What host are you working with? If sheep or goats then just mix the 2g of faeces with 20mls of saturated NaCl solution. Adding 20mls of water will just dilute any salt solution you subsequently add and the oocysts will sink..

Forgot to add this. Oocyst burdens can be quite high in otherwise normal young lambs. Counts of 1,000,000 oocysts per gram of faeces were not unusual.

Dear Paul Mason,

Thank you so much for your help.

Yes, I am working with sheep and goats actually... So you are saying I can fill the haematocytometer counting chamber with a mixture 2g of faeces and 20mls salt solution? What factor do I then multiply the total number of oocysts counted by i.e. the factor that brings it to OPG.

Thank you so much in anticipation.

Best regards,

Adeyemi Oluwayomi O.

Dear Paul Mason,

I should also add that I tried mixing 20 mls salt solution to filtered faecal samples (i.e. I did not dilute with water this time around). I still did not find any oocysts in the counting chamber.

Thanks

Hello,

the hemacytometer is not the best chamber to count oocysts. You should use a MacMaster counting chamber, for which the volume is much bigger, so you can find oocysts. The method I use is to dilute 3 g of faeces in 42 mL salt saturated water (1 g for 14 mL ratio, with a final volume of about 15 mL), and fill one chamber of the MacMaster counting cell. The amount of oocysts you cound is multiplied by 100 to get the concentration in the sample. If there are too many oocysts for a correct count, then dilute 1/10 or 1/100 (always with salted water) for an easier count, and multiply the number with 100 and the level of dilution (X10 or X100...).

Before counting on the MacMaster, after filling the chamber, wait about 10 mn for the oocysts to come up and float at the grid level of the chamber.

Hope this will help!

Yours

Good answer Jean-Michel Reperant.

@Jean-Michel Reperant. Thank you so much for your response. Unfortunately, I do not have access to a McMaster Chamber now. I am trying to make do with an haemocytometer.

@Paul Mason. Thank you very much too. I followed your procedure and it worked. I could count the parasites off the chamber of the haemocytometer. But by what factor do I multiply the total counts? Thanks, in anticipation.

@ Jean-Michel Reperant. Thank you so much for your response. Unfortunately, I do not have access to a McMaster Chamber now. I am trying to make do with an haemocytometer.

@ Paul Mason. Thank you very much too. I followed your procedure and it worked. I could count the parasites off the chamber of the haemocytometer. But by what factor do I multiply the total counts? Thanks, in anticipation.

@ Jean-Michel Reperant. Thank you so much for your response. Unfortunately, I do not have access to a McMaster Chamber now. I am trying to make do with an haemocytometer.

@ Paul Mason. Thank you very much too. I followed your procedure and it worked. I could count the parasites off the chamber of the haemocytometer. But by what factor do I multiply the total counts? Thanks, in anticipation.

Jean-Michel Reperant. Thank you so much for your response. Unfortunately, I do not have access to a McMaster Chamber now. I am trying to make do with an haemocytometer.

Paul Mason. Thank you very much too. I followed your procedure and it worked. I could count the parasites off the chamber of the haemocytometer. But by what factor do I multiply the total counts? Thanks, in anticipation.

@Jean-Michel Reperant. Thank you so much for your response. Unfortunately, I do not have access to a McMaster Chamber now. I am trying to make do with an haemocytometer. @Paul Mason. Thank you very much too. I followed your procedure and it worked. I could count the parasites off the chamber of the haemocytometer. But by what factor do I multiply the total counts? Thanks, in anticipation.

you can use 2gm of faecal in 28ml of saturated salt buffer or 4gm in 56ml then fill the chamber, and wait 5min to float the oocyst then multiply my 10000