Canada's border closures may have stemmed COVID-19 variant imports
Dynamic restrictions on nonessential foreign travel into Canada helped slow COVID-19 variant introductions in early 2020 and 2021, allowing the government more time to scale up vaccination, testing, and contact tracing programs, according to a study published yesterday in eLife.
A team led by University of British Columbia researchers genetically sequenced SARS-CoV-2 samples in the first and second pandemic waves to estimate variants' geographic origins. They identified 2,263 introductions of SARS-CoV-2 variants into Canada, including 680 that went on to circulate within the country and 1,582 that didn't appear to circulate.
In the first wave, 49% of the sublineages originated in the United States and were introduced mainly into Quebec (39%) and Ontario (36%). While the United States was still the predominant source of variants in the second wave (43%), India and the United Kingdom made up 16% and 7% of introductions, respectively.
After Canada closed its borders to foreign travel on Apr 22, 2020, viral importations, which had peaked at 58.5 sublineages a week, fell 3.4-fold within 2 weeks and 10.3-fold within 4 weeks. New variants, however, continued to be introduced at a low rate until the second wave began in August 2020, possibly fueled by essential foreign workers supporting the supply chain.
In October 2020, after travel restrictions were eased slightly, SARS-CoV-2 introductions increased, and by the end of February 2021, an estimated 30 B.1.1.7 sublineages had been introduced.
Senior author Jeffrey Joy, PhD, of the University of British Columbia, said in an eLife news release that broad and long-term restrictions against nonessential international travel aren't necessarily advisable in light of their economic impacts.
"However, our analysis suggests that swift and stringent travel bans towards localities harbouring a high frequency of a new variant of concern, or an outbreak of an entirely new virus, not yet identified domestically, should be seriously considered to reduce the probability of seeding multiple, simultaneous outbreaks and overwhelming healthcare systems," he said.
Aug 2 eLife study and news release
Rhode Island reports Jamestown Canyon virus case
The Rhode Island Department of Health (RIDH) has reported a Jamestown Canyon virus case, which appears to be the first US case of the year. In a statement, it said the patient is a resident in his or her 50s who lives in Washington County in the southwest.
The individual had neurologic symptoms and is now recovering.
Jamestown Canyon virus is transmitted by mosquitoes, mostly between deer and mosquitoes, but it can also infect people. Illnesses can range from asymptomatic or mild to severe, resulting in meningitis or encephalitis.
Last year, Rhode Island reported its first Jamestown Virus case since 2013. According to the Centers for Disease Control and Prevention (CDC), infections typically occur from April through September. While the virus has been found throughout most of the United States, most infections have been reported in Minnesota and Wisconsin. The nation averages about 16 cases of the neuroinvasive form of the disease each year.
Aug 1 RIDH press release
CDC background on Jamestown Canyon virus
Dec 8, 2021, CIDRAP News scan on previous case
H5N1 avian flu infects more US wild birds, Russian poultry
The US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) reported 114 more highly pathogenic H5N1 avian flu detections in wild birds, bringing the total since the middle of January to 2,004.
Most of the detections were from eastern states, including Florida, Maine, Massachusetts, New York, and Pennsylvania. Several seabirds were among the birds found dead with the virus from Maine and Massachusetts. Florida again reported several detections in black vultures.
In the west, Alaska, California, Oregon, Utah, and Washington reported detections in a variety of birds, including waterfowl, raptors, and a few ravens.
Sporadic detections and outbreaks in poultry have continued over the summer, both in the United States and Europe.
In related news, Russia reported H5N1 in poultry for the first time in Magadan oblast in the eastern part of the country, according to a notification from the World Organization for Animal Health (WOAH). Most of Russia's earlier H5N1 outbreaks in poultry have occurred in the west. The latest outbreak began on Jul 22 and killed 6,443 of 7,775 chickens at a commercial farm.
USDA APHIS update on avian flu in wild birds
Aug 2 WOAH report on H5N1 in Russia