|SEM photo of D. marci from the paper|
Microsporidians are found in a wide range of animals including vertebrates such as fish and reptiles, as well as invertebrates such as insect, crustaceans, and nematode worms. The host of N. marsiprofundi, a nematode named Desmodora marci (see above), is one of the more abundant animal at methane seeps. There can be as many as twenty worms for each millilitre of carbonate rocks from such locales, and over half of those worms would be infected with N. marsiprofundi. This parasite seems to be common at such vents and were found at sites which are 15 kilometres, so N. marsiprofundi is not localised to just a particular location and/or worm population.
|Spores of N. marisprofundi|
(image from the paper)
While their presence in the body wall and the effects they have on their host's muscle indicates they can be quite harmful and may transmit through means other than the worms' sexual activities, that is not to say that this parasite might not exploit multiple mode of transmission. Some parasite change their shape and infect different host tissue at different stages of their lives, and it is possible that N. marisprofundi can both be sexually transmitted and also eventually kill their host to allow their spores to disperse from a rotting cadaver
Studies like this shows parasites might be more common in the deep sea that we might have previously suspected, and that even in seemingly extreme environments like hydrothermal vents, there is good living to had as a parasite. Parasitism is everywhere on this planet, and while many people may think parasites are odd freaks of nature, in reality they are just a normal part of life on Earth.
Sapir, A., Dillman, A. R., Connon, S. A., Grupe, B. M., Ingels, J., Mundo-Ocampo, M., Levin, L. A., Baldwin, J. G., Orphan, V. J. & Sternberg, P. W. (2014). Microsporidia-nematode associations in methane seeps reveal basal fungal parasitism in the deep sea. Frontiers in Microbiology 5: 43.