"So, naturalists observe, a flea has smaller fleas that on him prey; and these have smaller still to bite ’em; and so proceed ad infinitum."
- Jonathan Swift
November 7, 2010
November 7 - Syngamus trachea
Syngamus trachea is a nematode known as the gapeworm, which infects birds such as chickens and turkeys. The name comes from the fact that they live in the birds' trachea and, when there are enough of them, they can cut off the airways, causing the bird to gape open their mouths. Females live in permanent conjoinment with males. When they lay eggs, the bird will cough them up and swallow them, and then they will pass out with its feces. Another bird may come along and ingest them or a snail or a worm may serve as an intermediate host.
Posted by Susan Perkins at 6:00 AM
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S. trachea is interesting for nematologists in that it has very large amphids on the anterior region of the body. These are combined secretory and chemosensory organs, and quite a bit of effort has gone into understanding how these organs work, and how the very active secretory systems in them tie into the chemosensory systems. S. trachea has earthworms as a secondary host, and this makes this nematode a pest in game farms.ReplyDelete
The best source of S. trachea adult worms for scientific work (short of breeding gamebirds to rear the worms in) is young rooks. These have the unusual but very useful behaviour of going through a stage in their juvenile development as "branchers", a sort of prelude to fledging when the young birds are out of the nest, able to flutter about a little in the canopy of the nesting trees, but unable to fly strongly.
At this stage, most young rooks are harbouring S. trachea nematode infestations which they eventually get rid of immunologically. So, as they're rather easy targets for a shotgun wielding nematologist and harvesting S. trachea nematodes from wild birds is easier than captive rearing them, that's exactly what is done.