Flu Scan for Apr 10, 2017

Tibet H7N9 case details
Avian flu on 3 continents
Bats and zoonotic flu emergence

Local source likely in Tibet's first H7N9 avian flu case

The recent report of Tibet's first human H7N9 avian influenza case appears to be locally acquired, according to an Apr 7 Tibet Autonomous Region government statement translated and posted by Avian Flu Diary.

Officials said the 41-year-old man is a migrant worker from Sichuan province who had been working with live poultry in Tibet since February and became ill in early April.

The incubation period for H7N9 ranges from 1 to 10 days, which means the man likely contracted the virus in Tibet.

China is in the midst of its fifth and biggest wave of H7N9 activity, and cases have been reported from a much wider geographic area than seen with earlier seasons. Contact with poultry or visiting live-poultry markets are the main risk factors.
Apr 8 Avian Flu Diary post


High-path avian flu outbreaks continue in Africa, Asia, Europe

Five countries reported more highly pathogenic avian flu outbreaks, including H5N1 events in Nigeria and Vietnam, more H5N8 detections in Europe, and more farms hit by H5N2 in Taiwan, according to the latest notifications from the World Organization for Animal Health (OIE).

Nigeria reported two more H5N1 outbreaks on commercial farms in Bauchi state in the central part of the country, one housing pullets and the other layer poultry. Between the two events the virus killed 262 of 2,630 birds. Vietnam's latest H5N1 outbreak struck backyard birds starting on Apr 5, killing all 43 birds.

In Europe, German officials said a wild duck found dead on Apr 5 in Bavaria state in the southeast tested positive for H5N8, as did fattening turkeys at a commercial farm housing 9,800 birds in Lower Saxony state in the northwest. Also, Lithuania reported that a mute swan found dead on Mar 29 on a river bank near the city of Kaunas tested positive for H5N8.

Elsewhere, Taiwan reported 10 more highly pathogenic H5N2 outbreaks, nine at commercial farms and one at a slaughterhouse. The events began from Mar 23 to Apr 1, affecting birds in Yunlin, Chiayi, Changhua, and Nantou counties, as well as in the cities of New Taipei and Tainan. The virus killed 5,774 of 110,959 susceptible birds, and the remaining ones have been culled.
Apr 10 OIE report on H5N1 in Nigeria
Apr 7 OIE report on H5N1 in Vietnam
Apr 7 OIE report on H5N8 in Germany
Apr 8 OIE report on H5N8 in Lithuania
Apr 10 OIE report on H5N2 in Taiwan

In research developments, South Korean researchers who experimentally infected dogs with H5N8 avian flu virus found some evidence for viral transmission and shedding. They reported their findings recently in the Journal of Veterinary Science.

During extensive poultry outbreak in South Korea in early 2014, a dog at one of the farms was found to have an H5N8 infection, and the researchers' goal was to explore the role of dogs in transmission and adaptation of H5N8 to mammals.

The investigators used 3-month-old pathogen-free beagles for the experiments. Four dogs were intranasally inoculated with H5N8 and kept in a cage with four that weren't inoculated. Two uninoculated dogs were placed in another cage and monitored. Researchers detected weak viral genes and seroconversion, even in contact dogs. Though H5N8 doesn't seem fully adapted to dogs, surveillance of farm dogs should continue, because the virus could acquire the capacity to infect mammals, the authors said.
Apr 6 J Vet Sci abstract


Study: Bat species has avian and human flu receptors

Little brown bats, widely found in North America, have both avian and human sialic acid receptors and could be co-infected with avian and human influenza A viruses (IAVs), an event that could lead to the emergence of zoonotic strains, a team led by Pennsylvania State University researchers reported in Scientific Reports.

Scientists are looking into bats' role in influenza virus epidemiology after two novel influenza-like viruses were found in fruit bats in 2013.

For the study, the researchers looked for influenza virus receptors in tissue sections of 10 juvenile and 10 adult little brown bats. They found abundant avian- and human-type influenza virus receptors throughout the animals' respiratory tracts, with avian receptors more predominant in the tracheal mucosa—similar to ducks—and human ones predominant in other tracheal tissues and in the lower airway. Both types of receptors were found in the bats' digestive tracts.

Virus-binding tests with low-pathogenic H5N2 and a human H1N1 virus revealed that the receptors in the little brown bats are compatible with avian and human IAV binding.

Other studies with cell lines from a range of bat species support influenza A virus replication, and the new findings on receptors suggests that bats could play an important role in influenza A epidemiology and zoonotic emergence, the scientists wrote. They added, "The extensive diversity of bat species globally and the limited understanding of the role of bats in IAV biology raises an urgent need for comprehensive epidemiological surveillance if IAVs across different bat species."
Apr 6 Sci Rep study

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