Liberty Times (LT): This year marks the 10th anniversary of the outbreak of SARS in 2003 that resulted in more than 700 deaths worldwide. Now this year, we are seeing outbreaks of the H7N9 avian influenza virus in China. Experts have warned that there may be further developments of the virus affecting both animals and humans. What are your views on the current outbreak ?
Su Ih-jen (蘇益仁): The transmission of an avian influenza virus usually proceeds from migratory birds, to water fowls (ducks), to domesticated poultry (chickens) and then to domesticated animals (pigs) or humans. For example, the SARS virus in 2003 started in bats, before moving from civet cats to humans.
The outbreak of the H5N1 virus in 2005 also started with poultry. The global scare about the spread of the H1N1 virus in 2008 was caused by a virus that had its primary infection host in pigs (swine flu). This time the H7N9 virus came from migratory birds, spread to poultry and then went on to infect humans.
This virus type, capable of infecting both animals and humans, seems able to spread quickly and affect larger areas in Asia. This is because cohabitation between humans and animals is more common in Asia. Also, Asians eat almost all species of poultry and wild fowl, so there is a greater likelihood of an infection spreading from animals to humans.
LT: The nation’s health authorities have officially listed H7N9 avian influenza as a category five notifiable communicable disease, enforced inspection and monitoring measures at national borders and have prepared medical systems in preparation. Are these measures enough?
Su: Migratory birds are the origins of the infection and they are migrating north at this time. Therefore, China should monitor if the infection is spreading from its southern regions northward.
For Taiwan, we must pay attention to migratory birds when they fly south for the winter. It is feared that there may be an even bigger outbreak during winter this year and early next year. Therefore, our epidemic prevention measures and warning systems must expanded by then. With SARS, it was relatively easy to monitor infected individuals as all cases showed signs of fever.
However, for the H7N9 virus, individuals may only develop a fever one or two days after infection. The latency period is longer and the virus may be spread via saliva and mucous of the respiratory tract even before a fever is noticeable.
Therefore, we will not be able to completely block virus carriers by monitoring and surveillance at border control points. We all must be prepared that H7N9 infections may arrive in Taiwan at anytime.
The main function of activating monitoring and surveillance at border controls is to delay the virus from entering the country and allow us more time to prepare to fight an outbreak.
When we launch monitoring and surveillance at border controls, contingency plans and preventative measures ought be instituted.
LT: The SARS outbreak spread worldwide because China initially covered up news about infected patients. China also delayed reporting the H7N9 virus. Could Taiwan and Hong Kong succumb to the outbreak, despite having launched preventative measures? Are there other infectious disease to watch out for?
Su: Seven of the past 10 large-scale influenza outbreaks in the world originated in China. Although in 2008 the reported cases of the H1N1 virus first came from Hong Kong and Vietnam, the patients were infected in China.