Microscope selection and use
There were a number of options I had to consider when purchasing a microscope for use in incubating Necator americanus hookworm larvae and Trichuris trichiura whipworm ova.
- A good lighting system was important. A mirror lighting system wouldn’t have been adequate, and a ‘scope with either a halogen or LED light source was likely to be best. A good iris and concentrator system were also important, as was a rheostat for dimming the light.
- A binocular microscope would cause me less eye fatigue and be easier to use, whereas a monocular one would be cheaper. A mechanical stage would make using the ‘scope easier for me, but one without a stage would be cheaper.
- I mainly use 40X magnification. Sometimes I may use 100x magnification for a closer look. It would be very unusual for me to need any stronger than this.
- I’ve seen it claimed online that 200x magnification is best for egg counting and larva identification, but I’ve never needed to do either of these. Egg counting is not necessary in order to incubate hookworm larvae, and, since I already know that the only species of worm I host is Necator americanus, there would be no point in attempting to determine the species of the the larvae that I’m culturing. Apart from this, I wouldn’t know how to encourage the larvae to turn and smile for the camera so that I could check their mouth parts!
- It’s been suggested online that working with trichuris species requires 100x magnification, but I use my lowest magnification (40x) for virtually everything I do, which is to count hookworm larvae and whipworm eggs. It has also been suggested that a microscope with the lens looking up from the bottom might be a better option, although the author of this comment may actually have been thinking of an upward-facing mirror rather than a light. However, I’ve only ever used a lens looking down from above, and always found this to be perfectly adequate.
- A very similar model to this one was recommended on a helminthic therapy discussion forum and is reasonably similar to the older scope that I have: Professional Biological Compound Microscope, from Precision World, 40X-1600X, AmScope, Model# B230A, for £170 ($260.00., €200) (see graphic 1A).
- An example of a much cheaper model - one that I considered using, and which might have worked - would be the 1000X Student Monocular Biological Compound Microscope, for about £55.00 ($80.00, €60) However, this model doesn't have a moveable stage, which would make it much easier to focus on the larvae and pick them up using a pipette. (see graphic 1B).
GX Optical may have the largest choice of stereo microscopes in Europe, and claim to be the largest independent microscope supplier in the UK.
Microscope case
I wasn’t sure a microscope case would be necessary, but eventually decided to get one. Various sites suggested that I could save money and yet make a decent case from a tool box with a very inexpensive inner lining made from a one person-sized (approximately 90-96 cm x 190-193 cm [36-38” x 75-76”]) egg crate foam mattress pad (e.g., Make a Carry Case for Your Microscope) I used a tool box similar in dimensions to a Plano 22 inch, extra deep, model 701, along with the egg crate foam. For the foam, I found a source similar to these: Eggcrate Wheelchair Cushion 40.64 cm x 45.72 cm x 7.62 cm by Wheelchairs / Sound insulation foam (3 pieces) by CONRAD. When I got the toolbox home, I had to use pliers-type wire cutters to cut off two internal projections that came down from the lid. Adding a few pieces of Styrofoam filled out the foam internal padding (see graphic 1C).
Digital Microscopes
Other options might include using a
- Plugable USB 2.0 Handheld Digital Microscope (see graphic 1D, and further details here),
- or a slightly more up-market version such as the DBPOWER 5 Megapixels 20X-300X USB Microscope Plugable Digital Magnifier with 8 LED Lights and Stand (see graphic 1E)
Another alternative could be to make a digital microscope
- using a smart phone for as little as $10 (see graphic 1F),
- or a 3D Printed Microscope with a mobile device for pennies (see graphic 1G).
USB devices could develop electronic and/or software faults that traditional microscopes will never have, and compound microscopes are preferred by the majority of helminth growers. Most of the USB scopes that have been tested so far have had problems, including poor optics and camera quality, as well as a lack of bottom illumination. The only exception has been the Carson MM-840 eFlex, which one user has found to be satisfactory, albeit with some limitations.
I used one last week for counting NA. It was quite cheap to buy, and I wanted something easy on the eye. I could use it without needing my reading glasses. It was quite easy to use, and you can take photos and video. Basically, it was just fine to use for counting the worms but I would have liked a little more magnification so I could have seen them up close. I wouldn't have been able to use it for counting eggs. I found it a little wobbly - it needed to be set up and then not touched, just move the slide. Another issue was that the worms all had shadows because of the white base. So what looked like two worms moving in exact unison was just one worm with a shadow! [1]Microscope use advice
Here's a basic video guide to using a microscope.
And further tips from the hive mind.
A good source to consult if I have microscope problems is Fecal Flotation: Common Problems With Microscopy (Download).
When using a microscope, it is essential to be comfortable.
I found that seating and posture is very important. I got a stool with the proper height and supported myself on the table while leaning in. With this I found that I could spend much more time focusing on trying to find eggs rather than thinking about how uncomfortable I was. [2]And here's a note for spectacle wearers.
If you wear glasses, beware when looking into the microscope, I scratched my lenses! [3]Microscope supplies
- Microscope optics cleaning kit
e.g., Optical Lens Cleaning Kit (see graphic 2A) / Matin Lens Cleaning Kit.
- Microscope slides, with box e.g.
- Microscope slides, plain glass, 72/pack
e.g., Item# MS-SLIDP72 (see graphic 2C).
- Slide storage box, 25 slides
e.g., Item# MS-SLBOX (see graphic 2D).See also
