THE THIN WHITE LINE: the history of a future avian influenza pandemic

Chapter 1: Outbreak

I had a little bird,
Its name was Enza,
I opened the window,
And in-flu-enza.

——playground rhyme during the 1918-19 Spanish Flu Pandemic

Patient zero

    On September 15, 2012, Zeng Yunshan, a restaurant worker living in Zhaoqing——a prefecture-level city in southern China’s Guangdong province, entered Duanzhou Hospital complaining of fever, headache, exhaustion, chills, body aches and a heavy cough that produced greenish-yellow sputum.
    He shuffled painfully into the emergency ward, supported by his daughter and brother, who told the admitting nurse that his biggest problem was breathing. His breath was shallow and labored. His face had become cyanotic, taking on a blue tint because his blood and organs were starved of oxygen. Without help, he would die, drowning in his own fluids while his organs failed.
    A doctor examined him and diagnosed him with influenza. Five days ago, he contracted it. Four days ago, he became contagious. Three days ago, he began showing symptoms. For the next five days, he would continue to be able to pass it on to others.
    Influenza is an infection caused by a range of flu viruses circulating at any given time that attack the respiratory tract——the nose, throat, lungs. It is distinguishable from most cases of common cold in that it causes fever and headache and knocks you flat.
    After an X-ray revealed spots on Zeng’s lungs, the doctor further diagnosed him with pneumonia; his alveoli, the microscopic sacs in the lungs that absorb oxygen, had become inflamed and filled with fluid.
    By now, he could barely breathe.
    The staff put him on a mechanical ventilator, a machine that facilitates the exchange of air between the lungs and the atmosphere, in the hospital’s Intensive Care Unit. They began drug therapy to combat the infection in his lungs.
    China’s vice minister of agriculture had warned local health officials to be vigilant for novel, or new, flu viruses as the seasons began to change. Nurses collected tissue samples from Zeng using nasopharyngeal swabs and sent them out for lab analysis. At the time, however, his doctor regarded his illness as severe, but not yet remarkable.
    A generation ago, some scientists believed modern medicine had conquered infectious disease after virtually wiping out smallpox and polio. Today, however, infectious diseases such as influenza remain the leading cause of death in the world. In fact, the flu alone is normally the sixth leading cause of death in Canada and the United States.
   Each year, various flu strains circulate among the world’s population, infecting 20 to 25 percent, with a mortality rate——death rate——of 0.1 percent, or more than a million people. In the northern hemisphere, infections increase during the late fall and early winter, peaking in January and February and falling off in March——the flu season. Most people who catch it get better in seven to 10 days, while older people, babies and people with chronic illness can die from it or complications arising from it, such as bacterial pneumonia. In short, Zeng was 67 years old and vulnerable. Flu season had begun, if a bit early this year, and a particularly tough variant of the H3N2 strain, A/Hong Kong, circulated. Doctors regarded severe cases as inevitable; with seasonal flu, in fact, about one-third of infected individuals seek help from healthcare providers and one in 10 requires intensive care in a hospital.
    Zeng Yunshan’s condition continued to deteriorate. Nothing the doctors did seemed to help. The virus proved resistant to amantadine, a generic antiviral drug. His lungs became increasingly inflamed and congested and he began coughing up blood.
    On September 17, he died. His lungs, which in a healthy man are the lightest organs in the body, had become two swollen sacks, about five times their normal weight and filled with a thin, frothy fluid.

     Epidemiologists believe Zeng Yunshan is the index case, or the first detected case, of the Pandemic, and some say he is also patient zero, the very first person to be infected by a novel virus. He could have caught it from a butcher in the wet market where he bought most of the meat for his restaurant, or directly from raw poultry or pork he handled.
    They eventually learned this because when an outbreak occurs, epidemiologists conduct contact tracing as an essential step to contain it. First, health authorities need to find out who caught the disease from whom, and follow the chain of infection so that it can be broken——usually by isolating all known cases; in this use of contact tracing, they trace the disease forward from patient zero or the index case. Second, they need to find out how patient zero caught the disease so they can locate the natural reservoir of the virus (what type of animal it came from, and where) and destroy it; in this use of contact tracing, they trace backward to the animal that infected patient zero.
    Zeng started a chain of infection that could not be halted. Before he died, he passed it on others, and the rest is known: A single mutation created a new virus that evaded sophisticated international surveillance and response systems, infected billions of people, killed tens of millions, crashed advanced healthcare systems and wrecked economies——all from what was essentially a single biological dice roll.
    In short, the conflagration of disease that killed more than 80 million people around the world in 2012 was likely sparked by a restaurant worker catching a virus——so small that millions of them could fit on the period at the end of this sentence——from a pig. And that was just the first wave. There may be a second, even a third, in our future.
    This was no miracle stroke of bad luck, however, but the product of millions of dice rolls; the right number simply came up. The evolution that humans experience over millions of years, a virus can go through in a single day.