H5N1

Eurosurveillance: Isolation of H5N6, H7N9, H9N2 from air at live poultry markets in China

Via Eurosurveillance: Isolation of H5N6, H7N9 and H9N2 avian influenza A viruses from air sampled at live poultry markets in China, 2014 and 2015. The abstract:

Zoonotic infections by avian influenza viruses occur at the human–poultry interface, but the modes of transmission have not been fully investigated. 

We assessed the potential for airborne and fomite transmission at live poultry markets in Guangzhou city and in Hong Kong Special Administrative Region (SAR), China, during 2014 and 2015. Viral genome and infectious avian influenza A viruses of H5N6, H7N9, and H9N2 subtypes were detected predominantly from particles larger or equal to 1 μm in diameter in the air sampled with cyclone-based bioaerosol samplers at the live poultry markets in Guangzhou. 

Influenza A(H9N2) viruses were ubiquitously isolated every month during the study period from air and environmental swabs, and different lineages of H9N2 virus were isolated from markets where chickens and minor land-based poultry were sold. 

The use of de-feathering devices increased the quantity of virus-laden airborne particles while market closure reduced the amount of such particles. The results highlight the possibility of airborne transmission of avian influenza viruses among poultry or from poultry to humans within such settings. 

This may explain epidemiological observations in which some patients with H7N9 infection reported being in markets but no direct contact with live poultry or poultry stalls.

CIDRAP news scan for May 23: Avian flu cases; pistachio Salmonella outbreak; flu antigenic mutations

Via CIDRAP: News Scan for May 23, 2016 | Avian flu cases; Pistachio Salmonella outbreak; Flu antigenic mutations. Excerpt:

Chinese officials reported another human case of H7N9 avian influenza, the second such infection in Hebei province in nearly 3 years, according to a post yesterday on Avian Flu Diary (AFD). Elsewhere, Egypt documented an H9 case in a toddler, according to a May 19 World Health Organization (WHO) report. 

The H7N9 case in China involved a 57-year-old man from Xinji city in Hebei. He experienced onset of headache and fever on May 10 and was hospitalized in Hengshui city on May 16, where he remains in serious condition. The patient is a farmer, and his close contacts are being monitored for signs of illness, AFD said. 

The infection is only the second H7N9 case in Hebei province since the virus emerged in China 4 years ago. Hebei's last H7N9 case occurred in July 2013, AFD said. 

The new case lifts the global H7N9 total to 789, according to a list maintained by FluTrackers, an infectious disease message board. 

Elsewhere, the WHO reported an H9 infection in an 18-month-old boy from Cairo governorate who was exposed to live poultry at a market. The boy developed symptoms on Apr 10 and is in good condition. Though this is not confirmed, his infection is likely due to H9N2, which causes mild illness, the WHO said. 

Globally, 28 cases of H9N2 have been reported, and the virus shows no evidence of human-to-human transmission, the WHO said.

Hong Kong: HKU breakthrough in fight against bird flu

When University of Hong Kong experts say something looks good, I believe them. Via The Standard, a March 17 report: HKU breakthrough in fight against bird flu.

University of Hong Kong scientists hope an experimental drug used for acute respiratory distress syndrome could better treat the dreaded bird flu H5N1 virus. 

The School of Public Health first discovered that H5N1 causes severe pneumonia by impairing proteins called sodium and chloride transporter molecules in the lungs that help draw fluid out of the organs. 

With the discovery of the mechanism of infection, the scientists have begun laboratory testing an experimental treatment for H5N1 using mesenchymal stromal cells. 

The bone marrow-derived stromal cells are already undergoing clinical trials for sepsis and acute respiratory distress syndrome in the United States. 

But no one has tested whether the same cells also could be effective against viral respiratory infections such as flu. 

The treatment strategy could also be used against other bird flu viruses, H7N9 and H9N2, as well as MERS and SARS coronaviruses, said the lead researcher, the school's assistant professor Michael Chan Chi-wai. 

Using laboratory mice, the 14-member team found that H5N1 infection impaired fluid clearance in the lungs' alveoli tiny sacs that allow oxygen and carbon dioxide to move between the lungs and bloodstream more than did seasonal virus. 

The infected cells release "soluble factors" that impair the alveolar sodium and chloride transporters, the team said. 

"Mesenchymal stromal cells prevented or reduced this effect in vitro and in vivo in H5N1-infected mice. These cells provide a potentially effective treatment for acute lung injury in severe influenza," the report concluded. 

Chan said: "We showed that when mice are infected with H5N1, it will inhibit the proteins and the mice developed edemas, lung infection and died. If we treat mice with mesenchymal stromal cells so that activity of sodium and chloride transporter proteins return back to normal, it resolved the edemas."

The study was published in PNAS, but I don't think it's online yet. If you know where the link is, please let me know and I'll update this post.

H5N1 in Egypt: 'Several hundred thousand' cases?

Via Emerging Infectious Diseases: Ahead of Print -Avian Influenza A(H5N1) Virus in Egypt. The abstract:

In Egypt, avian influenza A subtype H5N1 and H9N2 viruses are enzootic in poultry. The control plan devised by veterinary authorities in Egypt to prevent infections in poultry focused mainly on vaccination and ultimately failed. Recently, widespread H5N1 infections in poultry and a substantial increase in the number of human cases of H5N1 infection were observed. 

We summarize surveillance data from 2009 through 2014 and show that avian influenza viruses are established in poultry in Egypt and are continuously evolving genetically and antigenically. We also discuss the epidemiology of human infection with avian influenza in Egypt and describe how the true burden of disease is underestimated. We discuss the failures of relying on vaccinating poultry as the sole intervention tool. 

We conclude by highlighting the key components that need to be included in a new strategy to control avian influenza infections in poultry and humans in Egypt.

The startling conclusion: 

Results from a controlled, serologic cohort study of persons in Egypt exposed and not exposed to poultry estimated the seroprevalence of antibodies against H5N1 (titers >80) at 2%. If this seroprevalence were to be extrapolated to the entire poultry-exposed population in Egypt, the true number of infections would amount to several hundred thousand. These figures are even more striking when it comes to human infection with H9N2 viruses. The seroprevalence of H9N2 antibodies detected in the same cohort study ranged from 5.6% to 7.5%, whereas just 1 case of H9N2 infection was reported.

Novel H5N9 avian flu virus discovered in China

Via The Poultry Site: Novel Avian Flu Virus Discovered in China.

Chinese researchers who analysed influenza viruses from poultry in live-bird markets say they have discovered a novel H5N9 virus, which is a hybrid of various other avian influenza viruses. 

The hybrid received a highly pathogenic H5 gene from the H5N1 avian flu virus and an N9 gene from a human-infecting H7N9 virus, along with other elements. However, the virus only caused low mortality rates when tested on mice. 

The authors took samples in 2013 from seven chickens, a quail, and a duck at two live-bird markets in Hangzhou, a city in Zhejiang province, which were linked to outbreaks of human H7N9 cases. The report does not indicate that any of the birds were displaying symptoms of avian flu. 

The team isolated 13 viruses from the samples: 1 H5N1, 2 H5N9, 4 H9N2, and 6 H7N9. 

By sequencing the whole genomes of the two H5N9 isolates, the researchers determined that their hemagglutinin (H) protein matched that of a 2012 H5N1 isolate from Vietnam, while their neuraminidase (N) component derived from a human H7N9 isolate from Hangzhou. 

They also noted that the structure of the H cleavage site is characteristic of highly pathogenic viruses. The six internal genes resembled those of H5N1, H7N9, and H9N2 viruses. 

The pathogenicity of the novel virus in mammals was tested by exposing mice to various doses. Some mice exposed to the highest doses died, but mice receiving lower doses did not suffer from the disease, and the authors concluded that the virus causes low mortality in mice. They also found that the virus didn't spread from infected mice to others placed with them. 

The team determined that the novel H5N9 virus prefers avian-type cell receptors, known as alpha2,3 sialic acid, rather than the human-type receptor, called alpha2,6. They said this may explain why the virus caused low mortality in mice. 

The report says a highly pathogenic H5N9 virus was found in turkeys in Ontario in 1966, and low-pathogenic H5N9 strains have been found in mallards, northern pintails, and occasionally chickens in the past few decades. But the novel virus is "totally different" from those, the authors concluded. 

"This newly isolated H5N9 virus is a highly pathogenic reassortant virus originating from H5N1, H7N9, and H9N2 subtypes," they wrote. "Live bird markets represent a potential transmission risk to public health and the poultry industry."

The original report is here.

CIDRAP: More avian flu in US birds; Asian H9N2 found in Alaska

Robert Roos at CIDRAP writes: More avian flu in US birds; Asian H9N2 found in Alaska. Excerpt:

The highly pathogenic avian influenza (HPAI) viruses H5N2 and H5N8 are continuing to turn up in US birds, with the latest detections in Montana and California, while an Asian H9N2 virus was found in wild birds in western Alaska, according to recent reports. 

In Montana, the HPAI H5N2 virus was found in a captive gyrfalcon in Columbia Falls in the northwestern part of the state, the Montana Department of Livestock reported in a statement yesterday. The report apparently is the first discovery of the strain in the state. 

The agency said the falcon died of unknown causes and was sent to a state wildlife lab in Bozeman for analysis. The H5N2 finding was later confirmed by a US Department of Agriculture (USDA) lab in Ames, Iowa. 

The bird was owned by a falconer who has about 50 other captive birds, according to a story today in the newspaper The Missoulian. Martin Zaluski, DVM, state veterinarian, said the rest of the birds would be tested for the virus. It appears that the dead falcon was exposed to the disease through contact with a harvested wild duck, he reported. 

The H5N2 virus caused outbreaks in March on several commercial turkey farms in Minnesota, Missouri, and Arkansas, as well as a backyard flock in Kansas. 

H5N8 in wild California ducks 

Meanwhile in California, the HPAI H5N8 virus was found in wild wigeons in two counties, Colusa and Solano, says a report that the USDA filed yesterday with the World Organization for Animal Health (OIE). The report did not specify how many wigeons were infected. Colusa is in the Central Valley northwest of Sacramento, while Solano is in the San Francisco region. 

The H5N8 strain, which originated in Asia, made its first known US appearance in a captive gyrfalcon in Washington state last December. It has since been found in a number of wild birds in California, Oregon, Washington, Idaho, and Nevada, in commercial turkeys and chickens in California, and in backyard poultry in Oregon. 

H9N2 in Alaska 

In other news, researchers with the US Geological Survey reported that they found H9N2 viruses in two wild birds in Alaska that match strains from China and South Korea. 

The viruses were found in testing of samples from 2,924 wild birds at the Izembek National Wildlife Refuge in western Alaska, the researchers reported on Mar 30 in Virology. A fecal sample from an emperor goose and a cloacal sample from a northern pintail duck, both collected in September 2011, yielded the isolates. 

All eight gene segments of the two viruses were more than 99.4% the same as recent H9N2 isolates from Lake Dongting, China, and Cheon-su Bay, South Korea, the researchers wrote.

Will Egypt unleash another flu pandemic?

Via Nature Middle East, the most informative story I've seen so far on the current Egyptian H5N1 outbreak: Will Egypt unleash another flu pandemic? Excerpt:

Hardly a week has passed in 2015 without new cases of human H5N1 influenza infection occuring in Egypt. With at least 46 cases and 13 fatalities in just two months, the number is higher than those reported in the whole of 2014.  

So, what is the status of avian flu in Egypt? 

The story of H5N1 influenza in Egypt dates back to early 2006, when the first human case was detected in Qalyubia governorate shortly after the first outbreak that affected domestic poultry. 

Generally, Influenza viruses are a large group of pathogens that peacefully inhabit the guts of wild migratory waterfowl. These viruses are continuously evolving and occasionally acquire certain genetic changes that enable them to switch hosts and gain a foothold in domestic birds and mammals. Some are endowed with the right key combinations for decoding human cells, causing infections that can vary from isolated and mild disease to devastating pandemics.  

In case of Egypt’s first outbreak, it is believed that this H5N1 virus was a passenger on-board of a wild migratory duck1 visiting Damietta, most likely from Eurasia. Once in Egypt, the newly-arrived H5N1 virus found a hospitable host that allowed it to spread and evolve into a genetically distinct group of “naturalised” viruses. The disease was declared endemic in 2008, and after this recent surge of human cases, Egypt now has the highest number of confirmed human H5N1 cases worldwide.  

Another important subtype, known as H9N2, was reported to co-circulate2 with H5N1 in chickens, with evidence of human exposure3 and a recent case of a boy in Aswan. 

Fortunately, so far, transmission of H5N1 viruses from chickens to humans was very inefficient and no sustained human-to-human transmission has been detected. If these H5N1 viruses becoming human-adapted, and with the current volume of air passengers, an isolated outbreak could turn into a pandemic in no time.  

Pandemics don’t just cause deaths, which we know through modeling studies will be highest in developing countries, but have hefty economic tolls. A recent PNAS study4 has estimated the cost of an influenza pandemic to be somewhere between $374 billion to $7.3 trillion depending on its severity.

Coston on H9N2 and H5N1 in Egypt

At his blog Avian Flu Diary, Mike Coston has an important post: An H9N2 Infection In Egypt & Updated H5N1 Count – FAO/EMPRES. H9N2 is a rare infection in humans, and this appears to be the first Egyptian case. He's also reporting an update on Egyptian H5N1 cases.

CIDRAP: Two new H7N9 cases as experts suggest H9N2 control

Via CIDRAP, a report by Lisa Schnirring: Two new H7N9 cases as experts suggest H9N2 control. Click through for the full report and many links. Excerpt:

Two more H7N9 influenza cases were reported in China today, including the first one from Zhejiang province in 2 weeks, as health groups weighed in with risk assessment updates and experts from China suggested a new way to get a jump on H7N9 and other novel viruses. 

The newly confirmed infection from Zhejiang province, which last reported a case on Feb 12, involves a 2-year-old girl who is hospitalized with a mild illness, according to a provincial health department statement translated and posted by FluTrackers, an infectious disease news message board. Zhejiang province has the most H7N9 cases of any in China and has played a pivotal role in both outbreak waves. 

The other new case involves a 65-year-old woman from Guangdong province who is hospitalized in critical condition, according to an official statement translated by FluTrackers. 

The new cases lift the two-wave H7N9 outbreak total to 373, with 114 as the unofficial number of deaths. So far 237 illnesses have been detected in the outbreak's second wave, which began in October, compared with 136 in the first wave last spring. 

Risk assessment updates 

In other developments, the European Centre for Disease Prevention and Control (ECDC) and the Public Health Agency of Canada (PHAC) addressed the H7N9 threat in separate risk assessments. 

The ECDC's assessment came in a broader risk assessment of human avian influenza A infection in China, dated Feb 24. The PHAC posted its updated H7N9 risk assessment today. 

The ECDC assessment summarized H7N9 events as of Feb 18, and since then, cases have continued to taper off. However, it said the brisk pace of human infections that marked the second wave might point to a larger wild or domestic bird reservoir, an increase in the number of exposed people, increased transmissibility of the virus, a seasonal pattern, or a combination of factors. 

Meanwhile, the PHAC risk assessment update covers H7N9 developments in China through yesterday. The agency noted that poultry and environmental samples have been found in all areas that reported human cases, except for Jilin province and Beijing. 

The PHAC noted that, in the second wave, cases appear to be less skewed toward older adults, though more infections continue to be detected in males. Seven pediatric cases were reported in January, three of which involved mild illnesses, and so far no unusual clinical presentations have been reported, the agency said.

So far, the virus doesn't spread easily among people, though limited person-to-person transmission may occur when there is close contact, the update noted. The H7N9 virus bears close watching, though, because less severe cases have been seen in influenza-like illness surveillance, and the PHAC said it expects more cases to be reported as the flu season progresses.

Eurosurveillance: Possible pandemic threat from reassortment of H7N9, H9N2 viruses

Thanks to Greg Folkers for sending the link to this February 13 rapid communication in Eurosurveillance: Possible pandemic threat from new reassortment of influenza A(H7N9) virus in China. Rather than provide the brief abstract, here's the discussion:

Our analysis revealed dynamic reassortments between influenza A(H7N9) and A(H9N2) viruses since the outbreak of A(H7N9) virus infection in March 2013. 

To some extent, the continuous transmission of H7N9 in Chinese poultry has led to increasing diversity and new reassortment of A(H7N9) with local A(H9N2) strains. Our findings suggest that the re-emerged H7N9 infections may be triggered by new reassortment strains, such as those in the Guangdong/Hong Kong transmission of Cluster 3. 

In this regard, these infections may have implications for the traditional strategies of drug and vaccine development targeted against HA and NA genes [15].In particular, the new reassortments generated by A(H7N9) and local A(H9N2) strains may produce avian influenza virus strains that are more adaptive and have a higher pathogenicity in humans [16], emphasising the importance of continuously monitoring the A(H7N9) epidemic. 

To date, 127 cases of A(H7N9) virus infections have been reported in January 2014, almost the same number as reported in the spring of 2013 (n=133) [5,6]. Notably, Zhejiang and Guangdong provinces and the Shanghai metropolitan area, where new reassortment of A(H7N9) strains is being identified, have been the worst affected regions in China in 2014 [1,17,18]. 

Although the case-fatality rate in January 2014 (24%, 31/127) is not higher than that seen in the spring of 2013 (29%, 39/133) [5,6], the rapidly increasing number of cases of A(H7N9) virus infection in these three regions may raise concerns as to whether there is an  association between circulation of the new A(H7N9) reassortment strains identified and accelerated transmission of A(H7N9) virus in humans. 

Therefore, it is of the utmost importance to monitor the risk of a potential pandemic initiated by various influenza virus strains.