Flu activity up in most of Northern Hemisphere, with H3N2 dominating
Not surprisingly, the entire Northern Hemisphere is seeing increasing influenza activity, with H3N2 most common, but unfortunately in an antigenically drifted strain not well matched to the strain in this year's vaccine, according to an update yesterday from the World Health Organization (WHO).
The data as of Jan 9, gathered for the 2-week period ending Dec 27 from 80 countries, areas, and territories, showed 23,421 of 96,535 specimens positive for influenza, with 22,129 (94.5%) typed as influenza A and 1,292 (5.5%) as influenza B.
Subtyping of the flu A specimens showed 9,211 (98.3%) to be H3N2 and 163 (1.7%) to be 2009 H1N1. Of the subtyped flu B viruses, 423 (97.9%) were of the Yamagata lineage and 9 (2.1%) were of the Victoria lineage.
North America is seeing sharp increases in flu activity in most areas, with H3N2 most common, although influenza-like illness (ILI) is below expected rates in Canada, says the WHO report. US ILI, reported as high in 29 states, has increased rapidly to 5.9%, which was the peak seen during the 2012-13 season.
Other areas worldwide with increased activity include eastern Asia, northern and western Africa, and some countries in the Caribbean. H3N2 was predominant in all but the African countries, where type B was more common.
Flu activity in Central America decreased but respiratory syncytial virus activity remains high, and tropical countries of South America have low activity. Tropical Asia had slightly increased but still low activity, with type B flu predominating.
Jan 12 WHO update summary
Europe's flu season appears to be starting, but activity remains low so far. The European Centre for Disease Prevention and Control (ECDC) reported in an update yesterday that the proportion of sentinel specimens positive for influenza has been above 10% for 3 weeks running and reached 26% in the week ending Jan 4.
The ECDC says that protecting people at risk for severe outcomes of flu, such as the elderly and those with preexisting illness, is the priority for vaccine programs in Europe. The ECDC reported the same antigenic drift in the H3N2 strain.
The ECDC, like the WHO, also points out that the circulating flu viruses so far show susceptibility to neuraminidase inhibitor antiviral drugs and advises physicians to consider treatment or postexposure prophylaxis with the agents in infected and exposed persons.
Jan 12 ECDC update
China's Guangdong province reports 2 new H7N9 cases
H7N9 avian flu cases in Guangdong province in south China continue to mount this year, with two new cases, bringing the 2015 total for the province to seven, according to an update today from Hong Kong's Centre for Health Protection (CHP).
Citing provincial health authorities, the CHP said the new cases are in a 57-year-old woman who is hospitalized in critical condition and a 41-year-old man who is hospitalized in stable condition. The report did not say where specifically the patients live or provide any other details.
Guangdong province lies adjacent to Hong Kong. No other province has yet to report a case this year.
Five outbreaks of H5N2 in Taiwan affect 26,000 poultry
In a report posted by the World Organization for Animal Health (OIE) yesterday, Taiwanese authorities reported details on five outbreaks of avian flu in poultry attributed to a novel H5N2 strain and provided details of the virus.
Four of the outbreaks have affected goose farms in Yunlin County on the west coast of Taiwan, and one involves a duck farm in Pingtung County in the south.
The goose flocks ranged in size from 2,640 to 7,600 birds. Cases on three of the farms were all fatal, affecting 788, 1,790, and 7,300 birds, respectively. On the fourth farm, 125 geese were infected in a flock of 4,100, but only 4 of them died.
The duck farm houses 7,000 layer ducks; 1 bird became infected and died. All told, 10,004 of 26,290 birds in the five flocks contracted avian flu and 9,883 died. The OIE report did not mention culling efforts, which are typically used to contain domestic outbreaks of avian flu. But media reports have mentioned plans to cull surviving birds.
Previous media reports have also described an outbreak involving 120,000 chickens in Pingtung County, but that outbreak was not mentioned in today's report.
In describing the strain that has caused the outbreaks, Dr. Ping-Cheng Yang of the Council of Agriculture in Hsinchu City said in the OIE report, "The homology of H5 between the isolates from these infected farms and the South Korea 2014 H5N8 strain is near 99%. The homology of N2 between the isolates from these infected farms and the China 2011 H5N2 strain is 96%. This H5N2 strain is obviously novel to Taiwan."
In a story from Taiwan's Central News Agency (CNA) 2 days ago, Dr. Tsai Hsiang-jung of Taiwan's Animal Health Research Institute said the strain is also novel worldwide.
Jan 12 OIE report
Jan 11 CNA story
Related Jan 12 CIDRAP News story