Parawash Paper
ABSTRACT
from paper presented at ASM 1996, New Orleans
Parawash tm
C-109 Parawash as an odorless, Effective Substitute for Heno-De and Ethyl Acetate in the Formalin-Ethyl Acetate Concentration Technique, J.S. MATTHEWS* and J.L. PERRY. Department of Veterans Affairs Medical Center, Wichita, Kansas.
Hemo-De (HD) has replaced ethyl acetate (EA) in the formalin-ethyl acetate concentration technique in many laboratories. Reduction of toxic propoerties of ethyl acetate to skin and mucous membrances has been a motivating factor. HD< with d-limonene as a amajor component, has been reported to produce headaches and nausea and its use requires proper ventilation. Parawash (PW, Scientific Device Laboratory, Inc.)is a new product consisteing on an odor-free c10 petroleum naptha with a higher vapor density and flashpoint than HD. Nineteen positive fecal specimens preserved in 10% formalin were processed using EA, HD and PW as defatting agents and extractors of debris in the concentration technique. A comparison of parasite recovery with 1ml aliquots follows:
ORGANISM |
DIRECT |
EA |
HD |
PW |
| Ascaris egg | 156 |
53 |
108 |
99 |
| Entamoeba Coli | 103 |
104 |
150 |
183 |
| H. nana egg | 7 |
1 |
1 |
1 |
| Entamoeba Nana | 847 |
489 |
977 |
1106 |
| G. lamblia | 62 |
106 |
126 |
138 |
| I. butschlii | 219 |
85 |
259 |
284 |
| Hook egg | 16 |
16 |
17 |
11 |
| Trich egg | 20 |
16 |
14 |
17 |
| TOTALS | 1430 |
870 |
1652 |
1839 |
* No concentration procedure, 10ml of formalin/specimen
These data indicate equivelent or superior parasite recovery for PW compared to currently employed agents. PW is non-toxic, has no offensive odor, and is less expensive than HD or EA. PW appears to be an acceptable substitute to HD and EA in the concentration procedure.