Ode to a giant fish belly worm, and to a fish-shaped lake.

Ligula intestinalis popped up today on one of my favorite blogs, Parasite of the Day, and I had to do a little of my own searching after I read about it. As Mr. Leung from PoD explains, Ligula intestinalis is a tapeworm that infects fish, and it exists (among other places) in abundance in a reservoir in northeastern France, where it has been studied carefully for then last 20 years. Go and read the wonderful post about it, if you dare, to learn about the host transfer that has happened over the course of the study in the French reservoir!

If you took a peek at the photo in that article, you'll see that it's a very large worm to live in such a little fish. This video was not taken at the reservoir in France, but instead at at Lake Nyasa, a huge lake siatuated between Malawi, Mozambique and Tanzania. It gives you a sense of the size of this parasite in comparison to its host:

I realized that I know nothing about this African Lake, although it is the 8th largest lake in the world! So I looked up some information about Lake Nyasa itself. Last year the lake was declared a reserve by the government of Mozambique. In addition to being home to a very diverse community of birds, mammals and invertebrates, this lake contains an astonishing fish population, including hundreds of different species of cichlids. It is a very important source of food for local communities, and contains many fisheries. Overfishing has been a problem in this lake, but there is a lot of local effort going into preserving its biodiversity and taking care of this amazing resource and habitat.

A lot of fishies in Lake Nyasa are apparently infected with L. intestinalis--and the parasite attacks many different species there. This is a bad thing, because it can prevent its fish host from reproducing by inhibiting puberty! L. intestinalis also effects behavior, and can negatively affect fishing in the lake. Now something else about Lake Nyasa... is that it's SHAPED like a fish! (This is a view from orbit, taken by NASA.) Sometimes nature can be so CLEVER.

One more neat thing about the lake region is that a pack of 17 African Painted Dogs were recently discovered on the Malawi side of the lake--where these carnivores had long been thought to be extinct. I think these guys are some of the most beautiful critters in existence. Also, those wide, snouty faces look so kissable... although I'd probably get my lips ripped off if I tried.

Painted Dogs drinking, Perth Zoo, 2009, by Helenabella.