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the process work? The disease scientists are exploring those questions, among many others. Meanwhile, the concept is a hypothetical tool. Linda Selvey didn’t mention the FMD paradigm when she used the word “amplifier” in our conversation about Hendra virus, but I knew what she meant.
    Still . . . why horses? Why not kangaroos or wombats or koalas or potoroos? If the horse fills that amplifying role, one obvious fact deserves fresh attention: Horses aren’t native to Australia. They are exotic, first brought there by European settlers barely more than two centuries ago. Hendra is probably an old virus, according to the runic evidence of its genome, as read by molecular evolutionists. Distantly diverged from its morbillivirus cousins, it may have abided unobtrusively in Australia for a very long time. Bats too are an ancient part of the native fauna; the fossil record in Queensland shows that small bats have been there for at least 55 million years, and flying foxes may have evolved in the region during the early Miocene, about 20 million years ago. Human presence is more recent, dating back only tens of millennia. More precisely, humans have inhabited Australia since the pioneering ancestors of Australian aboriginal peoples first made their way, island hopping daringly in simple wooden boats, from southeastern Asia by way of the South China Sea and the Lesser Sunda Islands to the northwestern coast of the island continent. That was at least forty thousand years ago, possibly much earlier. So three of the four principals in this complex interaction—flying foxes, Hendra virus, and people—have probably coexisted in Australia since the Pleistocene era. Horses arrived in January 1788.
    It was a small change on the landscape, compared to all that would follow. Those earliest horses came aboard ships of the First Fleet, under command of Captain Arthur Phillip, who had sailed out from Britain to establish a convict colony in New South Wales. After five months of navigating the Atlantic, Phillip stopped at a Dutch settlement near the Cape of Good Hope to take on provisions and livestock before continuing eastward from Africa. He rounded Van Diemen’s Land (now Tasmania) and sailed north along mainland Australia’s east coast. Captain James Cook had already come and gone, “discovering” the place, but Phillip’s group would be the first European settlers. At a spot near what is now Sydney, within the fine natural harbor there, his penal arks put ashore 736 convicts, 74 pigs, 29 sheep, 19 goats, 5 rabbits, and 9 horses. The horses included two stallions, four mares, and three foals. Until that day there was no record, either fossil or historic, of members of the genus Equus in Australia. Nor were there any oral traditions (none shared with the world so far, anyway) of Hendra virus outbreaks among aboriginal Australians.
    As of January 27, 1788, then, the elements were almost certainly gathered in place—the virus, the reservoir hosts, the amplifier host, plus susceptible humans. And now another riddle presents itself. From the horses of Captain Arthur Phillip to the horses of Vic Rail is a gap of 206 years. Why did the virus wait so long to emerge? Or had it indeed emerged previously, maybe often, and never been recognized for what it is? How many past cases of Hendra, over two centuries or more, have been misdiagnosed as snakebite?
    Answer from the scientists: We don’t know but we’re working on it.
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    H endra virus in 1994 was just one thump in a drumbeat of bad news. The drumbeat has been sounding ever more loudly, more insistently, more rapidly over the past fifty years. When and where did it start, this modern era of emerging zoonotic diseases?
    To choose one point is a little artificial, but a good candidate would be the emergence of Machupo virus among Bolivian villagers between 1959 and 1963. Machupo wasn’t called Machupo at the start, of course, nor even recognized as a virus. Machupo is the name of a