Saturday, September 14, 2013

Risk of #MERS persists in Europe, ECDC says

September 13, 2013

Europe faces a continuing risk of Middle East respiratory syndrome coronavirus (MERS-CoV) cases, given the ongoing detection of cases in the Middle East, the European Centre for Disease Prevention and Control (ECDC) said in a short update on the topic today.

"Surveillance for cases is essential, particularly with expected increased travel to Saudi Arabia for the Hajj in October," the ECDC said in this week's Communicable Disease Threats Report for Sep 8 through 14.

The ECDC put the total number of MERS-CoV cases at 132, with 57 deaths. The agency reported 108 cases (both symptomatic and asymptomatic) with 47 deaths in Saudi Arabia, which differs from Saudi Arabia's own posted count of 104 cases and 47 deaths.

"The reason for the discrepancy between the number of cases reported for Saudi Arabia here and in the official Saudi Ministry of Health [MOH] website area is unclear and is being investigated," the ECDC said.

The ECDC global case count of 132 also exceeds the 130 cases listed here 2 days ago in the wake of the latest Saudi Arabian reports of a total of eight new cases. The World Health Organization has not issued an update on MERS-CoV cases since Sep 7.

Continued:  http://www.cidrap.umn.edu/news-perspective/2013/09/news-scan-sep-13-2013

H7N9 studies flesh out infectivity patterns in humans, pigs

[editing is mine]
Lisa Schnirring | Staff Writer | CIDRAP News  |
Sep 13, 2013
Researchers looking for molecular clues to help global health officials assess the risk from the new H7N9 virus in China reported this week that it is adept at attaching to human lower and upper respiratory tract cells and that it replicates efficiently in swine airway tissues.
In the first study, researchers from Erasmus University Medical Centre in the Netherlands explored airway attachment patterns of two genetically engineered H7 viruses that contained the hemagglutinin of either a Shanghai or Anhui H7N9 strain. They published their findings yesterday in the October issue of the American Journal of Pathology, published by Elsevier.

They used histochemical analysis to examine the patterns of attachment to different types of human airway tissues, and they compared patterns with those seen in other flu viruses that infect humans to different degrees, including H3N2, 2009 H1N1, and H5N1.

Similar to other avian influenza viruses, H7N9 attached more strongly to tissues in the lower than the upper airway, the authors found. But unlike other avian flu viruses, H7N9 had abundant attachments to epithelial cells in the bronchioles and alveoli and attached to a broader range of cell types.

Thijs Kuiken, DVM, PhD, said in an Elsevier press release, “These characteristics fit with increased virulence of these emerging avian H7 viruses compared to that of human influenza viruses.”

Another key finding from the experiments was more concentrated attachment of H7N9 viruses in ciliated cells in the nasal concha, trachea, and bronchi, which hint at the potential for efficient transmission in humans. However, Kuiken said the mainly sporadic pattern of H7N9 infections suggests that the virus hasn’t acquired all the properties it needs for efficient transmission among humans.

Continued:  http://www.cidrap.umn.edu/news-perspective/2013/09/h7n9-studies-flesh-out-infectivity-patterns-humans-pigs

 

IAEA and FAO Help Member States Detect Deadly Avian Influenza

September 13, 2013
A deadly form of "bird 'flu'", the H7N9 Avian Influenza A virus, was detected in four provinces of eastern China, where it has infected 135 people, and 44 of the infected individuals have died in the course of the past five months. These incidents are of particular importance, since it is the first time that this subtype of the Avian Influenza A virus has been verifiably transmitted from infected poultry to humans. The public health risk remains low at present. No cases of poultry or human infection from this novel H7N9 subtype have yet been reported outside China. The virus is classified as "low pathogenic", which means that the infected birds appear healthy although they carry the H7N9 virus and are thus a potential threat to human health.

"Bird Flu" is caused by a virus present among wild birds. Usually, wild birds, resistant to the disease, carry and secrete the virus, transmitting it to domesticated birds, such as chicken, duck, and turkey, which are susceptible to infection and can become sick and die. In the case of Avian Influenza H7N9, both nuclear and nuclear related technologies play a critical role in detecting and analysing the virus. Gerrit Viljoen, Head of the Animal Production and Health Section of the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, explained that "he most sensitive and cost effective pathogen detection and characterization applications require radioisotopes. Nuclear and nuclear related applications, together with the irradiation of harmful pathogens, are essential tools in any diagnostic veterinary laboratory."

To help IAEA Member States respond effectively to the emergence of this new avian influenza virus, Adama Diallo, Head of the Joint FAO-IAEA Division's Animal Production and Health Laboratory said, "We develop, evaluate, validate and disseminate guidelines, procedures and SOPs to Member States and follow this with individual and group training. We are conducting two training courses on the serological and molecular detection of H7N9 in order to contribute to the early detection of this virus and early reaction capabilities in Member States."

Continued:  http://www.iaea.org/newscenter/news/2013/influenza.html

Friday, September 13, 2013

Natural Human Interferon (Alpha-n3) is Active Against Both Wild-Type and Oseltamivir Resistant Avian-Origin Influenza A (H7N9) Virus

PHILADELPHIA, Sept. 12, 2013 (GLOBE NEWSWIRE) -- Hemispherx Biopharma (NYSE MKT:HEB) announced that at the 53rd annual meeting of Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in Denver, Colorado during September 9-13, 2013, that William Mitchell, MD, Ph.D., Professor Pathology, Microbiology, and Immunology, Vanderbilt University, presented the results of a study of Hemispherx product, Alferon N Injection(R), the only multi-species, natural interferon approved in the U.S. for the treatment of human refractory HPV genital warts, against wild type and oseltamivir (Tamiflu)-resistant H7N9 influenza virus.

The increasing prevalence of oseltamivir-resistant Influenza A Virus, particularly against H7N9, has been widely reported and is due in large part to the fact that just a single-step mutation in this genetically unstable virus makes it resistant to oseltamivir. Dr. Mitchell, who is member of the Board of Directors of Hemispherx, discussed new experiments on the inhibition of Tamiflu(R)-resistant H7N9 virus by Alferon N Injection(R).

These experiments were conducted at Kansas State University by Professor Juergen Richt, DVM, Ph.D., Director of the U.S. Department of Homeland Security Center of Excellence for Emerging and Zoonotic Animal Diseases (CEEZAD), Regents Distinguished Professor of Veterinary Medicine at Kansas State University and an Eminent Scholar of Kansas Bioscience Association (KBA) along with his staff.

Continued:  http://finance.yahoo.com/news/natural-human-interferon-alpha-n3-120000949.html

Visterra Shows Neutralization of H5N1 & H7N7 in Preclinical Results

September 12, 2013

Visterra Announces an Oral Presentation of VIS410 Data that Showed Neutralization of H5 and H7 Influenza Strains with Pandemic Potential Preclinical results presented at ICAAC 2013 demonstrated the ability of VIS410 to neutralize influenza strains with pandemic potential, H5N1 and H7N9 VIS410, a novel engineered human antibody against seasonal and pandemic flu, is advancing to the clinic in 2014

http://ca.finance.yahoo.com/news/visterra-announces-oral-presentation-vis410-230000576.html

Thursday, September 12, 2013

#MERS #Coronavirus Saudi Arabia MOH Update September 11, 2013

September 11, 2013
Translation

In the framework of Investigation epidemiological and continuous follow-up carried out by the Ministry of Health for HIV (Corona) that causes AIDS Middle East respiratory MERS-COV Ministry announces the registration of four cases of HIV infection in Riyadh, the first resident at the age of 51 years, mixing with the confirmed cases, and in stable condition.

 The second case is a resident working in the health sector at the age of 47 years, and developed symptoms of a minor, and the third case of a resident at the age of 39 years working in the health sector and developed symptoms of minor Also, The fourth case is a resident working in the health sector at the age of 38 years, all of whom Mkhalton confirmed cases and health status is stable and thankfully.

http://www.moh.gov.sa/CoronaNew/PressReleases/Pages/MediaStatement-2013-09-11-001.aspx

Eight new Saudi cases push global MERS total to 130


  | 
Sep 11, 2013


Saudi Arabia's health ministry today and yesterday announced eight new Middle East respiratory syndrome (MERS) cases, all of which involved contact with previously confirmed cases, including four possible healthcare exposures.
The patients are all younger or middle-aged adults from Riyadh and Medina, and most have mild infections or are asymptomatic, the Saudi Ministry of Health (MOH) said. The new detections lift the unofficial global total to 130 cases, of which 57 have been fatal.
Three of the four cases reported yesterday were asymptomatic: a 22-year-old man from Medina, a 24-year-old man who works in a health setting in Medina, and a 60-year-old man from Riyadh. The other patient is a 47-year-old man from Riyadh who is in stable condition, according to the MOH.
Of the four MERS cases reported today, all were reported from Riyadh, and three involve healthcare workers: a 47-year-old woman who had mild symptoms, a 39-year-old woman who had mild symptoms, and a 38-year-old man whose health status is stable, the MOH said. The fourth patient is a 51-year-old woman who is also in stable condition.
The newly announced cases follow closely on the heels of eight other cases that the health ministry announced on Sep 7 and Sep 8. Three of those infections were fatal.
The World Health Organization, which has not issued a MERS update since Sep 7, lists 114 global cases, 54 of which were fatal. That total does not include the 16 most recent Saudi cases.
Marc Sprenger, MD, PhD, director of the European Centre for Disease Prevention and Control (ECDC) told CIDRAP News that his agency continues to collect and analyze data about new cases and research findings to update its risk assessments. So far the ECDC views the pandemic potential as low and well below the epidemic threshold. He noted that one of the biggest questions is how humans are become infected with MERS.
Transmission patterns in Saudi Arabia, with many sporadic cases distributed over a large geographic area, point to infrequent introductions of the virus from a continuous nonhuman source, Sprenger said. "But unrecognized circulation among humans cannot be ruled out."
Zeroing in on the source of virus transmission is key to formulating guidance on how to reduce the risk of exposure and further spread of MERS, Sprenger said.
Yesterday the ECDC weighed in on a study published last week that found more evidence that camels in the Middle East have been exposed to MERS coronavirus (MERS-CoV) or a close relative. In two sets of tests, dromedary camels in Egypt had high antibody titers to MERS-CoV, but tests of humans, water buffaloes, cows, and other domestic animals in Egypt and Hong Kong found no such antibodies.
In a statement the ECDC said the new findings are in line with earlier findings of high titers in dromedary camels from Oman. The new data lead to the assumption that the animals can be infected with a MERS-CoV–like virus that is probably circulating at high levels among camels in Northern Africa and the Arabian Peninsula.
"The serological evidence is clear, but we have yet to see any direct detection or genetic characterization of the responsible virus in the dromedaries," the ECDC said.
The study's human serology findings, based on samples used in a community-based flu study in Egypt, didn't include any information on risk factors, such as close contact with or handling dromedaries, the ECDC noted. It added that more research is needed to determine if camels are the source of MERS-CoV in humans or are incidentally infected.

 http://www.cidrap.umn.edu/news-perspective/2013/09/eight-new-saudi-cases-push-global-mers-total-130

#MERS #Coronavirus Saudi Arabia City Adm. Statement Denies Spread in Military Hospital

Riyadh, Saudi United (CNN) - issued a "city of Prince Sultan Military Medical" in Saudi Arabia, a statement denied that the virus Corona has spread in deferred from the emergency department where, also denied the death of a nurse Saudi Arabia due to infection, but confirmed that five people inside who "had contact" cases have already greeted the city.
The city administration said in a statement: "What to ask about this topic is not based on true scientific reference as accurate as it is properly the death of a Saudi nurse or her." She added that "fact" is in front of the city medical cases of HIV infection moved them from outside the city medical and had been dealt with "by preventive measures."
He said the city administration in a statement: "She died one of those cases had already been announced and died another case, the presence of a companion virus disease led to her death."
However, the city continued to say that it deliberately, according to the directives of the World Health Organization and the instructions of the Ministry of Health to conduct a survey and detection of Mkhaltin of cases of practitioners, health workers and patients numbered nearly 300 people, was the discovery of five cases, were also receiving two additional headquarters of residence, have no relationship Previous cases in the city.
 She said the Medical City in a statement that most of those "in the improvement in symptoms and receive medical care," but pointed out that they received during the past year 15 cases died four of them, whereas converged five cases of healing, and the remaining six cases under medical care, and concluded by stressing that the situation the city's public "very reassuring and there is nothing to worry about."
It is noteworthy that Saudi Arabia has seen since the start of the spread of the virus, which infects the respiratory tract and the death of 43 cases due to the injury, noting that the Kingdom accounts for more than eighty percent of the cases detected, no precise information on the spread of the virus around the world due to the difficulty in determining the number of persons who have been cases of medium infection, or they do not have signs of the disease despite the injury.
It is noteworthy that the "City of Prince Sultan Military Medical" Riyadh-based and includes three military hospitals where more than 900 beds and generalized more than seven thousand people of different nationalities, and also many of the clinics and hospital departments.

Wednesday, September 11, 2013

MERS Mounts Up

[I'll adjust my total to reflect Flu Tracker's.  I have way too much going on in my life right now, to keep correct count of MERS cases.]
September 11, 2013
In a strange coincidence of numerals, the 4th Middle East respiratory syndrome coronavirus (MERS-CoV) report in a row from the Ministry of Health (MOH) of the Kingdom of Saudi Arabia (KSA) contains very little on 4 cases

I use below, the FluTracker's (FT) case numbering scheme because frankly, they produce the only numbering schemes for tracking cases of new or returning infectious disease that are systematic, reliable and worthy of our trust

It should form the basis for a worldwide numbering system for infectious disease outbreaks because it is also freely and publicly available such that any potential manuscript author can easily check it before submitting a research paper and then we could all know which case is being discussed. And by "we" I mean fellow researchers, not just interested parties. 

The KSA MOH could consider running their own table of data akin to that of FluTrackers, but augmented and using an adapted version of Crawford Killian's wishlist to the MOH. Each (deidentified) case entry should include the following headings along the top row, filled out if and as they become relevant:
  1. A unique, continuous identifying code specific to this emerging virus
  2. Sex
  3. Age
  4. Occupation
  5. Co-morbidities
  6. Date of illness onset
  7. Town of illness onset
  8. Town of acquisition acquisition
  9. Date of hospitalisation
  10. Type of laboratory testing
  11. Date of laboratory confirmation
  12. Date of death
  13. Date of release from hospital
  14. Treatments/management
  15. Town of treatment
  16. Relationships to any other cases
Today's MERS-CoV cases are mostly asymptomatic. These cases are announced amid rumours of larger case numbers being tested, panic in hospitals over potential MERS cases, frustration from within KSA over the MOH's poor performance, and of the KSA cracking down on healthcare workers passing on rumours.

Today we have:

  1. FT#125: 22-year old asymptomatic male, citizen of Madinha (Medina), contact of another confirmed case (we shall call him Mr/Mrs/Ms/Dr X)
  2. FT#126: 24-year old asymptomatic male healthcare worker in Madinha
  3. FT#127: 60-year old asymptomatic male citizen of Riyadh, contact of another case (also unknown)
  4. FT#128: 47-year old male citizen of Riyadh, contact of another unknown case, symptomatic but stable

This brings the tally to 128 with 57 deaths (proportion of fatal cases, PFC, at 45%). Where data for sex exists, males comprise 63% of cases and 74% of deaths in people confirmed as positive for MERS-CoV. 82% of cases come from the KSA and, if counting back to the retrospectively identified cases from Jordan, we take the first week of disease associated with MERS-CoV infection as that beginning 19-Mar-=2013, then we are in 78th week of MER. 

http://virologydownunder.blogspot.com/2013/09/mers-mounts-up.html

#MERS #Coronavirus KSA: Sources: 10 new infections "Corona" HIV deaths in Riyadh

[Same story as previous post, but better read]
9/11/13 - Translation/Excerpt


Find rebounds
  informed sources record the number of infections Coruna in the city of Prince Sultan Military Medical in the capital Riyadh, an estimated ten cases.Sources said the "economic", said that among the injured doctor esoteric Saudi recent graduate Enter intensive care in the hospital, although there a number of cases still is among the suspected cases, in addition to record the status of the death of a nurse from sexual Filipino. comes amid silence by officials of the hospital, where I called the "economic" a number of them to clarify the matter, but attempts met with no response or apology and a promise to issue a statement demonstration during the coming period, without specifying a specific date. The sources pointed out that there are a number of actions taken by the management of the hospital to prevent the transmission of infection among inpatients and staff of the hospital and dismissal, noting that there استنفارا medically and meetings between the leaders until the preparation of the news. explained that the spread of the news of the existence of injuries between employees of the hospital raised the panic many of the reviewers, which led to their absence from attending appointments during the past two days. comes amid Declaration and Ministry of Health number of deaths virus Corona, within the work of continuous monitoring 

...continued:  http://www.najdnews.com/news-action-show-id-15615.htm

#MERS #Coronavirus Saudi Arabia - Estimate 10 Suspected in Hospital & Death of Nurse

Amid the silence of administration .. Sources for "economic

 

Deaths and 10 injuries uncertain 'Corona' in a hospital in Riyadh


September 11, 2013
Translation


Confirmed for "economic" informed sources record the number of HIV infections in the city of Corona military medical Prince Sultan in the capital Riyadh, an estimated ten cases. 
The sources said that among the injured doctor esoteric Saudis, a recent graduate, enter the intensive care unit at the hospital, although there are a number of cases still is among the suspected cases, in addition to recording the event of the death of a nurse from the Philippine citizenship.
This comes amid silence by officials of the hospital, where he contacted the "economic" a number of them to clarify the matter, but attempts met with no reply or an apology and promise to issue a statement demonstration during the coming period, without setting a specific date.
The sources pointed out that there are a number of actions taken by the management of the hospital to prevent the transmission of infection among inpatients and employees of the hospital and dismissal, noting that there are medically استنفارا and meetings between the leaders until the preparation of the news.
She explained that the spread of the news of the existence of injuries among the employees of the hospital sparked panic many of the reviewers, which led to their absence from attending appointments during the past two days.
This comes amid Declaration and the Ministry of Health in a number of deaths virus Corona, within the work of continuous monitoring and investigation carried out by the ministry for the virus Corona new virus that causes AIDS Middle East respiratory MERS-COV, as announced in a statement yesterday, for the registration of four new cases of the virus, the first a citizen in Medina at the age of 22 years, Mkhalta to certain infected with the virus, and did not showing Oaradalmred.
The second is a citizen at the age of 24 years, working in the health sector in Medina, too, as well as not showing any symptoms, and the third case of a citizen at the age of 60 years in Riyadh, Mkhalta case-infected uncertain, did not show symptoms of the disease as well, and was The fourth case of a 70-year-old citizen also in Riyadh, mixer case of infected uncertain, and his condition is stable.
It was a few days ago announced record two deaths virus, the first of a resident in the area of ​​Medina at the age of 56 years, and works in the health sector, and the second of a citizen in the area of ​​Riyadh at the age of 53 years suffering from chronic diseases, multiple, also announced record two cases the first citizen of the 18-year-old, and the other for three-year-old girl, and attributed the to مخالطتهما the cause of confirmed cases in the Batin area, pointing out that he did not show them any symptoms and in good health condition.
Thus an infected cases at the level of Saudi Arabia since the emergence of the disease hundred cases, of whom 47 died, according to the website of the Ministry of Health.
According to the outcome of the recent World Health Organization issued on 30 August, the death of 50 people out of 108 confirmed cases in the world, from HIV Corona, which leads to respiratory problems and renal insufficiency fast, and Saudi Arabia is the country most affected by it - according to the "French" .
The new virus, which belongs defined by the World Health Organization as "the Middle East respiratory syndrome," "Mirs" to the viruses that faction led to the severe acute respiratory syndrome "SARS", which led to the deaths of about 800 people around the world in 2003.

#H7N7 Italy - Third case of human infection. To date six outbreaks in Emilia-Romagna

September 11, 2013
Excerpt - Translation

Third case of human infection of avian influenza in Emilia-Romagna. The confirmation came yesterday afternoon, Tuesday 10 September, the Institute of Health. It is an operator - dependent of the cooperative engaged in felling operations - which had tested positive for the tests performed at St. Orsola in Bologna.
Again, like the previous two, the worker was subjected to isolation at home and were supplied hygienic to follow and is in active surveillance until clinical recovery. Until now, there are three cases occurred and relate to workers.
For 59 workers exposed in the first 4 farms , prior to detection of outbreaks has ended health surveillance . Aworker of the fifth outbreak (the brooding of Mordano ) is now in active surveillance by public health professionals, as well as family members of 6 cases or suspected . They are also in active monitoring 10 people for the outbreak of rural Bondeno (Ferrara).
For all other workers involved (about 300) - however busy with various tasks and duration in the monitoring of outbreaks - there is a specific health surveillance 
The Regional Director for Health Policies, Carlo Lusenti made ​​the point - during the session of the Legislative Assembly of September 10 - the epidemic of bird flu that has affected several farms in Emilia-Romagna.

ProMED: Avian influenza, human (114): China (H7N9) receptor properties

Archive Number: 20130910.1935545
Published Date: 2013-09-10 17:54:22
Subject: PRO/AH/EDR> Avian influenza, human (114): China (H7N9) receptor properties


[1]  
Date: Tue 10 Sep 2013
Source: News Medical [edited]
http://www.news-medical.net/news/20130910/Emerging-H7N9-virus-has-potential-to-cause-a-pandemic.aspx


A new study has found that the novel avian-origin H7N9 influenza A virus, which has recently emerged in humans, attaches moderately or abundantly to the epithelium of both the upper and lower respiratory tracts. This pattern has not been observed before for other avian influenza A viruses. The report, published in the October 2013 issue of The American Journal of Pathology, suggests that the emerging H7N9 virus has the potential to cause a pandemic, since it may transmit efficiently in humans and cause severe pneumonia.

The 1st report of infections of humans with the influenza A virus of the subtype H7N9 surfaced in March 2013. Three patients from eastern China developed severe pneumonia and acute respiratory distress syndrome and died as a result. By 30 May 2013, the H7N9 infection was confirmed in 132 patients from China and Taiwan, 37 of whom died, according to the World Health Organization. Infected poultry were thought to be the source of the virus.

In the current study, investigators focused on the virus' pattern of attachment in order to assess its potential transmissibility and virulence. "Abundant virus attachment to the human upper respiratory tract correlates with efficient transmissibility among humans," explains Thijs Kuiken, DVM, PhD of the Department of Viroscience at Erasmus University Medical Centre in Rotterdam, The Netherlands. "Virus attachment to Clara cells in the bronchioles and pneumocytes and macrophages in the alveoli correlates with high virulence."

Using virus histochemical analysis, the investigators looked at the pattern of attachment of 2 genetically engineered emerging H7 viruses (containing the hemagglutinin (HA) of either influenza virus A/Shanghai/1/13 or A/Anhui/1/13) to fixed human respiratory tract tissues and compared the findings to attachment patterns seen with human influenza viruses with high transmissibility but low virulence (seasonal H3N2 and pandemic H1N1) and highly pathogenic avian influenza (HPAI) viruses with low transmissibility and high virulence (H5N1 and H7N7). They found that like other avian influenza viruses, the H7N9 viruses attached more strongly to lower parts of the human respiratory tract than to upper parts. However, compared to other avian influenza viruses, the attachment to epithelial cells by H7N9 in the bronchioles and alveoli of the lung was more abundant, and the viruses attached to a broader range of cell types. "These characteristics fit with increased virulence of these emerging avian H7 viruses compared to that of human influenza viruses," says Dr. Kuiken.

A 3rd notable finding was a more concentrated attachment of H7N9 viruses in ciliated cells of the nasal concha, trachea, and bronchi, suggesting the potential for efficient transmission among humans. "However, the fact that the emerging H7N9 virus has caused infection mainly in individual human cases suggests that it has not acquired all the necessary properties for efficient transmission among humans," notes Dr. Kuiken. "Our results indicate that based just on the pattern of virus attachment, the H7N9 currently emerging in China has the potential both to cause severe pulmonary disease and to be efficiently transmitted among humans," says Dr. Kuiken. He emphasizes that attachment is only the 1st step in the replication cycle of influenza virus in its host cell, and that other steps, as well as the host response, need to be taken into account to fully understand the potential of these emerging H7 viruses to cause an influenza pandemic.

******
[2]
Date: 5 Sep 2013
Source: Science DOI: 10.1126/science.1242917 [edited]
http://www.sciencemag.org/content/early/2013/09/04/science.1242917


Structures and Receptor Binding of Hemagglutinins from Human-Infecting H7N9 Influenza Viruses. (By Y Yi Shi and 20 other contributors).

Abstract:
An avian-origin human-infecting influenza (H7N9) virus has recently been identified in China. Here, we have evaluated the viral hemagglutinin (HA) receptor binding properties from 2 human H7N9 isolates, A/Shanghai/1/2013 (SH-H7N9) (containing the avian-signature Q226) and A/Anhui/1/2013 (AH-H7N9) (containing the mammalian-signature L226). We found that SH-H7N9 HA preferentially binds the avian receptor analog, whereas the AH-H7N9 HA binds both avian and human receptor analogs. Furthermore, an AH-H7N9 mutant HA (L226Q) has dual receptor binding property, indicating that other amino acid substitutions contribute to the receptor binding switch. The structures of SH-H7N9 HA, AH-H7N9 HA, and its mutant in complex with either avian or human receptor analogs show how the AH-H7N9 can bind human receptors yet also retain the avian receptor binding property.

--
Communicated by:
ProMED-mail
<promed@promedmail.org>

[In the 1st report above, the authors believe that, based just on the pattern of virus attachment, the H7N9 currently emerging in China has the potential both to cause severe pulmonary disease and to be efficiently transmitted among humans and cause severe pneumonia. However, the fact that the emerging H7N9 virus has caused infection mainly in individual human cases suggests that it has not acquired all the necessary properties for efficient transmission among humans.

The authors of the 2nd report above conclude that "loss of affinity for the avian receptor may be an important factor for development of efficient human-to-human transmission; however, to date, limited human-to-human transmission has been observed for H7N9 virus, which might be a result of retention of high affinity for the avian receptor." The authors of the Science report showed that, "in contrast to the H5N1 HA, the Q226L substitution is not solely responsible for the avian-to-human receptor binding switch for H7 HA." They conclude that: "We believe that surveillance of H7N9 virus isolates for detection of the new amino acid substitutions is essential for the future implementation of control strategies." - Mod.CP

A HealthMap/ProMED-mail map can be accessed at: http://healthmap.org/r/1zaU.]


http://beta.promedmail.org/direct.php?id=20130910.1935545