The research project is part of the Association’s comprehensive research program encompassing all phases of poultry and egg production and processing.
Dr. Benham Abasht and colleagues at the Univ. of Delaware found that the early lesions of the condition could be found in the breast tissue of one-week old broilers, and the first stage of the condition involves inflammation of the veins in the breast tissue and accumulation of lipid around the affected veins. The study went onto say that this condition was followed over time by muscle cell death and replacement by fibrous and fatty tissue. Genetic analyses also indicated that there was dysfunction in lipid metabolism in affected birds. This new understanding that inflammation of veins is the likely cause of wooden breast lesions in broilers will provide important direction for future research on this condition. READ MORE
With the subheading of “Guidelines for a responsible use of antibiotics in the modern broiler production,” the event afforded participants the opportunity to consider a host of different viewpoints.
Expert speakers explored the role of genetics, nutrition, biosecurity and farm management.
Highly interactive exchanges throughout the event converged on the idea that a holistic approach is the way forward in reducing antibiotics while maintaining high performing flocks.
UofG alumni Vic Parks and his wife, Uta, have generously donated almost $40,000 to be used in the area of most need for the PHRN.
“The generous gift by the Parks family will have an immense impact on the PHRN,” says Shayan Sharif, an immunologist in the Ontario Veterinary College’s department of pathobiology and leader of the PHRN. “This gift will afford PHRN the opportunity to serve its stakeholders, including industry, government and academia, more effectively through enhanced learning opportunities, research activities and knowledge mobilization.”
The Parks have a strong family history with the University of Guelph and particularly the Ontario Veterinary College (OVC) and Ontario Agricultural College (OAC).
Vic Parks graduated from the Ontario Veterinary College with his DVM in 1964 and both the Parks’ daughters are also OVC grads. Both Mrs. Parks and their son, Jason, graduated from OAC’s School of Landscape Architecture.
With their daughters’ close ties to poultry health and welfare, “it seemed a good fit to provide this most recent donation to support poultry research at OVC,” says Vic, who began his career in large animal practice, before moving into companion animal medicine. He worked in marketing with Novartis Animal Health in Mississauga for 20 years before his retirement in 2006. During this time the Parks also had a farm near Guelph where they raised Limousin cattle.
The Parks fell in love with Salt Spring Island on a trip to British Columbia more than 30 years ago and now live there, near Mount Maxwell Provincial Park.
In addition to their donation to the PHRN, the Parks previously established an endowed Parks Family Travel Grant in OAC, as well as an endowed Parks Family Travel Grant in OVC. The latter is presented annually to a fourth-year Doctor of Veterinary Medicine student entering the Food Animal Stream for assistance travelling outside of Ontario on an external rotation.
Activation of innate immunity
The emergence and spread of resistant bacteria are rendering current antibiotics less useful. Furthermore, the controversial practice of prophylactic use of antibiotics encourages the emergence of antibiotic-resistant microbes. Therefore there is a need for the development of novel alternative strategies to antimicrobials for infectious disease control.
CPRC has recently funded a project that will investigate an innate immune-based method of disease protection as an alternative strategy to antimicrobial use. During initial exposure to pathogens, birds are reliant on their innate immunity for protection against infection. Innate immune responses are not pathogen-specific but are activated by features/patterns characteristic of pathogens. The innate immune system is capable of limiting a variety of infections once activated. Although the innate immune system of chickens is developed at hatch, it is not activated; therefore, microbial agents (particularly bacterial pathogens) can infect chicks at the time of placement in the barn.
Professor Susantha Gomis, from the University of Saskatchewan has studied the effects of a pattern characteristic of bacterial DNA, known as CPG-motifs to induce or activate the innate immunity. Research has shown that synthetically generated CPG-motifs or ‘CpG-ODN’ as an immune system stimulant is capable of protecting neonatal chickens against specific bacterial infections. Results obtained to date show that intranasal delivery of CpG-ODN is advantageous to in ovo delivery as innate immune stimulation coincides with the first week of the birds’ life, which is the most vulnerable period for bacterial infections. Dr. Gomis’s current research will develop an effective method of intra-nasal delivery of CpG-ODN at hatch. The research approach will be to initially develop a CpG-ODN delivery prototype for intranasal delivery of the CpG-ODN to neonatal chicks followed by field efficacy and safety trials.
This research is also funded by NSERC, Chicken Farmers of Saskatchewan, (Saskatchewan Chicken Industry Development Fund), Alberta Livestock and Meat Agency Ltd., Western Economic Diversification Canada, Sunrise Poultry Hatchery, BC and Prairie Pride Natural Foods Ltd., SK.
Activation of adaptive immunity
Respiratory viruses have a negative impact on the poultry industry. Although vaccination against respiratory viruses is used to control these common viral diseases, “vaccine failures” remain common.
CPRC has recently funded a project that will investigate the use of innate immune stimulants to induce adaptive immunity against respiratory viruses. Adaptive immune responses are pathogen-specific and recognition of the pathogen results in both antibody-related and cell-mediated immunity. Adaptive immune responses are slow to develop and may take up to a week before the responses are effective.
Associate Professor Faizal Careem, from the University of Calgary, has studied the effects of synthetic Pathogen Associated Molecular Patterns (PAMPs) in activation of innate immune responses. Research has shown that these PAMPs are effective in reducing the impact of a number of avian bacteria and viruses. PAMPS are also a known to increase the immune response of experimental vaccines when incorporated with these vaccines as ‘immune response enhancers’.
Dr. Careem, will investigate the role of innate immune stimulants in the induction of adaptive immunity to respiratory viruses. Results obtained in his prior research have demonstrated that in ovo delivered PAMPs can reduce a specific viral load in the respiratory tract of embryos and neonatal chicks. in ovo delivered PAMPs also increases innate immune cell responses in neonatal chicks. These responses have been shown to promote the development of adaptive immune responses in mammals. Overall, this study will determine the efficacy and mechanism of in ovo delivered PAMPs in inducing pathogen specific adaptive immune responses against respiratory viruses. The approach is centralized on stimulation of the innate immunity to reduce the viral replication at the site of entry allowing birds to acquire adaptive immunity.
This research is also funded by NSERC and Alberta Livestock and Meat Agency Ltd.
When it comes to developing a vaccine in response to emerging diseases that threaten the lives of animals, a pharmaceutical company needs to move quickly.
What it comes down to is being “first to know” and “fast to market”, said Dr. Raja Krishnan, formerly senior director of Swine and Poultry Research and Development for Zoetis and now of companion animal and equine biological research. Speaking to the Poultry Industry Council Health Day in Stratford, Ont., Krishnan put a global perspective on some of the corporate thought processes that precede his company’s decision to develop a vaccine.
Use of surveillance
“The world is becoming a smaller village,” said Krishnan. Zoetis, a leading pharmaceutical company with 10,000 employees in 120 countries, has access to global surveillance networks that use targeted regional surveillance to help guide rapid, high quality product development.
As an example, Krishnan called Avian Influenza (AI) a “disease that is travelling around the world, creating headaches.” With that kind of migration, how do we become proactive? How do we get ahead of the next round of disease? “It’s a decision that can’t wait,” said Krishnan. “Seasons change whether we’re ready or not,” leaving the company to do the right thing for their customers and the entire industry, sometimes making those decisions in a matter of minutes.
The AI outbreak affected over 48 million birds between December 2014 and June 2015. A lot of questions swirled around the decision to develop a vaccine; the disease was moving quickly. Did the industry want a vaccine? Would they use it? Would the government endorse it? Would the USDA recommend culling or vaccinating? Even if a product were developed, would it be relevant? Does it make sense?
Adding to this uncertainty is the fact that AI doesn’t play by the rules. The virus can mutate rapidly, meaning that the vaccine needs to be changed frequently. That’s one of the challenges. “AI constantly surprises us,” said Krishnan. “Nothing beats preparedness but we may have to course-correct collectively.”
When asked about the drivers behind the U.S. poultry industry deciding to use or not use the AI vaccine, Krishnan listed several of the questions such as, when will the product be available? Is there a risk of AI going into broilers as we go into the winter? Will this pressure us to act?
“Let’s not underestimate the economic and trade implications,” said Krishnan, what he called “the political aspects.” Will use of a vaccine result in trade restrictions? How does the issue get played out in the news? How does the consumer view the issue? What will the government do? How will pressure from retailers like Walmart affect vaccine use? He described the vaccination issue as “a jigsaw puzzle with so many uncertain parameters.”
Under a similar disease challenge in April 2013, Porcine Epidemic Diarrhea (PED) was identified in the United States; by September 2014, conditional vaccine licenses were being issued in the U.S. Everything happened rapidly, said Krishnan, fuelled by a commitment to U.S. pork producers and the veterinarians who support them to help contain an outbreak in 30 states that was responsible for the deaths of more than seven million piglets in the U.S..
What if their company goes down the wrong path? Krishnan admitted that sometimes a vaccine works in a test tube but falls apart in the real world; sometimes a disease doesn’t cause a problem, in which case the resources will be pulled back and re-invested.
With AI, are we headed in the right direction? Is it easier to cull the birds, clean up and move on? “That’s the million dollar question,” answered Krishnan. Thirty years from now we’ll have stories to tell.
January 18, 2016 - The United States Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS) has confirmed the pathogenicity of eight of the nine H7N8 avian influenza detections announced on January 16. The turkey flocks have been confirmed as low pathogenic avian influenza, with additional testing ongoing for the ninth flock.
These January 16 detections were identified as part of surveillance testing in the control area surrounding the initial highly pathogenic H7N8 avian influenza (HPAI) case in that state, identified on January 15.
“It appears that there was a low pathogenic virus circulating in the poultry population in this area, and that virus likely mutated into a highly pathogenic virus in one flock,” said Dr. John Clifford, USDA Chief Veterinarian. “Through cooperative industry, state and federal efforts, we were able to quickly identify and isolate the highly pathogenic case, and depopulate that flock. Together, we are also working to stop further spread of the LPAI virus, and will continue aggressive testing on additional premises within the expanded control area to ensure any additional cases of either HPAI or LPAI are identified and controlled quickly.”
APHIS continues to work closely with the Indiana State Board of Animal Health and the affected poultry industry on a joint incident response. State officials quarantined the additional affected premises and depopulation of birds has already begun. Depopulation prevents the spread of the disease. Birds from the flock will not enter the food system.
No human infections associated with avian influenza A viruses of this particular subtype (i.e., H7N8) have ever been reported. As a reminder, the proper handling and cooking of poultry and eggs to an internal temperature of 165 ˚F kills bacteria and viruses, including HPAI.
As part of existing avian influenza response plans, Federal and State partners continue to work on additional surveillance and testing in the nearby area. No new presumptive cases have been identified since January 16.
The rapid testing and response in this incident is the result of months of planning with local, state, federal and industry partners to ensure the most efficient and effective coordination. Since the previous HPAI detections in 2015, APHIS and its state and industry partners have learned valuable lessons to help implement stronger preparedness and response capabilities. In September, APHIS published a HPAI Preparedness and Response Plan that captures the results of this planning effort, organizing information on preparatory activities, policy decisions and updated strategy documents.
Despite routine utilization of standard vaccination protocols in broiler breeder and broiler flocks, outbreaks of diseases in broiler flocks still occur. However, limited data on pathogen prevalence and associated risk factors among commercial broiler flocks in Canada are available.
Dr. Michele Guerin, a Poultry Epidemiologist from the University of Guelph recently completed a comprehensive project that investigated the prevalence of nine viruses * and four bacteria of health significance for the Ontario broiler industry. The study included the associations of exposure to the pathogens with management and biosecurity practices, flock mortality, and condemnations.
“As a contribution to disease control initiatives, this study will enable producers to adopt better strategies to reduce the incidence of these pathogens within their flocks,” said Dr. Guerin in an interview.
Guerin’s team investigated 231 randomly selected Ontario broiler flocks and results showed frequent exposure to AAAV, ARV, CAV, pathogenic FAdV species, IBDV, Clostridium perfringens, and Enterococcus cecorum, and no exposure to, or low prevalence of, AEV, IBV, ILTV, NDV, Brachyspira spp., and Clostridium difficile.
Beyond prevalence, the genotypes of several of these pathogens were determined.
“Potentially pathogenic genotypes of FAdV, IBDV, and IBV were identified that can guide vaccine development and disease control efforts in Ontario,” she explains.
Although no specific management or biosecurity practice was identified as a predictor of all pathogens investigated, several factors were significantly associated with the prevalence of more than one pathogen (e.g. feed, barn and environmental conditions, hatchery, manure disposal, and antimicrobial use).
“Geographic and seasonal variation in the prevalence of a number of pathogens was evident,” Dr. Guerin indicated. “However no one district or season stood out as being a hot-spot or time period of high prevalence for all pathogens investigated.”
Of interest, a high proportion of Clostridium perfringens isolates were found to be resistant to antimicrobials commonly used in feed, and use of these antimicrobials was a risk factor in the development of resistance.
“Finding alternatives to the use of antimicrobials in the feed to prevent necrotic enteritis should continue to be a priority for the industry,” Dr. Guerin asserted.
Dr. Guerin highlights that of all the pathogens surveyed, only Clostridium difficile poses a potential risk of infection for humans via the food chain, and despite the fact that toxigenic strains were found among the isolates, the proportion of positive flocks was low.
This research was funded by the Animal Health Laboratory’s AHSI, Poultry Industry Council, OMAFRA- U of G Partnership, and Chicken Farmers of Ontario.
*Avian adeno-associated virus (AAAV), Avian encephalomyelitis virus (AEV), Avian reovirus (ARV), Chicken anemia virus (CAV), Fowl adenovirus (FAdV), Infectious bronchitis virus (IBV), Infectious bursal disease virus (IBDV), Infectious laryngotracheitis virus (ILTV), Newcastle disease virus (NDV).
Dr. Suresh Neethirajan and his team from the “BioNano Laboratory” of the University of Guelph have worked to develop a new detection system capable of detecting small amounts of avian influenza virus within minutes. It’s a diagnostic tool not only capable of detecting the virus rapidly on-site, but that will also enable field deployable, point-of-care diagnostic systems.
Influenza is one of the most common infectious diseases, resulting in up to half a million human deaths annually. Influenza A, a subtype of the virus associated with pandemics and causing most deaths, is further classified according to the properties of two viral surface proteins called hemagglutin (HA) and neuraminidase (NA). The H1N1 human-adapted strain of the virus caused up to 40 million human deaths in 1919 and the recently detected H5N1 avian influenza strain, commonly termed “bird flu”, has resulted in up to half a million human deaths since 2000.
“Considering the threat which avian influenza poses to human health and the growth of the agricultural sector, investing in disease control strategies is vital”, explains Dr. Suresh Neethirajan in describing the issue at hand. “Preventing the spread of the infection is the best way to keep the disease under control. Prevention in this case starts with effective surveillance.”
Dr. Neethirajan explains the current status of their findings in a report: “a novel sensing mechanism for quicker detection of avian influenza. Sensitivity of the sensing mechanism is possible for both H1N1-HA and H5N1-HA allowing the discrimination between avian and human influenza. This proves to be extremely valuable in the recent human influenza pandemic caused by poultry birds.
We have created a rapid animal health pen side diagnostic tool that only needs less volume of blood, less chemicals and less time compared to the currently used methods. The sensing mechanism and the technique have the potential to serve as a feasible and sensitive diagnostic tool for influenza virus detection and discrimination for poultry industries, with further improvement on the architectures”.
The developed sensing assay will aid not only the poultry industries, producers and farmers, but also the public. The technology under development will ultimately be deployed towards early diagnosis of avian influenza. The results from the proposed point of care test for early diagnosis will assist in identifying potential public health threats.
This project was funded by the Poultry Industry Council and the Turkey Farmers of Ontario.
April 15, 2015 - U.S. Department of Agriculture (USDA) scientists have developed an improved Newcastle disease virus (NDV) vaccine evaluation procedure that could be used to select better vaccines to treat the disease.
Newcastle disease, one of the most important poultry diseases worldwide, can cause severe illness in chickens and other birds. Severe, or virulent, strains rarely occur in poultry species in the United States, but they are regularly found in poultry in many foreign countries.
Available commercial NDV vaccines perform well in chickens infected with virulent NDV under experimental conditions. They also perform well under field conditions where virulent virus is not common. However, they often fail in countries where virulent viruses are endemic.At the Agricultural Research Service's (ARS) Southeast Poultry Research Laboratory (SEPRL) in Athens, Georgia, microbiologist Claudio Afonso and veterinary medical officer Patti Miller have updated the traditional vaccine evaluation method, which does not compare vaccines or take into account suboptimal field conditions.
Under perfect conditions, vaccines should work, but conditions are not always perfect in the field, according to Miller. Chickens sometimes get less than the required vaccine dose and don't always have the minimum amount of time required to develop an optimum immune response.
The improved vaccine-evaluation procedure compares vaccines made using genes from the same viral strain-or genotype-that the birds are exposed to in the field to vaccines made with a strain that differs from the virus birds are exposed to.
Using the improved procedure, scientists inoculated chickens with different vaccine doses before exposure to a high dose of virulent NDV. Birds given the genotype-matched vaccine had reduced viral shedding, superior immune responses, reduced clinical signs, and increased survival than the birds vaccinated with a different-genotype vaccine.
By using genotype-matched vaccines, viral shedding and death were significantly reduced.ARS is USDA's principal intramural scientific research agency, and this research supports the USDA priority of promoting international food security.
March 4, 2015 - Prairie Diagnostic Services Inc. will receive $549,278 from Ottawa for new equipment to "expand and modernize'" its testing efficiency. Brad Trost, MP for Saskatoon-Humboldt, said the funding will help veterinarians, livestock and feed producers and exporters to be able to better ensure Canada's food safety both domestically and abroad. He says the new equipment will help with bacteriology, toxicology, pathology and food testing. The Leader Post reports.
A number of poultry industry groups are using a less costly method to collect avian influenza virus samples, thanks to U.S. Department of Agriculture (USDA) scientists.
At the Agricultural Research Service’s (ARS) Southeast Poultry Research Laboratory (SEPRL) in Athens, Ga., scientists conduct studies not only to identify various avian influenza virus strains, but also to determine their origin and whether current tests and vaccines are effective against them. In addition, the scientists investigate the best methods for collecting virus samples from poultry for testing.
In the United States, all meat chickens and turkeys must be tested for avian influenza before processing. Sample collection is an important component of this process.
A certain number of swab samples, taken from inside the birds’ mouths, are needed per flock to get a reasonable virus sample, according to microbiologist Erica Spackman, who works in SEPRL’s Exotic and Emerging Avian Viral Diseases Research Unit. The current method used to determine if virus is present works well, but requires placing only one to five swab samples in a tube.
Spackman found that improvements could be made by switching the type of swab used and increasing the number or swabs in each tube.
“One of the most important variables is the number of swabs required—the sample size we take from inside the mouth of the chicken or turkey to see if the virus is there,” Spackman says. “We need to collect a certain number of swab samples per flock to get a reasonable virus sample.”
Swab samples are collected from the same flock and put into tubes for testing. Traditionally, each tube contains 1-5 swab samples. The idea was to determine whether more swab samples could be pooled together into a single tube without inhibiting or affecting the sensitivity of the test.
Spackman found that putting 1, 5, or 11 swab samples in the same tube did not affect testing. A similar experiment with Newcastle virus samples had the same results.
This research, which was published in BioMed Central Veterinary Research in 2013, supports the USDA’s priority of promoting international food security.
ARS is USDA’s principal intramural scientific research agency.
Today, two breeders dominate the international market for layers, broilers (90 per cent) and turkeys. As well, there are hardly any middle-level breeders left in Canada, and until recently, five Canadian institutions conducting agricultural research kept 38 populations of chickens and Japanese quail.
The Pacific Agri-Food Research Centre in Agassiz, B.C,, has recently terminated its poultry unit, including nine lines of chickens and nine lines of Japanese quail.
It is clear that avian researchers and the poultry industry have experienced a massive loss of genetic resources. Maintaining live flocks is impractical and very costly, and economical methods of preserving poultry genetics for future use are badly needed, as genetic resources continue to narrow.
In the recent past, the only effective method of conserving poultry germplasm has been in living animals. Alternative options have been attempted over the years, but results have not been very promising. Fertility obtained from cryopreserved chicken semen is unpredictable and the structure of the avian egg prevents its cryopreservation. Embryonic cells can be stored and used to generate germline chimeras (organisms with a mixture of cells from different embryos), but this requires complex procedures and results in very low efficiency. Over the past century, chicken ovarian transplantation has been attempted with limited success.
Successful development of techniques for cryopreservation and transplantation of ovaries and testicles of birds can provide the means of maintaining the genetic variation needed for full differentiation of markets for poultry meat and eggs. Dr. Fred Silversides, formerly of Agriculture and Agri-Food Canada, together with Drs. Yonghong Song (Dubai), Jianan Liu (USDA post-doctoral research fellow) and Kim Cheng (UBC), has been working on optimizing cryopreservation and transplantation of avian gonadal tissue.
The first step in this research, which was Dr. Jianan Liu’s PhD project, was aimed at simplifying the storage process for cryopreserved genetic material by using vitrification, which converts liquid to a glass-like substance instead of ice crystals, and has several advantages over slow-freezing procedures in preserving tissue.
A vitrification protocol was developed to preserve Japanese quail ovarian and testicular tissue, using cryoprotective agents and acupuncture needles to facilitate tissue handling. Rather than using cryovials typically used for cryopreservation, a simpler straw system was tested and found to be an ideal storage medium, as it has the advantage of fitting into existing systems for storage and transport.
Normal morphology of testicular tissue was observed after in ovo culture and live offspring were produced by performing surgical insemination directly into the hen’s oviduct with the extrusion of cryopreserved testicular tissue. Donor-derived offspring were also efficiently produced from cryopreserved and transplanted ovarian tissue.
Also, because gonadal transplantation is critical to functional recovery of cryopreserved tissue but can be limited by tissue rejection, the researchers used thymic tissue to improve the efficiency of immunological acceptance. Donor thymic tissue was implanted into recipient embryos, and gonadal tissue from the same donor was transplanted under the skin to the recipient after hatching. Transplant viability and histology were also examined.
It was found that thymic implantation might improve survival of gonadal transplants from chicken to chicken, but not transplants from quail to chickens. Investigations into avian ovarian transplantation led to intriguing additional observations: donor-derived offspring were produced from transplanted adult quail ovarian tissue, although delayed age at first egg and reduced reproductive longevity were observed with the transplants. As well, offspring with chimeric plumage coloration were produced from cryopreserved and transplanted chicken ovarian tissue, indicating chimeric folliculogenesis.
This project provides a successful model of cryobanking avian gonadal tissue using a simple vitrification method and suggests future directions in improving transplantation tolerance and using gonadal transplantation in avian research. This is good news for the poultry industry, as cryobanking of germplasm is both economical and ensures availability of genetic resources for years to come. To read more about this research project, please visit www.poultryindustrycouncil.ca.
The Poultry Industry Council congratulates Dr. Fred Silversides on his 2013 Poultry Science Association American Egg Board Research Award.
The American Egg Board Research Award is given to increase the interest in research pertaining to egg science technology or marketing that has a bearing on egg or spent hen utilization. The award is given to an author for a manuscript published in Poultry Science or The Journal of Applied Poultry Research during the preceding year.
Aug. 14, 2013 - A serology study in a Chinese province hit hardest by novel H7N9 influenza found evidence of asymptomatic or mild infections in poultry workers, further strengthening suspicions that poultry are the source of the outbreak.
The study focused on members of the general public, poultry workers, and patients with lab-confirmed H7N9 infections in Zhejiang province, which has recorded 45 cases during the outbreak thus far. The Chinese researchers published their findings in the Aug 9 early online edition of the Journal of Infectious Diseases. The full article can be purchased here.
They collected and analyzed serum samples, along with epidemiologic data, from 1,129 people from three Zhejiang cities in the province that had human H7N9 cases. The group also collected serum samples and nasal swabs from 396 people who had occupational exposure to poultry in districts where human cases had been found.
Among poultry workers, 6.3% had antibodies against the new H7N9 virus, based on hemagglutinin inhibition (HI) assay titers of 80 or greater. In contrast, the investigators found no evidence of antibodies in the general population.
No viral evidence was found in the workers' nasal swab samples.
The results weren't surprising, because a study more than a decade ago in poultry workers showed a similar seroprevalence to avian H7 subtypes, according to the report.
"Our data support the conclusion that H7N9 virus or a closely related virus is circulating in live poultry markets and that infected poultry is the principal sources for human infections," they wrote.
Serum findings in poultry workers also hint that subclinical infections occur. However, the researchers noted that an earlier study using blood samples collected from poultry workers in four provinces found no evidence of H7N9 exposure, suggesting that the workers in Zhejiang only recently developed the antibodies against the virus.
The team said it's possible that the H7N9 antibodies they detected in the poultry workers might reflect exposure to other similar H7 avian influenza viruses, including an H7N3 virus that affected ducks in the regions.
The lack of findings in the general population could signify that cross-species transmissions are recent and sporadic events, and the ability of H7N9 to spread between humans is so far limited, the team concluded.
China reports another H7N9 death
Meanwhile, a 61-year-old patient recently announced as Hebei province's first case died today, raising the number of deaths from the disease to 44, according to Xinhua, China's state news agency. The patient's illness was first announced in the middle of July.
Though the number of infections have tailed off in China, the country continues to report sporadic cases, the latest one a 51-year-old poultry worker from Guangdong province whose suspected infection was first reported on Aug 9.
China's National Health and Family Planning Commission has confirmed the woman's infection, according to a statement yesterday from the World Health Organization (WHO). Her illness raises the outbreak's total to 135 cases.
The woman got sick on Jul 27 and was hospitalized the following day. She is in critical condition.
So far there is no sign of sustained human-to-human transmission, the WHO said. At this point four patients sickened in the outbreak are still hospitalized, and 87 have been discharged, the agency added.
Aug. 7, 2013 - The first report of probable person to person transmission of the new avian influenza A (H7N9) virus in Eastern China has been published on bmj.com. The findings provide the strongest evidence yet of H7N9 transmission between humans, but the authors stress that its ability to transmit itself is "limited and non-sustainable."
The Avian influenza A (H7N9) virus was recently identified in Eastern China, and as of June 30, 2013, 133 cases have been reported, resulting in 43 deaths.
Most cases appear to have visited live poultry markets or had close contact with live poultry seven to 10 days before illness onset. Currently no definite evidence indicates sustained human-to-human transmission of the H7N9 virus, but the study reports a family cluster of two patients (father and daughter) with H7N9 virus infection in Eastern China in March 2013.
The first (index) patient – a 60 year old man – regularly visited a live poultry market and became ill five to six days after his last exposure to poultry. He was admitted to hospital on March 11.
When his symptoms became worse, he was transferred to the hospital's intensive care unit (ICU) on March 15. He was transferred to another ICU on March 18 and died of multi-organ failure on May 4th.
The second patient, his healthy 32 year old daughter, had no known exposure to live poultry before becoming sick. However, she provided direct and unprotected bedside care for her father in the hospital before his admission to intensive care.
She developed symptoms six days after her last contact with her father and was admitted to hospital on March 24. She was transferred to the ICU on March 28 and died of multi-organ failure on April 24.
Two almost genetically identical virus strains were isolated from each patient, suggesting transmission from father to daughter.
Forty-three close contacts of both cases were interviewed by public health officials and tested for influenza virus. Of these, one (a son in law who helped care for the father) had mild illness, but all contacts tested negative for H7N9 infection.
Environmental samples from poultry cages, water at two local poultry markets, and swans from the residential area, were also tested. One strain was isolated but was genetically different to the two strains isolated from the patients.
The researchers acknowledge some study limitations, but say that the most likely explanation for this family cluster of two cases with H7N9 infection is that the virus "transmitted directly from the index patient to his daughter." But they stress that "the virus has not gained the ability to transmit itself sustained from person to person efficiently."
They believe that the most likely source of infection for the index case was the live poultry market, and conclude: "To our best knowledge, this is the first report of probable transmissibility of the novel virus person to person with detailed epidemiological, clinical, and virological data. Our findings reinforce that the novel virus possesses the potential for pandemic spread."
So does this imply that H7N9 has come one step closer towards adapting fully to humans, ask James Rudge and Richard Coker from the London School of Hygiene and Tropical Medicine, based in Bangkok, in an accompanying editorial?
Probably not, they say. Limited transmission between humans "is not surprising, and does not necessarily indicate that the virus is on course to develop sustained transmission among humans."
Nevertheless, they point to several traits of H7N9 are of particular concern, and conclude that, while this study might not suggest that H7N9 is any closer to delivering the next pandemic, "it does provide a timely reminder of the need to remain extremely vigilant: the threat posed by H7N9 has by no means passed."
The authors also summarise their findings in a video abstract. Dr Zhou says that the reason for carrying out this study was because there was "no definite evidence to show that the novel virus can transmit person-to-person," plus she and her co-authors wanted to find out whether the novel avian influenza virus possesses the capability to transmit person-to-person. She concludes that "the infection of the daughter is likely to have resulted from her father during unprotected exposure" and suggest that the virus possesses the ability to transmit person-to-person in this cluster. She does add however that the infection was "limited and non-sustainable as there is no outbreak following the two cases."
For more information on the research, please see the video abstract provided by BMJ.com:
Management is key to antibiotic-free productionIn November 2016, poultry producers from around the world gathered…
Why is biosecurity so difficult?They’re an ancient foe, a worthy opponent. For over 300…
Heritage chicks available in AlbertaApril 4, 2017, Edmonton, Alta – The popular University of…
ILT Disease Advisory for Ontario's Dufferin CountyApril 17, 2017, Dufferin County, Ont. – On behalf of…
PIC Research DayWed May 10, 2017 @10:00AM - 04:00PM
Western Meeting of Poultry Clinicians and PathologistsWed May 17, 2017
B.C. Poultry SymposiumThu May 18, 2017
Turkey Academy 2017Thu Jun 01, 2017 @ 8:30AM - 02:30PM
Canadian Meat Council 97th Annual ConferenceMon Jun 05, 2017