In PLOS Pathogens, researchers from the US Food and Drug Administration, the Nihon University School of Medicine, and other international centers present findings from a genomic analysis of nearly 300 newly sequenced norovirus isolates collected from infected humans across four continents over almost five decades, from 1972 to 2019. Their results provide clues to the genomic evolution and spread of norovirus, including the circulation of independently evolving norovirus populations in parallel in the same human populations. "Using this novel dataset, we found evidence for restrictions in the recombination of genetically disparate viruses and that diversifying selection results in new variants with different epidemiological profiles," the team reports, adding that "new insights on the diversification of noroviruses could provide baseline information for the study of future epidemics and ultimately the prevention of norovirus infections."
A team from the Harvard T.H. Chan School of Public Health, Yale School of Public Health, and elsewhere retrace SARS-CoV-2 virus concentration dynamics during acute infection events for a paper in PLOS Biology. Using RT-qPCR data generated for a prospective study of SARS-CoV-2 infections in dozens of National Basketball Association players, staff, and vendors after the basketball season restarted in 2020, the researchers found that viral concentrations typically reached their peak some three days after SARS-CoV-2 infection, on average, clearing within just more than a week in individuals with symptom-free infections and extending nearly 11 days in those with symptomatic infections. "The ability to chart patients' progress through their infection underpins our ability to provide appropriate clinical care and to institute effective measures to reduce the risk of onward transmission," the authors conclude. "Marginally more sophisticated diagnostic and screening algorithms may greatly enhance our ability to manage the spread of SARS-CoV-2 using tests that are already available."
A zoonotic disease called Q fever, caused by Coxiella burnetii bacteria carried by cattle and other domestic animals, appeared to cause an outbreak China's Zhuhai city in late 2018 and early 2019, according to a metagenomic sequencing study in PLOS Neglected Tropical Diseases. Researchers at the Fifth Affiliated Hospital of Sun Yat-Sen University, the Beijing Institute of Microbiology and Epidemiology, BGI-Shenzhen, and elsewhere did metagenomic sequencing on blood plasma samples from nearly 2,400 individuals treated for acute fevers at a Zhuhai hospital in 2018 and 2019, identifying genomic DNA from C. burnetii in 138 patients, including dozens of individuals treated between November of 2018 and the following March. "We confirmed an epidemic of human Q fever in Zhuhai, a contemporary city in China, using clinical metagenomic next-generation sequencing (mNGS) and cell phone location data," they report. "Our results indicate that [C. burnetii]-infected goats and cattle at the only official authorized slaughterhouse in Zhuhai were the likely infection source for the Q fever epidemic."