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The final part of the summer series on vacation viruses is one you can catch without going anywhere: West Nile virus. Florian Krammer explains why this flavivirus is closely related to Japanese and St. Louis encephalitis virus, how it mysteriously showed up in New York in 1999 - most likely via mosquitoes on a container ship and spread across the entire US within a few years.

Part three of the summer series on viruses you can pick up on vacation. After Italy and Scandinavia, it's off to the tropics. Oropouche virus causes Oropouche fever and is spread not by mosquitoes but mainly by tiny midges — the same bloodsuckers that transmit bluetongue disease.

Part two of the summer series on viruses you might pick up on vacation — this time heading north. Sindbis virus is transmitted by ordinary Culex mosquitoes and causes a disease known variously as Pogosta disease, Ockelbo disease, or Karelian fever. Florian Krammer explains why it's closely related to chikungunya (you could call it the chikungunya of the north), how migratory birds spread it across Eurasia and Africa, and why most infections go unnoticed — there are 20 to 40 asymptomatic cases for every symptomatic one.

The first of a short series on viruses you might encounter while travelling: Pappataci fever is transmitted by sandflies and caused by viruses like Toscana virus, Naples virus, and Sicilian sandfly fever virus. Florian Krammer explains where the Italian name comes from, why these tiny 3-millimetre flies are poor fliers and therefore stay close to the ground, and why up to 25% of people in affected regions carry antibodies without ever having felt sick. Most infections are mild, but Toscana virus is neurotropic and can, in rare cases, cause meningitis or encephalitis. There's no vaccine and no treatment — insect...

In this episode of viroLOGICAL, Florian Krammer explains the Marburg virus, a filovirus closely related to Ebola that causes severe hemorrhagic fever. He discusses how the virus is structured, how it enters cells, how it is transmitted from animals and between humans, and why infection is associated with very high mortality.

This time it's not about a virus, but about one of the most exciting developments in modern medicine: therapeutic cancer vaccines based on mRNA. Florian Krammer explains the basic principle — how a patient's tumor is sequenced, how the mutated genes (so-called neoantigens) are turned into a personalized vaccine, and how that vaccine trains the immune system to recognize and destroy cancer cells.

A new tick-borne virus has just been detected in Austria for the first time and antibodies found in two people suggest it can infect humans here too. Florian Krammer explains what makes the Alongshan virus so unusual: it belongs to the Jingmen viruses, a group of segmented flaviviruses that are built almost like a hybrid between a flavivirus and an influenza virus.

The second part of the HIV series covers everything that happened after the virus was discovered: the intense stigma of the early years, the US government's years of inaction under Reagan and the activism that drove the development of treatments and public awareness. Florian Krammer explains how a near-certain death sentence became a manageable chronic condition, what PrEP is and how it works, and how a handful of people (the "Berlin patients") were actually cured of HIV. The episode closes with the current situation: why UNAIDS estimates that the withdrawal of US funding could lead to millions of additional infections...

The first of a two-part series on HIV starts with the virus itself and its history. Florian Krammer explains why HIV is one of the most cunning viruses we know: it infects the very cells of the immune system, permanently writes itself into our DNA, and hides from immune detection.

To wrap up the hepatitis series, this episode covers the final letter: hepatitis E. A virus that's harmless for most people, often going completely unnoticed, but can be life-threatening for pregnant women and those with weakened immune systems.