TWiV 394: Cards in a hand

Vincent and Alan speak with Erica Ollmann Saphire about her career and her work on understanding the functions of proteins of Ebolaviruses, Marburg virus, and other hemorrhagic fever viruses, at ASM Microbe 2016 in Boston, MA.

You can find TWiV #394 at, or listen or watch the video below.

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TWiV 283: No Reston for the weary

On episode #283 of the science show This Week in Virology, Jens Kuhn speaks with the TWiV team about filoviruses, including the recent Ebola virus outbreak in Guinea.

You can find TWiV #283 at

TWiV 44: No hysteria

twiv_aa_2001Hosts: Vincent Racaniello, Dick Despommier, Alan Dove, and Jennifer Drahos

In episode #44 of the podcast “This Week in Virology”, Vincent, Dick, Alan, and Jennifer Drahos consider Marburg virus in Egyptian fruit bats, bacterial citrus pathogen found in shipping facility, canine parvovirus in Michigan, Relenza-resistant influenza virus, new HIV from gorillas, and public engagement on H1N1 immunization program.

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Click the arrow above to play, or right-click to download TWiV #44 (54 MB .mp3, 78 minutes)

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Links for this episode:
Isolation of Marburg virus from Egyptian fruit bats
Inspectors find bacterial citrus pathogen in California
Parvovirus killing hundreds of dogs in Michigan
Relenza-resistant H1N1 identified in Australia (press and journal article)
New HIV from gorilla
CDC wants public comment on H1N1 vaccination
Original antigenic sin (article 1 and article 2)
Dr. Stanley Plotkin on Meet the Scientist (thanks Peter!)
audioBoo (iPhone app – thanks Jim!)
Audio clips (first and second) from the podcast No Agenda (thanks peripatetic apoplectic!)

Weekly Science Picks
Jennifer Piled Higher and Deeper (PhD Comics)
Vincent Giant Microbes (thanks Stephen!)
Dick Virology in the 21st Century
Alan Annals of the Former World by John McPhee

Send your virology questions and comments (email or mp3 file) to or leave voicemail at Skype: twivpodcast

Marburg virus in Egyptian fruit bats

marburg-antigens-bat-tissuesMarburg virus has been isolated from Egyptian fruit bats (Rousettus aegyptiacus) living in Kitaka Cave, Uganda, demonstrating that bats are a natural reservoir of the virus.

Marburg virus, the founding member of the Filoviridae, is an enveloped virus with a negative-strand RNA genome. Other members of the filovirus family are the five species of ebolavirus. Filoviruses are indigenous to Africa, but the animal reservoir for the virus has not been definitively identified. The first outbreaks of Marburg hemorrhagic fever took place in laboratories in Marburg, Frankfurt, and Belgrade in 1967. The virus was believed to originate from African green monkeys that were being used for laboratory research. However, these monkeys were trapped in regions of Uganda where fruit bats are common. Other evidence suggests that bats are the natural reservoir of filoviruses. For example, two patients who developed Marburg hemorrhagic fever in 1980 and 1987 in Kenya had been in a cave inhabited by bats before they became ill. In January 2009 the first US case of Marburg hemorrhagic fever was reported in Colorado. The patient had traveled to Uganda in December 2007 and visited a python cave that houses thousands of bats.

The study was undertaken to understand why miners working in Kitaka Cave in July and September 2007 developed Marburg hemorrhagic fever. The authors captured 611 bats and found Marburg viral RNA in 31. Given the population of 100,000 bats in Kitaka Cave, at least 5,000 are likely to harbor the virus. Antibodies to Marburg virus were also detected in bat sera, and infectious virus was recovered from 4 animals, all of which were healthy.

Filovirus antigens were detected in tissues of naturally infected bats for the first time. Viral antigens were detected by immunohistochemistry in the livers of two bats from which infectious Marburg virus was isolated in cell culture (illustrated). Viral antigens were also detected in the spleen of one bat, in the cytoplasm of mononuclear cells.

Nucleotide sequence analysis revealted that in the Kitaka Cave outbreak the two miners did not infect each other, but were infected separately by two independent introductions of virus from bats to humans. Furthermore, remarkable diversity – up to 21% between virus lineages – was observed in viral RNAs from the bat colony. This diversity suggests that the virus remains for long periods in its reservoir host, and also infects large numbers of bats. R. aegyptiacus bats migrate  over 300 miles to other colonies each season, providing a pool of millions of bathosts for Marburg virus.

These findings have clear implications for public health: the large numbers of bats that harbor Marburg virus have the potential to initiate epidemics of hemorrhagic disease in humans. There are many other caves throughout Africa that harbor similar colonies of bats. Given the high case fatality ratio of filovirus hemorrhagic fever – approaching 90% – it is clear that bat-infested caves should be avoided by miners and spelunkers.

Towner, J., Amman, B., Sealy, T., Carroll, S., Comer, J., Kemp, A., Swanepoel, R., Paddock, C., Balinandi, S., Khristova, M., Formenty, P., Albarino, C., Miller, D., Reed, Z., Kayiwa, J., Mills, J., Cannon, D., Greer, P., Byaruhanga, E., Farnon, E., Atimnedi, P., Okware, S., Katongole-Mbidde, E., Downing, R., Tappero, J., Zaki, S., Ksiazek, T., Nichol, S., & Rollin, P. (2009). Isolation of Genetically Diverse Marburg Viruses from Egyptian Fruit Bats PLoS Pathogens, 5 (7) DOI: 10.1371/journal.ppat.1000536