Hi Adi,

this is dependant on which parasite you want to count and the definition of simple. Leishmania for example, you can fix in 4% paraformaldehyde and count under a bright field microscope using a counting chamber.

Hope that helps.

ok.. So , to be precise.. I want to count the number of protozoans, not specific , in a medium which supports Zebrafish Larval growth. i.e in medium in which Zebrafish larvae are grown. So , I need a general protocol to count the overall number of protists in the fish medium.

Hi Adi,

I think the most common way for protist enumeration is epifluorescence microscopy of fixed cells (glutaraldehyde, formol), concentrated on polycarbonate filters (0,2-0,8µm pore size) and stained with fluorescent dyes (DAPI, FITC, or Primulin).

please check out Caron 1983 and literature cited herein:

https://www.sciencedirect.com/science/article/pii/0272771483900896?np=y

good luck

Felix

You can try the 'Sedgwick-Rafter counting cell and Whipple micrometer technique'. For more info study the link: http://www.jstor.org/discover/10.2307/3222321?uid=2129&uid=2&uid=70&uid=4&sid=21102486090257

Can we use a simple protocol as we use to count the WBC's on a hemocytometer... please let me know...

@Adi Mulay. If you try to count protists from Zebra culture water using a hemocytometer you might have a factor of 10-4 difference because protozoans in the culture usually measures >20microns and they are not really dense. The chances of a cell lodged in a .001mL is slim. Sedgewick rafter cell is much better.

You could use a plaque viable count test if you want them alive. You would grow an early stage lawn culture of a suitable bacterial strain which the protozoa could predate. Then add 10-fold dilutions of the protozoa. Incubate and count the plaques (each one from a single protozoal cell, theoretically), just as you would count colonies on plates. A little simple maths and you have your viable count.