China, Ghana, and Mexico report more avian influenza outbreaks
Three countries reported fresh avian influenza outbreaks today from four different strains, three of them highly pathogenic, according to separate reports to the World Organization for Animal Health (OIE).
China's agriculture ministry today reported two outbreaks involving two different high-path strains, H5N6 at a commercial farm in Guangdong province and H5N2 on a farm in Jiangsu province.
The H5N6 outbreak started on Aug 6 and killed 1,350 of 2,170 susceptible birds. The remaining ones were culled to curb the spread of the virus.
The H5N2 outbreak struck a commercial goose farm in Jiangsu province. The event began on Aug 3, and the disease killed 3,106 of 53,358 vulnerable geese. Authorities destroyed the rest as part of their control measures.
Ghana reported the other high-path outbreaks, which all involved H5N1. The virus recently reemerged in the country after a several-year hiatus. The newest Ghanian outbreaks are all reported from Greater Accra region, with start dates in late July and early August. Sites included a live bird market, a commercial farm, and backyard birds. In total, the virus wiped out 1,178 birds, with authorities culling the rest to contain the spread.
Aug 14 OIE report on H5N6 in China
Aug 14 OIE report on H5N2 in China
Aug 14 OIE report on H5N1 in Ghana
Mexico's outbreak involved the county's first reporting of the low-pathogenic H5N2 strain. The virus hit a large commercial egg farm in Sinaloa state, located in the west-central part of the country. The outbreak began on Jul 24 and was detected during veterinary ministry surveillance.
Extensive sampling of farms and backyards in a 10-km radius around the farm found no other evidence of the virus. A quarantine has been set up around the farm, and its 433,093 birds are set to be slaughtered, even though the virus detected was a low-pathogenic strain.
Aug 14 OIE report on low-path H5N2 in Mexico
Gene study shows influenza A diversity in Latin American pigs
A genetic study of swine influenza A isolates from Mexico and Chile found several isolates that have been circulating for decades, including four novel viruses that originated from human seasonal flu strains. A research team from the National Institutes of Health, Minnesota, and Chile reported their findings yesterday in the latest online edition of Public Library of Science (PLoS) Currents Outbreaks.
The group sequenced hemagglutinin sequences from 18 swine influenza A samples collected in 2012 from Chile and 51 from Mexican swine from 2010 through 2014. They found multiple novel human-origin H3N2 and H1N1 strains that hadn't previously been identified in Chilean and Mexican swine, which they said shows the importance of human-swine interactions in influencing swine influenza diversity in Latin America.
Also, they found two different lineages in Mexican swine that were related to North American swine influenza A, a classical H1N1 and an H3 cluster 4, which the researchers said hints at migration from US or Canadian swine herds into Mexico.
Genetic analysis suggested the possibility of two independent H3 introductions from humans and at least 12 introductions of human 2009 H1N1 pandemic virus since 2009, which the group said further influenced the diversity they saw.
The patterns could complicate the development of effective vaccines for the region, and expanded surveillance is needed, given the great diversity in Latin American swine herds, said the authors.
Aug 13 PLoS Currents Outbreaks study