The Role of Natural History in Retrospective Analyses
Updated: Dec 14, 2019
Natural History can be thought of as an encyclopedia of nature. It is a source of knowledge that observes and compares all aspects of the biological world. For our purposes, Natural History Museums build and preserve a reference collection that allows us to return to original data (preserved amphibian specimens) and analyze them with new molecular techniques. These collections bridge the scales of time and allows us to analyze disease emergence both spatially and temporally. Additionally, Natural History collections provide insights into the evolution of life and can sound the alarm for the loss of biodiversity we are experiencing at this point in time.
Natural History Museum in London (from tufing: https://www.tufing.com/img-inline-share/17natural-history-museum-paris-616317.png)
Is the spatio-temporal pattern of pathogen invasion consistent with an epizootic?
Amphibians are facing a global biodiversity crisis, with at least 32% of all species listed as globally threatened, and 43% of species showing population declines (see here). Though multiple factors influence these declines, the invasion and emergence of the fungal pathogen, Batrachochytrium dendrobatidis (Bd) is hypothesized to be a major factor. Bd, discovered in 1998, infects amphibians causing the lethal disease Chytridiomycosis and originates from Asia (check out earlier blog here). This disease is characterized by a thickening of the host skin, disruption of osmotic balance, and cardiac arrest. Many amphibian population declines occurred before the discovery of Bd in 1998. Mysterious population declines of amphibians in western Europe began in the late 1950’s, however, it remains unclear if Bd played a role. Present day, European Bd-epidemics are limited to the Pyrenees and the mountainous areas surrounding Madrid. However, the pre-epizootic history of Bd in the Pyrenean region has yet to be investigated and would help us better understand present day disease dynamics.
Our goal is to do a spatiotemporal analysis of the historical distribution of Bd in the Pyrenees to determine whether this infectious agent is the cause of enigmatic declines.
One priceless benefit of being a student researcher is that Natural History Museums around the world are very open to working with you and assisting with your data collection! An additional benefit of our sampling protocol is that it is non-invasive. This has allowed me to work with five herpetology collections from museums around the world.
We arrived at the Natural History Museum of Paris (MNHN) to sample preserved amphibian specimens that had been collected from the Pyrenees, specifically the French side of the mountain range (time travel). (A year ago, I had visited the Natural History Museum of Madrid to collect samples from specimens that had been gathered from the Spanish side of the range). At MNHN, I was joined by Alessandra Moyer (Vredenburg Lab Master’s student) and Adeline Loyau (P3 research ecologist) to sample 889 ethanol and formalin preserved specimens. Simply, we removed the desired specimens from their jars, rinse them with ethanol, and run a swab over their skin. These swabs are stored in tubes and taken back to San Francisco State University (SFSU) to be processed and run in qPCR assays. These qPCR assays allow us to test each swab/sample for the presence of Bd and track the emergence of this pathogen in the Pyrenees through space and time.
~2000 samples are being processed, and we will have the results soon!