Temporally structured metapopulation dynamics and persistence of influenza A H3N2 virus in humans

Populations of seasonal influenza virus experience strong annual bottlenecks that pose a considerable extinction risk. It has been suggested that an influenza source population located in tropical Southeast or East Asia seeds annual temperate epidemics. Here we investigate the seasonal dynamics and migration patterns of influenza A H3N2 virus by analysis of virus samples obtained from 2003 to 2006 from Australia, Europe, Japan, New York, New Zealand, Southeast Asia, and newly sequenced viruses from Hong Kong. In contrast to annual temperate epidemics, relatively low levels of relative genetic diversity and no seasonal fluctuations characterized virus populations in tropical Southeast Asia and Hong Kong. Bayesian phylogeographic analysis using discrete temporal and spatial characters reveal high rates of viral migration between urban centers tested. Although the virus population that migrated between Southeast Asia and Hong Kong persisted through time, this was dependent on virus input from temperate regions and these tropical regions did not maintain a source for annual H3N2 influenza epidemics. We further show that multiple lineages may seed annual influenza epidemics, and that each region may function as a potential source population. We therefore propose that the global persistence of H3N2 influenza A virus is the result of a migrating metapopulation in which multiple different localities may seed seasonal epidemics in temperate regions in a given year. Such complex global migration dynamics may confound control efforts and contribute to the emergence and spread of antigenic variants and drug-resistant viruses.     

Phylogenetic Analysis of MERS-CoV in a Camel Abattoir,Saudi Arabia, 2016–2018

We detected Middle East respiratory syndrome coronavirus (MERS-CoV) RNA in 305/1,131 (27%) camels tested at an abattoir in Al Hasa, Eastern Province, Saudi Arabia, during January 2016–March 2018. We characterized 48 full-length MERS-CoV genomes and noted the viruses clustered in MERS-CoV lineage 5 clade B.     

Obliteration of the Rectal Lumen After Stapled Hemorrhoidopexy: Report of a Case

We report an incident of complete stapled closure of the rectal lumen following stapled hemorrhoidopexy. A patient with symptomatic prolapsing hemorrhoids underwent a stapled hemorrhoidopexy as a day-case procedure. After application of the pursestring suture and firing of the dedicated stapler the rectal lumen was found to have been completely obliterated. Endoscopic assessment using a flexible sigmoidoscope confirmed the absence of a rectal lumen. The patient was woken up and a gastrograffin enema performed. Contrast was injected under high pressure into the rectal lumen and a small defect in the mid point of the staple line was revealed. A fine guidewire was passed and endoscopic balloon dilatation achieved. This complication could have had catastrophic consequences and potentially required major surgical intervention. Although unlikely to occur, we believe that surgeons should be aware of this possible problem and a radiologic/endoscopic approach should be considered before more aggressive surgical intervention is undertaken. Reprints are not available.