viroLOGICAL

Before SARS-CoV-2, there was SARS-CoV-1 - a closely related coronavirus that caused a serious outbreak in 2002–2003 with a case fatality rate of around 10%. Unlike its successor, SARS-CoV-1 only became transmissible after symptoms appeared, which made it possible to identify and isolate infected people even without PCR tests. The virus spread from China to Hong Kong, Canada, Singapore, and Vietnam via superspreader events before a global effort managed to contain it by June 2003. The likely origin: horseshoe bats at wet markets in Guangdong, with palm civets and raccoon dogs as intermediate hosts.

A virus previously known only from shrimp farms and fish is now linked to a serious eye disease in humans. Covert Mortality Nodavirus (CMNV) has been detected in over half of fish samples and nearly two-thirds of crab samples tested at markets and a new study in Nature Microbiology (March 2026) connects it to a persistent form of viral uveitis that can permanently damage the optic nerve and lead to severe vision loss.

Rhinoviruses are a highly diverse group of RNA viruses responsible for about half of all common cold infections and are something most people encounter multiple times in their lives. In this episode, Florian Krammer explains the biology of these non-enveloped viruses, their large number of strains, and how they infect the upper respiratory tract.

Lassa virus is a rodent-borne arenavirus that causes Lassa fever, a hemorrhagic disease endemic in West Africa with hundreds of thousands of infections each year. In this episode, Florian Krammer explains the biology of this ambisense RNA virus, including its segmented genome and how it interacts with the immune system. The discussion covers transmission through contact with infected rodents, human-to-human spread via bodily fluids, and typical symptoms ranging from mild flu-like illness to severe disease with bleeding, organ failure, and neurological complications.

Hepatitis B virus is a globally widespread infection that primarily targets the liver and can lead to chronic disease, cirrhosis, and liver cancer. In this episode, Florian Krammer explains the unique biology of this DNA virus, including its unusual replication strategy involving reverse transcription and its ability to persist in cells as a stable mini-chromosome.