Friday, July 27, 2012

Cockroach Clusters: Chickens visit Honeydukes in Hogsmeade... and other nerdy ramblings

Uni started back this week… not that it means I was actually there. Ok, so I went for one day; that’s still more than usual. However I have made a decision to make a conscious effort to attend lectures this semester, except for on those days where time spent in transit is greater than the number of hours of lectures. Any of my classmates who are reading this – please help me follow through!! Love y’all <3 

Now you may wonder what I do when I don’t go to lectures and the truth is, I’m not entirely sure myself. In the winter I seem to just shuffle around the house in my pyjamas drinking coffee , while in the summer I collapse into the hammock with a book and inhale the sea breeze (while wearing pyjamas, of course).  During the most recent break I committed to being the world’s geekiest hermit and spent most of the time holed up in my room, watching Doctor Who, Sherlock and Downton Abbey. This followed two weeks of winter semester spent inside a laboratory. Needless to say, I had been receiving rather limited exposure to natural light over the last month or so.

To compensate for my vitamin D deprivation over this period, I went back to the garden for a couple of days instead of making my way to class. The seeds we planted two weeks ago had shot up and the wee cabbages needed to be transplanted to some new garden beds. I did this with a student who is currently volunteering at the garden as part of her placement for her degree in Public Health. Making new friends never gets old so I enjoyed chatting over a garden bed, although I’m sure everyone else would have preferred if she was a veterinary science student… Behold, Felicity the chick:

As you can see, the poor baby girl has a bung eye. And this is where it comes to eating cockroaches – or rather, why you may be better off not eating them.

An official diagnosis of Felicity’s condition isn’t possible without laboratory tests and whatnot but Pedro (one of our chicken experts and resident plumber) came to the conclusion that she had an eyeworm. Initially we thought that she was being attacked by the older hens but lifting up the eyelid revealed the presence of a ~15mm long nematode.

Nematode infections in birds vary between those that are species-specific and are transmitted directly from bird-to-bird through the ingestion of infective eggs or larvae and those that are require an intermediate host such as insects. One such critter, Manson’s eyeworm (Oxyspirura mansoni), gets inside the bird by reaching their infective stage in an intermediate host – the Surinam cockroach. When a chicken eats an infected cockroach (maybe Felicity thought it was a peanut?), the larvae are liberated and migrate up the oesophagus, up to the mouth and then through the nasolacrimal duct to the eye. The other half of the cycle involves the worm going back through the pharynx (again via the nasolacrimal duct), being swallowed and then being passed into the faeces. It is in this form that the Surinam cockroach ingests the worm.

Photo from web
Exactly as it says in the online vet manual, Felicity had “inflammation, lacrimation, corneal opacity and [although we don’t know for sure] disturbed vision”.  The poor chicky. Luckily Pedro realised what was going on and removed just over half of the worm.  Obviously this treatment was somewhat a “backyard job” but she is being given saline drops every day which seems in line with what is suggested:

As a treatment for Manson’s eyeworm, a local anesthetic can be applied to the eye, and the worms in the lacrimal sac exposed by lifting the nictitating membrane. A 5% cresol solution (1-2 drops) placed in the lacrimal sac kills the worms immediately. The eye should be irrigated with sterile water immediately to wash out the debris and excess solution. The eyes improve within 48-72 hr and gradually become clear if the destructive process caused by the parasite is not too far advanced.”

Felicity will probably lose the sight in her left eye but at least she’ll survive the experience. She lost a fair bit of weight when initially infected but has quickly put back on some meat, probably as a result of the love and attention she’s been receiving. Maybe she’ll return the favour by laying us some beautiful eggs in the future.

- Matilda

1 comment:

  1. Very good analysis of the situation Matilda