Fowl Plague

Highly pathogenic avian influenza

More than a century ago, researchers confirmed the first outbreak of a particularly lethal form of avian influenza that they called “fowl plague.”²⁵⁴ Plague comes from the Greek word meaning “blow” or “strike.”²⁵⁵ Later, the name “fowl plague” was abandoned and replaced by “highly pathogenic avian influenza,” or HPAI.²⁵⁶

Highly pathogenic avian influenza viruses start out as low-grade viruses, so-called “low pathogenic avian influenza,” or LPAI, which may cause a few ruffled feathers and a drop in egg production.²⁵⁷ Low-grade viruses with H5 or H7 spikes are able to mutate into the high-grade variety that can cause devastating illness among the birds. Webster’s term for H5 and H7 strains of flu says it all: “the nasty bastards.”²⁵⁸ And you don’t get nastier than H5.

Besides his role as “Pope of Bird Flu,”²⁵⁹ Webster is the director of the U.S. Collaborating Center of the World Health Organization.²⁶⁰ Webster is credited as the one who first discovered the part avian influenza plays in triggering all known human pandemics. The Washington Post described him as “arguably the world’s most important eye on animal influenza viruses.”²⁶¹ Webster had more reason than most to be especially concerned about the death in Hong Kong. He had seen H5 before; he knew what it could do.

In 1983, an H5N2 virus struck commercial chicken operations in Pennsylvania. It quickly became the world’s largest outbreak of avian influenza and the most costly animal disease control operation in U.S. history.²⁶² Seventeen million chickens died or had to be killed. As striking as the numbers of deaths were, it was the way the chickens died that continues to haunt scientists. In the veterinary textbooks, the deaths are described as “a variety of congestive hemorrhagic, transudative and necrobiotic changes.”²⁶³ One researcher described it in lay terms: The chickens were essentially reduced to “bloody Jell-O.”²⁶⁴

In the spring of 1997, two months before Lam Hoi-ka fell ill, the same thing started happening in Hong Kong. Thousands of chickens were dying from H5N1. “Their bodies began shaking,” one farmer described, “as if they were suffocating and thick saliva starting coming out of their mouths. We tried to give the hens herbs to make them better, but it made no difference. The faces then went dark green and black, and then they died.”²⁶⁵ Some of the birds were asphyxiating on large blood clots lodged in their windpipes.²⁶⁶ “One minute they were flapping their wings,” another reported, “the next they were dead.”²⁶⁷ Others had given birth to eggs without shells.²⁶⁸ In the lab, the virus was shown to be a thousand-fold more infectious than typical human strains.²⁶⁹ The virus, one Hong Kong scientist remarked, “was like an alien.”²⁷⁰

Kennedy Shortridge, then chair of the University of Hong Kong’s Department of Microbiology, went personally to investigate. Growing up in Australia, Shortridge was shaken by his mother’s haunting stories of the 1918 pandemic and decided to dedicate his life to trying to understand the origins of influenza pandemics.²⁷¹ He had already been working 25 years on this question in Hong Kong before H5N1 hit. He found “chickens literally dying before our eyes.”²⁷² “One moment, birds happily pecked their grain,” he recalls, “the next, they fell sideways in slow motion, gasping for breath with blood slowly oozing from their guts.”²⁷³ On necropsy, pathologists found that the virus had reduced the birds’ internal organs to a bloody pulp. “We were looking at a chicken Ebola,” Shortridge recalls.²⁷⁴ “I had never seen anything like it.”²⁷⁵ “It was an unbelievable situation, totally frightening. My mind just raced,” he remembers. “I thought, ‘My God. What if this virus were to get out of this market and spread elsewhere?’”²⁷⁶