wet mounts

[jenfer]

Hi all,

I picked up a pigeon today who I saw spitting up seeds yesterday (at least I think it's the same pigeon). She was drooling when I looked in her beak after picking her up, and seeds were backed up.

Now that we're home, it seems the seeds have been swallowed, but there's some frothy mucus in the back of her throat. I figured I'd try to do a wet mount to look for trichomonads, but on my first try I couldn't see much of anything.

I have to say that I've never done a wet mount before, nor have I seen one done, so I'm not sure if it might be my technique that's failing me. I also want to say that using the 40x objective, it's extremely hard to be able to focus in on anything (I've had this same problem trying to do fecal floats).

What I'm doing: swabbing throat, smearing it on slide, dropping a few drops of saline on it, cover slipping, then looking at 640x magnification.

Help?

Jennifer

[Pidgey]

Well, a lot of bugs get swept completely to the sides when you put a drop on a fairly dry smear. Supposing you wipe the Q-Tip onto the slide and it leaves a rather dry blotch--no standing water. Then, you drop the drop or two (or more) on the slide and cover with a coverslip. What you'll sometimes get is that the trichomonads surf the expanding boundary of the drops all the way out to the edge. When you put the coverslip on, they might even be all the way out to the edge of the coverslip at that point. That's why I start with a very wet Q-Tip, swab inside the throat, then press the Q-Tip to the slide firmly and roll in place until I've got an actual droplet on the slide. Yes, they're usually a smaller droplet, but it seems to get me good results when I'm looking for those kinds of bugs: trichomonads or motile bacilli.

Pidgey

[jenfer]

OK, Pidgey, don't go away. I'm going to try this shortly and see how it works.

Jennifer

[AZWhitefeather]

I know nothing about doing a 'wet mouth', nor do I have any idea what it is, but can say that the majority of the time mucous is present it's an indication of advanced canker.

If there is no visible canker in his mouth, it's possible the bird has a good case of internal canker going on. JMO.

Cindy

[Pidgey]

A wet-mount is just a preparation technique where the sample is put on the slide wet and unprocessed, and then covered with a coverslip for viewing. It's a great way to detect some kinds of pathogens by their specific motility.

By the way, Jennifer, I usually go looking for trichomonads and motile bacilli with the 10x objective and don't resort to the higher mags unless I see an item of interest that I want to take a closer look at. However, we should have a little discussion about how you're doing it.

Pidgey

[jenfer]

Trying it your way, Pidgey, I see absolutely nothing, just a white field. I think the drop might not be wet enough (I wet the Q-tip before swabbing). And now that I look in her throat, there's no mucus at all, nor is there any visible canker. When I picked her up this afternoon, she was drooling.

Cindy, what was in her mouth was not quite as thick as mucus, although I called it that. In cases like this, I would normally treat presumptively for canker, but I thought doing diagnostics wouldn't be a bad idea, since I have the equipment for it.

I hope I've got the same bird as the one I saw yesterday, who seemed like a clear case of canker. This one is quite active and alert (she's thrashing against her cage right now).

Jennifer

[Pidgey]

Didja' stopper down the Abbe condenser to get the maximum possible contrast? Another thing that you sometimes need to do is focus up and down through the plane to find the level of the boundary of the coverslip. If you can't see anything, then move the slide over (by way of the mechanical stage controls) to the edge of the coverslip so that you can find the depth that you should be working at with your focal adjustments.

Pidgey