Avian Flu Scan for Aug 05, 2014

News brief

Letter raises possibility of human-adapted H5N1 in Canada case

An H5N1 avian flu virus that killed a Canadian woman in January had two uncommon mutations that may have helped increase its ability to bind to human cells, researchers from Singapore and Canada reported yesterday in a letter in Emerging Infectious Diseases.

The woman, who had visited China before her illness in December, had neurologic symptoms and no known contact with poultry. She remains Canada's only H5N1 patient.

The investigators note two previously reported mutations, R189K and G221R, in the hemagglutinin protein in the virus isolated from the patient. They write that both mutations are found in the immediate receptor-binding pocket, and G225R has been known to change specificity of an H3N2 virus toward human erythrocytes. The authors note that the two receptor-binding pocket mutations were not seen in the most closely related Asian H5N1 sequences.

They write, "Our results suggest that G225R could incur a relative predicted increase in binding to the human-like receptors. . . . The role of R193K is less clear with a slight predicted tendency of favoring avian-like receptors.
Aug 4 Emerg Infect Dis letter

Study: Korean H5N8 outbreak strain likely involved farm reassortment

Recent H5N8 avian flu outbreaks in South Korea were likely the result of introduction of the virus from wild birds to farm poultry, according to a separate letter yesterday in Emerging Infectious Diseases.

South Korean researchers conducted a BLAST (Basic Local Alignment Search Tool) search to identify the closest gene sequences of H5N8 isolates collected from waterfowl droppings in the area where the outbreak began in January and has since led to the culling of more than 12 million Korean poultry. They compared viruses from wild birds with those from affected poultry.

The scientists surmise that, because all eight genes of the waterfowl are closely related to an isolate from a duck farm, it is likely the outbreak strain originated from infected waterfowl that had visited poultry on an outbreak farm. They also determined that the H5N8 outbreak strain likely is a reassortment of segments from H5N1-like, H4N2-like, and H5N8-like strains.

The authors conclude, "Taken together, our data suggest that A/waterfowl/Korea/S005/2014 (H5N8) may have been reassorted in a duck farm in South Korea."
Aug 4 Emerg Infect Dis letter

News Scan for Aug 05, 2014

News brief

Enhanced UK MERS surveillance found 2 imported cases in 2012-13

An enhanced system of surveillance for MERS-CoV in England turned up 2 cases of the disease among 77 potential candidates meeting case definitions in its first year of operation, according to a dispatch yesteday in Emerging Infectious Diseases. The numbers are small, say the authors, but in the context of emerging pathogens, reporting data like theirs can help optimize case detection and surveillance systems.

The surveillance system was instituted by England's Health Protection Agency, now called Public Health England (PHE), in September 2012 after isolates from an ill Qatari patient who was transferred to an English hospital showed a virtual match to the virus identified in the first MERS-CoV (Middle East respiratory syndrome coronavirus) patient in Saudi Arabia earlier in the year.

PHE defined a possible MERS case as acute respiratory syndrome (fever of at least 38°C [100.4°F] or history of fever and cough) requiring hospitalization as well as clinical or radiologic evidence suggesting lower airway involvement not explained by another cause in a patient who had traveled to or resided in Saudi Arabia or Qatar (the only places with MERS at the time) within 10 days of illness onset.

Of 77 individuals meeting the case definition from Sep 24, 2012, to Oct 15, 2013, 2 cases were confirmed, as were cases in 2 contacts of the second case-patient. The positive predictive value of clinical manifestations increased as the severity of disease increased.

The authors write, "We encourage other countries to similarly report the characteristics of all patients tested for MERS-CoV to improve understanding of the predictive value of different clinical and epidemiologic manifestations in various populations at different times. This will help inform the evolving international public health response to this novel pathogen."
Aug 4 Emerg Infect Dis dispatch

CDC study: Reclassification affected foodborne outbreak data since 2009

At least some of the substantial decline in reports of foodborne disease outbreaks since 2009, when the National Outbreak Reporting System (NORS) began reporting all enteric disease outbreaks rather than only foodborne outbreaks, is accounted for by workers giving different classifications to outbreaks that would previously have been categorized as foodborne, say the authors of a study yesterday in Emerging Infectious Diseases.

In addition, a shortage of resources during the 2009 pandemic influenza outbreak may have played a role, they found.

With the enhanced reporting platform, enteric outbreaks that are transmitted by person-to-person contact, animal contact, environmental contamination, and indeterminate source are reported in addition to those classified as foodborne and waterborne.

The researchers, from the Centers for Disease Control and Prevention, conducted a voluntary survey of state and territory health department workers who enter enteric disease outbreak data into NORS.

Workers gave high priority to reporting foodborne disease outbreaks. However, 35 of 47 (74%) reported sometimes having difficulties in determining the primary mode of transmission in an outbreak in the enhanced system.

Specifically, 20 of 25 respondents (80%) said they had difficulty distinguishing between foodborne and person-to-person transmission. In addition, 26 of 47 (55%) reported they had used the new "indeterminate/other/unknown" category in cases in which the mode of transmission wasn't clear. Most respondents said they likely or very likely would have reported such outbreaks as foodborne in the pre-2009 system.

In answer to questions pertaining to health department resources during the 2009 flu pandemic, 19 of 35 (57%) said there were fewer resources available at that time for foodborne disease outbreak investigations.

"The results of this survey provide unique insights into the decline in the number of foodborne outbreak reports submitted in 2009 and thereafter," say the authors.
Aug 4 Emerg Infect Dis study