The H5N1 avian influenza virus strain can infect an unborn fetus by passing through the placenta. The virus can also infect other adult organs apart from the lungs, according to an article in The Lancet published this week.
Professor Jiang Gu, Peking University, Beijing, China and team examined post-mortem tissue samples of two adults, one male and one pregnant female. They also examined the dead fetus of the pregnant female. Their aim was to find out how H5N1 affects the organs of the human body.
“A pandemic outbreak of human infection with avian H5N1 currently poses a potentially serious health threat worldwide – little is known about the specific effects in organs and cells targeted by the virus,” explain the authors.
The scientists found viral genetic material and antigens in some trachea cells, the lungs, the T cells of the lymph node, brain neurons, and cells of the placenta. They detected viral genetic material in the intestinal mucosa, but ho H5N1 antigens.
In the fetus they detected antigens and genetic material in the lungs, circulating cells of the immune system, and liver cells.
“This study has shown the capacity for human vertical transmission of the H5N1 virus..(this) warrants careful investigation, since maternal infections with common human influenza virus are generally thought not to infect the fetus. We have shown that H5N1 virus spreads beyond the lungs..these newly obtained data are important in the clinical, pathological and epidemiological investigation of human H5N1 infection, and have implications for public-health and health care providers,” the authors wrote.
“Speculation about the fate of the fetus if the mother survived is interesting. With the development of antibodies in the mother and their transplacental crossing into the fetus, pathological lesions in the fetus may result,” Dr Wai Fu Ng, Department of Pathology, Yan Chai Hospital, Hong Kong, China and Dr Ka Fai To, Ki ka Shing Institute of Health Science, Hong Kong, China, wrote in an accompanying Comment.
Written by: Christian Nordqvist