The U.S. The U.S. Geological Survey and Fish and Wildlife Bats Service provided a disturbing update last month on the white-nose syndrome epidemic in North America. WNS was confirm in Myotis Lucifugus, a little brown bat, near North Bend, Washington. This is more than 1,300 miles from Nebraska, the western edge of the disease front.
WNS and the bat conservation community hit hard by the news. WNS spreads in a gradual manner from one state to another over the past 10 years. It is believe to have originate in Albany, New York. Researchers were able to predict the arrival of the pathogen Pseudogymnoascus structans on the Pacific Coast in 2026 because of this consistency.
Since 2007, researchers have been working on strategies to stop WNS spreading and prevent massive bat deaths. Yet, the disease is spreading faster than expected. Researchers are still trying to figure out how to stop this deadly disease from spreading faster than expected.
Gateway To The West Bats
To understand why this is so bad for bats, it’s important to understand how wildlife biologists try to stop the spread of deadly pathogens.
Many of the current strategies to reduce the impact of WNS upon susceptible bat populations are base on the idea of stop-gap, or methods that could be use at geographic choke points to slow down the spread of the disease. This would allow scientists to find permanent solutions such as vaccines and gene silencing, to stop the spread of the disease to new populations.
WNS’s arrival on the West Coast removes this option from the equation in many ways. It has already passed the geographic bottlenecks where scientists had hoped it would slow down. The WNS community has other concerns about this case.
Come Here Often
The pathogen has shown to be mono-clonal in studies of the eastern U.S. fungus. P. destructans from Georgia is genetically identical to P. destructans from Missouri and New York. This is good news for bats as it increases their chances of developing resistance.
The results of subsequent evaluations indicate that P.destructans is, as most fungi are, likely to participate in sexual reproduction where complementary mating types exist (think male and feminine, but with many potentially compatible “genders”) This, along with recent findings that P. destructans is widespread in eastern Asia, suggests that the West Coast case could have been introduced in a novel way or that it may be a different strain. It could also be a complementing mating type to P.destructans in the eastern U.S.
For several reasons, this could prove to be very dangerous for bats. Researchers will need to identify the source of this infection and determine if it is compatible with any existing isolates to understand how serious it could be for WNS in North America.
Stronger Than The Average Spore Bats
Conidia are spores, which are fungi-produced reproductive cells that reproduce in sexual reproduction. The sensitivity of conidia to any given control agent is the basis of all the work currently being done to make spores inactive and stop the spread of WNS.
However, this phylum, Ascomycota fungus can also reproduce sexually through a type spore called ascospores. Ascospores have proven to be more resistant than conidia in numerous Ascomycota cases.
Researchers may discover that P. destructans is capable of producing ascospores, which is sexual reproduction as opposed to conidia. If this is the case, then existing decontamination protocols must be modified to accommodate the increased resilience of these sexualspores.
A Red Queen And Brown Bats
The ultimate meaning of whether or not the fungus reproduces sexily is dependent on a long-debated theory in evolutionary biology, which many believe will eventually save vulnerable North American bat species. This theory is the Red Queen hypothesis.
In a system that has a parasite (P.destructans) and a host (bat), coevolution happens as the disease recurs over many generations. The parasite will not be tolerate if the host reproduces sexually (WNS in North America).
Coevolution is a mechanism that supports the status quo in systems where the parasite and host reproduce sexually. As bats develop tolerance to one strain P. destructans, another strain that results from sexual recombination and is capable of causing diseases in the new host will be the dominant strain.
The analogy of the Red Queen running found in Lewis Carroll’s Through the Looking-Glass, And What Alice Found There”. Even though evolution is happening (running), everyone’s evolving together so that the disease paradigm does not change.
This is why North American WNS may be affect by the introduction of a complementary mate type. The fungus reproduces sexually so bats will not be able develop significant tolerance. Bats also quickly adapt to any resistance.