, China, studied tissue taken from two people who died of H5N1 in China – a 24-year-old, pregnant
woman and a 35-year-old man.

The study is the first to come out of the Infectious Disease Center at Peking University in Beijing, which was established after the epidemic of severe acute respiratory syndrome (SARS), a new virus that spread out of China in 2003, killed 800 people and infected 8,000 others before it was stopped.

The H5N1 virus mostly infects birds, but occasionally infects people and has killed 200 out of 328 infected since 2003. The experts are studying the
cause of the pandemic in great detail the since they fear that it could kill millions of people.

Jiang Gu and colleagues at Peking University, who looked at tissue samples from throughout the bodies of the victims, found genetic material from the virus not only in the lungs (as expected) but also in the brain, the placenta, the intestines, and in immune system cells in the blood and the liver.

The four-month-old fetus, which died with its mother, was also infected, the researchers reported in the British medical journal Lancet.

Their findings support the theory of a ‘cytokine storm’ – the idea that the immune system overreacts to the virus in some cases, and sends out an overwhelming swarm of signaling chemicals that end up killing the patient.

The researchers found evidence that the virus damaged immune cells, including macrophages. This suggests that the virus not only over-stimulates parts of the immune system but can also suppress other parts.

Previous studies of H5N1 victims have produced evidence that the virus may have evaded their immune systems’ defenses by suppressing them.

The researchers noted that no one had thought human influenza could cross the placenta and affect unborn babies.