New to Science: the Tooth Fairy Bird – H5N1 vector

NOTES ON A SPECIES NEW TO SCIENCE – THE TOOTH FAIRY BIRD
Martin Williams and Nial Moores

Surely one of the most startling of the flurry of new findings made during the spread of H5N1 avian influenza has been the discovery of the Tooth Fairy Bird – which we believe is the first bird species to have been initially described by virologists, and is remarkable for being able to survive and sustain and spread H5N1. Here, we present a review of information on this intriguing taxon. Perhaps a single existing bird species, perhaps a closely or remotely related grouping of bird species, the Tooth Fairy Bird has never been certainly recorded, but like esoteric sub-atomic particles its existence has been inferred through a variety of indirect means.

By drawing on reports from virologists, agriculture and health officials and journalists – though as yet, alas, not ornithologists and birders – it is possible to describe the behaviour of this unusual bird, whose Latin name is yet to be settled upon, though suggestions include Robwebsters petnotionas, Vectorius (mythicus) invisiblus, and Anas stealthbomberensis.

In brief, the Tooth Fairy Bird is capable of both surviving infection by a strain of H5N1 that is otherwise highly lethal to all species it infects, and of flying long distances, efficiently spreading the virus at only few places it visits. Curiously, rather than follow major migration timings and flyways, it often flies long distances when many birds are not migrating, and has a strong tendency to follow railway lines and roads. Further, once the Tooth Fairy Bird has introduced the virus to a new area, it then plays little or no role in spreading the virus there; indeed, it may quickly vanish altogether.

The Tooth Fairy Bird – basic facts

Known Occurrences Never recorded with certainty. First reported in East Asia several years ago, though ancestral forms have previously been considered possibly present, the Tooth Fairy Bird seems to be a species still really known only to scientists, experts and newspaper journalists, and is already found in the annals of the FAO, WHO and other august bodies with names made up of two or three letters.

Appearance Unknown, though perhaps duck-like.

Habitats Although considered by some to be part-waterbird-part-seabird, it seems to feed or breed almost entirely near (or even in) chicken farms.

Migration Routes Said to be from China through Siberia, down through Europe into Nigeria and then up across the Arctic Circle into America, and presumably, following logical assumption, back round through Indonesia into China. Shows a curious tendency to follow railway lines, roads and smuggling routes.

Range Initially said to occur at two urban parks in Hong Kong, it subsequently spread through much of East Asia. More recently, has spread to Europe and Africa, yet has become extinct in its former range in East Asia including Hong Kong.

Behaviour It is an aggressive species, with a strong tendency to sneeze, cough and spit, especially on or by poultry in farms, and on ducks or swans that are invariably at wetlands near poultry farms.

Birdlife International classification Though regarded by many non-ornithological authorities as Highly or Near-threatening, the Tooth Fairy Bird is classed by Birdlife International as Non-existent, without actual scientific proof.

Ancestry of the Tooth Fairy Bird Notions wild birds might be responsible for spreading highly pathogenic avian influenza are not new. Indeed, significant proportions of wild birds are known to carry a variety of low pathogenic – mild – avian flus; waterfowl – swans, geese and ducks – are evidently the main reservoirs (Alexander).

These viruses may enter poultry farms, and here evolve to significantly higher virulence (Ewald; Ito et al 2001), becoming highly pathogenic avian influenza – HPAI, which we believe would be better termed poultry flu. Rare in the wild (one known case), HPAI evolve relatively frequently within poultry farms (Anon, 2004). Once HPAI have evolved, they tend to spread – and if the means of spread is unknown, well, it could be the agent is the Tooth Fairy Bird.

One of the first known instances the Tooth Fairy Bird was posited to exist was during an outbreak of H5N2 in poultry in Pennsylvania during 1983-1984 (Anon 1995). At the time, there was an ongoing outbreak of H5N2 in Mexico – so, perhaps migratory birds were carrying it the virus to the US. However, investigations revealed this was not the case: the Tooth Fairy Bird did not exist. In Australia, too, migratory birds have been considered potentially responsible for virus introduction during at least one HPAI outbreak in poultry; it appeared, though, that in each case the virus was from a local source (Tracey et al, 2004). Thus, we find the high confidence in the existence of the Tooth Fairy Bird is a new phenomenon, arising only with the recent spread of H5N1.

Initial Reports of the Tooth Fairy Bird as H5N1 Vector – death raining down from the sky Gulp! Perhaps the first reported occurrence of the Tooth Fairy Bird can be traced to Hong Kong in 2002. That year, there were H5N1 outbreaks in two urban parks, killing captive ducks, geese, swans and flamingos; a dead, wild little egret at one of the parks was confirmed to have H5N1. Though little egrets are mostly resident in Hong Kong, and no other migrants were found, and there were outbreaks in Hong Kong farms around this time, Hong Kong’s Secretary for Health, Welfare and Food later invoked the Tooth Fairy Bird: “Of course, we had incidents where migratory birds had brought some infections to some of our birds in the Penfold Park.” (HK Govt, 2003).

During 2003/2004, there were widespread outbreaks of H5N1 in poultry across East Asia. Suddenly, officials in various places announced their belief in the Tooth Fairy Bird, showing a tendency to blame “migratory birds” or “wild birds” whether or no any wild birds with H5N1 were found. The media loved the Tooth Fairy Bird theory. “For years, the greatest fear of many influenza experts has been the possibility that the H5N1 strain would infect migratory birds,” noted a rather over-excited Time magazine.

“Since huge amounts of virus are shed in bird feces, such an epidemic among migratory birds would mean death raining down from the sky in the form of H5N1 virus.” Alas, there were few details given regarding the wild, migratory birds that were supposedly responsible, and when one of us (MW) considered migrations of known bird species, it was found the pattern and timings of the H5N1 outbreaks did not fit – there was no real evidence for the Tooth Fairy Bird, especially as all wild birds known to have H5N1 were dead or dying (Williams, 2004). Likewise, Sims et al (2005) concluded, “There is little reason to believe that wild birds have played a more significant role in spreading disease than trade through live bird markets and movement of domestic waterfowl.”

The Tooth Fairy Bird as a Vector for Qinghai H5N1 While many media reporters have shown a readiness to believe in the Tooth Fairy Bird – for there’s surely a good story to be had in wild birds spreading a disease that could cause a terrible pandemic, I mean come on, if that won’t boost ratings, what will? – it’s only since a major outbreak at Qinghai Lake in spring 2005 that “experts” (a term that, curiously, appears to not include ornithologists) have become true Tooth Fairy Bird believers. “That was the tipping point. The virus really got into the migratory birds at that point,” said flu expert and non-ornithologist Robert Webster – and never mind that so far as is known, all the wild birds it got into at Qinghai were also killed. Now, assert some virologists and flu experts, wild birds aka the Tooth Fairy Bird can not only harbour regular wild bird flus, but also sustain and spread a poultry-evolved variant: the Qinghai strain of H5N1. As H5N1 including this strain tends to be lethal to all it infects, with many waterbirds including geese dying at Qinghai, these wild birds clearly belong to a very special taxon: which we might call the Tooth Fairy Bird, variant Q.

Although some have suggested the Tooth Fairy Bird is Bar-headed Goose; others Pochard; and it’s been dubbed Ruddy Shelduck, or Pintail and Garganey, for a few hours some seabird such as a shearwater, even for a few minutes, Tree Sparrow!, and purported photos have shown a Snow Geese [a North American species] and a flightless farm duck – this latest, most widely believed in Tooth Fairy Bird is a species of duck, or maybe several species of ducks (we should perhaps forgive these “experts” for being so vague, since after all, none of them are ornithologists) – closely allied to the so-called Trojan ducks of southeast Asian rice fields.

These Trojan ducks have been shown to play a role in sustaining and spreading H5N1 in Thailand and Vietnam. However, even in these artificial situations, it seems the Trojan ducks are not highly efficient at sustaining H5N1, which apparently decreases markedly if there are no further infections. For some time, the Tooth Fairy Bird proved extremely elusive.

”Wild birds found to have been infected with HPAI were either sick or dead,” noted a report that seemed aimed at proving the Tooth Fairy Bird’s existence (Avian Influenza Technical Task Force, FAO, 2005). “This could possibly affect the ability of these birds to carry HPAI for long distances.” Indeed it could, indeed it could. But, the Tooth Fairy Bird hunters were not deterred. And in summer 2005, they discovered birds that just might be Tooth Fairy Birds. A few “healthy” wild waterbirds were found to have H5N1. But though reportedly healthy, there were doubts over their identification: perhaps capture methods affected results, and one of the birds was a juvenile grebe – which had clearly caught H5N1 in its birthplace.

With these birds found in areas known to already have H5N1 in nearby poultry farms, the records were especially uncertain: which infection came first, the chicken, or the wild birds? No matter. As H5N1 of Qinghai form spread further west during autumn 2005, the Tooth Fairy Bird was said to be behind the spread, even though no one could find it, as it clearly flew “under the radar”. As one reporter put it, the wild bird spreading H5N1 was the “avian equivalent of the stealth bomber”.

Then in February 2006 came a paper by lots of virologists and veterinarians but no ornithologists, on a study focused on analyses of 13,115 cloacal and fecal specimens from migratory birds (including 4,674 from captured migratory ducks) from Hong Kong and Poyang Lake, east China, in winter 2004/2005. To the delight of Tooth Fairy Bird believers, these showed six apparently healthy ducks at Poyang had H5N1. At last! To believers, this was the evidence they were looking for.

“Taken together, Webster says, the study findings hint that large numbers of wild ducks and other waterfowl may now be carrying dangerous strains of H5N1 without showing symptoms.” (Harder, 2005). Believers seemed not to care that the six ducks had two genotypes – two very distinct kinds – of H5N1. Nor that the ducks perhaps survived because they had been “pre-immunised” with H5 bird flu. Nor that no ducks from Hong Kong tested positive: Hong Kong poultry was H5N1-free during the study, but the Tooth Fairy Bird hunters had no info about H5N1 in poultry at and around Poyang, or north China. Nor that the bulk of the study showed wild birds play a small, perhaps insignificant role in sustaining and spreading H5N1.

Because there were similarities between virus at Poyang and at Qinghai, Webster considered ducks took the viruses from Poyang to Qinghai, more than 1,700 kilometres away. Again, facts that didn’t fit the story didn’t matter – Webster is not the sort of fellow to be concerned with trivia such as there being no known migration route from Poyang to Qinghai, as Poyang birds head to north and northeast Asia, where no H5N1 was found in spring/summer 2005 (sibeflyway map; Migration of Waterfowl in the East Asian Flyway and Spatial Relationship to HPAI H5N1 Outbreaks). (“That’s my story and I’m sticking to it” is clearly the Robert Webster mantra.) And as for Qinghai. “That was the tipping point. The virus really got into the migratory birds at that point,” said Webster (Anon, 2006).

Again, any bothersome facts – such as the virus killing all migratory birds it was known to get into at Qinghai – were clearly unnecessary. And then, the Tooth Fairy Bird was unleashed! On it went, across Russia, to Europe, on to Africa. No one ever found it, but it was clearly around as the virus in all cases was very similar, and never mind about the Tooth Fairy Bird following roads and railway lines, and smuggling routes. Curiously, unnoticed and unlamented by most virologists, agriculture and health officials and journalists, even as it spread west the Tooth Fairy Bird vanished from its former haunts in east Asia.

The Tooth Fairy Bird and Officials Many officials clearly love the Tooth Fairy Bird as much as journalists. As during the spread in East Asia during 2003/2004, the officials don’t need to actually see the Tooth Fairy Bird to believe in it, nor even any evidence of its presence. Instead, when H5N1 arrives by means unknown, they can simply assert, “it was migratory birds”. After all, who can prove they are wrong?

Perhaps the leading official believer in the Tooth Fairy Bird is Dr Joseph Domenech, chief vet of the FAO. During 2005, he was often to be found in the media, predicting the Tooth Fairy Bird would arrive here (“One of our major concerns is now the potential spread of avian influenza through migratory birds to northern and eastern Africa,” Domenech warned – H5N1 indeed reached Africa, but via smuggling it appears – FAO, 2005), or saying the Tooth Fairy Bird was there. And there’s another recent, big believer: “The U.N.’s avian influenza coordinator, David Nabarro, warned on Wednesday that the disease, which has spread among birds from Asia to Europe, could result in a North American outbreak in six to 12 months, possibly sooner. According to Dr. Nabarro, flight patterns of migratory birds could bring infected fowl to Alaska from Africa, then south, resulting in a mainland outbreak of the H5N1 strain of avian flu.” (Clyne, 2006) Sadly, Dr Nabarro is yet another “expert” who seems happy to make bold pronouncements with little or no basis from our knowledge of actual wild birds.

Conclusion

As this brief review reveals, the Tooth Fairy Bird is clearly an intriguing scientific and social phenomenon – never yet found, existing most strongly in the brains of certain virologists, officials and journalists (and, of course, some bloggers, bless ‘em), and with a strong and widespread hold in the popular imagination. Like the mythical bogeyman that some parents find convenient, the Tooth Fairy Bird is ever ready for blaming when bird flu strikes, always available for helping sound dire warnings of doom.

References

Alexander, D.J, A review of avian influenza

Anon (1995) Avian Influenza in Mexican Poultry: Wildlife Implications SCWDS Briefs, April 1995, 11.1

Anon (2004) Previous outbreaks of highly pathogenic avian influenza worldwide

Anon (2006) New study examines bird flu’s genesis in China

Avian Influenza Technical Task Force, FAO. (2005) Update on the Avian Influenza situation (As of 01/09/2005) – Issue no. 33.’ Chen et al. (2006) Establishment of multiple sublineages of H5N1 influenza virus in Asia: Implications for pandemic control PNAS

Clyne, M. (2006) U.N. Warns Avian Flu to Hit U.S. http://www.nysun.com/national/un-warns-avian-flu-to-hit-us/28917/

Ewald, P.W. Guarding Against the Most Dangerous Emerging Pathogens: Insights from Evolutionary Biology http://www.cdc.gov/ncidod/eid/vol2no4/ewald.htm

FAO (2005) http://www.fao.org/world/regional/rne/News/news359_en.htm

Harder, B. (2005) When flu flies the coop: a pandemic threatens Science News

Hong Kong Government Transcript of Secretary for Health, Welfare and Food http://www.info.gov.hk/gia/general/200302/21/0221208.htm

Ito et al (2001) Generation of a Highly Pathogenic Avian Influenza A Virus from an Avirulent Field Isolate by Passaging in Chickens

Mandavilli, A. (2003) Profile: Robert Webster Nature Medicine 9, 1445 sibeflyway map http://www.sibeflyway.org/Map-Eastern-web.html

Sims, L.D. et al (2005) Origin and evolution of highly pathogenic H5N1 avian influenza in Asia

Williams, M.D. (2004) Dead Ducks Don’t Fly