Dossier H7N7 in Holland: comparing culling methods

During the outbreak of H7N7 in Holland, 29,500.000 birds were killed at the farm. This presentation compares different culling techniques, such as stable gas, container gassing and electrocution.

Share

Dossier Hyderabad: 250.000 chickens killed by twisting the neck

Hyderabad, April 22, 2015: Veterinary officials ordered 250,000 birds to be slaughtered in India’s Telangana district, after cases of the H5N1 virus were identified. Veterinary staff from the local government’s animal husbandry department carried out the cull – which included destroying hundreds of thousands of infected eggs – at Thorrur village in the Ranga Reddy district.

The chickens and other poultry have been culled by twisting the neck, following the outbreak of a highly contagious strain of bird flu in India. The virus which can be deadly in humans, caused the deaths of nearly 400 people and hundreds of millions of poultry after it spread from Asia into Europe and Africa. Killing birds by twisting the neck is extremely labor intensive and demands hundreds of responders.

The risk that responders get infected and become carrier of the disease is high and this method should be banned as method of mass culling. As a cheap alternative, the authorities could have ordered the use of solid CO2 (dry ice) instead. The use of dry ice in plastic bags is 100% effective and reduces direct contact between animals and humans.

The lack of proper preparation by the local veterinary authorities caused that they didn’t have any alternative method available, what then forced them to apply hundreds of people to kill the infected birds by hand. It is to be expected that HP H5N1 will continue to reoccur in India via the route of this type of emergency response, unless the authorities step up their control measures and start using culling methods that exclude contact between infected animals and responders.

The carcasses and the eggs, including those stored in warehouses, were dumped in a pit.Bird feed stock was burned and the sites were all thoroughly disinfected in a bid to stop the virus from spreading. India has culled 6.4 million birds due to bird flu since 2006.

Share

Dossier AI Transmission: Public statements about infectiousness H5N2 is only half the story

The risk that a highly infectious strain of avian flu virus named H5N2 will infect humans is “low at this time,” CDC officer Alicia Fry said during a press conference on April 22, 2015. The virus, which infects turkeys and chickens, is different from previous flu strains that have been able to infect humans, she said. So far, it has “not caused infections in humans anywhere in the world.”

Yes, she is absolutely correct: at this moment, H5N2 doesn’t pose a threat to human health. The general public doesn’t have to fear that the Spanish flu will repeat itself, and that is probably the reason CDC organized this press conference, so the public can go on with their life as if nothing has happened. But the risk of human infection is only half of the story: H5N2 is like EBOLA to poultry, especially to turkeys. Therefore the public should be careful when they enter wildlife areas, and farmers should mistrust each and every visitor to their farm, because the public is not aware of these risks. And this unawareness of the public poses an absolute risk for the poultry industry. To demonstrate this, I would like to share the story how in 2003 Belgium farms most likely got infected during the European outbreak of H7N7:

The news media was trying to cover an outbreak of AI in Holland, and in order to get a better view on what was happening on the farm, the film crew went (without protective clothing) over the barrier, on to the farmland, close to the barn. Halfway they’re filming, the local police, who spotted the film crew in the possible infected field, stopped them and ordered them to leave the area immediately. Because they had to deliver their material before a specific deadline, they crossed the nearby border between Holland and Belgium, and finished their film on a similar looking farm, 40 km into Belgium, were there were no outbreaks of AI at that time. They managed to end their reportage in time for the 8 O’clock, but with the result that soon after that, the first outbreak occurred in Belgium at the farm where the crew had finished their reportage. Later on, in search of what caused the virus to jump from Holland to Belgium, this event was mentioned as the most likely route.

The moral of this story is that the message that H5N2 poses little risk on human infections, but that the infection risks for poultry are extremely high: avoid the risk of spreading contaminated materials to farm areas!

Share

Dossier AI Transmission: Evidence that link outbreaks in Eurasia, China, South Korea, USA and Canada

In a new study published in the Journal Virology on March 31, 2015, scientists from the U.S. Geological Survey and U.S. Fish and Wildlife Service harnessed a new type of DNA technology to investigate avian influenza viruses in Alaska. Using a “next generation” sequencing approach, which identifies gene sequences of interest more rapidly and more completely than by traditional techniques, scientists identified low pathogenic avian influenza viruses in Alaska that are nearly identical to viruses found in China and South Korea. This publication provides even more evidence of this intercontinental avian influenza exchange program.
The viruses were found in an area of western Alaska that is known to be a hot spot for both American and Eurasian forms of avian influenza. “Our past research in western Alaska has shown that 70 percent of avian influenza viruses isolated in this area were found to contain genetic material from Eurasia, providing evidence for high levels of intercontinental viral exchange,” said Andy Ramey, a scientist with the USGS Alaska Science Center and lead author of the study. “This is because Asian and North American migratory flyways overlap in western Alaska.”

In this study, led by the USGS, low pathogenic H9N2 viruses were found in an Emperor Goose and a Northern Pintail. Both of the H9N2 viruses were nearly identical genetically to viruses found in wild bird samples from Lake Dongting, China and Cheon-su Bay, South Korea.
“These H9N2 viruses are low pathogenic and not known to infect humans, but similar viruses have been implicated in disease outbreaks in domestic poultry in Asia,” said Ramey. “There is no commercial poultry production in western Alaska and highly similar H9N2 virus strains have not been reported in poultry in East Asia or North America, so it is unlikely that agricultural imports influenced this result.”
The finding provides evidence for intercontinental movement of intact avian influenza viruses by migratory birds. The USGS recently released a publication about the detection of a novel highly pathogenic H5N8 virus in the U.S. that is highly similar to the Eurasian H5N8 viruses. This suggests that the novel re-assortment may be adapted to certain waterfowl species, enabling it to survive long migrations. That virus, and associated strains, has now spread from early detections in wild and domestic birds in Pacific states to poultry outbreaks in Minnesota, Missouri and Arkansas.

“The frequency of inter-hemispheric dispersal events of avian influenza viruses by migratory birds may be higher than previously recognized,” said Ramey. While some of the samples for the project came from bird fecal samples collected from beaches at Izembek National Wildlife Refuge, most of the samples came from sport hunters.

“For the past several years, we’ve worked closely with sport hunters in the fall to obtain swab samples from birds and that has really informed our understanding of wildlife disease in this area,” said Bruce Casler, formerly a biologist with the USFWS Izembek National Wildlife Refuge and a co-author of the study.

Share

Dossier AI Transmission: David Stallknecht doubts the role migratory birds spreading AI

The question what causes the current outbreaks in Minnesota is heavily discussed, especially the role of migratory birds. USDA APHIS tends to the opinion that migratory birds play an important role. In that case, H5N2 will likely remain a threat to U.S. poultry for three to five years, Olson said, citing information from wildlife experts. That is how long it will take wild birds to develop immunity to the disease. Since the beginning of the year, the flu, which can kill nearly an entire poultry flock within 48 hours, has also been found in birds from Oregon to Arkansas. The discoveries have prompted major overseas buyers such as Mexico and Canada to limit imports of U.S. poultry and companies such as Tyson Foods Inc to strengthen measures to keep the disease off farms.

The number of infections is climbing as migratory ducks, which are believed to be spreading the disease, return to Minnesota to breed after spending the winter farther south, said Beth Thompson, assistant director of the Minnesota Board of Animal Health. The larger number of ducks likely increases the risk for wild birds to transmit the virus.

Farm workers are probably infecting turkeys by tracking the virus into barns after stepping in contaminated duck feces, said John Glisson, vice president of research for the U.S. Poultry and Egg Association. Chicken flocks are also vulnerable. “Minnesota is a real hotbed for returning waterfowl,” Glisson said. The USDA has said it believes migratory ducks are spreading the flu and sent a team to Minnesota to determine how it is moving into poultry flocks. So far, efforts to stop the spread by controlling human and vehicle traffic on farms have not worked.

The number of infections may continue to rise through mid-May, when spring migration ends, said Steve Olson, executive director of the Minnesota Turkey Growers Association. New cases may accelerate again in the autumn when recently hatched ducks, which have never been exposed to the virus, begin migrating south, he added.

In the absence of reliable epidemiological data about the spreading under wildfowl population, the source of infection will continue to spark speculations about the role of migratory birds.

Despite all evidence, there are scientists who have reason to doubt the thesis that migratory birds are to blame, like Professor David Stallknecht from University of Georgia’s College of Veterinary Medicine. David is openly questioning the USDA’s conclusion. David Stallknecht called the notion that avian flu originated in wild birds “pure speculation” in a story posted by the University of Minnesota’s Center for Infectious Disease Research and Policy (CIDRAP).

David Stallknecht: “It is based on circumstantial evidence that is rapidly becoming accepted dogma. The avian flu saga dates back to late last year, when H5N2 struck several farms in British Columbia. That sparked surveillance programs in the U.S., which turned up cases of pintail duck virus in Washington and a related strain in a captive gyrfalcon nearby. Since then, cases of H5N2 have shown up in poultry in several states, including Idaho, Minnesota and Arkansas.”

In order to stop large-scale outbreaks, more efforts have to be undertaken to protect commercial flocks and to predict future outbreaks. Even more reasons to increase the active surveillance efforts, including the crucial active surveillance programs under wild birds, like Stallknecht suggests.

Share

Dossier AI in the USA: Massive blow to the Minnesota turkey industry

The commercial turkey industry in Minnesota has been hit hard by the current HPAI outbreak. Could this been prevented? Is the USA prepared for large-scale outbreaks of Avian Influenza?

Does the United States have the strongest AI surveillance program in the world, as claimed on the website of USDA APHIS? If so, how come that the current outbreak was detected in Canada, weeks or even longer before the first outbreaks within the poultry population were detected just on the other side of the border in the US?

And why doesn’t the AI surveillance program include large-scale active field surveillance within the wild birds population? Why took it so long before the potential impacts associated with the introduction of HPAI viruses into wild bird populations were understood by the industry?

The current epidemiological efforts are insufficient to determine the risks of other farms getting infected, because the mechanism of infection the current flocks is still unknown. Active laboratory surveillance is not the answer either to predict future outbreaks: Massive efforts in active field-based epidemiological research under wild birds and in wetlands are needed to as part of an early warning system; hunting, fishing and other activities that take place in the wetland areas have to be banned to prevent humans to enter the HPAI infection to the farm; and all commercial turkey farms need to be completely isolated as long as the risks of outbreaks is eminent.

Compared to other poultry species, turkeys need only 1/100 of the normal virus load on contaminated materials (soil, organic materials etc.) to become infected, with lethal consequences for the birds, and enormous financial consequences for the farming industry.

The turkey industry is still completely in the dark about the current outbreak situation. The USDA APHIS active laboratory surveillance programs might be one of the best in the world, is clearly not enough under the current circumstances to determine whether a flock has become infected. Unless the efforts to collect more valid data is substantially increased, followed by rigorous epidemiological analysis and a solid risk assessment, the turkey industry in Minnesota will probably see more outbreaks to come in the near future.

Share

Dossier H5N1: Local veterinary officials failed timely notifying large-scale HPAI outbreak

HYDERABAD: It was only after 39,240 birds perished that the state animal husbandry department woke up to the deadly avian influenza virus doing the rounds on the city outskirts. The deaths of layer birds (used for egg production) took place in two poultry farms in Thorrur village of Hayatnagar mandal a full one week before the government declared the bird flu outbreak.

The owners of the two poultry farms, V Bala Krishna Reddy and Srinivas Reddy, had reported the deaths of the birds from April 6-April 13 to the Bhopal-based High Security Animal Diseases Laboratory (HSADL). The lab, in turn, informed the central government following the samples of the dead birds sent to them by the Reddy brothers turning positive for the H5N1 virus.

The state animal husbandry department, which was in the dark of the developments all this while, was finally informed about the outbreak by the central government’s department of animal husbandry, dairy development and fisheries.

The break-up of poultry deaths that fell prey to the avian influenza include 80 (April 6), 160 (April 7), 400 (April 8), 1,600 (April 9), 2,500 (April 10), 17,500 (April 11), 9,000 (April 12) and 7,500 deaths (April 13) respectively, as per records in possession with TOI.

“This is a glaring example of how the government officials had utterly failed in reporting the disease, which is mandatory for all notified diseases including H5N1, as required under The Prevention and Control of Infectious and Contagious Diseases in Animals Act, 2009. The stakeholders must be held accountable now as the damage has already been done,” said city-based wildlife expert Dr C Srinivasulu.

In fact, the Section 4 of the Act states that it is obligatory for the owner or any person in charge of any animal which he has reason to believe to be infective of a scheduled disease, to report the fact to village panchayat or villager officer, who in turn has to report it to the nearest government veterinarian.

However, it is learnt that nothing of this sort happened with top officials of the directorate of animal husbandry, Telangana, admitting that neither their veterinary assistant surgeon Anand Reddy nor two village livestock officers (VLOs) of Hayatnagar mandal in Ranga Reddy had any inkling of the outbreak in their local jurisdiction.

Interestingly, Dr Y Thirupathaiah, additional director, directorate of animal husbandry, Telangana gave a clean chit to their officials. “Our people cannot be blamed as the burden of sharing information about the outbreak of infective diseases vests with the village officer and the panchayat. We will be writing to the Ranga Reddy collectorate for action against the erring officials,” he said, acknowledging that they learnt about the outbreak from central government sources on April 13.

Share

Dossier wild ducks: Role wild ducks introducing LP Avian Influenza on free range farms in Holland

Lelystad, April 2015: According to a recently published study (in Dutch) by the University of Wageningen, wild ducks are are identified as a high risk factor for the introduction of Low Pathogen Avian Influenza viruses in free-range laying hens.

Through a case-control study investigated presumed risk factors for introduction of low-pathogenic avian influenza (LPAI) virus in poultry laying farms free range. Under a LPAI virus was defined in this study: an avian influenza virus of each subtype (H1 H16 tm), with the exception of the highly pathogenic avian influenza (HPAI) viruses.

In order to determine the potential risk factors for infection with LPAI virus, forty Dutch free range poultry farms where the introduction of Low Pathogen Avian Influenza virus has been confirmed in the past (cases) were compared with 81 free range poultry farms where no introduction has taken place (controls). Questions about the presence of potential risk factors through surveys submitted to the poultry farmers.

The analysis of the various factors shows that the risk of introduction of LPAI virus on free range laying farms 3.3 (95% CI: 1.2-9.7) times higher as mallards has identified by the farmer entering the free range area at least once a week, in comparison to free-range laying farms where wild ducks have been identified by the farmer once a month or less.

It seems logical that the regular presence of wild ducks in the free-range increases the risk exposure of the chickens LPAI virus since wild waterfowl are the natural reservoir of avian influenza viruses.

The study also revealed that the risk factor for free range layer farms located on clay is 5.8 (95% CI: 2.2-15.1) times have higher risk of introduction of LPAI virus then free range layer farms on sandy soil or a soil other than clay. The soil on which the free range farm is situated is probably an indirect risk factor (association and not causation): especially in case the farm is located near the coast or close to rivers.

Share