WHO: Global flu levels still high, influenza A predominating
In its latest global flu update yesterday, the World Health Organization (WHO) said flu levels are still elevated across much of the globe, with 79.2% of recent lab specimens testing positive for influenza A.
Though influenza B activity has defined the season in some countries in North America, only 29.8% of recent samples worldwide were classified as influenza B. Of the characterized B viruses, 1.4% belonged to the Yamagata lineage and 98.6% to the Victoria lineage, the WHO said. Of the subtyped influenza A viruses, 58.8% were influenza 2009 H1N1 and 41.2% were influenza H3N2.
Flu activity remains high in North America, with H1N1 and B viruses circulating, the WHO said. H1N1 is increasing in Mexico.
Though influenza activity remains high across Europe, several northern European countries reported a decrease of detections, including Ireland, England, and Wales. A decrease in flu activity was also seen across North Africa.
Russia has reported a predominance of influenza B, as have several countries in central Asia.
Flu activity remains elevated in most East Asia countries. Influenza-like activity seems to have decreased in China but remains high, with H3N2 and influenza B co-circulating.
Feb 3 WHO update
Editor's note: This scan was updated Feb 7, 2020, with a clarification to reflect tissue sampling in elk samples.
Montana game farm quarantined after CWD detection in elk samples
For the first time since 1999, chronic wasting disease (CWD) has been detected in elk tissue samples from a Montana game farm.
According to the Montana Department of Livestock (MDL), the detection was made via routine testing by the US Department of Agriculture CWD Herd Certification Program, which requires all deaths in captive animals greater than 12 months of age be tested for the deadly prion disease.
The animal had appeared healthy, and the detection has prompted a quarantine as the MDL investigates.
"An epidemiologic investigation will be conducted, but at this time, the source of the disease is unknown,” said State Veterinarian Marty Zaluski, DVM, in an MDL press release. "We will look at historical elk movements associated with this captive herd and proximity to infected wildlife to try to determine the source of exposure."
CWD is a progressive neurologic prion disease that affects cervids, including deer, elk, and moose.
Jan 31 MDL press release
Pronghorn, mountain goats, bighorn sheep might be susceptible to CWD
Wild animals not in the deer family (or cervids) that might be susceptible to chronic wasting disease (CWD) include pronghorn, mountain goats, and bighorn sheep but probably not bison, according to a phylogenic analysis published yesterday in the journal Prion.
Scientists with the University of Alberta reviewed the literature on mammals naturally or experimentally exposed to CWD to identify susceptible and resistant species. They then created a phylogeny of these animals using cytochrome B, a protein found in mitochondria that can help assess the relatedness of species—and found that CWD susceptibility followed the phylogenic tree they created.
Using this phylogeny, the group estimated the probability of CWD susceptibility for wild ungulate species. They then compared the various forms of cellular prion protein, or PrPC, among these species to identify which sites segregated between CWD-susceptible and CWD-resistant species. (PrPC is the prion that, when misfolded, causes CWD). The researchers also identified sites that were significantly associated with susceptibility, but these sites were not completely discriminating.
Finally, they sequenced prion proteins from 578 wild ungulates (hoofed animal) to further evaluate their potential susceptibility and also looked at the animals' ranges in western Canada (CWD has been found in Alberta, Saskatchewan, and Quebec). Their analysis of the combined data suggests that CWD could affect pronghorn, mountain goats, and bighorn sheep, but bison are likely to be more resistant. They say pronghorn are most likely to be susceptible, at least in Canada.
The authors conclude, "Our current analysis highlights pronghorn antelope should be prioritized for inclusion in CWD surveillance activities given the proximity of the enzootic region in Canada to the pronghorn distribution."
Feb 3 Prion study