When people think about viruses, one of the first things that comes to mind is that they’re small. And to be honest, that's how I would describe them too. I mean, that’s how we discovered viruses in the first place: they passed through filters that trapped bacteria, so we knew this infectious substance had to be smaller than any known cell.

So when scientists came across the very first giant virus, they naturally assumed it must be a brand-new bacterium. In fact, this “mystery microbe” spent nearly a decade in a freezer before anyone realized it wasn’t a bacterium at all.

This discovery opened the door to an entirely new world of giant viruses, which had gone unnoticed simply because no one was looking for something so large in the virus realm. And it also raised an important question that remains controversial: If some of these giant viruses cause disease in humans?

*

If you enjoyed this episode and want to stay updated on more virology stories, please follow @virology_podcast or @karolina_science on Instagram :). The podcast is also available in Czech as “Podcast o virech”.

*

Sources:

B. La Scola, 2003: A giant virus in amoebae • C. Abergel, 2015: The rapidly expanding universe of giant viruses: Mimivirus, Pandoravirus, Pithovirus and Mollivirus • N. Brandes, 2019: Giant Viruses—Big Surprises • D. R. Wessner, 2010: Discovery of the Giant Mimivirus • B. La Scola, 2008: The virophage as a unique parasite of the giant mimivirus • F. Sakhaee, 2022: Detection of Mimivirus from respiratory samples in tuberculosis‑suspected patients • J. M. Claverie, 2018: Mimiviridae: An Expanding Family of Highly Diverse Large dsDNA Viruses Infecting a Wide Phylogenetic Range of Aquatic Eukaryotes • D. Raoult, 2006: Laboratory infection of a technician by mimivirus • N. Yutin, 2014: Origin of giant viruses from smaller DNA viruses not from a fourth domain of cellular life • M. Khan, 2007: Pneumonia in mice inoculated experimentally with Acanthamoeba polyphaga mimivirus • T. J. Rowbotham, 1983: Isolation of Legionella pneumophila from clinical specimens via amoebae, and the interaction of those and other isolates with amoebae • D. Raoult, 2007: The discovery and characterization of Mimivirus, the largest known virus and putative pneumonia agent • A. Levasseur, 2016: MIMIVIRE is a defence system in mimivirus that confers resistance to virophage • J. M. Claverie, 2016: CRISPR-Cas-like system in giant viruses: why MIMIVIRE is not likely to be an adaptive immune system • J. Abrahao, 2018: Lack of evidence of mimivirus replication in human PBMCs

I spent a good portion of the last episode telling you that HIV cannot be cured and our best option is to keep it under control with medication.

But here’s the thing: I wasn’t telling you the whole truth.

In a handful of cases, people have been declared cured of HIV. The first was known as the Berlin Patient, and since then, fewer than 10 cases have followed.

Today, I’d like to share their story and explain why we shouldn’t hold out hope for a miracle pill—because this cure isn't some simple medication. Instead, these people received a high-risk bone marrow transplant from a donor genetically resistant to HIV.

*

If you enjoyed this episode and want to stay updated on more virology stories, please follow @virology_podcast or @karolina_science on Instagram :). The podcast is also available in Czech as “Podcast o virech”.

*

Sources:

T. R. Brown, 2015: I Am the Berlin Patient: A Personal Reflection • G. Hütter, 2009: Long-Term Control of HIV by CCR5 Delta32/Delta32 Stem-Cell Transplantation • R. K. Gupta, 2019: HIV-1 remission following CCR5Δ32/Δ32 haematopoietic stem-cell transplantation • J. Hsu, 2023: HIV-1 remission and possible cure in a woman after haplo-cord blood transplant • W. A. Paxton, 1996: Relative resistance to HIV-1 infection of CD4 lymphocytes from persons who remain uninfected despite multiple high-risk sexual exposure • J. Novembre, 2005: The geographic spread of the CCR5 Delta32 HIV-resistance allele • A. P. Galvani, 2005: The evolutionary history of the CCR5-Delta32 HIV-resistance mutation • L. Kordelas, 2014: Shift of HIV tropism in stem-cell transplantation with CCR5 Delta32 mutation • T. J. Henrich, 2014: Antiretroviral-free HIV-1 remission and viral rebound after allogeneic stem cell transplantation: report of 2 cases • S. Yandrapally, 2021: HIV co-receptor-tropism: cellular and molecular events behind the enigmatic co-receptor switching

In the 1980s, doctors began noticing a troubling pattern: previously healthy individuals were succumbing to rare diseases that their immune systems couldn’t fend off. This alarming phenomenon was traced back to the HIV virus, which ultimately leads to the development of AIDS—a condition where the immune system stops functioning properly.

In today's episode, we delve into the scientific quest to uncover the origins of this medical mystery, explore the origins of the virus, and bring a warning about proper hygiene when hunting monkeys.

*

If you enjoyed this episode and want to stay updated on more virology stories, please follow @virology_podcast or @karolina_science on Instagram :). The podcast is also available in Czech as “Podcast o virech”.

*

Sources:

CDC, 1981: Pneumocystis Pneumonia -- Los Angeles • CDC, 1981: Kaposi's sarcoma and Pneumocystis pneumonia among homosexual men--New York City and California • F. Barré-Sinoussi, 1983: Isolation of a T-lymphotropic retrovirus from a patient at risk for acquired immune deficiency syndrome (AIDS) • J. Hemelaar, 2012: The origin and diversity of the HIV-1 pandemic • T. Zhu, 1998: An African HIV-1 sequence from 1959 and implications for the origin of the epidemic • M. Worobey, 2008: Direct evidence of extensive diversity of HIV-1 in Kinshasa by 1960 • D. Quammen, 2015: The Chimp and the River • PM. Sharp, 2011: Origins of HIV and the AIDS Pandemic • T. Cihlar, 2016: Current status and prospects of HIV treatment • LG. Bekker, 2024: Twice-Yearly Lenacapavir or Daily F/TAF for HIV Prevention in Cisgender Women • J. Paik, 2022: Lenacapavir: First Approval • M. Worobey, 2016: 1970s and ‘Patient 0’ HIV-1 genomes illuminate early HIV/AIDS history in North America • RA McKay, 2014: Patient Zero • B. Lein, 2024: AIDS treatment activism, a Bay area story (online, accessed 14/07/2024)