Virol J
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The first known cases of Middle East respiratory syndrome (MERS), associated with infection by a novel coronavirus (CoV), occurred in 2012 in Jordan but were reported retrospectively. The case first to be publicly reported was from Jeddah, in the Kingdom of Saudi Arabia (KSA). Since then, MERS-CoV sequences have been found in a bat and in many dromedary camels (DC). ⋯ Sero-surveys have found widespread evidence of past infection in adult camels and limited past exposure among humans. Sensitive, validated reverse transcriptase real-time polymerase chain reaction (RT-rtPCR)-based diagnostics have been available almost from the start of the emergence of MERS. While the basic virology of MERS-CoV has advanced over the past three years, understanding of the interplay between camel, environment, and human remains limited.
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Hepatitis B virus (HBV) DNA in serum of chronically infected patients declines by 3-4 log10 units at loss of HBe antigen (HBeAg) from serum. The mechanisms behind this decline, and the much smaller decline of surface antigen (HBsAg) levels, are still not well known. The aim of this study was to get a better understanding of this process by analysing both serum and intrahepatic markers of HBV replication. ⋯ The marked reduction of HBV DNA in serum after loss of HBeAg appears to be due to combined reduction of cccDNA, pgRNA and yet unidentified mechanisms downstream of reverse transcription. Such mechanisms include faster clearance of circulating virus or blocked secretion of virions, the latter supported by the observed relative increase of ihDNA in HBeAg-negative patients. The smaller reduction of S-RNA than of pgRNA partly explains why HBsAg remain high in the HBeAg-negative stage, supporting the possibility of HBsAg synthesis from integrated HBV DNA.