Transmissible cancers, infected snails as a human delicasy, Chickenpox and Google, woodpeckers and their fungal helpers, and soldier trematodes

Once again, I have reached the point where I have accumulated so much awesome recent parasite ecology that I can’t devote an entire blog post to each paper (without falling behind in field work). Therefore, today’s blog post is a parasite ecology bonanza with a little bit of something for everyone. Enjoy!

Apparently we now know about five different transmissible cancers! That’s up from the last time I tuned in. And for canine transmissible venereal tumour disease, the cancer has acquired new mitochondria from canine hosts at least five times! Ed Yong has the story here.

I just finished up a post series about parasites/pathogens and host species extinction, so here’s a follow up idea: if a parasite/pathogen has greatly reduced a host population, maybe even bringing the host species to the brink of extinction, we should stop harvesting the remaining host individuals for food/fuel/fiber, right? Well, it depends. If we can eat infected individuals without getting sick, selectively harvesting the infected individuals can actually benefit the struggling host species. This might work out well for abalone infected by the pathogen that causes withering syndrome; individual abalone are worth so much that the diagnostic costs of determining whether a snail has the pathogen are relatively small, and harvesting (infected) snails may paradoxically benefit abalone populations. (You may have seen parts of this in a talk at EEID2016.)

Not all countries require that cases of the chickenpox be reported to national agencies. So how can we estimate the size of chickenpox outbreaks and the impacts of chickenpox vaccination? We can look at the frequency with which worried parents google chickenpox symptoms!

I’ve been meaning to blog about this really neat symbiont story that was picked up by mainstream media, but I’m somehow months behind! As a primary cavity excavator, the endangered red-cockaded woodpecker is an important ecosystem engineer. But woodpeckers don’t work alone: it turns out that woodpeckers disperse wood decaying fungi that may help with excavation.

Finally, I have somehow never blogged about the fact that some trematodes have social castes! In particular, when snails are first intermediate hosts for trematodes, the trematode rediae within the snail come in two flavors: those that produce more rediae or free-living trematode larvae, and those that don’t reproduce. The rediae that don’t reproduce are a morphologically distinct soldier class with one job: kill any other trematodes that try to establish in the snail. And excitingly, the list of trematode species with a soldier caste just got longer.


Punnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnns. Anyone have any to add?



6 thoughts on “Transmissible cancers, infected snails as a human delicasy, Chickenpox and Google, woodpeckers and their fungal helpers, and soldier trematodes

  1. Don’t have any puns that immediately spring to mind, but you’ve made me realise the guys who made the Worms games might have been onto something!

  2. Pingback: Parasite ecology bonanza | Parasite Ecology

  3. Pingback: Best parasite ecology cartoon of 2016? | Parasite Ecology

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