New Omicron subvariant mutation tied to kids' neurologic complications
Researchers in Taiwan have discovered a new mutation in the SARS-CoV-2 Omicron BA.2.3.7 subvariant that they suggest may be responsible for severe neurologic complications observed in young children on the island. Their study was published yesterday in the International Journal of Infectious Diseases.
The team analyzed the medical records of five pediatric COVID-19 patients hospitalized with severe neurologic complications such as seizures, symptoms indicating involvement of the meningeal layer of the brain, and encephalopathy in May 2022, about a month after Omicron began circulating in Taiwan.
The patients were 1 to 5 years old and experienced neurologic symptoms within 1 or 2 days after the onset of respiratory symptoms and fever. All patients had elevated levels of several inflammatory biomarkers, but none of their cerebrospinal fluid samples tested positive for COVID-19.
Whole-genome sequencing revealed that all viruses were Omicron BA.2.3.7 and that they had a previously unidentified K97E mutation on the spike protein that differed from other BA.2.3.7 strains. Genome mapping of the mutation showed similar sequences in patients in Hong Kong, Japan, and the United States at roughly the same time.
One child died of acute cerebral edema, brainstem compression, and multi-organ failure. The other patients recovered fully and were released from the hospital after 4 to 9 days.
The authors said their findings suggest that the neurologic complications are related to mutation-triggered hyperimmune states rather than direct viral invasion of the central nervous system. They also noted that other mutations in the same area of the SARS-CoV-2 spike protein have been linked to immune evasion.
"The K97E mutation, which has not been observed in Taiwan previously, potentially explains the sudden increase in incidence of severe neurological symptoms in pediatric patients due to its possible effect on immune regulation," the researchers concluded.
Sep 7 Int J Infect Dis study
Flu continues drop in Southern Hemisphere
Flu activity declined further in the Southern Hemisphere and is low in most of the world, except for some tropical locations, the World Health Organization (WHO) said in its latest update, which covers roughly the middle 2 weeks of August.
In Southern Asia, flu activity continues, with the 2009 H1N1 strain now dominant, especially in India. In Laos and Thailand, flu activity increased, and in East Asia, levels increased in northern China, mainly led by the H3N2 strain. Western Africa also reported a slight increase.
Of respiratory samples that were positive for flu at national flu labs in the middle part of August, influenza A made up 95.3% of samples. And, of subtyped influenza A viruses, 90% were H3N2.
Sep 5 WHO global flu update
Avian flu hits Minnesota poultry as H5N1 confirmed in Florida dolphin
Minnesota reported another highly pathogenic avian flu outbreak at a commercial poultry farm, and a handful of states reported more H5N1 detections in wild birds, according to updates from the US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS).
In Minnesota, which recently reported an uptick in poultry outbreaks, the virus struck a turkey farm housing 50,000 birds in Morrison County in the central part of the state.
Also, the USDA reported 51 more H5N1 detections in wild birds, raising the total to 2,240. Most of the new detections involved waterfowl found dead, mostly from Utah's Box Elder and Davis counties. A new detections were also reported from New York and Oregon.
USDA APHIS poultry outbreak updates
USDA APHIS wild bird outbreak updates
In other avian flu developments, scientists at the University of Florida have reported H5N1 for the first time in an American dolphin. Swedish officials recently reported the virus in a porpoise, the first report of a detection in a cetacean.
In a statement, University of Florida Health said the virus was found in a young male dolphin found dead in March in Dixie County's Horseshoe Beach. The veterinary team initially did not suspect anything unusual when they performed the necropsy, but tests for common causes of deaths in dolphins were negative.
The animal had inflammation in and around the brain, and brain and lung samples were sent for further testing to Bronson Animal Disease Diagnostic Laboratory in Kissimmee, Florida, which identified avian flu. The National Veterinary Diagnostic Laboratory in Ames, Iowa, confirmed the strain as H5N1.
Sep 7 University of Florida Health statement