Portal:Viruses

Hepatitis delta virus or hepatitis D virus (HDV) is a small virusoid, the sole member of the Deltavirus genus. It infects humans. A subviral satellite, it can only replicate in the presence of a hepatitis B (HBV) helper virus. The spherical virion is 36 nm in diameter, with an envelope containing three HBV proteins. The single-stranded, negative-sense, circular RNA genome of 1679 nucleotides is smaller than that of any known animal virus. It has an unusual base composition for an entity that infects animals, and is extensively bound to itself to form a partially double-stranded, rod-shaped structure. These features have led to suggestions that HDV might be related to viroids, small unencapsidated circular RNAs that infect plants. Unlike viroids, HDV encodes a protein, hepatitis D antigen.

Both HDV and HBV enter liver cells using the sodium/bile acid cotransporter as their receptor. They are mainly transmitted via injecting drug use and blood products. More than 15 million people are infected with both viruses, which is associated with a greater risk of liver complications than HBV infection alone. Around one in five jointly infected patients die. The HBV vaccine protects against HDV.

• ...that during the Boonah crisis in October 1918, 31 people died of the Spanish flu aboard the Australian troopship the HMAT Boonah (pictured)?
• ...that Deng Hongkui and Chen Hu were the first to use CRISPR gene editing on an HIV patient?
• ...that adenovirus serotype 14 is an emerging virus, related to the common cold, that has recently caused 10 deaths in the United States, including at least one healthy young adult?
• ...that the phage group was an informal network of biologists centered around Max Delbrück that contributed heavily to the origins of molecular biology?
• ...that polio eradication efforts in Pakistan were hampered by a vaccination campaign conducted by the CIA as cover in the search for Osama bin Laden?

Sir Frank Macfarlane Burnet (3 September 1899 – 31 August 1985) was an Australian virologist, microbiologist and immunologist. His early virological studies were on bacteriophages, including the pioneering observation that bacteriophages could exist as a stable non-infectious form that multiplies with the bacterial host, later termed the lysogenic cycle.

With the outbreak of World War II, Burnet's focus moved to influenza. Although his efforts to develop a live vaccine proved unsuccessful, he developed assays for the isolation, culture and detection of influenza virus, including haemagglutination assays. Modern methods for producing influenza vaccines are still based on his work improving virus-growing processes in hen's eggs. He also researched influenza virus genetics, examining the genetic control of virulence and demonstrating, several years before influenza virus was shown to have a segmented genome, that the virus recombined at high frequency.

May 1955: First issue of Virology; first English-language journal dedicated to virology

4 May 1984: HTLV-III, later HIV, identified as the cause of AIDS by Robert Gallo and coworkers

5 May 1939: First electron micrographs of tobacco mosaic virus taken by Helmut Ruska and coworkers

5 May 1983: Structure of influenza neuraminidase solved by Jose Varghese, Graeme Laver and Peter Colman

8 May 1980: WHO announced formally the global eradication of smallpox

11 May 1978: SV40 sequenced by Walter Fiers and coworkers

12 May 1972: Gene for bacteriophage MS2 coat protein is sequenced by Walter Fiers and coworkers, the first gene to be completely sequenced

13 May 2011: Boceprevir approved for the treatment of chronic hepatitis C virus (HCV) infection, the first direct-acting antiviral for HCV

14 May 1796: Edward Jenner inoculated James Phipps (pictured) with cowpox

15/16 May 1969: Death of Robert Rayford, the earliest confirmed case of AIDS outside Africa

18 May 1998: First World AIDS Vaccine Day

20 May 1983: Isolation of the retrovirus LAV, later HIV, by Luc Montagnier, Françoise Barré-Sinoussi and coworkers

23 May 2011: Telaprevir approved for the treatment of chronic HCV infection

25 May 2011: WHO declared rinderpest eradicated

31 May 1937: First results in humans from the 17D vaccine for yellow fever published by Max Theiler and Hugh H. Smith

Nevirapine (also Viramune) is an antiretroviral drug used in the treatment of HIV/AIDS caused by HIV-1. It was the first non-nucleoside reverse transcriptase inhibitor to be licensed, which occurred in 1996. Like nucleoside inhibitors, nevirapine inhibits HIV's reverse transcriptase enzyme, which copies the viral RNA into DNA and is essential for its replication. Unlike nucleoside inhibitors, it binds not in the enzyme's active site but in a nearby hydrophobic pocket, causing a conformational change in the enzyme that prevents it from functioning. Mutations in the pocket generate resistance to nevirapine, which develops rapidly unless viral replication is completely suppressed. The drug is therefore only used together with other anti-HIV drugs in combination therapy. The HIV-2 reverse transcriptase has a different pocket structure, rendering it inherently resistant to nevirapine and other first-generation NNRTIs. A single dose of nevirapine is a cost-effective way to reduce mother-to-child transmission of HIV, and has been recommended by the World Health Organization for use in resource-poor settings. Other protocols are recommended in the United States. Rash is the most common adverse event associated with the drug.

Subcategories of virology: