Chinese researchers report novel triple-reassortant flu viruses in swine
Chinese researchers today reported novel triple-reassortant influenza strains in swine, and the viruses carry genes that have been noted in human flu infections, according to a study in Emerging Microbes & Infections.
During surveillance of pigs in Guangxi province, the investigators isolated 11 H1N1 and 3 H3N2 viruses of swine origin. Out of the 14 isolates, 10 were novel triple-reassortant viruses that contained the surface genes hemagglutinin and neuraminidase from Eurasian avian-like (EA) H1N1 or seasonal human-like H3N2, matrix (M) genes from 2009 H1N1 pandemic or EA H1N1, nonstructural (NS) genes from classical swine flu, and the remaining genes from 2009 H1N1.
In addition, mouse studies indicated that the novel swine-origin viruses replicate efficiently, with some isolates demonstrating lethality in the animals. The researchers also noted that the reassortant EA H1N1 viruses with EA-like M gene have been reported in human infections.
"Further investigations will help to assess the potential risk of these novel triple-reassortant viruses to humans," the authors concluded.
In related research, a separate group of Chinese researchers analyzed flu isolates from environmental and animal sampling and report that influenza viruses are widespread on pig farms and demonstrate an association between the different types of environmental sampling used. Their study was also published today in the same journal.
May 16 Emerg Microb Infect study on triple-reassortant viruses
May 16 Emerg Microb Infect study on swine surveillance
H5N8 avian flu reported in South Africa, Denmark
South Africa and Denmark yesterday reported new highly pathogenic H5N8 avian flu detections, according to separate reports to the World Organization for Animal Health (OIE).
South African officials confirmed that the virus infected 29 ostriches on a farm of 3,720 birds in Western Cape province, beginning on May 5. Outbreak response steps have included destruction of animal products, disposal of droppings, and disinfection.
In a separate OIE report, South African agriculture officials reported 11 separate outbreaks, mostly affecting terns, gulls, and cormorants, but also a backyard swan. The largest of the wild bird outbreaks involved 4,177 swift terns found dead in West Cape province and 1,728 deaths and 1,778 cases in swift terns in the same province. Both outbreaks occurred in March.
The swan died on Apr 12 and was part of a flock of 40 backyard birds in Mpumalanga province, which is near Johannesburg. All told, the 11 outbreaks involved 1,966 H5N8 cases and 5,909 deaths in birds.
Denmark, meanwhile, reported that, from wild birds found dead Feb 13 through Apr 4, H5N8 avian flu was confirmed in 19 separate outbreaks throughout the eastern half of the country. Affected species were white-tailed eagles, common buzzards, crows, gulls, mute swans, and a cormorant. Testing revealed the virus in 23 birds.
May 15 OIE report on South Africa ostrich outbreak
May 15 OIE report on other South Africa detections
May 15 OIE report on Denmark