During this spring, American poultry producers lost birds by the millions, due to the High Pathogenic Avian Influenza outbreaks on factory farms. USDA APHIS applied the stamping out strategy in an attempt to prevent the flu from spreading.
With stamping out as the highest priority of the response strategy, large numbers of responders are involved. With in average almost 1 million caged layers per farm in Iowa, there is hardly any room for a proper bio security training for these responders. And existing culling techniques had insufficient capacity, the authorities had to decide to apply drastic techniques like macerating live birds in order to take away the source of virus reproduction.
This strategy didn’t work; on the contrary. Instead of slowing down the spreading of the virus, the outbreaks continue to reoccur and have caused death and destruction in 15 USA states, killing almost 50 million birds on mote than 220infected commercial poultry farms, all within a very small time frame.
The question is whether the priority of the response strategy should be on neutralizing the transmission routes instead of on stamping out infections after they occur. All indicators currently point out into the direction that the industry should prioritize on environmental drivers: the connection between outbreaks and wild ducks; wind-mediated transmission; pre-contact probability; on-farm bio security; transmission via rodents etc.
Once the contribution of each transmission route has been determined, a revolutionary new response strategy can be developed based on the principle of neutralizing transmission routes. Neutralizing risks means that fully new techniques need to be developed, based on culling the animals without human – to – animal contact; integrating detergent application into the culling operations; combining culling & disposal into one activity. This new response strategy will be the main subject of the FLI Animal Welfare and Disease Control Seminar, organized at September 23, 2015 in Celle, Germany.
This international – English-language based – seminar is open for animal welfare specialists, veterinary specialists, and emergency response experts. The event takes place on the premises of FLI; starts at 9 AM; and closes at 4 PM, after the general discussion. In case you need more information or any assistance, please contact me on: 0046 761 731 779 or by mail on email@example.com.
You are very welcome to pass this invitation to all of your colleagues, who may also be interested in the seminar.
The routes of virus transmission risks can be split into three categories:
1. Introduction of the infection into the farm
2. Onward-spread between farms
3. Spreading during outbreaks
Introduction into the farm entails the target farm’s exposure through incoming contacts (human and fomite), through inputs such as feed and egg trays and through neighborhood-related risks such as air-borne contamination. Onward spreading and spreading during outbreaks can be through farm outputs (waste and non-waste), outgoing contacts (human and fomite) and contamination of the neighborhood (e.g., through emissions from the farm). Therefore, all day-to-day farm activities involving people and/or materials and/or equipment going in or out of the farm must be systematically analyzed.
Category 1: Introduction of the infection into the farm
During the last HPAI H5N8 epidemic in the Netherlands (2014), a total of 5 traditional poultry became infected by separate introductions, from outside the building to inside and in contact with the birds. The risk of introducing the virus to a farm can be determined from the farm’s neighborhood characteristics, its contact structure and its biosecurity practices .
Neighborhood characteristics include factors such as the presence of water bodies (accessed by wild birds), the density of poultry farms (together with the number and type of birds on these farms) and poultry-related businesses and the road network. The use of manure in the farm’s vicinity is also deemed to be risky.
In nature, disease-causing strains of avian influenza rarely spread far because the birds sicken and die before they can fly to spread it to others. However, in unnatural, intensive agricultural systems, pathogens are more easily able to evolve from mild strains to dangerous, highly pathogenic forms.
Category 2: Onward-spread between farms
In Iowa, cage layer housing conditions (confining in average more than 100,000 animals each) may have an effect on immunity, but there is no such thing as being more or less susceptible to avian influenza virus infection; poultry in outdoor facilities that have more opportunities to engage in natural behavior are not more resistant to AI infection.
Probably the housing conditions themselves (windowless sheds, intensely overcrowded, unsanitary, with stressful living conditions for the birds) make exposure to AI virus easier. In the Netherlands it has been shown that. layer farms with outdoor facilities and therefore more and better contact with wild water birds have a much higher probability of introduction of AI virus than traditional indoor layer farms (which do not have windowless sheds).
Nine out of 10 chickens used for egg production in the U.S. are confined in barren wire cages. Due to the extreme confinement, hens —highly intelligent and social animals — cannot engage in natural behaviors. High levels of stress can lead to weakened immunity, rendering animals much more susceptible to disease. This makes the average caged layer farm in Iowa a plausible hotbed for outbreaks of avian flu.
Still, it is unlikely that the confinement of hens in cages is the only explanation for the current outbreaks in the U.S, especially in Iowa. The industrial indoor housing in remote locations with large distances between farm locations has always been considered as the perfect protection against introduction of viruses to the farm. Considering the current pace of outbreaks over large areas, other factors might have caused the transmission between farms, like:
a) Transmission through contact structure between farms
b) Wind-mediated spread
c) Transmission via rodents and farm dogs
a) Transmission through contact structure between farms
Contacts between people, equipment and vehicles prior and during outbreak situations are critical to determine the possible source of infection of a farm . Hired laborers are known to play a big role in interconnecting farms.
The farm’s exposure through incoming contacts (human and fomite), through inputs such as feed and egg trays and through neighborhood-related risks such as air-borne contamination. The latter can be through farm outputs (waste and non-waste), outgoing contacts (human and fomite) and contamination of the neighborhood (e.g., through water- or airborne emissions from the farm).
b) Wind-mediated spread
In the study, published in 2012 by Rolf Ypma et al, a comparison between the transmission risk pattern predicted by the model and the pattern observed during the 2003 Netherlands epidemic reveals that the wind-borne route alone is insufficient to explain the observations although it could contribute substantially to the spread over short distance ranges, for example, explaining 24% of the transmission over distances up to 25 km.
c) Rodents, scavengers and farm dogs
Besides a study published in 2007 Taiwan, little research has been undertaken into the transmission routes via rodents, scavengers and farm dogs. There are strong indicators for the assumption that rodents, scavengers and farm dogs could play a role in distributing and reintroducing HPAI.
Recently Avian Influenza was found in a farm dog in South Korea. The dog had antigens for the highly pathogenic H5N8.
Since the first case of a dog being infected with the poultry virus in March 2014, there have been 55 dogs found with antibodies to the bird flu virus. This is the first time bird flu has been found in a dog in Korea through the detection of antigens.
Category 3: Spreading during outbreaks
The impact of the outbreak of the Avian Flu Epidemic outbreak in the Netherlands in 2003 shows that biosecurity during outbreaks is one of the main issues to address. An estimated 1.000 people, possibly more have been shown to carry antibodies to the H7N7 virus active at that time.
Although the risk of transmission of these viruses to humans was initially thought to be low, an outbreak investigation was launched to assess the extent of transmission of influenza A virus subtype H7N7 from chickens to humans.
Most H7 cases were detected in the cullers. The attack rate (proportion of persons at risk that developed symptoms) of conjunctivitis was highest in veterinarians, and both cullers and veterinarians had the highest estimated attack rate of confirmed A/H7N7 infections.
From all people that had been questioned, 453 people had health complaints—349 reported conjunctivitis, 90 had influenza-like illness, and 67 had other complaints. We detected A/H7 in conjunctival samples from 78 (26·4%) people with conjunctivitis only, in five (9·4%) with influenza-like illness and conjunctivitis, in two (5·4%) with influenza-like illness only, and in four (6%) who reported other symptoms.
Most positive samples had been collected within 5 days of symptom onset.
A/H7 infection was confirmed in three contacts (of 83 tested), one of whom developed influenza-like illness. In three of these exposed contacts an A/H7N7 infection was confirmed. All three were household contacts. The first contact was the 13-year-old daughter of a poultry worker, who developed conjunctivitis approximately 10 days after onset of symptoms in her father. Six people had influenza A/H3N2 infection.
During the FLI Animal Welfare and Disease Control Seminar, organized at September 23, 2015 in Celle, Germany, a group of international experts will give their vision on how the possible contribution of each transmission route could be determined and how a revolutionary new response strategy could be developed, based on the principle of neutralizing transmission routes.
A selection of key experts in their field will be presenting their vision, like:
• Dr. Michael Marahrens, host of the event, presenting the theme of the day: Animal disease control in Germany: past – present – future
• Dr. Marien Gerritzen (Wageningen UR) who will discuss Welfare aspects of methods for emergency killing of poultry during disease outbreaks
• Dr. F. J. Conraths (Institute of Epidemiology, FLI, Greifswald – Insel Riems) who will present the role of wild birds in the transmission of influenza virus infections to poultry
• Dr. Guus Koch (Wageningen UR), explaining the virus sequence network of an avian influenza epidemic reveals virus adaptation and unexpected trans-mission chains
• Dr. Elbers (Wageningen UR), presenting the virus transmission during the out-break in the Netherlands, 2003
• Dr. J. Harlizius (Chamber of Agriculture North Rhine – Westphalia), discussing Lessons learnt from the outbreak of classical swine fever in Germany, 2006
• Dr. A. vom Schloß (North Rhine – Westphalia Animal Diseases Fund), discussing the reorganization of the provisions for animal disease control in Germany
• Dr. I. Schwarzlose (Institute of Animal Welfare and Animal Husbandry, FLI, Celle), explaining Animal Welfare during disease outbreaks and control measures in the context of European and German legal framework
• Mr. W. Hung (Environment & Animal Society of Taiwan (EAST), explaining the relevance of OIE guidelines during the HPAI outbreak in Taiwan.
• AVT participates in the seminar, discussing how to implement animal welfare in Standard Operating Procedures during culling of animals.
You are more than welcome to participate in this English-spoken event. You can sign up by replying your name, including the name of your institute/company, to firstname.lastname@example.org, or by fax: +49/5141-3846-117.
We wanted this seminar to be accessible for all, and for that reason, the participation fee is € 70 only. Unfortunately, the number of participants is limited, so in case you’re interested, please let us know and respond before August 31, 2015. After you signed up, you will receive your detailed payment instructions.