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Poultry, Not Wild Birds, Most Often Carries Deadly Avian Flu to Africa
Quote:By David Brown
Washington Post Staff Writer
Thursday, February 16, 2006The lethal strain of H5N1 bird flu found in Nigeria this month probably got there in poultry and not through the movement of wild birds, according to migratory-bird experts and several lines of circumstantial evidence.
The first Nigerian cases were found at a commercial farm with 46,000 chickens, not among backyard flocks that would have greater contact with wild birds. Nigeria imports more than a million chicks a year from countries that include Turkey, where H5N1 appeared last fall, and China, where it has circulated for a decade.
Furthermore, the infected flocks in two of Nigeria’s northern states are not near wetlands where migratory birds spend the winter. There are no reports of waterfowl die-offs like those in Asia and Eastern Europe. The few wild species known to occasionally harbor H5N1 arrived months ago and are about to leave.
If it turns out that trade, not nature, was responsible for introducing H5N1 to Africa, better control of trade in domesticated birds may be able to limit the virus’s spread there and on other continents, public health experts said.
“If you put all the possible factors in perspective, we wouldn’t jump to the conclusion as others do that it was wild birds that brought it,” said Ward Hagemeijer, an ornithologist at Wetlands International, a Dutch conservation organization.
William B. Karesh, a veterinarian with the Wildlife Conservation Society in New York, said: “I would never rule out wild birds. But I think we have to look at the most probable routes, and the most probable route would be poultry. How did it skip the whole Nile Delta and get to Nigeria? That kind of bothers me. Common sense would dictate that it should be all over Egypt by now.”
The spread of H5N1 by wild birds “is a horrible assumption that a lot of people are making,” agreed Peter Marra, an ecologist with the Smithsonian Institution’s Migratory Bird Center at the National Zoo. “There is no question that migratory birds are playing a role, but they are not the main players.”
Marra said more attention should be given to the legal — and illegal — movement of poultry and pet-trade birds because “that is where you can actually do something about it.”
Some of this reasoning appears to have support in Nigeria, as well.
The Guardian, a daily newspaper published in Lagos, recently quoted the country’s agriculture minister, Adamu Bello, as saying, “We think someone may have imported or smuggled in contaminated birds.”
…
In 2002, Nigeria imported 1.2 million chickens, according to statistics on the U.N. Food and Agricultural Organization (FAO) Web site. Nearly all the birds were day-old chicks.China, Nigeria and the FAO signed a $22.7 million agreement in March 2003 to have 520 Chinese agriculture experts, including poultry technicians, help Nigerian farmers. Nigeria also imported live birds from China until January 2004, when the trade was banned because of bird flu outbreaks in Asia.
Despite the import ban, numerous reports say chickens continue to come in from China. At a news conference last week, Bello said that “birds come every day from China, Turkey . . . so Nigeria is exposed,” according to a newspaper report.
In a study published this month in the journal Proceedings of the National Academy of Sciences, an international team led by two Chinese researchers reported that a survey of more than 50,000 birds in live-poultry markets there found 1 percent were infected with H5N1 virus.
The researchers also sampled about 13,000 migratory birds and found that six were carrying H5N1 and did not appear to be ill — evidence that healthy migrants may be able to carry the microbe long distances.
The genetic diversity in the virus samples from domestic chickens led the researchers to deduce that “H5N1 virus is perpetuated in poultry largely through the movement of poultry and poultry products, rather than by . . . migrating birds.”
Although no H5N1 has been found in wild birds in West Africa, elsewhere the virus has been found in three duck species that spend winter in Africa. They are the garganey, the northern pintail and the northern shoveller — about 3.5 million birds in all — said Alex Kaat of Wetlands International.
None of the wintering places are close to the chicken outbreaks, however, Kaat said.
From report on Nigerial poultry trade in 2002:
Quote:At present, a majority of the poultry meat imported into Nigeria enters the country illegally and evades duty payment. Most imported frozen poultry are being supplied by European exporters, such as the Netherlands, France and Belgium. U.S. poultry meat comes enters this market occasionally. Prior to the ban, legal poultry imports were discouraged by the GON’s decision to increase the duty from 55 percent to 75 percent in January 2001. Nigerian traders routinely buy from importers situated in neighboring countries. Despite the large import volumes of frozen poultry in CY2001, the Nigerian Customs Service has no record of any importer who shipped products legally and paid the required duty. Frozen poultry enter through Nigerian borders without official payment of duties. Additional costs are however, incurred in unofficial payments to Nigerian border officials (unofficial payments have increased following the announcement of the ban). After purchasing at a cold storage facility in the neighboring country, boxes of chicken are ferried across the border on the heads of laborers. After clearing the border point, the chicken is reloaded onto trucks or other vehicles and moved to interior consumption points. Imported chicken often is transported and handled without refrigeration, with food quality and safety becoming a major concern.http://www.fas.usda.gov/gainfiles/200211/145784683.pdf
Quote:The recent outbreak of bird flu in the country must not be seen in isolation but in line with other variables confronting the poultry sector in the country. The pigeon that brought the disease to the country is traceable to Canada. Economic sabotage cannot be ruled out in the whole saga. The infection is found at just two poultries in Kano and Kaduna States. The north produces only two per cent of total chicken consumption in the country. The occurrence in an area that produces two per cent should not be made to affect other areas where the incident is yet to be recorded. The clamour by some people that our borders should be thrown open to importation of chickens is very suspicious. These are people who profit from smuggling of poultry products into the country. They want to cause confusion in the country and create a panicky situation. They are not happy with the progress Nigeria is recording in the area of chicken production. In countries that have recorded bird flu, it is only the poultries affected that would be quarantined and the affected birds killed and buried. Records have shown that the birds from the Kano and Kaduna cases were not from registered hatcheries. The outbreak must have come as a result of unprofessional poultry farming practice. If you breed chickens, ducks, turkey etc with animals such as pigs, the rate of infection is high. Also, poultry farm practice in which chickens, ducks etc are reared in an enclosure that have no barriers from where human beings live is dangerous. It is advisable that people do not buy chickens and other poultry product from open markets or across the country’s border because the susceptibility to the disease is high. They should buy from registered hatcheries. This will guarantee quality. Currently, Nigeria supplies the bulk of poultry need in West Africa despite the consumption of two million chickens daily in the country.Bird flu, a sabotage – Badmus The National Chairman, Poultry Association of Nigeria, Chief Olatunde Badmus, spoke with our correspondent, TUNDE ODESOLA, on the recent outbreak of Bird Flu in the country
It’s a guess, but only that.
Geese also feed in stubble fields, yet few geese.
(worrying re red-breasted geese – a globally threatened species – just now; hoping there isn’t major outbreak among them)First major die-off in wild/ornamental birds with H5N1 of Guangdong goose 96 lineage was in 2002, in Hong Kong.
Were more deaths in 2003/04.
But, didn’t cause so much fuss as those now – and Qinghai Lake incident remarkable.
So, seems H5N1 has always been deadly to wild birds. Some variations in ducks (rather more guff in another thread or two here:Trojan ducks, PNAS paper).A puzzle.
I don’t believe there was already H5N1 in all the places dead swans with H5N1 found (seems there have been movements spurred by freezing weather).
Yet, puzzling re just how and where they are being/have been infected.
(Earlier, had swans arrive Hungary in autumn, evidently healthy; move to Romania, and infected and dying – but H5N1 not found on ponds where they were dying.)Are swans in east Asia, too; not many mute swans tho (the species impacted w Asia/Europe I believe). Not south to HK, but are in Japan westwards.
Yet, no problems evident w swans here, not even back to 2003/04.
Get various birds die from H5N1 – herons, egrets, gulls etc etc (even if you consider ducks somehow immune [by no means certain], or so few die that won’t be evident).
Why, then, (mute) swans in Europe/w Asia?Might guess the virus would change if migration – notably, towards a less virulent strain.
from Richard Thomas of Birdlife, re the FAO guff:
Quote:I’m rather surprised to see someone describe this as a “reasonably balanced assessment of the Nigerian situation.”It somehow fails to mention several relevant facts, such as the 150 km from the first affected farm to the Hadeja-Nguru wetlands; the presence of “flu-free” farms between the wetlands and the farm; the flu-free farm less than 5 km from the first affected farm with, wait for it: ostriches in the dangerous open air; the testing of wild birds at Hadeja-Nguru last October – all of them negative; nor the lack of die-offs in wild birds reported there this winter.
…Despite the Agriculture Minister saying several times the virus arrived with imported poultry, all we get is one brief paragraph:
“The introduction of the disease through illegal trade cannot be excluded. The introduction could have happened through illegal importations of poultry or more likely poultry products. No data are available at the moment to confirm or rule out this possibility.”
No data available? That’s surprising. Has the government’s Special Programme on Food Security (launched in January 2002 and jointly implemented with the FAO) really not looked into this issue?
The programme includes:
Quote:• The establishment of Trans-border Animal Disease Information Implementation (Phase 1 and Phase II)
• The establishment of a Ministerial Animal Disease Emergency Committee.Thanks, Les
Just downloaded and had quick read.
For anyone not wanting to do so, it includes:Quote:In favour of the wild bird introduction hypothesis, it is noteworthy that the outbreak site in Nigeria is located at southern edge of the major Chad basin including the Hadejjia-Nguru wetland area, both considered as major wintering areas in the region for long-distance migrant species coming from Europe and Russia, including palearctic ducks. Two migrant species coming from Europe and Russia: Pintails (Anas acuta) and Garganeys (Anas querquedula), are known to overwinter in considerable numbers in Northern Nigeria in the Hadejjia-Nguru and Chad basin Wetlands.
…
The introduction of the disease through illegal trade cannot be excluded. The introduction could have happened through illegal importations of poultry or more likely poultry products. No data are available at the moment to confirm or rule out this possibility.After this, fair amount of info on migratory birds, especially pintail and garganey.
Mentions testing is underway; but of course, with H5N1 now present, finding wild birds with H5N1 in affected areas surely doesn’t prove they brought it in.And yet, very little regarding Nigeria’s poultry trade. Even though mentions that poultry production has declined, yet demand has increased (so, presumably, more incentive for smuggling – especially with govt clamping down on imports).
No mention, say, of FAO warning re day-old chick imports by air in 2004; nor even of Nigerian govt having recently said smuggling was likely cause of H5N1 being introduced.
Curious…First wild bird cases of avian influenza in European Union
BirdLife news releaseThree swans and a wild goose in Greece, up to 22 dead swans in southern
Italy and Sicily, and a swan in Slovenia have died of avian influenza.
Five of the Italian birds have tested positive for the deadly strain of
the H5N1 virus that originated in poultry and has been circulating
widely within Asia for the last decade. Bulgaria is expected to announce
its first cases of the virus soon in infected geese.This is another worrying development in the spread of avian influenza
following the virus’s appearance, last week, in Nigeria. Unlike the
African outbreak, however, which is restricted to poultry and was linked
by the government to the illegal import of infected chickens, the
European outbreaks involve wild birds.All the swans are believed to be Mute Swans Cygnus olor, a species that
visits southern Italy and Greece from the Black Sea region. Their
movement into southern Europe is likely to be in response to freezing
weather conditions around the Black Sea.In outbreaks of H5N1 so far, wild birds normally die within a few days
of infection. The appearance of the swans in Italy, Slovenia and Greece
indicates they were likely infected just prior to setting off on their
journeys.It is possible the swans caught the disease from other wild birds,
although this is unlikely given the tens of thousands of waterfowl that
have tested negative for H5N1 over the last decade. A more likely route
is through contact with infected poultry or their faeces. Mute Swans,
like wild geese but unlike most ducks, often feed by grazing on
agricultural fields.
The practice of spreading poultry manure onto
fields as fertiliser is widespread in many parts of Eastern Europe, and
this is a possible source of infection. The United Nations Food and
Agriculture Organisation (FAO) has warned “Viruses can stay alive in the
manure for many weeks. If the manure is spread too quickly in the
fields, the virus may contaminate poultry.” The swan deaths highlight
the need for implementation of strict biosecurity measures in infected
areas, and also highlight the need for monitoring of healthy wild birds
for the presence of the virus.Swans seem particularly susceptible to H5N1 avian influenza, and Mute
Swan deaths have previously been reported in Russia and in October 2005
in Croatia. Tests on the Croatian swans found the birds excreted tiny
amounts of the virus. Even so, it was remarkable that waterbirds sharing
the same fish ponds as infected swans remained free of the disease.The finding of dead swans will fuel the debate over how H5N1 is
spreading. However, if wild birds had been spreading the disease across
continents there would have been trails of dead birds following
migration routes, which isn’t the case.The “wild bird” theory for the
spread of H5N1 provides no explanation as to why certain countries on
flight paths of birds from Asia remain flu-free, whilst their neighbours
suffer repeated infections, nor of why only a single strain of H5N1 is
found in outbreaks west of China.from Birdlife International (news release):
Outbreaks in Nigeria suggest controls on international poultry movements
are widely floutedThe recent outbreak of H5N1 avian ‘flu in Nigeria show that poultry
movements can cause the deadly virus to jump across countries and even
continents. With poor enforcement of controls already blamed for
outbreaks in China, South East Asia and Turkey, the Nigerian outbreak
further demonstrates that lapses in biosecurity are the major reason for
avian ‘flu’s continuing spread around the world.Whilst the precise nature of the outbreak is unknown, it seems more than
likely that the virus arrived through infected poultry brought into the
country in defiance of Nigeria’s import controls. Speaking at a press
conference, Nigeria’s Agriculture Minister, Adamu Bello, said “Birds
come every day from China, Turkey, into Nigeria, and from Europe and
also from Latin America. So Nigeria is exposed. Illegal importation of
poultry by people who have farms, bringing in poultry from places and
smuggling them in…could also have been a cause.”Mr Bello was also reported by Nigeria’s Guardian newspaper group as
saying: “We think someone may have imported or smuggled in contaminated
birds.”Large scale commercial poultry farms need a regular supply of day old
chicks, and this has created a global trade in supplying the industry in
countries such as Nigeria, which are unable to undertake all the stages
of commercial production. Contesting the ban on imports of day-old stock
earlier in 2005, a poultry industry spokesman said “Nigeria does not
possess the temperature, weather conditions and much-needed technology
to produce Grand Parent stock (day old chickens) now, which is the life
wire of poultry business.”“Globalisation has turned the chicken into the world’s number one
migratory bird species” said Leon Bennun, Director of Science of
BirdLife International. “Movements of chickens around the world take
place 365 days a year, unlike the seasonal migrations of wild birds”,
Bennun added.“It is important that strict biosecurity measures are imposed to stop
further spread not only within Nigeria but also to neighbouring
countries”, says Bennun.However BirdLife is concerned that the authorities in Nigeria receive
appropriate support and advice from the international agencies managing
avian ‘flu and that resources are targeted effectively.It is extraordinary, given the strong circumstantial evidence
implicating illegal poultry movements, and the repeated opinion of
Agriculture Minister Bello, that some representatives of the UN Food and
Agriculture Organisation have announced that wild migratory birds are
the source of the outbreak.One senior FAO representative has even been quoted in the press as
saying: “If it’s not wild birds, it will be difficult to understand.
There is no real trade between the Middle East and Asia and Nigeria.”
Yet according to the websites of China’s embassy in Nigeria and their
Ministry of Commerce,”the trade volume between the two countries in 2003
reached US$ 1.86 billion,” and has continued to grow so that “Nigeria is
now China’s second largest export market and fourth largest trade
partner in Africa”.Nigeria is a major oil producing nation, and with around 25 percent of
the population of Africa within its borders to provide a market for
imports, it is increasingly being sought out as a trading partner. The
largest-scale industrial poultry production in Africa is concentrated
within Nigeria’s northern states. If the global trade in poultry is
spreading avian ‘flu, it was predictable that it would hit Nigeria
before other African countries.“Perhaps the time has come for an independent inquiry into the spread of
H5N1 over the past few years,” says Bennun. “This could help the world
to learn lessons on what could have been done differently to halt the
spread of the disease and help to stop further outbreaks.”A dead Red-breasted Goose found on Skiros Island, Greece, has tested positive for H5N1. Another, found nearby, being tested. This is a beautiful goose species, regarded as globally Vulnerable to extinction
Quote:Nigeria is not a gigantic poultry producer. Nigeria’s poultry industry is very low. Until recently, 80 per cent of the chicken we ate in Nigeria were imported. It is now we are just beginning to build up, even then, we are still far away from where we are supposed to get to.
Lately, we had a problem of lack of parent stock, therefore, we do not have enough hatchable eggs for our poultry. Last Christmas, there was a huge shortage of chicken in Nigeria. Although, we are very good eaters, we are not producers.Nigeria’s not prepared for a bird flu pandemic —Emmanuel Ijewere
“If it’s not wild birds, it will be difficult to understand,” Domenech [of FAO] said. “There is no real trade between the Middle East and Asia and Nigeria.”
http://www.latimes.com/news/printedition/asection/la-sci-birdflu9feb09,0,7038039.story?coll=la-news-a_sectionHmm…
Quote:China and Nigeria have signed a series of agreements on trade, economic and technical cooperation, as well as on promotion and protection of mutual investment and so on.During 1999 to 2004, bilateral trade volume has increased remarkably from US$ 578 million to US$ 1.5 billion (till Sep. 2004). China’s main exports to Nigeria are light-industrial, mechanical, and electrical products, and its imports from Nigeria are oil products, timber and agricultural products among others.
Up to now, more than 67 Chinese company invested into Nigeria in the area of telecommunication, civil engineering project, steel & power, motorcycle assembling and fishing etc, with an outstanding investment amount of US$ 88.6 million. Apart from the above, the coming cooperation in oil exploration and exploitation will attract around US$ 1 billion into Nigeria. There are still more investment projects under negotiation.
Regarding Civil Engineering Contract Project, more than 15 Chinese corporations are engaged in around 50 projects with a total amount of US$ 1.5 billion.
From 2002, Chinese government has provided RMB111.4 million gratuitous assistance to Nigeria including rural water supply project, anti-malaria drugs and other relief goods. Under TCDC training course, more than 200 Nigerian have been trained in China on several subjects. In accordance with the Agreement between FAO, Nigerian and Chinese Government, 391 Chinese agriculture experts are serving in Nigeria now.
http://nigeria2.mofcom.gov.cn/aarticle/bilateralcooperation/inbrief/200412/20041200008435.html
Couldn’t readily find re Nigeria-Turkey trade links, say; but still – makes me wonder if Joseph D is so authoritative here.
Post edited by: martin, at: 2006/02/13 09:41
It’s tedious to have to keep repeating arguments re wild birds not being major carriers of H5N1;
Tedious to continually find wild birds blamed, invariably with scant evidence (as yet, not one H5N1 positive wild bird in Africa);
Tedious that even when a paper shows poultry trade is by far most important for sustaining and spreading H5N1, it’s taken as evidence wild birds are important vectors;
Tedious that for many officials, wild birds are so quickly and readily blamed (round up all the usual suspects).
And yet, it’s important as there are conservation implications, in turn with implications for people.
For to some officials, it now appears “biosecurity” should involve clearing/culling wild birds, by straightforward hunting, as well as deterring breeding, even draining wetlands. (Mao tried wiping out “sparrows” in China as they were supposedly pests; proved a major blunder.)
Unnecessary fear has been stirred far too widely.
So yes, it’s tedious, it’s frustrating.
But those wild birds were not responsible for creating the strains of H5N1, yet directly and indirectly wild birds can become victims;
wild birds have no voice of their own. (Nor any huge, powerful lobby group behind them.)Martin
Post edited by: martin, at: 2006/02/13 01:03
CENTRAL BANK OF NIGERIA
REPORT FOR THE FIRST
HALF OF 2005NOVEMBER 18, 2005
“Other factors were the official initiatives, including the Special Programme on Food Security (SPFS), jointly implemented with the Food and
Agricultural Organization (FAO); subsidy on fertilizer and zero tariffs on imported agro-chemicals; and the tightening of controls on illegal import of agricultural products, for example, poultry products and rice.”http://www.cenbank.org/OUT/PUBLICATIONS/REPORTS/RD/2006/2005%20HALF%20YEAR%20REPORT.PDF
Message I’ve sent to group re h5n1 and conservation:
Swan infections indeed extraordinary.
Are these all mute swans, from Caspian Sea westward?Though had whooper swan die in Mongolia last summer, no other wild swan deaths that I’ve noticed in east Asia.
Bewick’s swans winter at Poyang, say, in some numbers (sorry, don’t have figures; quick google reveals a bird tour counting over a thousand).
Were some bird deaths at Poyang around time Guan Yi et al obtained samples including from six ducks with H5N1 – but if lots of swan deaths, it has been kept quiet. If few or no swans died there, when sharing shallow lagoons [as reserve appeared to me my one visit – the huge lake shrinks in winter, only part is reserve] with infected ducks, surely more puzzling.
As I recall, black and black-necked swans have died of H5N1, in captivity in Hong Kong and neighbouring Shenzhen.Qinghai indicates geese (well, bar-headed, tho again have been deaths in captivity) highly susceptible. Also graze in fields [as swans may do]
info from ornithologist Chris Feare:
Quote:Swans do indeed seem to be highly vulnerable and I cannot say why. They do
graze arable crops and grass, and they can forage on the bottom of water
bodies deeper than accessed by dabbling ducks. There may also be some
unknown physiological suscepribility – all speculation at this stage. Mute
swans forced to move by cold weather may be more susceptible to AI due to
stress/starvation. But cold weather might also force them to exploit unusual
food sources, possibly bringing them closer to infected material of some
sort.We must, however, be clear about movements. The swans involved now are most
likely dispersing away from areas that are apparently experiencing extreme
cold in eastern Europe and western Asia. Mute Swans cannot feed on frozen
water bodies and so must move in search of open water. These birds have not
just arrived from Russia, but will have spent some weeks in areas that we
now know have infections in poultry. Furthermore, they are definitely not on
migration to Africa. Migrant mute swans occasionally reach Egypt and
possibly Algeria, but uncommon (Birds of Africa). Egypt does have some feral
mute swans, as does the Eastern Cape of South Africa. Whooper and Bewicks
swans both rarely visit N Africa. The current events, assuming they are
moving away from ice, do suggest that infected birds can travel a some
hundreds of km before dying, or that the infection is present over a wider
area than we thought and they pick it up on arrival at the new venue. The
implications of this are worrying.I emailed Drs Robert Webster and Guan Yi, re the PNAS paper. Various questions. Dr (Prof) Guan promptly sent email with some brief answers:
Re species carrying virus between Poyang and Qinghai: "As we point out in our paper, it is migratory duck." – I’ve replied, saying this isn’t detailed enough. He and his team rightly want detail re virology. But detail needed too re wild birds. Especially where no migration routes (so far as I’ve seen) known to link Poyang and Qinghai – and places Poyang birds known to migrate to did not suffer major die-offs.
Qn: What information do you have on H5N1 in poultry and wild birds elsewhere in central and northern China, especially between Poyang and Qinghai? "As far as I know, no any other groups would like working as hard as our group to do surveillance study for long-term. So, H5N1 information between Poyang and Qinghai is not clear. If you can provide some information to fill the gap, it would be very useful." – well, wish I could supply or find such info. But with a vacuum of data for north China, saying there is certainly a direct link between Poyang and Qinghai is surely impossible (well, not if good science anyway).
Qn: Did you consider transport within the poultry trade, even smuggling – perhaps of those apparently healthy chickens? "There is no limitation for poultry movement, but it would not make any sense if poultry were transported that far away." – directly from Poyang to Qinghai would indeed seem silly. But transportation networks in n China? Remembering, too, an outbreak at goose farm in nw Xinjiang. Point: A previous outbreak in poultry in Tibet was traced to a source in Lanzhou – not a great distance from Qinghai, so trade/smuggling would seem plausible. "Do you have convince data to prove this link? How closely related between the virus from Tibet and Lanzhou? Please think question in molecular virology point of view as well." – sent the info, which from an FAO report; nothing on virology tho.
Qn: I’m curious: why were you able to obtain so many specimens from birds at Poyang? "I have big group in mainland working for me."
Qn: Further, were there indications of H5N1 killing wild birds at Poyang? "Some of them, Yes. Died birds were observed during some seasons." [would be good if had info on poultry farming around and fish farming at Poyang. inc whether any domestic duck farms – this is the kind of place where wild birds might mingle with domestic] Nothing yet to my follow-up email.
Nothing, too, from Robert Webster (inc no answer to whether he is fully objective!) [third time, I think, I’ve tried emailing Robert W; wonder if should really be hopeful] Article on Webster, inc re his belief birds are pivotal with flu, and dangerous pandemic may loom: Profile: Robert Webster
"Perhaps his most valued contribution is the idea that wild birds are a reservoir of influenza viruses" – now, seemingly aiming to show wild birds can also carry dangerous Poultry Flu. And not too fussed about fiddly things like details re wild bird species, migration routes and timings.
Quote:Cheikh Sadibou Fall, co-ordinator of the national anti-bird flu committee in Senegal, mainland Africa’s most westerly country, said they were on the alert. "We will study the cases to see whether migratory birds will spread the virus, and take appropriate measures … for the time being, we are on alert against any suspect cases of dead birds,"he said. Celia Abolnik, a senior researcher at South Africa’s Onderstepoort Veterinary Institute, said the institute was expecting samples for testing soon from live waterfowl in Malawi, Sudan and Kenya.– "take appropriate measures" ? I’m afraid that seems rather sinister to me. So, hope wild bird tests prove negative – but with all the poultry infections in Nigeria, will surely be infected wild birds around. While in Nigeria:
Quote:Market sellers in northern Nigeria are doing a roaring trade in chickens which died from a mystery infection, despite fears of a deadly strain of bird flu, traders said on Wednesday.When H5N1 reached Russia, I posted on a forum notions re H5N1 infections in and near a poultry area (in northwest China? – for instance, northern Xinjiang which had big outbreak in farm geese) might lead to fall in prices, and perhaps then trade of birds to areas that had no bird flu. I was ridiculed for this. And yet, still seems plausible to me. Infections in an area, prices fall; traders/farmers still want to sell birds – especially if compensation inadequate, and fear having flocks destroyed – and so birds sold on, moving H5N1 along trade routes. If so, maybe not too ridiculous to suggest that places that had seemed far from H5N1 might not have been over concerned about it. Webster et al in PNAS found that apparently healthy chickens could be infected – maybe as protected by another flu form, maybe as poor vaccines used. [What of vaccines; are they also smuggled? – been smuggled to Thailand, but I don’t know re to Russia, Europe, even Nigeria]
from Richard Thomas of Birdlife International:
1) I believe I’m correct that one of the two dead ducks with H5N1 in Turkey was a Pintail.
2) Regarding the Nigerian outbreak: the commercial poultry farm where the disease was first reported is some 150 km from the (can’t recall spelling!) Hadeja-xxx wetlands. Between the two places are flu-free farms.
Testing of wild birds for H5N1 at the wetlands took place last October – all with negative results. BirdLife has a local NGO Partner in Nigeria who monitor the wetlands and they have seen no die-offs of wild birds.
3) We have been told that prior to the 2004 import ban on poultry imports to Nigeria, Day-Old-Chicks arrived by air at Kanu. The Agriculture Minister, Adamu Bello, said at a press conference a day or two ago that illegal imports from China, Turkey and elsewhere arrive daily in the country.
4) The Nigerian outbreak, whilst disasterous for Nigeria and its people, is the best opportunity the world has yet had for identifying the vector by which the disease is being moved around the world. It would be an international tragedy if a thorough and balanced investigation of all possible vectors was not carried out as a matter of extreme urgency; the opportunity must not be wasted. Already we have seen FAO and WHO leaning towards wild birds as the cause, but this doesn’t appear to be the most plausible explanation.
Hooray – a home for Nimanists!
Here’s hoping there’s no sunshine there, so trolls will continue having fun.
Good luck chaps!
Rather odd situation, with Deborah MacKenzie of New Scientist – now gungh-ho re blaming wild birds for spreading H5N1 it seems (see also thread New Scientist dodgy re H5N1 spread to Europe – has confidently written of wild ducks carrying H5N1 to Nigeria, even though (as yet) not one wild bird in Africa has tested positive for H5N1.
Nial Moores of Birds Korea sent Deborah an email, questioning this; cc’d me, and Deborah has replied, likewise including me among recipients. Interesting email from her – indeed plausible that ducks from H5N1 hit areas in summer may have arrived in Nigeria for winter.
But, well, here’s email I’ve sent her:
Thanks for the email; glad you are willing to look at this in some detail. However, your argument is not solid. And, curiously, you ignore the absence of H5N1 across a swathe of land, from Iran east to Japan, where most of north Asia’s waterbirds winter, yet there are no outbreaks in migratory wetland birds. Hong Kong is a notable site here: has some 50,000 waterbirds, including pintail (garganey pass through on migration): not one healthy wild bird has tested positive, among over 16,000 [by some reports; PNAS for some reason gives 13,000 I think, without re-checking.] Currently getting H5N1 in birds, inc poultry; maybe after higher poultry demand at Chinese New Year; and mentioning this, seen report that Nigerian smuggling can increase around Hajj. Hong Kong is at a crossroads for migrants in southern China, right at the epicentre of H5N1 outbreaks. Had H5N1 in birds, inc two urban parks (ornamental waterfowl, at least 2 wild little egrets, which likely residents). So, blithely ignoring not easy. Further, PNAS paper is overall strongly counter to ideas wild birds spread H5N1. Witness regional forms of H5N1: if wild birds could indeed carry and introduce to poultry (and do so readily), why do we see these? It seems curious logic to say poultry trade spreads over short distances, but wild birds over long range.
There is long distance trade, inc smuggling – cf large batch of smuggled poultry from China arriving in Italy. "one detects the presence of the virus chiefly because it causes outbreaks in poultry if the wild birds contact them" – wild birds contact poultry? Where? [maybe it does happen in Nigeria – but people hunt waterbirds there, so might figure wild birds avoid humans as much as possible] "The ducks themselves, at least those that made it through migration, dont die of it, so you wont see it that way." – questionable; are ducks that die of it, plus can get significant death rates – very high in Qinghai – in birds sharing wetlands with them. "A very low prevalence of sampling, if there is even that, cannot prove absence," No need for sampling at Qinghai – the virus made its presence very clearly known. Elsewhere, it is scarce or rare in wild; get some die-offs but need monitoring to find them.. "Flu is highly contagious. It spreads from bird to bird." Ah, now here’s an important one. You refer to "flu" – and make this rather casual statement. Regular wild bird flus do indeed seem highly contagious, among waterbirds (with caveats; seasonal changes, can get variations depending on bird type). But, evidence is that H5N1 in wild birds is not highly contagious. Qinghai the exception. But otherwise, we don’t see H5N1 readily spreading among wild birds. Hong Kong again – has had dead waterbirds found at/near wetland with the waterbirds, but no spread. (Just lately, a dead little egret a few km from Deep Bay.) Mongolia’s Erkhel – "the disease appeared self-limiting in wild birds", researchers had to look hard to find it., and then o only in dead birds Thailand openbill storks – only few amongst large numbers of birds Romania: infected swans on ponds did not infect other waterbirds sharing ponds (this by lack of deaths, also as several of these birds tested)
Romanian swans excreting low amounts of virus. Webster’s ducks with H5N1 that didn’t readily kill them likewise excreted low amounts; High amounts respiratory tracts – but ducks not prone to sneezing/French kissing.
"Selling their birds off at market is what they are reportedly doing even now." – so, do you think others with infected birds, or near infected birds, might have sold them off at markets? To people from non-infected areas. Nigeria had banned poultry imports; yet domestic demand surely still there. Surely tempting to smuggle in birds at bargain prices.
"especially the Z genotype that has been responsible for virtually all commercial poultry outbreaks in east Asia" – This is the Z genotype. One of its variants, but it’s Z. " birds at Poyang Lake in southeast China in March, some of which migrated to Qinghai." – Which ones migrated this way? I know of none that migrate Poyang to Qinghai. I’ve studied some of the Poyang winter birds on migration along east coast of China (can be certain re Siberian cranes) – a long way from Qinghai. [I’ve asked Guan Yi and Robert Webster just which species they say migrated; so far, just told "migratory ducks". Detail is important with virology; also important here re wild birds.]
"timing of the outbreaks in Siberia, Turkey, the Black Sea and Nigeria exactly fit the known movements of some species" Not so with the timing of the outbreaks in Siberia. Link from Qinghai to Siberia doesn’t work: especially timing, in July, when birds from Qinghai not migrating north [many of geese flightless at this time]
"They are kicking birds around because they are rural people, that is how that culture treats animals," – how astonishingly patronising. I have seen rural people interacting with wild birds; maybe hunt n trap and so on, but never this. New Scientist not read there, perhaps, but New Sci taken as authoritative, reaches newspapers and other media
"Were there geese, which do die of this virus, at Poyang as there were at Qinghai?" – Yes, many thousands, including much of world population of swan goose. Also geese, cranes etc. All sharing shallow wetlands, at high densities.
"the Poyang and Qinghai viruses differ from any that have ever been seen in poultry in China." By no means all poultry in China have been tested. Witness PNAS – north China, inc between Poyang and Qinghai, just a blank on the map. I’ve asked Guan Yi; they lack data. So, you are only making guesses re virus in poultry n China. The team found 4 distinct forms in mainland China (seen Guan mention 250 strains); how to be certain a form in north isn’t as per Qinghai?
"The commercial transport of poultry should transport genotypes pretty much at random – smugglers dont genotype infected birds before they ship" – Why at random? If birds from n China to Russia/Kazakhstan, and then onwards by transport links such as railway – and the timings indeed fit this pattern too – would be same strain.
"the only spread long distance so far has coincided with migratory pathways, " Not so; has been spread to Indonesia, Tibet (one case traced to poultry shipped 1500km, Lanzhou to Lhasa), more recently the spread to Russia and so on. Again, it baffles me why this notion re long distance spread by wild birds, short distance within poultry trade. This is not borne out by bulk of PNAS paper – notice re an introduction to Vietnam, evidently by transport from China. But, convenient for officials. [cf with foot n mouth; reached continent from UK – but there, no flying cows as convenient scapegoats]
Quote:Feb. 10 (Bloomberg) — Nigeria blamed smugglers for bird-flu infections that have spread to at least four farms, as authorities in Greece and Bulgaria probe possible outbreaks of the lethal H5N1 virus strain, the first in the European Union.The “activities of illegal importers and smugglers of pets and birds” brought the virus to Nigeria, Agriculture Minister Adamu Bello said yesterday as the virus was found on three more farms. The World Organization for Animal Health said migratory birds most likely introduced the disease, which killed 40,000 fowl in an initial outbreak in Nigeria that began a month ago.
http://www.bloomberg.com/apps/news?pid=10000087&sid=a5Yrp7T2ICr4&refer=top_world_news
red-whiskered bulbul found dead at same Mong Kok school; no news yet re whether H5 positive.
Another common HK resident.Email just in from Agriculture, Fisheries and Conservation Department:
Quote:According to the information from our Veterinary Officers, the concerned Magpie Robin is probably a wild bird as the features of captive/cage birds mentioned in your e-mail below could not be found. In addition, they examined the stomach of the bird and found that it was empty.[my email:
Have they been examined for signs they may have been captive birds:
feather wear, damage to bills, feet etc; even examination of stomach
contents?
– and are there other indicators of whether they were likely local wild
birds, or of captive origin? (any differences between our birds, and
those that are imported) ]Post edited by: martin, at: 2006/02/10 07:45
Seemed possible to me for at least one case, a mynah near major temple. Also, high poultry demand here and nearby Guangdong over cny. Thread re wild birds in HK with H5N1
Hi Neil:
Well, we’re in realm of guesswork I think – Nigerian outbreak is new.
But I suspect poultry; Nigeria clamped down on poultry imports to guard against H5N1 and, ironically, perhaps so boosted demand for smuggled birds.
(This outbreak on battery farm; if they couldn’t supply all demand, maybe turned to outside source.)More info needed.
But for spread to nw China, thence across Russia to e Europe, I’m more confident re poultry trade/smuggling (even Moscow Zoo’s chief vet said he thought smuggling).Martin
email from Nial Moores of Birds Korea:
Species like Garganey can switch wintering areas from India to eastern Africa dependent on wetland availability, according to Bird families of the World. However, as Martin suggests most logical is that Garganey from western Europe migrate to western Africa, leaving Europe in ca October and returning in late March.
…Is this correct: this latest outbreak is in western Africa in mid-winter, months after wild birds from western Europe (a region without H5N1) migrated there; in chicken battery farms. Those suggesting wild birds are at the cause of spread should first identify (with supporting data) which species were responsible (birds from affected regions like Turkey???, arriving in Nigeria in late January as virus so virulent: which species? None); explain why outbreaks in wild birds have not been detected there (possible?); and explain the exact mechanism how wild birds came to infect poultry (possible?).
Concentrations of poultry and caged birds, time and time again, have been shown to be the viral factories for H5N1,and Nigeria has been ramping up its poultry production with the aim of becoming a net exporter. At least as late as 2002, local producers were worried about the amount of illegal poultry imports/trade (see URL below).
Large-scale concentrations of poultry often lead to environmental contamination (run off and manure heaps), and provide the only logical hypothesis for infection of non-migratory scavenging wild birds. Is it supposed to be more rational that wild ducks somehow fly into the chicken pens, excrete there without being noticed so that they infect the poor poultry, and then fly off again?
In 35 years of birding I have seen one wild duck in a free-range chicken pen once – on an offshore island in Korea where there was no other duck habitat, not near some wetland where there would be plenty of natural food available for wetland species without the risk of being hunted by people. It does just not make common sense, and is not supported by any evidence – so why even start to make such an assumption before considering movement of poultry first, caged bird trade second.
Need to repeat too, sadly how can anyone ever anywhere disprove it was wild birds? There are migratory birds in most nations; with birds moving at all times of the year. Therefore people who want to believe that spread into Africa (or elsewhere) of H5N1 was by wild birds will easily find something to convince themselves – whatever evidence is provided to the contrary or not.
It therefore seems more than a little time-wasting to repeatedly provide detailed information each time to such persons and then to have such advice pretty much ignored, the original story written, original line taken, even sometimes with the comment that bird conservationists are too defensive to see the truth. This is a large part of what has been so disappointing and frustrating about this whole saga.
Please, show me the asymptomatic Garganey with HPAI H5N1 in Nigeria; show me other infected Garganey elsewhere; show me Garganey having contact with chickens, and then I promise I will invest the time looking for data on Garganey movements for you. Otherwise, best to look at poultry and caged bird trade first –
General note on trade:
http://www.unescap.org/tid/tisnet/news505.asp
Google search using words Nigeria poultry Import
http://64.233.179.104/search?q=cache:HNGrXnqkv5IJ:www.ams.usda.gov/poultry/mncs/International/2002Reports/x121002.pdf+Nigeria+Poultry+Import&hl=en&ct=clnk&cd=1
which talks of illegal imports.China and Nigeria have many trade links and recently boosted trade initiatives. Nigeria has trade with many other nations etc etc. Eliminate those, then lets talk about the hypothetical role of wild birds in spread to Africa.
more from a correspondent:
Quote:Perhaps you know this “experimental” incidence (coevolution
of pathogens with hosts):http://www.rabbit-control-forum.net/Speeches/Kerr.pdf
“Myxoma Virus and Rabbits”This example was also referred to by our specialist in predicting
the future of H5N1, but he said “there is a tendency like this,
but uncertainties remain”. This myxoma virus (though it’a a vector-
mediated) once got less lethal, but regained half-lethal, perhaps
a result of some sort of host-pathogen equilibrium. A frequently
cited example in an ecology textbook.Quote:Yet another – evolution of host-pathogen relation, and
possible emergence of virulence from population structure:http://www.sciencemag.org/cgi/content/full/303/5659/842
“Large Shifts in Pathogen Virulence Relate to Host Population
Structure”Here we show that rapid evolution of virulence can occur as
a consequence of bistability in the evolutionary dynamics of
pathogens associated with changes in host social structure.whew! – correspondence on this topic getting pretty long, but may be some useful guff within.
Another email from me, to Wendy Orent:
“Change the conditions, and you change the equation” looks to me like what I know of re equilibrium (from physical chemistry).
As you say, each strain (even indiv virus) responds to conditions: important here, what’s likelihood it can be passed to another host. Then, as many different strains/individual viruses, see an overall picture, a population.
To me, seems similar to ensemble (I think that called – some time ago now!) in phys chem. Whole lot of possible states – perhaps of atoms or molecules; as change one or more important variables, change likelihood of occurrence of each of them, and get shift in overall population.So with ducks, being stubborn here (!), we see equilibrium for reasons you note: dead ones don’t fly/move, their virus populations go extinct (tho always latent potential for creating them in numbers), and see population of low-path virus.
Shove ducks together, so v sick ones can more readily pass high-path strains, and the higher path strains can increase. See a shift in the equilibrium point – overall virus population moves to higher path, tho still a mix, with potential to have lower path virus as well as higher path.
Move back to having ducks in wild conditions, needing to fly to transmit, and those higher path viruses will disappear again, the lower path ones will increase. Equilibrium point shifts back.
or am I talking codswallop; hazy thinking this morning for some reasonI hadn’t been aware re population biologists thinking on – err – population levels. Whole lot of giraffes growing longer necks, instead of some individuals born with longer, some shorter, and longer more successful (as it looks to me like you’re saying). Curious; treating at population levels would just seem convenient way of achieving some simplification, which could be useful, whilst surely should remain keenly aware of individuals.
Wenday again:
Quote:natural selection isn’t a population-level phenomenon. Evolution is – in the sense that individuals don’t evolve. But selection has everything to do with competition within populations. Population biologists know this, in a sense, but they often don’t keep the levels of selection straight and they keep slipping.The term “equilibrium” as you used it in the last e-mail is very slippery – I think the analogy to chemistry may not be helpful. You do get different strains within a population of hosts, which is why, for example, you can’t just go get a marmot and hope to isolate from that marmot a killer strain of plague – or dig up any old anthrax spores from the soil and think you’re going to get a bioweapon. But that doesn’t mean the strains are in any sort of balance, or that it’s in the least helpful to think of them that way. Viruses are continuously generating variation: some changes will lead to greater virulence, some to less.
The reason many are so prone to copying error, which is what mutation is, is that they have to keep changing to meet changing conditions in their host population. (i.e. they might encounter stronger or less-strong immune systems; their hosts might be in a greater or worse position to pass strains on, etc.) Some of these “errors” will benefit the virus in a particular line, and they’ll be selected. That is what adaptation is.
You can see that process at work in one or two Turkish cases – scientists found that some of the swarms of strains in the host’s body showed some better adaptation to people. They were better able to adhere to non-ciliated cells (human flu receptors), and they were able to grow higher up in the nasal passages – therefore at cooler temperatures. But the hosts were dead and the new lineages died with them.
These results show that the H5N1 virus can adapt, at least a bit, to human beings. There was no reason to think it couldn’t. But you’d need a long chain of human beings passing on these changes from one to another for any real adaptation to occur – i.e. before bird-adapted H5N1 flu became human-adapted H5N1. Could it happen? Yes – if governments keep covering up their bird flu cases. Is it likely? Not very – but it is certainly possible.
Surveillance is the single best way to stop it – quarantine would work very well before the virus got very adapted to people. Once it is, you can’t control human-adapted flu with quarantine. But you can BEFORE it gets there. That’s why the phrase “mutate to transmissibility” is so ridiculous. It implies that one or two chance mutations can produce adaptation – in the absence of natural selection.
(translation: to “mutate to transmissibility” means that some chicken, somewhere, is carrying a strain that has somehow mutated to be adapted to people. It then infects a person, who passes it on – and bingo. But selection does not and cannot work this way. A change that pre-adapts the strain for human infection and transmissbility cannot survive in chickens. Someone would have to catch it before the miraculously-mutated human-adapted strain got pushed aside by selection for chicken flu within the chicken’s own body. Thinking probabilistically – this chance is, uh, vanishingly small. Not to say non-existent.)
You can talke about “evolve to transmissibility” – but that’s a host/pathogen activity – it requires long chains of human beings (no one know how long – but more than a few, simply because so many changes are obviously required.) This process can happen, and has happened, with earlier flus. That is not in doubt. But the human-adapted flu strains will lose virulence, or never evolve it, because of the requirements imposed by transmission. Res ipsa locutor.
me again:
My equilibrium notions from now somewhat hazy memories of phase space, from lectures. Think I retain the gist, and not slippery.
Continuous variation – multitude of potential states – crucial here too. But overall picture not random.Key, perhaps, would be:
With flu – would we expect overall virus to have different levels of virulence, which could be predicted if we have all the equations and numbers (surely impossible)?
Suppose had variations as follows – and only these variations (would be considerably more complex in practice):Zero or effectively zero probability of spread by immobile carriers.
10% probability of spread by immobile carriers
30% probability of spread by immobile carriers
70% probability of spread by immobile carriersIf, over time, virus [as population] would evolve to a certain level of virulence, and maintain it while conditions persist, would surely have equilibrium. (Even though in each case, still potential for individual viruses to replicate to different states. Equilibrium at macro level doesn’t mean that stopped the perpetual mutations etc to various states – it’s just that probabilities individual states can persist/increase have changed.)
If levels of virulence of virus population would just fluctuate wildly, not settling over time, then indeed no equilibrium.
From all I’d seen before, I’d thought “miraculously-mutated human-adapted strain” was what all disease experts believed in; hadn’t really thought more re this – if WHO etc said it was so that virus could mix in a pig, then go on to devastate humanity, maybe it was so.
Back to Wendy:
Quote:As for equilibrium, I think you make a reasonable argument – and that it is one way to look at what we’re seeing. The problem is that it is a species – or population-level argument – which is not Darwinian. (translation: no traits can evolve or be maintained anywhere, under any circumstances, that are bad for the individual or individual genetic line, and good for the group. Darwin himself that that if one such example could be found, it would destroy his entire theory.Keeping a population at some sort of equilibrium suggests that there is an advantage to the population as a whole in having variants around. Sounds good, but evolution, if you will forgive my putting it so bluntly, doesn’t work that way. Any traits that exist for the benefit of the group that jeopardizes its carrier’s fitness will be swiftly eliminated.
Only the traits that enhance their carrier’s fitness will be represented in the next generation – there are accidents, of course, like a tree falling on all the fittest members of the group, but natural selection will zap the less fit in the next generation. Remember that natural selection is not “survival of the fittest” but rather “differential reproduction.” )
To say that, for instance, flu viruses in wild birds are essentially stable simply means, from the perspective of evolutionary biology, that the strategy of low virulence continues to work well, and that the environmental conditions the bug finds itself in are stable. It doesn’t mean the bug isn’t just as mutagenic as ever; it’s just that low-pathogenic strains will continue to be at a selective advantage, which keeps the phenotypic variability in check.
So from this perspective, “settling over time” just means that the environmental conditions are stable. Certainly viral evolution will occur more quickly as a virus adapts to a new host. The mutation rate doesn’t change, so far as we know, though it might…we just don’t know if there is an actual viral mechanism to increase copying error; it sure sounds unlikely to me, but you never know. But selection pressure is more intense. We could see intensive selection pressure to adapt to human beings – but you’d need a string of human beings, ad seriatum, for the virus to adapt to.
Have I misunderstood anything in your argument? Please let me know.
to which I added:
What you write doesn’t seem at variance with my picture, deluded as I may be!
Equilibrium at macro level doesn’t mean all is nice n stable for individual viruses.Phase space, as I recall rather more dimly than i might wish, partly about probabilities for individual states.
So here with flu, there’s a host of probabilities for forms a virus might take – here, only worrying re those that are more or less virulent (but surely others that better for being passed on, several that utterly useless).
All occurring – so with a virus, surely can have carriers lacking fitness for being passed on, for replicating. Not many of them, and as they are dead ends with normal conditions (virus that could wipe out the planet, say), they remain tiny populations, so nigh on invisible when look at population as a whole.
Can get “sports” in larger animals – birds with oddly curved mandibles etc, but v few (large animal populations tiny compared to viruses), and not surviving long enough or well enough to continue. So, see variations around some kind of mean.
But, one example known in UK is a moth: usually pale, resting on silver birch during day; a few dark variants. Add pollution, darken trees, get more predation of normal light form, and dark form became dominant near factories etc.Change the conditions w virus, here to immobile carriers, and those rare mutations leading to increased virulence can increase, as they are passed on, can multiply; so virus as a whole becomes more virulent. Still all the mutations happening.
Reduce immobile carrier transmission, and these virulent forms become scarcer again, the virus back to low virulence.HIV again: i saw re drug resistant strains appearing in people taking drugs. Again, surely v rare normally – maybe examine the virus population and wouldn’t notice them. But, when regular HIV blocked, the resistant strains become dominant (which to me looks like shift in equilibrium point).
Stop the drugs with this person, and evolves back again, so that later can again use the drugs.Post edited by: martin, at: 2006/02/09 12:26
Quote:Seems like he birds with H5N1 are now just dropping out of the sky in Hong Kong.Ain’t that the truth!
I now don’t venture outside without wearing a crash helmet, and a big rubber suit I had my wife make for me.There are no ready sources that I know of (asked this question by science journalist yesterday; he’s looked at some migration routes etc, but likewise found no ideal source of info). I earlier gave partial answer re flyways in email to same journo, which I posted to thread at: Migration Flyways V briefly here (I’ll add a bit more to that thread):
Nigeria is on migration flight paths, but for birds from Europe – ie west of areas known to have H5N1 before birds migrate. Few areas of land on the planet are not on flight paths. You live in the US, so you are on or near flight paths (with higher densities over Missouri than over many places). Wild birds likely migrate right over your house. But you’re not on flight paths of birds from areas known to have H5N1
