swine and human flu viruses would have swapped genes with avian viruses, ultimately giving rise to the dangerous assortment of genes carried by the 1918 virus. This work suggests that the generation of pandemic strains
swine and human flu viruses and created family trees based on DNA sequence information. By estimating the amount of time it would take to accumulate the differences in DNA sequences found in human and swine viruses,
the researchers determined that a precursor to at least one 1918 flu gene was present in mammals before 1911.
Instead, the new findings suggest that an avian strain entered pig and human populations, and then swapped genes with mammalian flu viruses before becoming a pandemic.
and swine forms of H1n1 shared a common ancestor years before 1918. But he remains unconvinced by the series of genetic swaps proposed by the paper.
A new study released today By nature suggests that people alive during the infamous 1918 influenza outbreak have the greatest protection against the current swine flu1.
including mice, miniature pigs, ferrets and macaques. In all but the pig, the virus yields an infection in the lungs that is more severe than would be expected from an average seasonal flu, according to Yoshihiro Kawaoka of the University of Wisconsin-Madison and his colleagues,
who conducted the study. Kawaoka's team also confirmed that some commercially available antiviral drugs,
but pigs showed no outward signs of disease even though the virus reproduced capably in the swine respiratory system.
This, the authors suggest, could explain why farmers have not reported an outbreak of sick pigs.
The animal studies used higher doses of virus than humans would normally encounter a practice that is common for such experiments.
Dirty pigs are healthy pigs: Nature Newsliving like a pig could be good for you. Research has shown how dirty piglets obtain'friendly'bacteria that help them to develop healthy immune systems later in life.
The results, published online in BMC Biology1, provide the first direct link between dirty living, immune health and genetic expression.
They also indicate that manipulating gut bacteria early in life might reduce allergies and other autoimmune diseases, says Denise Kelly, a gut immunologist at the University of Aberdeen, UK and one of the study's authors.
Researchers began with 54 piglets and divided them equally between an outdoor environment, an indoor environment,
and an isolated environment where they were fed antibiotics on a daily basis. The scientists then killed piglets on days 5 (neonatal stage), 28 (weaning age),
The study found that 90%of bacteria in the guts of the outdoor piglets came from the phylum Firmicutes.
In contrast, the Firmicutes bacteria made up less than 70%and just more than 50%of the gut flora in indoor and isolated bred pigs respectively.
The pigs also had much smaller proportions of bacteria from the lactobacillaceae family. The team also found that the differences in gut microbial communities affected the expression of genes associated with the piglets'immune system.
Animals raised in the isolated environment expressed more genes involved in inflammatory immune responses and cholesterol synthesis,
whereas genes associated with T cells were expressed in the outdoor-reared pigs. Kelly says that until now,
because the study was carried out in pigs, there is no way to be certain that the results are relevant to humans.
and pig guts and their comparable size in organs, makes pigs a good model animal to study.
He's pigs; I'm dogs, said the Seoul National University cloning specialist with a smile,
Both laboratories are working on transgenic pigs that can produce tissues for transplant into humans. What we are doing is really
Dirty pigs beat disease: Nature Newsliving like a pig could be good for you, according to research showing that dirty piglets pick up'friendly'bacteria that help them to develop robust immune systems later in life.
The results provide support for the hygiene hypothesis, which suggests that a lack of exposure to microbes in early life can affect development of the immune system and increase susceptibility to certain disorders, such as allergies and inflammatory bowel disease.
Denise Kelly, a gut immunologist at the University of Aberdeen, UK, who worked on the study,
The researchers took 54 piglets and divided them equally between an outdoor environment, an indoor environment and isolated conditions in which they were fed antibiotics daily.
The scientists then killed piglets on day 5 (neonatal stage), day 28 (weaning age) and day 56 (nearing maturity) to study their gut tissue and faeces.
The study found that 90%of bacteria in the guts of the outdoor piglets came from the phylum Firmicutes.
Firmicutes made up less than 70%of the gut flora in indoor pigs and slightly more than 50%of that in isolated pigs.
Pigs from these cleaner environments also had much smaller proportions of bacteria from the Lactobacillaceae.
Kelly's team also found that the differences in gut microbes affected the expression of genes associated with the piglets'immune systems.
whereas genes linked with infection-fighting T cells were expressed in the outdoor-bred pigs. Glenn Gibson, a food microbiologist at the University of Reading, UK, says that previous studies have suggested that immune responses are linked to organisms in the gut.
because the study was carried out in pigs, there is no way to be certain that the results are relevant to humans.
as did the cleaner piglets. But, he adds, patients with Crohn's also have reduced overall bacterial diversity,
similar to the outdoor pigs, suggesting that the results might not extrapolate directly to human disease.
however, that the comparable organ sizes of humans and pigs, and the similarities between the microorganisms found in their guts,
makes pigs good model animals for such studies.
Altered microbe makes biofuel: Nature Newsin a bid to overcome the drawbacks of existing biofuels,
and pigs to locate them there's folklore behind it. And while most other mushrooms can be cultivated
The truffle's smell lures female pigs which, mistaking the aroma for an irresistibly scented boar,
We're making silk purses from sows'ears, says Gregg Marland, a scientist with the Energy department's Carbon dioxide Information Analysis Center (CDIAC) in Oak ridge, Tennessee.
such as chickens and pigs, for antibodies that signal the presence of pathogens. Both methods put people at risk of exposure to the viruses.
In both people and pigs, newborns with cystic fibrosis tend to have abnormally low levels of a hormone called insulin-like growth factor 1 (IGF1),
Unlike in healthy controls, in mutant pigs IGF1 levels do not increase over time. The blood concentration of IGF1 could one day be used as a marker to predict
Stoltz and his collaborators took advantage of a pig model of cystic fibrosis that they debuted in 20084.
the team found that newborn mutant pigs had significantly less IGF1 in their blood at birth.
Like the pigs, the babies carried significantly less hormone than controls. The data seem very robust,
The researchers found abnormally low levels of growth hormone in pituitary slices from the mutant pigs
it would be smart to try it in piglets.
Sterile moths wipe out cotton pest: Nature Newsbetween May and October for four consecutive years, aeroplanes crisscrossed the morning skies above Arizona's cotton fields, dropping millions of tiny moths onto the croplands below.
But the team has found evidence of a'henipa-like'virus in domestic pigs from two villages about 70 kilometres north of Accra.
In a paper published on 22 september in Plos ONE, the team reports finding antibodies against members of the Henipavirus genus in 5%of 97 pigs studied.
Nipah virus is known to multiply in pigs, and the species had a key role in a 1999 outbreak in Malaysia that killed more than 100 people.
It looks like there is spill over from bats to pigs in Ghana, says Cunningham. This is the first step along the line to a public-health threat.
Examples from the CDM include siphoning off the methane produced by pig farms and feeding it to a power plant that would
the situation is far worse in pigs, where there is almost no systematic surveillance, even in richer countries.
H5n1 infections in pigs are uncommon and cause only mild illness, creating little economic incentive to monitor them4.
Genbank contains partial sequences from just 24 pig H5n1 isolates. Yet pigs are a likely source of a human pandemic H5n1 virus
because they are susceptible to both human and avian viruses, creating opportunities for genetic reassortment in co-infected animals.
On 4 january, the agency banned unapproved uses of cephalosporins in cattle, pigs, chickens and turkeys a ban that it had ordered already in 2008,
On 4 Â January, the agency said that it would prohibit certain uses of cephalosporins in farm animals including cattle, pigs, chickens and turkeys,
and pig flu deposited in the US National Center for Biotechnology Information s Influenza Virus Sequence Database between 2003 and 2011.
The number of pig sequences deposited remained relatively flat from 2003 to 2010 before jumping dramatically in 2011.
The jump in the number of pig sequences also disappears (see Delayed sequencing. Roughly 30%of the sequences are from isolates collected before 2003.
and pig sequences but it is aimed at increasing the genomic knowledge base, rather than real-time surveillance.
Even fewer pig sequences were collected, with one-third of the countries that are home to more than 4 million pigs depositing none at all (see The pig in the room).
Surveillance of avian flu viruses is bad, but that of pig viruses is worse. Yet pigs are a serious pandemic risk:
they can be infected co with both human and avian flu strains, which means that they provide ample opportunity for gene swapping and, thereby,
the emergence of pandemic strains such as the 2009 H1n1 pandemic virus. The world is home to some 1 billion domestic pigs, almost half
of which are in China, yet only 7, 679 pig flu sequences were collected between 2003 and 2011.
Just three countries the United states, China and Hong kong  collected more than 1, 000 swine flu sequences each,
Poland, the Philippines, Denmark and The netherlands are each home to more than 10 million pigs. In pigs, flu tends to be mild,
so there is little economic incentive for surveillance. Moreover, the pork industry often doesn t want the negative image of having swine flu detected in its farms.
are compiling one of the world's single largest sources of pig sequences. They get their viral isolates from abattoirs,
Because more than 90%of the pigs slaughtered in Hong kong come from ten provinces in Mainland china
The pandemic risk posed by pigs has risen also since 2009. The 2009 pandemic H1n1 virus,
which is now endemic in pigs, is unusual in that it contains the triple reassortant internal gene (TRIG) cassette,
and endemic swine viruses, says Peiris. Another pig virus that has the TRIG cassette, H3n2, infected 12 people in the United states in 2011."
"I think that this is just the tip of the iceberg and such reassortments are surely going on worldwide,
or no sequences have poor veterinary systems and flu-prone farming systems, such as backyard farms and mixed poultry and pig farms,
Model pigs face messy paththe three litters of Yucatan miniature piglets, born in late May,
As the United states first genetically engineered (GE) pigs with muscular dystrophy, the creatures could be used to test treatments for the disease.
which aims to sell GE pig models for use in academic and pharmaceutical laboratories, has bred so far about 275 Â pigs some with cystic fibrosis, others with heart disease, arrhythmia or cancer,
and now muscular dystrophy. Because pigs mimic these human diseases more closely than mice, they are desirable models for drug testing
and for studying the disease process. However, as the first company to seek approval for a disease model in a GE animal that could, in theory,
In 2009, the company submitted its first application to the FDA for approval of its cystic fibrosis pig model."
Nevertheless, the company remains hopeful that its pigs will skirt the hardships that have befallen other GE animals in the pipeline.
With salmon frozen in the pipeline, Exemplar s piglets might skip to the front of the queue."
"GE pigs for medical models could move more quickly because there s a strong need for them in the medical community,
Although animal-rights advocates may object to disease-model pigs, Swart predicts that they will avoid intense public scrutiny
While the pigs plod through the process one step at a time, a handful of investigators at US universities have begun already to study how diseases develop in the transgenic animals.
Because the pigs aren approved t federally, Exemplar must track each pig from birth to beyond the grave.
If a scientist in Iowa sends tissue from one of the animals to a colleague in California,
Moreover, without approval, Exemplar cannot promote the pig models for drug testing based on what the researchers find.
Swart calls the wait worthwhile if Exemplar s pigs can help pharmaceutical companies to predict whether a drug will work."
Santiago had pigs and goats. Pinta had goats, but only for 20  years. Espa  ola had goats for probably 100  years,
Pig fever sweeps across Russiarussian authorities have incinerated tens of thousands of pigs and closed roads in the past few weeks,
in an attempt to contain an emerging outbreak of African swine fever, a viral disease so lethal to the animals that it has been likened to Ebola.
the Russian Federation lost 300,000 of the country s 19 million pigs to swine fever, at an estimated cost of about 7. 6  billion  roubles (US$240  million).
African swine fever was detected also for the first time in Ukraine in late July, and European and Asian countries are on the alert to deal with outbreaks that could cost their pork industries billions of dollars.
Scientists first encountered African swine fever in the 1920s in domestic pigs in Kenya, where the vicious haemorrhagic fever felled nearly every animal infected.
which is carried also by warthogs and ticks without causing disease, is now endemic in much of Sub-saharan africa,
limiting pig farming there. It does not infect humans. In 1957, the virus jumped to Portugal after pigs near Lisbon s airport were fed infected human food scraps (the virus particles can survive meat curing processes.
It then hit Spain, and import of the region s ham including the coveted jam  n ibã rico was banned by many countries,
says Linda Dixon, an expert on African swine fever at the Institute for Animal health in Pirbright, UK.
before fanning out across Russia (see Pig plague). Source: C. Netherton/OIETHE recent spread of the virus means that the Ukrainian outbreak,
now under control after authorities culled 208 pigs and instituted quarantine measures, did not come as a surprise,
home to more than 1 Â billion pigs. China also risks importing the virus through its growing trade with African nations.
Europe s large pig farms are buffered by better biosecurity and hygiene practices. But agencies such as the UK Department of Environment, Food and Rural affairs in London are
The variety of ways in which African swine fever spreads only increases the uncertainty. Pigs can leave virus particles on transport vehicles,
for example, exposing whole shipments of uninfected animals. Biosecurity measures, such as scrubbing trucks and decontaminating farmers before they enter
and leave pig pens, can help to contain outbreaks. But infected wild boar, whose populations stretch across Russia
and Europe, pose a transmission threat that is harder to control.""Boars don t require visas to move across borders,
says Lubroth. The pigs food can also carry the virus if it includes contaminated pork products.
Swill feeding, in which pigs are fed scraps of human food waste, is popular among small-scale farmers.
Limiting this practice (which is banned in the European union) or heat-sterilizing the food scraps can prevent disease transmission,
He had a cooker with a big pan of entrails that he was feeding to pigs
and he had a little tray of disinfectant outside the pig pens. The FAO warns that continued spread of African swine fever could be very costly Russia does not export its pork,
but trade restrictions could prove expensive for other countries where the disease becomes endemic.""If you are a small producer,
and you lose all your five pigs, that is devastating to the family. Denis Kolbasov, director of the National Research Institute for Veterinary Virology and Microbiology of Russia in Pokrov, says that officials often have little appetite for expensive countermeasures such as widespread culling
and you lose all your five pigs, that is devastating to the family, says Lubroth.""That is the situation I see in many parts of Europe and Africa.
African swine fever was especially costly in South Ossetia during a 2008 conflict with Georgia,
While animal health officials focus on containing the spread of African swine fever, scientists believe that it should be possible to develop a vaccine to eradicate the disease.
The lucky few pigs that survive infection are rendered immune, so Dixon s lab and others are working to identify which of the virus s 175
And the white-lipped peccary, a species closely related to pigs, has been completely wiped out there, the assessment shows.
"In most places, jaguars, tapirs, woolly spider-monkeys and white-lipped peccaries weren t even in living memory,
Swine-flu alert The number of reported cases in an outbreak of H3n2v virus a variant strain of swine flu that can pass from pigs to humans took a sudden spike last week.
and all are the result of contact with pigs by farmers or through agricultural fairs.
Need for flu surveillance reiteratedthe emergence of the H1n1 influenza virus that leapt from pigs to humans in 2009,
reminded us of the need to monitor animals such as pigs that can host the development of dangerous viral strains.
and his colleagues have isolated a new strain of H1n2 influenza from Korean pigs that kills infected ferrets the model animal of choice for influenza work
and can spread through the air 1."It shows that there are very nasty viruses being generated in swine,
"And these viruses are coming out of apparently healthy pigs. Like that responsible for the 2009 pandemic, the new strain, known as Sw/1204, is a'triple-reassortant'virus that is, one with genes from avian, swine and human flu.
Such viruses, which first appeared in North america in 1998, have been circulating in Korean pigs for at least a decade.
Choi wanted to assess the pandemic potential of Korean strains. His team tested two H1n2
and two H3n2 viruses isolated from pig abattoirs before the 2009 pandemic. Most of these viruses did not cause any signs of serious disease in ferrets.
and spread among swine. The HA225G mutation allows the virus to bind more effectively to receptors in the lungs of its hosts,
The US National institutes of health (NIH) occasionally supports research on transgenic pigs that model human diseases, but rarely funds proposals to produce drugs or vaccines in the milk of transgenic livestock.
And China invested nearly $800 million in transgenic pigs, cattle, sheep and crops between 2008 and 2012, says Ning Li, director of the State Key Laboratories for Agrobiotechnology in Beijing.
And in pigs, scientists have used an enzyme called a TALEN2 to scramble a gene that would normally help remove cholesterol.
who contributed to the work in pigs.""In essence, we are just mimicking an evolutionary process with precise, man-made editors.
Pigs with this condition may be reliable models of human atheroscelerosis in biomedical research. The TALEN-modified pig is not the first model of human heart disease (see Model pigs face a messy path),
but the technique makes genetic engineering less costly and more efficient.""I d be exaggerating if
I said that pigs and cows can now be thought of as big mice, but we are moving in that direction,
Pig geneticists go the whole hogt. J. Tabasco is something of a porcine goddess at the University of Illinois, Urbana-Champaign, where her ruddy,
For the past couple of decades they have been slowly teasing information from the pig genome,
applying it to breed healthier and meatier pigs, and to try to create more faithful models of human disease.
and perhaps even allow pigs to be engineered to provide organs for transplant into human patients."
"The pig industry has an excellent track record for rapid adoption of new technologies and knowledge.
T. J.,a domestic Duroc pig (Sus scrofa domesticus), was born in Illinois in 2001. The next year, Schook and his colleagues generated a fibroblast cell line from a small piece of skin from her ear
One set of clones was created at the National Swine Resource and Research center (NSRRC) in Columbia, Missouri,
along with genetically engineered pigs with genes added or deleted to mimic human diseases.""Making such pigs has got increasingly easier as knowledge of the genome increases,
says physiologist Randall Prather, a co-director of the NSRRC, which is funded by the National institutes of health (NIH).
Geneticist Martien Groenen, part of the team that sequenced the pig genome, chews the fat with Thea Cunningham.
The NIH launched the NSRRC in 2003 to encourage research in pig disease models. Pigs are more expensive to keep than rodents,
and they reproduce more slowly. But the similarities between pig and human anatomy and physiology can trump the drawbacks.
For example, their eyes are a similar size, with photoreceptors similarly distributed in the retina. So the pig became the first model for retinitis pigmentosa, a cause of blindness.
And four years ago, researchers created a pig model of cystic fibrosis2 that unlike mouse models, developed symptoms resembling those in humans.
Geneticist and veterinarian Eckhard Wolf at the Ludwig-Maximilian University in Munich, Germany, has exploited the similarity between the human
and pig gastrointestinal system and metabolism like us, pigs will eat almost anything and then suffer for it to develop models of diabetes.
One pig model carries a mutant transgene that limits the effectiveness of incretin, a hormone required for normal insulin secretion3.
Mice with the transgene developed unexpectedly severe diabetes, but the pigs have a more subtle pre-diabetic condition that better models the human disease."
"This shows the importance of using an animal with a relevant physiology, says Wolf. Pig models are now being developed for other common conditions,
including Alzheimer s disease, cancer and muscular dystrophy. This work will be enriched by the discovery, reported in the genome paper,
Knowledge of the genome is also allowing scientists to try to engineer pigs that could be the source of organs,
Pig organs are roughly the right size, and researchers hope to create transgenic pigs carrying genes that deceive the immune system of recipients into not rejecting the transplants.
Back on the farm early knowledge about the pig genome led to the discovery in 1991 of a gene involved in porcine stress syndrome, in
which the stress of overheating, being moved or even having sex causes the animals to die suddenly4.
It then became possible to test for the gene and select pig stocks free of it.
a viral disease costing the US pig industry US$600 Â million per year. The PRRS Host Genetics Consortium, a network of US research groups
But the pig genome is not just about applications. Lead co-author Martien Groenen, a genome researcher from Wageningen University in The netherlands, has resequenced the genomes of scores of different strains of wild and domestic pigs,
and used the information to show that the pig was domesticated independently in Asia and Europe.
He has started also to work out which genes were involved in the selection of desired traits such as a longer spine to give more bacon on different continents."
and 0. 5 billion pigs not to mention a vast population of wild birds, including many migratory species
density in 2010), pigs (B), chickens (C) and ducks (D) in China and Asia in general.
Note different scale for pigs. H7n9 case locations courtesy of EMPRES, FAO, Rome. Human population from ASIAPOP.
An international team of researchers compiled maps for Nature showing the population densities of chickens, pigs, ducks and humans in many parts of China and throughout Asia.
47 million domestic ducks and 22 million pigs live within a 50-kilometre radius of each of the 60 H7n9 human cases that had occurred up to 16 april.
But despite intensive surveillance of poultry, wild birds, pigs and other animals, the animal reservoirs remain largely unknown.
which was a mix of viruses that infect birds, pigs and humans. Most of the genetic analyses are still being carried out confidentially within THE WHO's global flu-research networks.
pigs might be another source, says Tashiro. Flu experts say that other urgent requirements include testing any human cases of serious pneumonia for traces of the virus
Deadly pig virus slips through US bordersthe pathogen, a type of coronavirus called porcine epidemic diarrhoea virus (PEDV),
As pigs there developed immunity, the virus petered out and now causes only occasional, isolated outbreaks.
And although adult pigs typically recover PEDV can kill 80-100%of the piglets it infects.
The virus poses no health threat to humans. The US Department of agriculture (USDA) had tried to keep PEDV and other diseases out of the country by restricting imports of pigs and pork products from certain nations, such as China.
But on 10 Â May, the Veterinary Diagnostic Laboratory at Iowa State university in Ames confirmed that PEDV had infected pigs in Iowa, the leading producer of US pork.
The lab then screened samples taken earlier from other states and found a case from Ohio submitted on 16 Â April that is now the earliest known US detection of PEDV,
and could become an epidemic (see Pig virus on the wing). SOURCE: US Department of agriculture"It s a real threat, says Lisa  Becton, a veterinary surgeon and director of swine health information at the National Pork Board, an industry group in Des Â
Moines, Iowa. To understand the virus s enigmatic US entry, scientists are sequencing VIRAL DNA isolated from pigs and comparing it with PEDV variants from elsewhere in the world.
Researchers are also trying to create rapid diagnostic tests and vaccines to prevent the virus from spreading.
because the pathogen thrives in the specific conditions found in pig guts. Researchers in Europe and Asia have managed already to infect cells,
and pig antibodies.""What s hampering the research is that we don t have reagents, says Linda  Saif, a virologist at Ohio State university in Wooster.
In the meantime, other research groups have focused on detecting VIRAL DNA in sick pigs and on sequencing viral genes.
the main source of pigs entering the United states, does not import pigs from China either.
And although researchers know that the virus can be transported in faeces, they do not know how long it can survive outside pigs intestines,
so it is unclear if a dirty boot, a contaminated package or an illegal import carried PEDV into the country.
Vets say that pig farmers are now restricting access to farms, and are cleaning pig manure more carefully off their clothes
and trucks as they move between barns. And researchers still hope that they can elucidate the virus s international and domestic path by looking for subtle evolutionary changes in viral genome sequences of samples from Asia and different US states.
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